//
// Copyright (c) 2017-2018 Advanced Micro Devices, Inc. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#ifndef AMD_VULKAN_MEMORY_ALLOCATOR_H
#define AMD_VULKAN_MEMORY_ALLOCATOR_H

#ifdef __cplusplus
extern "C" {
#endif

/** \mainpage Vulkan Memory Allocator

<b>Version 2.0.0</b> (2018-03-19)

Copyright (c) 2017-2018 Advanced Micro Devices, Inc. All rights reserved. \n
License: MIT

Documentation of all members: vk_mem_alloc.h

\section main_table_of_contents Table of contents

- <b>User guide</b>
  - \subpage quick_start
    - [Project setup](@ref quick_start_project_setup)
    - [Initialization](@ref quick_start_initialization)
    - [Resource allocation](@ref quick_start_resource_allocation)
  - \subpage choosing_memory_type
    - [Usage](@ref choosing_memory_type_usage)
    - [Required and preferred flags](@ref choosing_memory_type_required_preferred_flags)
    - [Explicit memory types](@ref choosing_memory_type_explicit_memory_types)
    - [Custom memory pools](@ref choosing_memory_type_custom_memory_pools)
  - \subpage memory_mapping
    - [Mapping functions](@ref memory_mapping_mapping_functions)
    - [Persistently mapped memory](@ref memory_mapping_persistently_mapped_memory)
    - [Cache control](@ref memory_mapping_cache_control)
    - [Finding out if memory is mappable](@ref memory_mapping_finding_if_memory_mappable)
  - \subpage custom_memory_pools
    - [Choosing memory type index](@ref custom_memory_pools_MemTypeIndex)
  - \subpage defragmentation
  - \subpage lost_allocations
  - \subpage statistics
    - [Numeric statistics](@ref statistics_numeric_statistics)
    - [JSON dump](@ref statistics_json_dump)
  - \subpage allocation_annotation
    - [Allocation user data](@ref allocation_user_data)
    - [Allocation names](@ref allocation_names)
- \subpage usage_patterns
  - [Simple patterns](@ref usage_patterns_simple)
  - [Advanced patterns](@ref usage_patterns_advanced)
- \subpage configuration
  - [Pointers to Vulkan functions](@ref config_Vulkan_functions)
  - [Custom host memory allocator](@ref custom_memory_allocator)
  - [Device memory allocation callbacks](@ref allocation_callbacks)
  - [Device heap memory limit](@ref heap_memory_limit)
  - \subpage vk_khr_dedicated_allocation
- \subpage general_considerations
  - [Thread safety](@ref general_considerations_thread_safety)
  - [Allocation algorithm](@ref general_considerations_allocation_algorithm)
  - [Features not supported](@ref general_considerations_features_not_supported)

\section main_see_also See also

- [Product page on GPUOpen](https://gpuopen.com/gaming-product/vulkan-memory-allocator/)
- [Source repository on GitHub](https://github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator)




\page quick_start Quick start

\section quick_start_project_setup Project setup

Vulkan Memory Allocator comes in form of a single header file.
You don't need to build it as a separate library project.
You can add this file directly to your project and submit it to code repository next to your other source files.

"Single header" doesn't mean that everything is contained in C/C++ declarations,
like it tends to be in case of inline functions or C++ templates.
It means that implementation is bundled with interface in a single file and needs to be extracted using preprocessor macro.
If you don't do it properly, you will get linker errors.

To do it properly:

-# Include "vk_mem_alloc.h" file in each CPP file where you want to use the library.
   This includes declarations of all members of the library.
-# In exacly one CPP file define following macro before this include.
   It enables also internal definitions.

\code
#define VMA_IMPLEMENTATION
#include "vk_mem_alloc.h"
\endcode

It may be a good idea to create dedicated CPP file just for this purpose.

\section quick_start_initialization Initialization

At program startup:

-# Initialize Vulkan to have `VkPhysicalDevice` and `VkDevice` object.
-# Fill VmaAllocatorCreateInfo structure and create #VmaAllocator object by
   calling vmaCreateAllocator().

\code
VmaAllocatorCreateInfo allocatorInfo = {};
allocatorInfo.physicalDevice = physicalDevice;
allocatorInfo.device = device;

VmaAllocator allocator;
vmaCreateAllocator(&allocatorInfo, &allocator);
\endcode

\section quick_start_resource_allocation Resource allocation

When you want to create a buffer or image:

-# Fill `VkBufferCreateInfo` / `VkImageCreateInfo` structure.
-# Fill VmaAllocationCreateInfo structure.
-# Call vmaCreateBuffer() / vmaCreateImage() to get `VkBuffer`/`VkImage` with memory
   already allocated and bound to it.

\code
VkBufferCreateInfo bufferInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufferInfo.size = 65536;
bufferInfo.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

VmaAllocationCreateInfo allocInfo = {};
allocInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;

VkBuffer buffer;
VmaAllocation allocation;
vmaCreateBuffer(allocator, &bufferInfo, &allocInfo, &buffer, &allocation, nullptr);
\endcode

Don't forget to destroy your objects when no longer needed:

\code
vmaDestroyBuffer(allocator, buffer, allocation);
vmaDestroyAllocator(allocator);
\endcode


\page choosing_memory_type Choosing memory type

Physical devices in Vulkan support various combinations of memory heaps and
types. Help with choosing correct and optimal memory type for your specific
resource is one of the key features of this library. You can use it by filling
appropriate members of VmaAllocationCreateInfo structure, as described below.
You can also combine multiple methods.

-# If you just want to find memory type index that meets your requirements, you
   can use function vmaFindMemoryTypeIndex().
-# If you want to allocate a region of device memory without association with any
   specific image or buffer, you can use function vmaAllocateMemory(). Usage of
   this function is not recommended and usually not needed.
-# If you already have a buffer or an image created, you want to allocate memory
   for it and then you will bind it yourself, you can use function
   vmaAllocateMemoryForBuffer(), vmaAllocateMemoryForImage().
   For binding you should use functions: vmaBindBufferMemory(), vmaBindImageMemory().
-# If you want to create a buffer or an image, allocate memory for it and bind
   them together, all in one call, you can use function vmaCreateBuffer(),
   vmaCreateImage(). This is the recommended way to use this library.

When using 3. or 4., the library internally queries Vulkan for memory types
supported for that buffer or image (function `vkGetBufferMemoryRequirements()`)
and uses only one of these types.

If no memory type can be found that meets all the requirements, these functions
return `VK_ERROR_FEATURE_NOT_PRESENT`.

You can leave VmaAllocationCreateInfo structure completely filled with zeros.
It means no requirements are specified for memory type.
It is valid, although not very useful.

\section choosing_memory_type_usage Usage

The easiest way to specify memory requirements is to fill member
VmaAllocationCreateInfo::usage using one of the values of enum #VmaMemoryUsage.
It defines high level, common usage types.
For more details, see description of this enum.

For example, if you want to create a uniform buffer that will be filled using
transfer only once or infrequently and used for rendering every frame, you can
do it using following code:

\code
VkBufferCreateInfo bufferInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufferInfo.size = 65536;
bufferInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

VmaAllocationCreateInfo allocInfo = {};
allocInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;

VkBuffer buffer;
VmaAllocation allocation;
vmaCreateBuffer(allocator, &bufferInfo, &allocInfo, &buffer, &allocation, nullptr);
\endcode

\section choosing_memory_type_required_preferred_flags Required and preferred flags

You can specify more detailed requirements by filling members
VmaAllocationCreateInfo::requiredFlags and VmaAllocationCreateInfo::preferredFlags
with a combination of bits from enum `VkMemoryPropertyFlags`. For example,
if you want to create a buffer that will be persistently mapped on host (so it
must be `HOST_VISIBLE`) and preferably will also be `HOST_COHERENT` and `HOST_CACHED`,
use following code:

\code
VmaAllocationCreateInfo allocInfo = {};
allocInfo.requiredFlags = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT;
allocInfo.preferredFlags = VK_MEMORY_PROPERTY_HOST_COHERENT_BIT | VK_MEMORY_PROPERTY_HOST_CACHED_BIT;
allocInfo.flags = VMA_ALLOCATION_CREATE_MAPPED_BIT;

VkBuffer buffer;
VmaAllocation allocation;
vmaCreateBuffer(allocator, &bufferInfo, &allocInfo, &buffer, &allocation, nullptr);
\endcode

A memory type is chosen that has all the required flags and as many preferred
flags set as possible.

If you use VmaAllocationCreateInfo::usage, it is just internally converted to
a set of required and preferred flags.

\section choosing_memory_type_explicit_memory_types Explicit memory types

If you inspected memory types available on the physical device and you have
a preference for memory types that you want to use, you can fill member
VmaAllocationCreateInfo::memoryTypeBits. It is a bit mask, where each bit set
means that a memory type with that index is allowed to be used for the
allocation. Special value 0, just like `UINT32_MAX`, means there are no
restrictions to memory type index.

Please note that this member is NOT just a memory type index.
Still you can use it to choose just one, specific memory type.
For example, if you already determined that your buffer should be created in
memory type 2, use following code:

\code
uint32_t memoryTypeIndex = 2;

VmaAllocationCreateInfo allocInfo = {};
allocInfo.memoryTypeBits = 1u << memoryTypeIndex;

VkBuffer buffer;
VmaAllocation allocation;
vmaCreateBuffer(allocator, &bufferInfo, &allocInfo, &buffer, &allocation, nullptr);
\endcode

\section choosing_memory_type_custom_memory_pools Custom memory pools

If you allocate from custom memory pool, all the ways of specifying memory
requirements described above are not applicable and the aforementioned members
of VmaAllocationCreateInfo structure are ignored. Memory type is selected
explicitly when creating the pool and then used to make all the allocations from
that pool. For further details, see \ref custom_memory_pools.


\page memory_mapping Memory mapping

To "map memory" in Vulkan means to obtain a CPU pointer to `VkDeviceMemory`,
to be able to read from it or write to it in CPU code.
Mapping is possible only of memory allocated from a memory type that has
`VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` flag.
Functions `vkMapMemory()`, `vkUnmapMemory()` are designed for this purpose.
You can use them directly with memory allocated by this library,
but it is not recommended because of following issue:
Mapping the same `VkDeviceMemory` block multiple times is illegal - only one mapping at a time is allowed.
This includes mapping disjoint regions. Mapping is not reference-counted internally by Vulkan.
Because of this, Vulkan Memory Allocator provides following facilities:

\section memory_mapping_mapping_functions Mapping functions

The library provides following functions for mapping of a specific #VmaAllocation: vmaMapMemory(), vmaUnmapMemory().
They are safer and more convenient to use than standard Vulkan functions.
You can map an allocation multiple times simultaneously - mapping is reference-counted internally.
You can also map different allocations simultaneously regardless of whether they use the same `VkDeviceMemory` block.
They way it's implemented is that the library always maps entire memory block, not just region of the allocation.
For further details, see description of vmaMapMemory() function.
Example:

\code
// Having these objects initialized:

struct ConstantBuffer
{
    ...
};
ConstantBuffer constantBufferData;

VmaAllocator allocator;
VmaBuffer constantBuffer;
VmaAllocation constantBufferAllocation;

// You can map and fill your buffer using following code:

void* mappedData;
vmaMapMemory(allocator, constantBufferAllocation, &mappedData);
memcpy(mappedData, &constantBufferData, sizeof(constantBufferData));
vmaUnmapMemory(allocator, constantBufferAllocation);
\endcode

\section memory_mapping_persistently_mapped_memory Persistently mapped memory

Kepping your memory persistently mapped is generally OK in Vulkan.
You don't need to unmap it before using its data on the GPU.
The library provides a special feature designed for that:
Allocations made with #VMA_ALLOCATION_CREATE_MAPPED_BIT flag set in
VmaAllocationCreateInfo::flags stay mapped all the time,
so you can just access CPU pointer to it any time
without a need to call any "map" or "unmap" function.
Example:

\code
VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufCreateInfo.size = sizeof(ConstantBuffer);
bufCreateInfo.usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT;

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_CPU_ONLY;
allocCreateInfo.flags = VMA_ALLOCATION_CREATE_MAPPED_BIT;

VkBuffer buf;
VmaAllocation alloc;
VmaAllocationInfo allocInfo;
vmaCreateBuffer(allocator, &bufCreateInfo, &allocCreateInfo, &buf, &alloc, &allocInfo);

// Buffer is already mapped. You can access its memory.
memcpy(allocInfo.pMappedData, &constantBufferData, sizeof(constantBufferData));
\endcode

There are some exceptions though, when you should consider mapping memory only for a short period of time:

- When operating system is Windows 7 or 8.x (Windows 10 is not affected because it uses WDDM2),
  device is discrete AMD GPU,
  and memory type is the special 256 MiB pool of `DEVICE_LOCAL + HOST_VISIBLE` memory
  (selected when you use #VMA_MEMORY_USAGE_CPU_TO_GPU),
  then whenever a memory block allocated from this memory type stays mapped
  for the time of any call to `vkQueueSubmit()` or `vkQueuePresentKHR()`, this
  block is migrated by WDDM to system RAM, which degrades performance. It doesn't
  matter if that particular memory block is actually used by the command buffer
  being submitted. 
- Keeping many large memory blocks mapped may impact performance or stability of some debugging tools.

\section memory_mapping_cache_control Cache control
  
Memory in Vulkan doesn't need to be unmapped before using it on GPU,
but unless a memory types has `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` flag set,
you need to manually invalidate cache before reading of mapped pointer
using function `vkvkInvalidateMappedMemoryRanges()`
and flush cache after writing to mapped pointer
using function `vkFlushMappedMemoryRanges()`.
Example:

\code
memcpy(allocInfo.pMappedData, &constantBufferData, sizeof(constantBufferData));

VkMemoryPropertyFlags memFlags;
vmaGetMemoryTypeProperties(allocator, allocInfo.memoryType, &memFlags);
if((memFlags & VK_MEMORY_PROPERTY_HOST_COHERENT_BIT) == 0)
{
    VkMappedMemoryRange memRange = { VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE };
    memRange.memory = allocInfo.deviceMemory;
    memRange.offset = allocInfo.offset;
    memRange.size   = allocInfo.size;
    vkFlushMappedMemoryRanges(device, 1, &memRange);
}
\endcode

Please note that memory allocated with #VMA_MEMORY_USAGE_CPU_ONLY is guaranteed to be host coherent.

Also, Windows drivers from all 3 PC GPU vendors (AMD, Intel, NVIDIA)
currently provide `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` flag on all memory types that are
`VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT`, so on this platform you may not need to bother.

\section memory_mapping_finding_if_memory_mappable Finding out if memory is mappable

It may happen that your allocation ends up in memory that is `HOST_VISIBLE` (available for mapping)
despite it wasn't explicitly requested.
For example, application may work on integrated graphics with unified memory (like Intel) or
allocation from video memory might have failed, so the library chose system memory as fallback.

You can detect this case and map such allocation to access its memory on CPU directly,
instead of launching a transfer operation.
In order to do that: inspect `allocInfo.memoryType`, call vmaGetMemoryTypeProperties(),
and look for `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` flag in properties of that memory type.

\code
VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufCreateInfo.size = sizeof(ConstantBuffer);
bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;

VkBuffer buf;
VmaAllocation alloc;
VmaAllocationInfo allocInfo;
vmaCreateBuffer(allocator, &bufCreateInfo, &allocCreateInfo, &buf, &alloc, &allocInfo);

VkMemoryPropertyFlags memFlags;
vmaGetMemoryTypeProperties(allocator, allocInfo.memoryType, &memFlags);
if((memFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) == 0)
{
    // Allocation ended up in mappable memory. You can map it and access it directly.
    void* mappedData;
    vmaMapMemory(allocator, alloc, &mappedData);
    memcpy(mappedData, &constantBufferData, sizeof(constantBufferData));
    vmaUnmapMemory(allocator, alloc);
}
else
{
    // Allocation ended up in non-mappable memory.
    // You need to create CPU-side buffer in VMA_MEMORY_USAGE_CPU_ONLY and make a transfer.
}
\endcode

You can even use #VMA_ALLOCATION_CREATE_MAPPED_BIT flag while creating allocations
that are not necessarily `HOST_VISIBLE` (e.g. using #VMA_MEMORY_USAGE_GPU_ONLY).
If the allocation ends up in memory type that is `HOST_VISIBLE`, it will be persistently mapped and you can use it directly.
If not, the flag is just ignored.
Example:

\code
VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufCreateInfo.size = sizeof(ConstantBuffer);
bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;
allocCreateInfo.flags = VMA_ALLOCATION_CREATE_MAPPED_BIT;

VkBuffer buf;
VmaAllocation alloc;
VmaAllocationInfo allocInfo;
vmaCreateBuffer(allocator, &bufCreateInfo, &allocCreateInfo, &buf, &alloc, &allocInfo);

if(allocInfo.pUserData != nullptr)
{
    // Allocation ended up in mappable memory.
    // It's persistently mapped. You can access it directly.
    memcpy(allocInfo.pMappedData, &constantBufferData, sizeof(constantBufferData));
}
else
{
    // Allocation ended up in non-mappable memory.
    // You need to create CPU-side buffer in VMA_MEMORY_USAGE_CPU_ONLY and make a transfer.
}
\endcode


\page custom_memory_pools Custom memory pools

A memory pool contains a number of `VkDeviceMemory` blocks.
The library automatically creates and manages default pool for each memory type available on the device.
Default memory pool automatically grows in size.
Size of allocated blocks is also variable and managed automatically.

You can create custom pool and allocate memory out of it.
It can be useful if you want to:

- Keep certain kind of allocations separate from others.
- Enforce particular, fixed size of Vulkan memory blocks.
- Limit maximum amount of Vulkan memory allocated for that pool.
- Reserve minimum or fixed amount of Vulkan memory always preallocated for that pool.

To use custom memory pools:

-# Fill VmaPoolCreateInfo structure.
-# Call vmaCreatePool() to obtain #VmaPool handle.
-# When making an allocation, set VmaAllocationCreateInfo::pool to this handle.
   You don't need to specify any other parameters of this structure, like usage.

Example:

\code
// Create a pool that can have at most 2 blocks, 128 MiB each.
VmaPoolCreateInfo poolCreateInfo = {};
poolCreateInfo.memoryTypeIndex = ...
poolCreateInfo.blockSize = 128ull * 1024 * 1024;
poolCreateInfo.maxBlockCount = 2;

VmaPool pool;
vmaCreatePool(allocator, &poolCreateInfo, &pool);

// Allocate a buffer out of it.
VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufCreateInfo.size = 1024;
bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.pool = pool;

VkBuffer buf;
VmaAllocation alloc;
VmaAllocationInfo allocInfo;
vmaCreateBuffer(allocator, &bufCreateInfo, &allocCreateInfo, &buf, &alloc, &allocInfo);
\endcode

You have to free all allocations made from this pool before destroying it.

\code
vmaDestroyBuffer(allocator, buf, alloc);
vmaDestroyPool(allocator, pool);
\endcode

\section custom_memory_pools_MemTypeIndex Choosing memory type index

When creating a pool, you must explicitly specify memory type index.
To find the one suitable for your buffers or images, you can use helper functions
vmaFindMemoryTypeIndexForBufferInfo(), vmaFindMemoryTypeIndexForImageInfo().
You need to provide structures with example parameters of buffers or images
that you are going to create in that pool.

\code
VkBufferCreateInfo exampleBufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
exampleBufCreateInfo.size = 1024; // Whatever.
exampleBufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; // Change if needed.

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY; // Change if needed.

uint32_t memTypeIndex;
vmaFindMemoryTypeIndexForBufferInfo(allocator, &exampleBufCreateInfo, &allocCreateInfo, &memTypeIndex);

VmaPoolCreateInfo poolCreateInfo = {};
poolCreateInfo.memoryTypeIndex = memTypeIndex;
// ...
\endcode

When creating buffers/images allocated in that pool, provide following parameters:

- `VkBufferCreateInfo`: Prefer to pass same parameters as above.
  Otherwise you risk creating resources in a memory type that is not suitable for them, which may result in undefined behavior.
  Using different `VK_BUFFER_USAGE_` flags may work, but you shouldn't create images in a pool intended for buffers
  or the other way around.
- VmaAllocationCreateInfo: You don't need to pass same parameters. Fill only `pool` member.
  Other members are ignored anyway.


\page defragmentation Defragmentation

Interleaved allocations and deallocations of many objects of varying size can
cause fragmentation, which can lead to a situation where the library is unable
to find a continuous range of free memory for a new allocation despite there is
enough free space, just scattered across many small free ranges between existing
allocations.

To mitigate this problem, you can use vmaDefragment(). Given set of allocations,
this function can move them to compact used memory, ensure more continuous free
space and possibly also free some `VkDeviceMemory`. It can work only on
allocations made from memory type that is `HOST_VISIBLE`. Allocations are
modified to point to the new `VkDeviceMemory` and offset. Data in this memory is
also `memmove`-ed to the new place. However, if you have images or buffers bound
to these allocations (and you certainly do), you need to destroy, recreate, and
bind them to the new place in memory.

For further details and example code, see documentation of function
vmaDefragment().

\page lost_allocations Lost allocations

If your game oversubscribes video memory, if may work OK in previous-generation
graphics APIs (DirectX 9, 10, 11, OpenGL) because resources are automatically
paged to system RAM. In Vulkan you can't do it because when you run out of
memory, an allocation just fails. If you have more data (e.g. textures) that can
fit into VRAM and you don't need it all at once, you may want to upload them to
GPU on demand and "push out" ones that are not used for a long time to make room
for the new ones, effectively using VRAM (or a cartain memory pool) as a form of
cache. Vulkan Memory Allocator can help you with that by supporting a concept of
"lost allocations".

To create an allocation that can become lost, include #VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT
flag in VmaAllocationCreateInfo::flags. Before using a buffer or image bound to
such allocation in every new frame, you need to query it if it's not lost.
To check it, call vmaTouchAllocation().
If the allocation is lost, you should not use it or buffer/image bound to it.
You mustn't forget to destroy this allocation and this buffer/image.
vmaGetAllocationInfo() can also be used for checking status of the allocation.
Allocation is lost when returned VmaAllocationInfo::deviceMemory == `VK_NULL_HANDLE`.

To create an allocation that can make some other allocations lost to make room
for it, use #VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT flag. You will
usually use both flags #VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT and
#VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT at the same time.

Warning! Current implementation uses quite naive, brute force algorithm,
which can make allocation calls that use #VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT
flag quite slow. A new, more optimal algorithm and data structure to speed this
up is planned for the future.

<b>Q: When interleaving creation of new allocations with usage of existing ones,
how do you make sure that an allocation won't become lost while it's used in the
current frame?</b>

It is ensured because vmaTouchAllocation() / vmaGetAllocationInfo() not only returns allocation
status/parameters and checks whether it's not lost, but when it's not, it also
atomically marks it as used in the current frame, which makes it impossible to
become lost in that frame. It uses lockless algorithm, so it works fast and
doesn't involve locking any internal mutex.

<b>Q: What if my allocation may still be in use by the GPU when it's rendering a
previous frame while I already submit new frame on the CPU?</b>

You can make sure that allocations "touched" by vmaTouchAllocation() / vmaGetAllocationInfo() will not
become lost for a number of additional frames back from the current one by
specifying this number as VmaAllocatorCreateInfo::frameInUseCount (for default
memory pool) and VmaPoolCreateInfo::frameInUseCount (for custom pool).

<b>Q: How do you inform the library when new frame starts?</b>

You need to call function vmaSetCurrentFrameIndex().

Example code:

\code
struct MyBuffer
{
    VkBuffer m_Buf = nullptr;
    VmaAllocation m_Alloc = nullptr;

    // Called when the buffer is really needed in the current frame.
    void EnsureBuffer();
};

void MyBuffer::EnsureBuffer()
{
    // Buffer has been created.
    if(m_Buf != VK_NULL_HANDLE)
    {
        // Check if its allocation is not lost + mark it as used in current frame.
        if(vmaTouchAllocation(allocator, m_Alloc))
        {
            // It's all OK - safe to use m_Buf.
            return;
        }
    }

    // Buffer not yet exists or lost - destroy and recreate it.

    vmaDestroyBuffer(allocator, m_Buf, m_Alloc);

    VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
    bufCreateInfo.size = 1024;
    bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

    VmaAllocationCreateInfo allocCreateInfo = {};
    allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;
    allocCreateInfo.flags = VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT |
        VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT;

    vmaCreateBuffer(allocator, &bufCreateInfo, &allocCreateInfo, &m_Buf, &m_Alloc, nullptr);
}
\endcode

When using lost allocations, you may see some Vulkan validation layer warnings
about overlapping regions of memory bound to different kinds of buffers and
images. This is still valid as long as you implement proper handling of lost
allocations (like in the example above) and don't use them.

You can create an allocation that is already in lost state from the beginning using function
vmaCreateLostAllocation(). It may be useful if you need a "dummy" allocation that is not null.

You can call function vmaMakePoolAllocationsLost() to set all eligible allocations
in a specified custom pool to lost state.
Allocations that have been "touched" in current frame or VmaPoolCreateInfo::frameInUseCount frames back
cannot become lost.


\page statistics Statistics

This library contains functions that return information about its internal state,
especially the amount of memory allocated from Vulkan.
Please keep in mind that these functions need to traverse all internal data structures
to gather these information, so they may be quite time-consuming.
Don't call them too often.

\section statistics_numeric_statistics Numeric statistics

You can query for overall statistics of the allocator using function vmaCalculateStats().
Information are returned using structure #VmaStats.
It contains #VmaStatInfo - number of allocated blocks, number of allocations
(occupied ranges in these blocks), number of unused (free) ranges in these blocks,
number of bytes used and unused (but still allocated from Vulkan) and other information.
They are summed across memory heaps, memory types and total for whole allocator.

You can query for statistics of a custom pool using function vmaGetPoolStats().
Information are returned using structure #VmaPoolStats.

You can query for information about specific allocation using function vmaGetAllocationInfo().
It fill structure #VmaAllocationInfo.

\section statistics_json_dump JSON dump

You can dump internal state of the allocator to a string in JSON format using function vmaBuildStatsString().
The result is guaranteed to be correct JSON.
It uses ANSI encoding.
Any strings provided by user (see [Allocation names](@ref allocation_names))
are copied as-is and properly escaped for JSON, so if they use UTF-8, ISO-8859-2 or any other encoding,
this JSON string can be treated as using this encoding.
It must be freed using function vmaFreeStatsString().

The format of this JSON string is not part of official documentation of the library,
but it will not change in backward-incompatible way without increasing library major version number
and appropriate mention in changelog.

The JSON string contains all the data that can be obtained using vmaCalculateStats().
It can also contain detailed map of allocated memory blocks and their regions -
free and occupied by allocations.
This allows e.g. to visualize the memory or assess fragmentation.


\page allocation_annotation Allocation names and user data

\section allocation_user_data Allocation user data

You can annotate allocations with your own information, e.g. for debugging purposes.
To do that, fill VmaAllocationCreateInfo::pUserData field when creating
an allocation. It's an opaque `void*` pointer. You can use it e.g. as a pointer,
some handle, index, key, ordinal number or any other value that would associate
the allocation with your custom metadata.

\code
VkBufferCreateInfo bufferInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
// Fill bufferInfo...

MyBufferMetadata* pMetadata = CreateBufferMetadata();

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;
allocCreateInfo.pUserData = pMetadata;

VkBuffer buffer;
VmaAllocation allocation;
vmaCreateBuffer(allocator, &bufferInfo, &allocCreateInfo, &buffer, &allocation, nullptr);
\endcode

The pointer may be later retrieved as VmaAllocationInfo::pUserData:

\code
VmaAllocationInfo allocInfo;
vmaGetAllocationInfo(allocator, allocation, &allocInfo);
MyBufferMetadata* pMetadata = (MyBufferMetadata*)allocInfo.pUserData;
\endcode

It can also be changed using function vmaSetAllocationUserData().

Values of (non-zero) allocations' `pUserData` are printed in JSON report created by
vmaBuildStatsString(), in hexadecimal form.

\section allocation_names Allocation names

There is alternative mode available where `pUserData` pointer is used to point to
a null-terminated string, giving a name to the allocation. To use this mode,
set #VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT flag in VmaAllocationCreateInfo::flags.
Then `pUserData` passed as VmaAllocationCreateInfo::pUserData or argument to
vmaSetAllocationUserData() must be either null or pointer to a null-terminated string.
The library creates internal copy of the string, so the pointer you pass doesn't need
to be valid for whole lifetime of the allocation. You can free it after the call.

\code
VkImageCreateInfo imageInfo = { VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO };
// Fill imageInfo...

std::string imageName = "Texture: ";
imageName += fileName;

VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;
allocCreateInfo.flags = VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT;
allocCreateInfo.pUserData = imageName.c_str();

VkImage image;
VmaAllocation allocation;
vmaCreateImage(allocator, &imageInfo, &allocCreateInfo, &image, &allocation, nullptr);
\endcode

The value of `pUserData` pointer of the allocation will be different than the one
you passed when setting allocation's name - pointing to a buffer managed
internally that holds copy of the string.

\code
VmaAllocationInfo allocInfo;
vmaGetAllocationInfo(allocator, allocation, &allocInfo);
const char* imageName = (const char*)allocInfo.pUserData;
printf("Image name: %s\n", imageName);
\endcode

That string is also printed in JSON report created by vmaBuildStatsString().


\page usage_patterns Recommended usage patterns

\section usage_patterns_simple Simple patterns

\subsection usage_patterns_simple_render_targets Render targets

<b>When:</b>
Any resources that you frequently write and read on GPU,
e.g. images used as color attachments (aka "render targets"), depth-stencil attachments,
images/buffers used as storage image/buffer (aka "Unordered Access View (UAV)").

<b>What to do:</b>
Create them in video memory that is fastest to access from GPU using
#VMA_MEMORY_USAGE_GPU_ONLY.

Consider using [VK_KHR_dedicated_allocation](@ref vk_khr_dedicated_allocation) extension
and/or manually creating them as dedicated allocations using #VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT,
especially if they are large or if you plan to destroy and recreate them e.g. when
display resolution changes.
Prefer to create such resources first and all other GPU resources (like textures and vertex buffers) later.

\subsection usage_patterns_simple_immutable_resources Immutable resources

<b>When:</b>
Any resources that you fill on CPU only once (aka "immutable") or infrequently
and then read frequently on GPU,
e.g. textures, vertex and index buffers, constant buffers that don't change often.

<b>What to do:</b>
Create them in video memory that is fastest to access from GPU using
#VMA_MEMORY_USAGE_GPU_ONLY.

To initialize content of such resource, create a CPU-side (aka "staging") copy of it
in system memory - #VMA_MEMORY_USAGE_CPU_ONLY, map it, fill it,
and submit a transfer from it to the GPU resource.
You can keep the staging copy if you need it for another upload transfer in the future.
If you don't, you can destroy it or reuse this buffer for uploading different resource
after the transfer finishes.

Prefer to create just buffers in system memory rather than images, even for uploading textures.
Use `vkCmdCopyBufferToImage()`.
Dont use images with `VK_IMAGE_TILING_LINEAR`.

\subsection usage_patterns_dynamic_resources Dynamic resources

<b>When:</b>
Any resources that change frequently (aka "dynamic"), e.g. every frame or every draw call,
written on CPU, read on GPU.

<b>What to do:</b>
Create them using #VMA_MEMORY_USAGE_CPU_TO_GPU.
You can map it and write to it directly on CPU, as well as read from it on GPU.

This is a more complex situation. Different solutions are possible,
and the best one depends on specific GPU type, but you can use this simple approach for the start.
Prefer to write to such resource sequentially (e.g. using `memcpy`).
Don't perform random access or any reads from it, as it may be very slow.

\subsection usage_patterns_readback Readback

<b>When:</b>
Resources that contain data written by GPU that you want to read back on CPU,
e.g. results of some computations.

<b>What to do:</b>
Create them using #VMA_MEMORY_USAGE_GPU_TO_CPU.
You can write to them directly on GPU, as well as map and read them on CPU.

\section usage_patterns_advanced Advanced patterns

\subsection usage_patterns_integrated_graphics Detecting integrated graphics

You can support integrated graphics (like Intel HD Graphics, AMD APU) better
by detecting it in Vulkan.
To do it, call `vkGetPhysicalDeviceProperties()`, inspect
`VkPhysicalDeviceProperties::deviceType` and look for `VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU`.
When you find it, you can assume that memory is unified and all memory types are equally fast
to access from GPU, regardless of `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT`.

You can then sum up sizes of all available memory heaps and treat them as useful for
your GPU resources, instead of only `DEVICE_LOCAL` ones.
You can also prefer to create your resources in memory types that are `HOST_VISIBLE` to map them
directly instead of submitting explicit transfer (see below).

\subsection usage_patterns_direct_vs_transfer Direct access versus transfer

For resources that you frequently write on CPU and read on GPU, many solutions are possible:

-# Create one copy in video memory using #VMA_MEMORY_USAGE_GPU_ONLY,
   second copy in system memory using #VMA_MEMORY_USAGE_CPU_ONLY and submit explicit tranfer each time.
-# Create just single copy using #VMA_MEMORY_USAGE_CPU_TO_GPU, map it and fill it on CPU,
   read it directly on GPU.
-# Create just single copy using #VMA_MEMORY_USAGE_CPU_ONLY, map it and fill it on CPU,
   read it directly on GPU.

Which solution is the most efficient depends on your resource and especially on the GPU.
It is best to measure it and then make the decision.
Some general recommendations:

- On integrated graphics use (2) or (3) to avoid unnecesary time and memory overhead
  related to using a second copy.
- For small resources (e.g. constant buffers) use (2).
  Discrete AMD cards have special 256 MiB pool of video memory that is directly mappable.
  Even if the resource ends up in system memory, its data may be cached on GPU after first
  fetch over PCIe bus.
- For larger resources (e.g. textures), decide between (1) and (2).
  You may want to differentiate NVIDIA and AMD, e.g. by looking for memory type that is
  both `DEVICE_LOCAL` and `HOST_VISIBLE`. When you find it, use (2), otherwise use (1).

Similarly, for resources that you frequently write on GPU and read on CPU, multiple
solutions are possible:

-# Create one copy in video memory using #VMA_MEMORY_USAGE_GPU_ONLY,
   second copy in system memory using #VMA_MEMORY_USAGE_GPU_TO_CPU and submit explicit tranfer each time.
-# Create just single copy using #VMA_MEMORY_USAGE_GPU_TO_CPU, write to it directly on GPU,
   map it and read it on CPU.

You should take some measurements to decide which option is faster in case of your specific
resource.

If you don't want to specialize your code for specific types of GPUs, yon can still make
an simple optimization for cases when your resource ends up in mappable memory to use it
directly in this case instead of creating CPU-side staging copy.
For details see [Finding out if memory is mappable](@ref memory_mapping_finding_if_memory_mappable).


\page configuration Configuration

Please check "CONFIGURATION SECTION" in the code to find macros that you can define
before each include of this file or change directly in this file to provide
your own implementation of basic facilities like assert, `min()` and `max()` functions,
mutex, atomic etc.
The library uses its own implementation of containers by default, but you can switch to using
STL containers instead.

\section config_Vulkan_functions Pointers to Vulkan functions

The library uses Vulkan functions straight from the `vulkan.h` header by default.
If you want to provide your own pointers to these functions, e.g. fetched using
`vkGetInstanceProcAddr()` and `vkGetDeviceProcAddr()`:

-# Define `VMA_STATIC_VULKAN_FUNCTIONS 0`.
-# Provide valid pointers through VmaAllocatorCreateInfo::pVulkanFunctions.

\section custom_memory_allocator Custom host memory allocator

If you use custom allocator for CPU memory rather than default operator `new`
and `delete` from C++, you can make this library using your allocator as well
by filling optional member VmaAllocatorCreateInfo::pAllocationCallbacks. These
functions will be passed to Vulkan, as well as used by the library itself to
make any CPU-side allocations.

\section allocation_callbacks Device memory allocation callbacks

The library makes calls to `vkAllocateMemory()` and `vkFreeMemory()` internally.
You can setup callbacks to be informed about these calls, e.g. for the purpose
of gathering some statistics. To do it, fill optional member
VmaAllocatorCreateInfo::pDeviceMemoryCallbacks.

\section heap_memory_limit Device heap memory limit

If you want to test how your program behaves with limited amount of Vulkan device
memory available without switching your graphics card to one that really has
smaller VRAM, you can use a feature of this library intended for this purpose.
To do it, fill optional member VmaAllocatorCreateInfo::pHeapSizeLimit.



\page vk_khr_dedicated_allocation VK_KHR_dedicated_allocation

VK_KHR_dedicated_allocation is a Vulkan extension which can be used to improve
performance on some GPUs. It augments Vulkan API with possibility to query
driver whether it prefers particular buffer or image to have its own, dedicated
allocation (separate `VkDeviceMemory` block) for better efficiency - to be able
to do some internal optimizations.

The extension is supported by this library. It will be used automatically when
enabled. To enable it:

1 . When creating Vulkan device, check if following 2 device extensions are
supported (call `vkEnumerateDeviceExtensionProperties()`).
If yes, enable them (fill `VkDeviceCreateInfo::ppEnabledExtensionNames`).

- VK_KHR_get_memory_requirements2
- VK_KHR_dedicated_allocation

If you enabled these extensions:

2 . Use #VMA_ALLOCATOR_CREATE_KHR_DEDICATED_ALLOCATION_BIT flag when creating
your #VmaAllocator`to inform the library that you enabled required extensions
and you want the library to use them.

\code
allocatorInfo.flags |= VMA_ALLOCATOR_CREATE_KHR_DEDICATED_ALLOCATION_BIT;

vmaCreateAllocator(&allocatorInfo, &allocator);
\endcode

That's all. The extension will be automatically used whenever you create a
buffer using vmaCreateBuffer() or image using vmaCreateImage().

When using the extension together with Vulkan Validation Layer, you will receive
warnings like this:

    vkBindBufferMemory(): Binding memory to buffer 0x33 but vkGetBufferMemoryRequirements() has not been called on that buffer.

It is OK, you should just ignore it. It happens because you use function
`vkGetBufferMemoryRequirements2KHR()` instead of standard
`vkGetBufferMemoryRequirements()`, while the validation layer seems to be
unaware of it.

To learn more about this extension, see:

- [VK_KHR_dedicated_allocation in Vulkan specification](https://www.khronos.org/registry/vulkan/specs/1.0-extensions/html/vkspec.html#VK_KHR_dedicated_allocation)
- [VK_KHR_dedicated_allocation unofficial manual](http://asawicki.info/articles/VK_KHR_dedicated_allocation.php5)



\page general_considerations General considerations

\section general_considerations_thread_safety Thread safety

- The library has no global state, so separate #VmaAllocator objects can be used
  independently.
  There should be no need to create multiple such objects though - one per `VkDevice` is enough.
- By default, all calls to functions that take #VmaAllocator as first parameter
  are safe to call from multiple threads simultaneously because they are
  synchronized internally when needed.
- When the allocator is created with #VMA_ALLOCATOR_CREATE_EXTERNALLY_SYNCHRONIZED_BIT
  flag, calls to functions that take such #VmaAllocator object must be
  synchronized externally.
- Access to a #VmaAllocation object must be externally synchronized. For example,
  you must not call vmaGetAllocationInfo() and vmaMapMemory() from different
  threads at the same time if you pass the same #VmaAllocation object to these
  functions.

\section general_considerations_allocation_algorithm Allocation algorithm

The library uses following algorithm for allocation, in order:

-# Try to find free range of memory in existing blocks.
-# If failed, try to create a new block of `VkDeviceMemory`, with preferred block size.
-# If failed, try to create such block with size/2, size/4, size/8.
-# If failed and #VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT flag was
   specified, try to find space in existing blocks, possilby making some other
   allocations lost.
-# If failed, try to allocate separate `VkDeviceMemory` for this allocation,
   just like when you use #VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT.
-# If failed, choose other memory type that meets the requirements specified in
   VmaAllocationCreateInfo and go to point 1.
-# If failed, return `VK_ERROR_OUT_OF_DEVICE_MEMORY`.

\section general_considerations_features_not_supported Features not supported

Features deliberately excluded from the scope of this library:

- Data transfer - issuing commands that transfer data between buffers or images, any usage of
  `VkCommandList` or `VkCommandQueue` and related synchronization is responsibility of the user.
- Support for any programming languages other than C/C++.
  Bindings to other languages are welcomed as external projects.

*/

// For skia we don't include vulkan.h here. Before including this header we always include
// GrVkDefines which has a user defined header. Additionally we don't require vulkan/vulkan.h to be
// on the include path.
// #include <vulkan/vulkan.h>

/** \struct VmaAllocator
\brief Represents main object of this library initialized.

Fill structure VmaAllocatorCreateInfo and call function vmaCreateAllocator() to create it.
Call function vmaDestroyAllocator() to destroy it.

It is recommended to create just one object of this type per `VkDevice` object,
right after Vulkan is initialized and keep it alive until before Vulkan device is destroyed.
*/
VK_DEFINE_HANDLE(VmaAllocator)

/// Callback function called after successful vkAllocateMemory.
typedef void (VKAPI_PTR *PFN_vmaAllocateDeviceMemoryFunction)(
    VmaAllocator      allocator,
    uint32_t          memoryType,
    VkDeviceMemory    memory,
    VkDeviceSize      size);
/// Callback function called before vkFreeMemory.
typedef void (VKAPI_PTR *PFN_vmaFreeDeviceMemoryFunction)(
    VmaAllocator      allocator,
    uint32_t          memoryType,
    VkDeviceMemory    memory,
    VkDeviceSize      size);

/** \brief Set of callbacks that the library will call for `vkAllocateMemory` and `vkFreeMemory`.

Provided for informative purpose, e.g. to gather statistics about number of
allocations or total amount of memory allocated in Vulkan.

Used in VmaAllocatorCreateInfo::pDeviceMemoryCallbacks.
*/
typedef struct VmaDeviceMemoryCallbacks {
    /// Optional, can be null.
    PFN_vmaAllocateDeviceMemoryFunction pfnAllocate;
    /// Optional, can be null.
    PFN_vmaFreeDeviceMemoryFunction pfnFree;
} VmaDeviceMemoryCallbacks;

/// Flags for created #VmaAllocator.
typedef enum VmaAllocatorCreateFlagBits {
    /** \brief Allocator and all objects created from it will not be synchronized internally, so you must guarantee they are used from only one thread at a time or synchronized externally by you.

    Using this flag may increase performance because internal mutexes are not used.
    */
    VMA_ALLOCATOR_CREATE_EXTERNALLY_SYNCHRONIZED_BIT = 0x00000001,
    /** \brief Enables usage of VK_KHR_dedicated_allocation extension.

    Using this extenion will automatically allocate dedicated blocks of memory for
    some buffers and images instead of suballocating place for them out of bigger
    memory blocks (as if you explicitly used #VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT
    flag) when it is recommended by the driver. It may improve performance on some
    GPUs.

    You may set this flag only if you found out that following device extensions are
    supported, you enabled them while creating Vulkan device passed as
    VmaAllocatorCreateInfo::device, and you want them to be used internally by this
    library:

    - VK_KHR_get_memory_requirements2
    - VK_KHR_dedicated_allocation

When this flag is set, you can experience following warnings reported by Vulkan
validation layer. You can ignore them.

> vkBindBufferMemory(): Binding memory to buffer 0x2d but vkGetBufferMemoryRequirements() has not been called on that buffer.
    */
    VMA_ALLOCATOR_CREATE_KHR_DEDICATED_ALLOCATION_BIT = 0x00000002,

    VMA_ALLOCATOR_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
} VmaAllocatorCreateFlagBits;
typedef VkFlags VmaAllocatorCreateFlags;

/** \brief Pointers to some Vulkan functions - a subset used by the library.

Used in VmaAllocatorCreateInfo::pVulkanFunctions.
*/
typedef struct VmaVulkanFunctions {
    PFN_vkGetPhysicalDeviceProperties vkGetPhysicalDeviceProperties;
    PFN_vkGetPhysicalDeviceMemoryProperties vkGetPhysicalDeviceMemoryProperties;
    PFN_vkAllocateMemory vkAllocateMemory;
    PFN_vkFreeMemory vkFreeMemory;
    PFN_vkMapMemory vkMapMemory;
    PFN_vkUnmapMemory vkUnmapMemory;
    PFN_vkBindBufferMemory vkBindBufferMemory;
    PFN_vkBindImageMemory vkBindImageMemory;
    PFN_vkGetBufferMemoryRequirements vkGetBufferMemoryRequirements;
    PFN_vkGetImageMemoryRequirements vkGetImageMemoryRequirements;
    PFN_vkCreateBuffer vkCreateBuffer;
    PFN_vkDestroyBuffer vkDestroyBuffer;
    PFN_vkCreateImage vkCreateImage;
    PFN_vkDestroyImage vkDestroyImage;
    PFN_vkGetBufferMemoryRequirements2KHR vkGetBufferMemoryRequirements2KHR;
    PFN_vkGetImageMemoryRequirements2KHR vkGetImageMemoryRequirements2KHR;
} VmaVulkanFunctions;

/// Description of a Allocator to be created.
typedef struct VmaAllocatorCreateInfo
{
    /// Flags for created allocator. Use #VmaAllocatorCreateFlagBits enum.
    VmaAllocatorCreateFlags flags;
    /// Vulkan physical device.
    /** It must be valid throughout whole lifetime of created allocator. */
    VkPhysicalDevice physicalDevice;
    /// Vulkan device.
    /** It must be valid throughout whole lifetime of created allocator. */
    VkDevice device;
    /// Preferred size of a single `VkDeviceMemory` block to be allocated from large heaps > 1 GiB. Optional.
    /** Set to 0 to use default, which is currently 256 MiB. */
    VkDeviceSize preferredLargeHeapBlockSize;
    /// Custom CPU memory allocation callbacks. Optional.
    /** Optional, can be null. When specified, will also be used for all CPU-side memory allocations. */
    const VkAllocationCallbacks* pAllocationCallbacks;
    /// Informative callbacks for `vkAllocateMemory`, `vkFreeMemory`. Optional.
    /** Optional, can be null. */
    const VmaDeviceMemoryCallbacks* pDeviceMemoryCallbacks;
    /** \brief Maximum number of additional frames that are in use at the same time as current frame.

    This value is used only when you make allocations with
    VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT flag. Such allocation cannot become
    lost if allocation.lastUseFrameIndex >= allocator.currentFrameIndex - frameInUseCount.

    For example, if you double-buffer your command buffers, so resources used for
    rendering in previous frame may still be in use by the GPU at the moment you
    allocate resources needed for the current frame, set this value to 1.

    If you want to allow any allocations other than used in the current frame to
    become lost, set this value to 0.
    */
    uint32_t frameInUseCount;
    /** \brief Either null or a pointer to an array of limits on maximum number of bytes that can be allocated out of particular Vulkan memory heap.

    If not NULL, it must be a pointer to an array of
    `VkPhysicalDeviceMemoryProperties::memoryHeapCount` elements, defining limit on
    maximum number of bytes that can be allocated out of particular Vulkan memory
    heap.

    Any of the elements may be equal to `VK_WHOLE_SIZE`, which means no limit on that
    heap. This is also the default in case of `pHeapSizeLimit` = NULL.

    If there is a limit defined for a heap:

    - If user tries to allocate more memory from that heap using this allocator,
      the allocation fails with `VK_ERROR_OUT_OF_DEVICE_MEMORY`.
    - If the limit is smaller than heap size reported in `VkMemoryHeap::size`, the
      value of this limit will be reported instead when using vmaGetMemoryProperties().

    Warning! Using this feature may not be equivalent to installing a GPU with
    smaller amount of memory, because graphics driver doesn't necessary fail new
    allocations with `VK_ERROR_OUT_OF_DEVICE_MEMORY` result when memory capacity is
    exceeded. It may return success and just silently migrate some device memory
    blocks to system RAM.
    */
    const VkDeviceSize* pHeapSizeLimit;
    /** \brief Pointers to Vulkan functions. Can be null if you leave define `VMA_STATIC_VULKAN_FUNCTIONS 1`.

    If you leave define `VMA_STATIC_VULKAN_FUNCTIONS 1` in configuration section,
    you can pass null as this member, because the library will fetch pointers to
    Vulkan functions internally in a static way, like:

        vulkanFunctions.vkAllocateMemory = &vkAllocateMemory;

    Fill this member if you want to provide your own pointers to Vulkan functions,
    e.g. fetched using `vkGetInstanceProcAddr()` and `vkGetDeviceProcAddr()`.
    */
    const VmaVulkanFunctions* pVulkanFunctions;
} VmaAllocatorCreateInfo;

/// Creates Allocator object.
VkResult vmaCreateAllocator(
    const VmaAllocatorCreateInfo* pCreateInfo,
    VmaAllocator* pAllocator);

/// Destroys allocator object.
void vmaDestroyAllocator(
    VmaAllocator allocator);

/**
PhysicalDeviceProperties are fetched from physicalDevice by the allocator.
You can access it here, without fetching it again on your own.
*/
void vmaGetPhysicalDeviceProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceProperties** ppPhysicalDeviceProperties);

/**
PhysicalDeviceMemoryProperties are fetched from physicalDevice by the allocator.
You can access it here, without fetching it again on your own.
*/
void vmaGetMemoryProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceMemoryProperties** ppPhysicalDeviceMemoryProperties);

/**
\brief Given Memory Type Index, returns Property Flags of this memory type.

This is just a convenience function. Same information can be obtained using
vmaGetMemoryProperties().
*/
void vmaGetMemoryTypeProperties(
    VmaAllocator allocator,
    uint32_t memoryTypeIndex,
    VkMemoryPropertyFlags* pFlags);

/** \brief Sets index of the current frame.

This function must be used if you make allocations with
#VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT and
#VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT flags to inform the allocator
when a new frame begins. Allocations queried using vmaGetAllocationInfo() cannot
become lost in the current frame.
*/
void vmaSetCurrentFrameIndex(
    VmaAllocator allocator,
    uint32_t frameIndex);

/** \brief Calculated statistics of memory usage in entire allocator.
*/
typedef struct VmaStatInfo
{
    /// Number of `VkDeviceMemory` Vulkan memory blocks allocated.
    uint32_t blockCount;
    /// Number of #VmaAllocation allocation objects allocated.
    uint32_t allocationCount;
    /// Number of free ranges of memory between allocations.
    uint32_t unusedRangeCount;
    /// Total number of bytes occupied by all allocations.
    VkDeviceSize usedBytes;
    /// Total number of bytes occupied by unused ranges.
    VkDeviceSize unusedBytes;
    VkDeviceSize allocationSizeMin, allocationSizeAvg, allocationSizeMax;
    VkDeviceSize unusedRangeSizeMin, unusedRangeSizeAvg, unusedRangeSizeMax;
} VmaStatInfo;

/// General statistics from current state of Allocator.
typedef struct VmaStats
{
    VmaStatInfo memoryType[VK_MAX_MEMORY_TYPES];
    VmaStatInfo memoryHeap[VK_MAX_MEMORY_HEAPS];
    VmaStatInfo total;
} VmaStats;

/// Retrieves statistics from current state of the Allocator.
void vmaCalculateStats(
    VmaAllocator allocator,
    VmaStats* pStats);

#define VMA_STATS_STRING_ENABLED 1

#if VMA_STATS_STRING_ENABLED

/// Builds and returns statistics as string in JSON format.
/** @param[out] ppStatsString Must be freed using vmaFreeStatsString() function.
*/
void vmaBuildStatsString(
    VmaAllocator allocator,
    char** ppStatsString,
    VkBool32 detailedMap);

void vmaFreeStatsString(
    VmaAllocator allocator,
    char* pStatsString);

#endif // #if VMA_STATS_STRING_ENABLED

/** \struct VmaPool
\brief Represents custom memory pool

Fill structure VmaPoolCreateInfo and call function vmaCreatePool() to create it.
Call function vmaDestroyPool() to destroy it.

For more information see [Custom memory pools](@ref choosing_memory_type_custom_memory_pools).
*/
VK_DEFINE_HANDLE(VmaPool)

typedef enum VmaMemoryUsage
{
    /** No intended memory usage specified.
    Use other members of VmaAllocationCreateInfo to specify your requirements.
    */
    VMA_MEMORY_USAGE_UNKNOWN = 0,
    /** Memory will be used on device only, so fast access from the device is preferred.
    It usually means device-local GPU (video) memory.
    No need to be mappable on host.
    It is roughly equivalent of `D3D12_HEAP_TYPE_DEFAULT`.

    Usage:
    
    - Resources written and read by device, e.g. images used as attachments.
    - Resources transferred from host once (immutable) or infrequently and read by
      device multiple times, e.g. textures to be sampled, vertex buffers, uniform
      (constant) buffers, and majority of other types of resources used by device.

    Allocation may still end up in `HOST_VISIBLE` memory on some implementations.
    In such case, you are free to map it.
    You can use #VMA_ALLOCATION_CREATE_MAPPED_BIT with this usage type.
    */
    VMA_MEMORY_USAGE_GPU_ONLY = 1,
    /** Memory will be mappable on host.
    It usually means CPU (system) memory.
    Resources created in this pool may still be accessible to the device, but access to them can be slower.
    Guarantees to be `HOST_VISIBLE` and `HOST_COHERENT`.
    CPU read may be uncached.
    It is roughly equivalent of `D3D12_HEAP_TYPE_UPLOAD`.

    Usage: Staging copy of resources used as transfer source.
    */
    VMA_MEMORY_USAGE_CPU_ONLY = 2,
    /**
    Memory that is both mappable on host (guarantees to be `HOST_VISIBLE`) and preferably fast to access by GPU.
    CPU reads may be uncached and very slow.

    Usage: Resources written frequently by host (dynamic), read by device. E.g. textures, vertex buffers, uniform buffers updated every frame or every draw call.
    */
    VMA_MEMORY_USAGE_CPU_TO_GPU = 3,
    /** Memory mappable on host (guarantees to be `HOST_VISIBLE`) and cached.
    It is roughly equivalent of `D3D12_HEAP_TYPE_READBACK`.

    Usage:

    - Resources written by device, read by host - results of some computations, e.g. screen capture, average scene luminance for HDR tone mapping.
    - Any resources read or accessed randomly on host, e.g. CPU-side copy of vertex buffer used as source of transfer, but also used for collision detection.
    */
    VMA_MEMORY_USAGE_GPU_TO_CPU = 4,
    VMA_MEMORY_USAGE_MAX_ENUM = 0x7FFFFFFF
} VmaMemoryUsage;

/// Flags to be passed as VmaAllocationCreateInfo::flags.
typedef enum VmaAllocationCreateFlagBits {
    /** \brief Set this flag if the allocation should have its own memory block.
    
    Use it for special, big resources, like fullscreen images used as attachments.
   
    This flag must also be used for host visible resources that you want to map
    simultaneously because otherwise they might end up as regions of the same
    `VkDeviceMemory`, while mapping same `VkDeviceMemory` multiple times
    simultaneously is illegal.

    You should not use this flag if VmaAllocationCreateInfo::pool is not null.
    */
    VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT = 0x00000001,

    /** \brief Set this flag to only try to allocate from existing `VkDeviceMemory` blocks and never create new such block.
    
    If new allocation cannot be placed in any of the existing blocks, allocation
    fails with `VK_ERROR_OUT_OF_DEVICE_MEMORY` error.
    
    You should not use #VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT and
    #VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT at the same time. It makes no sense.
    
    If VmaAllocationCreateInfo::pool is not null, this flag is implied and ignored. */
    VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT = 0x00000002,
    /** \brief Set this flag to use a memory that will be persistently mapped and retrieve pointer to it.
    
    Pointer to mapped memory will be returned through VmaAllocationInfo::pMappedData.

    Is it valid to use this flag for allocation made from memory type that is not
    `HOST_VISIBLE`. This flag is then ignored and memory is not mapped. This is
    useful if you need an allocation that is efficient to use on GPU
    (`DEVICE_LOCAL`) and still want to map it directly if possible on platforms that
    support it (e.g. Intel GPU).

    You should not use this flag together with #VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT.
    */
    VMA_ALLOCATION_CREATE_MAPPED_BIT = 0x00000004,
    /** Allocation created with this flag can become lost as a result of another
    allocation with #VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT flag, so you
    must check it before use.

    To check if allocation is not lost, call vmaGetAllocationInfo() and check if
    VmaAllocationInfo::deviceMemory is not `VK_NULL_HANDLE`.

    For details about supporting lost allocations, see Lost Allocations
    chapter of User Guide on Main Page.

    You should not use this flag together with #VMA_ALLOCATION_CREATE_MAPPED_BIT.
    */
    VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT = 0x00000008,
    /** While creating allocation using this flag, other allocations that were
    created with flag #VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT can become lost.

    For details about supporting lost allocations, see Lost Allocations
    chapter of User Guide on Main Page.
    */
    VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT = 0x00000010,
    /** Set this flag to treat VmaAllocationCreateInfo::pUserData as pointer to a
    null-terminated string. Instead of copying pointer value, a local copy of the
    string is made and stored in allocation's `pUserData`. The string is automatically
    freed together with the allocation. It is also used in vmaBuildStatsString().
    */
    VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT = 0x00000020,

    VMA_ALLOCATION_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
} VmaAllocationCreateFlagBits;
typedef VkFlags VmaAllocationCreateFlags;

typedef struct VmaAllocationCreateInfo
{
    /// Use #VmaAllocationCreateFlagBits enum.
    VmaAllocationCreateFlags flags;
    /** \brief Intended usage of memory.
    
    You can leave #VMA_MEMORY_USAGE_UNKNOWN if you specify memory requirements in other way. \n
    If `pool` is not null, this member is ignored.
    */
    VmaMemoryUsage usage;
    /** \brief Flags that must be set in a Memory Type chosen for an allocation.
    
    Leave 0 if you specify memory requirements in other way. \n
    If `pool` is not null, this member is ignored.*/
    VkMemoryPropertyFlags requiredFlags;
    /** \brief Flags that preferably should be set in a memory type chosen for an allocation.
    
    Set to 0 if no additional flags are prefered. \n
    If `pool` is not null, this member is ignored. */
    VkMemoryPropertyFlags preferredFlags;
    /** \brief Bitmask containing one bit set for every memory type acceptable for this allocation.

    Value 0 is equivalent to `UINT32_MAX` - it means any memory type is accepted if
    it meets other requirements specified by this structure, with no further
    restrictions on memory type index. \n
    If `pool` is not null, this member is ignored.
    */
    uint32_t memoryTypeBits;
    /** \brief Pool that this allocation should be created in.

    Leave `VK_NULL_HANDLE` to allocate from default pool. If not null, members:
    `usage`, `requiredFlags`, `preferredFlags`, `memoryTypeBits` are ignored.
    */
    VmaPool pool;
    /** \brief Custom general-purpose pointer that will be stored in #VmaAllocation, can be read as VmaAllocationInfo::pUserData and changed using vmaSetAllocationUserData().
    
    If #VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT is used, it must be either
    null or pointer to a null-terminated string. The string will be then copied to
    internal buffer, so it doesn't need to be valid after allocation call.
    */
    void* pUserData;
} VmaAllocationCreateInfo;

/**
\brief Helps to find memoryTypeIndex, given memoryTypeBits and VmaAllocationCreateInfo.

This algorithm tries to find a memory type that:

- Is allowed by memoryTypeBits.
- Contains all the flags from pAllocationCreateInfo->requiredFlags.
- Matches intended usage.
- Has as many flags from pAllocationCreateInfo->preferredFlags as possible.

\return Returns VK_ERROR_FEATURE_NOT_PRESENT if not found. Receiving such result
from this function or any other allocating function probably means that your
device doesn't support any memory type with requested features for the specific
type of resource you want to use it for. Please check parameters of your
resource, like image layout (OPTIMAL versus LINEAR) or mip level count.
*/
VkResult vmaFindMemoryTypeIndex(
    VmaAllocator allocator,
    uint32_t memoryTypeBits,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    uint32_t* pMemoryTypeIndex);

/**
\brief Helps to find memoryTypeIndex, given VkBufferCreateInfo and VmaAllocationCreateInfo.

It can be useful e.g. to determine value to be used as VmaPoolCreateInfo::memoryTypeIndex.
It internally creates a temporary, dummy buffer that never has memory bound.
It is just a convenience function, equivalent to calling:

- `vkCreateBuffer`
- `vkGetBufferMemoryRequirements`
- `vmaFindMemoryTypeIndex`
- `vkDestroyBuffer`
*/
VkResult vmaFindMemoryTypeIndexForBufferInfo(
    VmaAllocator allocator,
    const VkBufferCreateInfo* pBufferCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    uint32_t* pMemoryTypeIndex);

/**
\brief Helps to find memoryTypeIndex, given VkImageCreateInfo and VmaAllocationCreateInfo.

It can be useful e.g. to determine value to be used as VmaPoolCreateInfo::memoryTypeIndex.
It internally creates a temporary, dummy image that never has memory bound.
It is just a convenience function, equivalent to calling:

- `vkCreateImage`
- `vkGetImageMemoryRequirements`
- `vmaFindMemoryTypeIndex`
- `vkDestroyImage`
*/
VkResult vmaFindMemoryTypeIndexForImageInfo(
    VmaAllocator allocator,
    const VkImageCreateInfo* pImageCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    uint32_t* pMemoryTypeIndex);

/// Flags to be passed as VmaPoolCreateInfo::flags.
typedef enum VmaPoolCreateFlagBits {
    /** \brief Use this flag if you always allocate only buffers and linear images or only optimal images out of this pool and so Buffer-Image Granularity can be ignored.

    This is na optional optimization flag.

    If you always allocate using vmaCreateBuffer(), vmaCreateImage(),
    vmaAllocateMemoryForBuffer(), then you don't need to use it because allocator
    knows exact type of your allocations so it can handle Buffer-Image Granularity
    in the optimal way.

    If you also allocate using vmaAllocateMemoryForImage() or vmaAllocateMemory(),
    exact type of such allocations is not known, so allocator must be conservative
    in handling Buffer-Image Granularity, which can lead to suboptimal allocation
    (wasted memory). In that case, if you can make sure you always allocate only
    buffers and linear images or only optimal images out of this pool, use this flag
    to make allocator disregard Buffer-Image Granularity and so make allocations
    more optimal.
    */
    VMA_POOL_CREATE_IGNORE_BUFFER_IMAGE_GRANULARITY_BIT = 0x00000002,

    VMA_POOL_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
} VmaPoolCreateFlagBits;
typedef VkFlags VmaPoolCreateFlags;

/** \brief Describes parameter of created #VmaPool.
*/
typedef struct VmaPoolCreateInfo {
    /** \brief Vulkan memory type index to allocate this pool from.
    */
    uint32_t memoryTypeIndex;
    /** \brief Use combination of #VmaPoolCreateFlagBits.
    */
    VmaPoolCreateFlags flags;
    /** \brief Size of a single `VkDeviceMemory` block to be allocated as part of this pool, in bytes.

    Optional. Leave 0 to use default.
    */
    VkDeviceSize blockSize;
    /** \brief Minimum number of blocks to be always allocated in this pool, even if they stay empty.

    Set to 0 to have no preallocated blocks and let the pool be completely empty.
    */
    size_t minBlockCount;
    /** \brief Maximum number of blocks that can be allocated in this pool. Optional.

    Optional. Set to 0 to use `SIZE_MAX`, which means no limit.
    
    Set to same value as minBlockCount to have fixed amount of memory allocated
    throuout whole lifetime of this pool.
    */
    size_t maxBlockCount;
    /** \brief Maximum number of additional frames that are in use at the same time as current frame.

    This value is used only when you make allocations with
    #VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT flag. Such allocation cannot become
    lost if allocation.lastUseFrameIndex >= allocator.currentFrameIndex - frameInUseCount.

    For example, if you double-buffer your command buffers, so resources used for
    rendering in previous frame may still be in use by the GPU at the moment you
    allocate resources needed for the current frame, set this value to 1.

    If you want to allow any allocations other than used in the current frame to
    become lost, set this value to 0.
    */
    uint32_t frameInUseCount;
} VmaPoolCreateInfo;

/** \brief Describes parameter of existing #VmaPool.
*/
typedef struct VmaPoolStats {
    /** \brief Total amount of `VkDeviceMemory` allocated from Vulkan for this pool, in bytes.
    */
    VkDeviceSize size;
    /** \brief Total number of bytes in the pool not used by any #VmaAllocation.
    */
    VkDeviceSize unusedSize;
    /** \brief Number of #VmaAllocation objects created from this pool that were not destroyed or lost.
    */
    size_t allocationCount;
    /** \brief Number of continuous memory ranges in the pool not used by any #VmaAllocation.
    */
    size_t unusedRangeCount;
    /** \brief Size of the largest continuous free memory region.

    Making a new allocation of that size is not guaranteed to succeed because of
    possible additional margin required to respect alignment and buffer/image
    granularity.
    */
    VkDeviceSize unusedRangeSizeMax;
} VmaPoolStats;

/** \brief Allocates Vulkan device memory and creates #VmaPool object.

@param allocator Allocator object.
@param pCreateInfo Parameters of pool to create.
@param[out] pPool Handle to created pool.
*/
VkResult vmaCreatePool(
	VmaAllocator allocator,
	const VmaPoolCreateInfo* pCreateInfo,
	VmaPool* pPool);

/** \brief Destroys #VmaPool object and frees Vulkan device memory.
*/
void vmaDestroyPool(
    VmaAllocator allocator,
    VmaPool pool);

/** \brief Retrieves statistics of existing #VmaPool object.

@param allocator Allocator object.
@param pool Pool object.
@param[out] pPoolStats Statistics of specified pool.
*/
void vmaGetPoolStats(
    VmaAllocator allocator,
    VmaPool pool,
    VmaPoolStats* pPoolStats);

/** \brief Marks all allocations in given pool as lost if they are not used in current frame or VmaPoolCreateInfo::frameInUseCount back from now.

@param allocator Allocator object.
@param pool Pool.
@param[out] pLostAllocationCount Number of allocations marked as lost. Optional - pass null if you don't need this information.
*/
void vmaMakePoolAllocationsLost(
    VmaAllocator allocator,
    VmaPool pool,
    size_t* pLostAllocationCount);

/** \struct VmaAllocation
\brief Represents single memory allocation.

It may be either dedicated block of `VkDeviceMemory` or a specific region of a bigger block of this type
plus unique offset.

There are multiple ways to create such object.
You need to fill structure VmaAllocationCreateInfo.
For more information see [Choosing memory type](@ref choosing_memory_type).

Although the library provides convenience functions that create Vulkan buffer or image,
allocate memory for it and bind them together,
binding of the allocation to a buffer or an image is out of scope of the allocation itself.
Allocation object can exist without buffer/image bound,
binding can be done manually by the user, and destruction of it can be done
independently of destruction of the allocation.

The object also remembers its size and some other information.
To retrieve this information, use function vmaGetAllocationInfo() and inspect
returned structure VmaAllocationInfo.

Some kinds allocations can be in lost state.
For more information, see [Lost allocations](@ref lost_allocations).
*/
VK_DEFINE_HANDLE(VmaAllocation)

/** \brief Parameters of #VmaAllocation objects, that can be retrieved using function vmaGetAllocationInfo().
*/
typedef struct VmaAllocationInfo {
    /** \brief Memory type index that this allocation was allocated from.
    
    It never changes.
    */
    uint32_t memoryType;
    /** \brief Handle to Vulkan memory object.

    Same memory object can be shared by multiple allocations.
    
    It can change after call to vmaDefragment() if this allocation is passed to the function, or if allocation is lost.

    If the allocation is lost, it is equal to `VK_NULL_HANDLE`.
    */
    VkDeviceMemory deviceMemory;
    /** \brief Offset into deviceMemory object to the beginning of this allocation, in bytes. (deviceMemory, offset) pair is unique to this allocation.

    It can change after call to vmaDefragment() if this allocation is passed to the function, or if allocation is lost.
    */
    VkDeviceSize offset;
    /** \brief Size of this allocation, in bytes.

    It never changes, unless allocation is lost.
    */
    VkDeviceSize size;
    /** \brief Pointer to the beginning of this allocation as mapped data.

    If the allocation hasn't been mapped using vmaMapMemory() and hasn't been
    created with #VMA_ALLOCATION_CREATE_MAPPED_BIT flag, this value null.

    It can change after call to vmaMapMemory(), vmaUnmapMemory().
    It can also change after call to vmaDefragment() if this allocation is passed to the function.
    */
    void* pMappedData;
    /** \brief Custom general-purpose pointer that was passed as VmaAllocationCreateInfo::pUserData or set using vmaSetAllocationUserData().

    It can change after call to vmaSetAllocationUserData() for this allocation.
    */
    void* pUserData;
} VmaAllocationInfo;

/** \brief General purpose memory allocation.

@param[out] pAllocation Handle to allocated memory.
@param[out] pAllocationInfo Optional. Information about allocated memory. It can be later fetched using function vmaGetAllocationInfo().

You should free the memory using vmaFreeMemory().

It is recommended to use vmaAllocateMemoryForBuffer(), vmaAllocateMemoryForImage(),
vmaCreateBuffer(), vmaCreateImage() instead whenever possible.
*/
VkResult vmaAllocateMemory(
    VmaAllocator allocator,
    const VkMemoryRequirements* pVkMemoryRequirements,
    const VmaAllocationCreateInfo* pCreateInfo,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/**
@param[out] pAllocation Handle to allocated memory.
@param[out] pAllocationInfo Optional. Information about allocated memory. It can be later fetched using function vmaGetAllocationInfo().

You should free the memory using vmaFreeMemory().
*/
VkResult vmaAllocateMemoryForBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    const VmaAllocationCreateInfo* pCreateInfo,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/// Function similar to vmaAllocateMemoryForBuffer().
VkResult vmaAllocateMemoryForImage(
    VmaAllocator allocator,
    VkImage image,
    const VmaAllocationCreateInfo* pCreateInfo,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/// Frees memory previously allocated using vmaAllocateMemory(), vmaAllocateMemoryForBuffer(), or vmaAllocateMemoryForImage().
void vmaFreeMemory(
    VmaAllocator allocator,
    VmaAllocation allocation);

/** \brief Returns current information about specified allocation and atomically marks it as used in current frame.

Current paramters of given allocation are returned in `pAllocationInfo`.

This function also atomically "touches" allocation - marks it as used in current frame,
just like vmaTouchAllocation().
If the allocation is in lost state, `pAllocationInfo->deviceMemory == VK_NULL_HANDLE`.

Although this function uses atomics and doesn't lock any mutex, so it should be quite efficient,
you can avoid calling it too often.

- You can retrieve same VmaAllocationInfo structure while creating your resource, from function
  vmaCreateBuffer(), vmaCreateImage(). You can remember it if you are sure parameters don't change
  (e.g. due to defragmentation or allocation becoming lost).
- If you just want to check if allocation is not lost, vmaTouchAllocation() will work faster.
*/
void vmaGetAllocationInfo(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VmaAllocationInfo* pAllocationInfo);

/** \brief Returns `VK_TRUE` if allocation is not lost and atomically marks it as used in current frame.

If the allocation has been created with #VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT flag,
this function returns `VK_TRUE` if it's not in lost state, so it can still be used.
It then also atomically "touches" the allocation - marks it as used in current frame,
so that you can be sure it won't become lost in current frame or next `frameInUseCount` frames.

If the allocation is in lost state, the function returns `VK_FALSE`.
Memory of such allocation, as well as buffer or image bound to it, should not be used.
Lost allocation and the buffer/image still need to be destroyed.

If the allocation has been created without #VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT flag,
this function always returns `VK_TRUE`.
*/
VkBool32 vmaTouchAllocation(
    VmaAllocator allocator,
    VmaAllocation allocation);

/** \brief Sets pUserData in given allocation to new value.

If the allocation was created with VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT,
pUserData must be either null, or pointer to a null-terminated string. The function
makes local copy of the string and sets it as allocation's `pUserData`. String
passed as pUserData doesn't need to be valid for whole lifetime of the allocation -
you can free it after this call. String previously pointed by allocation's
pUserData is freed from memory.

If the flag was not used, the value of pointer `pUserData` is just copied to
allocation's `pUserData`. It is opaque, so you can use it however you want - e.g.
as a pointer, ordinal number or some handle to you own data.
*/
void vmaSetAllocationUserData(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void* pUserData);

/** \brief Creates new allocation that is in lost state from the beginning.

It can be useful if you need a dummy, non-null allocation.

You still need to destroy created object using vmaFreeMemory().

Returned allocation is not tied to any specific memory pool or memory type and
not bound to any image or buffer. It has size = 0. It cannot be turned into
a real, non-empty allocation.
*/
void vmaCreateLostAllocation(
    VmaAllocator allocator,
    VmaAllocation* pAllocation);

/** \brief Maps memory represented by given allocation and returns pointer to it.

Maps memory represented by given allocation to make it accessible to CPU code.
When succeeded, `*ppData` contains pointer to first byte of this memory.
If the allocation is part of bigger `VkDeviceMemory` block, the pointer is
correctly offseted to the beginning of region assigned to this particular
allocation.

Mapping is internally reference-counted and synchronized, so despite raw Vulkan
function `vkMapMemory()` cannot be used to map same block of `VkDeviceMemory`
multiple times simultaneously, it is safe to call this function on allocations
assigned to the same memory block. Actual Vulkan memory will be mapped on first
mapping and unmapped on last unmapping.

If the function succeeded, you must call vmaUnmapMemory() to unmap the
allocation when mapping is no longer needed or before freeing the allocation, at
the latest.

It also safe to call this function multiple times on the same allocation. You
must call vmaUnmapMemory() same number of times as you called vmaMapMemory().

It is also safe to call this function on allocation created with
#VMA_ALLOCATION_CREATE_MAPPED_BIT flag. Its memory stays mapped all the time.
You must still call vmaUnmapMemory() same number of times as you called
vmaMapMemory(). You must not call vmaUnmapMemory() additional time to free the
"0-th" mapping made automatically due to #VMA_ALLOCATION_CREATE_MAPPED_BIT flag.

This function fails when used on allocation made in memory type that is not
`HOST_VISIBLE`.

This function always fails when called for allocation that was created with
#VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT flag. Such allocations cannot be
mapped.
*/
VkResult vmaMapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void** ppData);

/** \brief Unmaps memory represented by given allocation, mapped previously using vmaMapMemory().

For details, see description of vmaMapMemory().
*/
void vmaUnmapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation);

/** \brief Optional configuration parameters to be passed to function vmaDefragment(). */
typedef struct VmaDefragmentationInfo {
    /** \brief Maximum total numbers of bytes that can be copied while moving allocations to different places.
    
    Default is `VK_WHOLE_SIZE`, which means no limit.
    */
    VkDeviceSize maxBytesToMove;
    /** \brief Maximum number of allocations that can be moved to different place.

    Default is `UINT32_MAX`, which means no limit.
    */
    uint32_t maxAllocationsToMove;
} VmaDefragmentationInfo;

/** \brief Statistics returned by function vmaDefragment(). */
typedef struct VmaDefragmentationStats {
    /// Total number of bytes that have been copied while moving allocations to different places.
    VkDeviceSize bytesMoved;
    /// Total number of bytes that have been released to the system by freeing empty `VkDeviceMemory` objects.
    VkDeviceSize bytesFreed;
    /// Number of allocations that have been moved to different places.
    uint32_t allocationsMoved;
    /// Number of empty `VkDeviceMemory` objects that have been released to the system.
    uint32_t deviceMemoryBlocksFreed;
} VmaDefragmentationStats;

/** \brief Compacts memory by moving allocations.

@param pAllocations Array of allocations that can be moved during this compation.
@param allocationCount Number of elements in pAllocations and pAllocationsChanged arrays.
@param[out] pAllocationsChanged Array of boolean values that will indicate whether matching allocation in pAllocations array has been moved. This parameter is optional. Pass null if you don't need this information.
@param pDefragmentationInfo Configuration parameters. Optional - pass null to use default values.
@param[out] pDefragmentationStats Statistics returned by the function. Optional - pass null if you don't need this information.
@return VK_SUCCESS if completed, VK_INCOMPLETE if succeeded but didn't make all possible optimizations because limits specified in pDefragmentationInfo have been reached, negative error code in case of error.

This function works by moving allocations to different places (different
`VkDeviceMemory` objects and/or different offsets) in order to optimize memory
usage. Only allocations that are in pAllocations array can be moved. All other
allocations are considered nonmovable in this call. Basic rules:

- Only allocations made in memory types that have
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` flag can be compacted. You may pass other
  allocations but it makes no sense - these will never be moved.
- You may pass allocations made with #VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT but
  it makes no sense - they will never be moved.
- Both allocations made with or without #VMA_ALLOCATION_CREATE_MAPPED_BIT
  flag can be compacted. If not persistently mapped, memory will be mapped
  temporarily inside this function if needed.
- You must not pass same #VmaAllocation object multiple times in pAllocations array.

The function also frees empty `VkDeviceMemory` blocks.

After allocation has been moved, its VmaAllocationInfo::deviceMemory and/or
VmaAllocationInfo::offset changes. You must query them again using
vmaGetAllocationInfo() if you need them.

If an allocation has been moved, data in memory is copied to new place
automatically, but if it was bound to a buffer or an image, you must destroy
that object yourself, create new one and bind it to the new memory pointed by
the allocation. You must use `vkDestroyBuffer()`, `vkDestroyImage()`,
`vkCreateBuffer()`, `vkCreateImage()` for that purpose and NOT vmaDestroyBuffer(),
vmaDestroyImage(), vmaCreateBuffer(), vmaCreateImage()! Example:

\code
VkDevice device = ...;
VmaAllocator allocator = ...;
std::vector<VkBuffer> buffers = ...;
std::vector<VmaAllocation> allocations = ...;

std::vector<VkBool32> allocationsChanged(allocations.size());
vmaDefragment(allocator, allocations.data(), allocations.size(), allocationsChanged.data(), nullptr, nullptr);

for(size_t i = 0; i < allocations.size(); ++i)
{
    if(allocationsChanged[i])
    {
        VmaAllocationInfo allocInfo;
        vmaGetAllocationInfo(allocator, allocations[i], &allocInfo);

        vkDestroyBuffer(device, buffers[i], nullptr);

        VkBufferCreateInfo bufferInfo = ...;
        vkCreateBuffer(device, &bufferInfo, nullptr, &buffers[i]);
            
        // You can make dummy call to vkGetBufferMemoryRequirements here to silence validation layer warning.
            
        vkBindBufferMemory(device, buffers[i], allocInfo.deviceMemory, allocInfo.offset);
    }
}
\endcode

Note: Please don't expect memory to be fully compacted after this call.
Algorithms inside are based on some heuristics that try to maximize number of Vulkan
memory blocks to make totally empty to release them, as well as to maximimze continuous
empty space inside remaining blocks, while minimizing the number and size of data that
needs to be moved. Some fragmentation still remains after this call. This is normal.

Warning: This function is not 100% correct according to Vulkan specification. Use it
at your own risk. That's because Vulkan doesn't guarantee that memory
requirements (size and alignment) for a new buffer or image are consistent. They
may be different even for subsequent calls with the same parameters. It really
does happen on some platforms, especially with images.

Warning: This function may be time-consuming, so you shouldn't call it too often
(like every frame or after every resource creation/destruction).
You can call it on special occasions (like when reloading a game level or
when you just destroyed a lot of objects).
*/
VkResult vmaDefragment(
    VmaAllocator allocator,
    VmaAllocation* pAllocations,
    size_t allocationCount,
    VkBool32* pAllocationsChanged,
    const VmaDefragmentationInfo *pDefragmentationInfo,
    VmaDefragmentationStats* pDefragmentationStats);

/** \brief Binds buffer to allocation.

Binds specified buffer to region of memory represented by specified allocation.
Gets `VkDeviceMemory` handle and offset from the allocation.
If you want to create a buffer, allocate memory for it and bind them together separately,
you should use this function for binding instead of standard `vkBindBufferMemory()`,
because it ensures proper synchronization so that when a `VkDeviceMemory` object is used by multiple
allocations, calls to `vkBind*Memory()` or `vkMapMemory()` won't happen from multiple threads simultaneously
(which is illegal in Vulkan).

It is recommended to use function vmaCreateBuffer() instead of this one.
*/
VkResult vmaBindBufferMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VkBuffer buffer);

/** \brief Binds image to allocation.

Binds specified image to region of memory represented by specified allocation.
Gets `VkDeviceMemory` handle and offset from the allocation.
If you want to create an image, allocate memory for it and bind them together separately,
you should use this function for binding instead of standard `vkBindImageMemory()`,
because it ensures proper synchronization so that when a `VkDeviceMemory` object is used by multiple
allocations, calls to `vkBind*Memory()` or `vkMapMemory()` won't happen from multiple threads simultaneously
(which is illegal in Vulkan).

It is recommended to use function vmaCreateImage() instead of this one.
*/
VkResult vmaBindImageMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VkImage image);

/**
@param[out] pBuffer Buffer that was created.
@param[out] pAllocation Allocation that was created.
@param[out] pAllocationInfo Optional. Information about allocated memory. It can be later fetched using function vmaGetAllocationInfo().

This function automatically:

-# Creates buffer.
-# Allocates appropriate memory for it.
-# Binds the buffer with the memory.

If any of these operations fail, buffer and allocation are not created,
returned value is negative error code, *pBuffer and *pAllocation are null.

If the function succeeded, you must destroy both buffer and allocation when you
no longer need them using either convenience function vmaDestroyBuffer() or
separately, using `vkDestroyBuffer()` and vmaFreeMemory().

If VMA_ALLOCATOR_CREATE_KHR_DEDICATED_ALLOCATION_BIT flag was used,
VK_KHR_dedicated_allocation extension is used internally to query driver whether
it requires or prefers the new buffer to have dedicated allocation. If yes,
and if dedicated allocation is possible (VmaAllocationCreateInfo::pool is null
and VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT is not used), it creates dedicated
allocation for this buffer, just like when using
VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT.
*/
VkResult vmaCreateBuffer(
    VmaAllocator allocator,
    const VkBufferCreateInfo* pBufferCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    VkBuffer* pBuffer,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/** \brief Destroys Vulkan buffer and frees allocated memory.

This is just a convenience function equivalent to:

\code
vkDestroyBuffer(device, buffer, allocationCallbacks);
vmaFreeMemory(allocator, allocation);
\endcode

It it safe to pass null as buffer and/or allocation.
*/
void vmaDestroyBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    VmaAllocation allocation);

/// Function similar to vmaCreateBuffer().
VkResult vmaCreateImage(
    VmaAllocator allocator,
    const VkImageCreateInfo* pImageCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    VkImage* pImage,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/** \brief Destroys Vulkan image and frees allocated memory.

This is just a convenience function equivalent to:

\code
vkDestroyImage(device, image, allocationCallbacks);
vmaFreeMemory(allocator, allocation);
\endcode

It it safe to pass null as image and/or allocation.
*/
void vmaDestroyImage(
    VmaAllocator allocator,
    VkImage image,
    VmaAllocation allocation);

#ifdef __cplusplus
}
#endif

#endif // AMD_VULKAN_MEMORY_ALLOCATOR_H

// For Visual Studio IntelliSense.
#ifdef __INTELLISENSE__
#define VMA_IMPLEMENTATION
#endif

#ifdef VMA_IMPLEMENTATION
#undef VMA_IMPLEMENTATION

#include <cstdint>
#include <cstdlib>
#include <cstring>

/*******************************************************************************
CONFIGURATION SECTION

Define some of these macros before each #include of this header or change them
here if you need other then default behavior depending on your environment.
*/

/*
Define this macro to 1 to make the library fetch pointers to Vulkan functions
internally, like:

    vulkanFunctions.vkAllocateMemory = &vkAllocateMemory;

Define to 0 if you are going to provide you own pointers to Vulkan functions via
VmaAllocatorCreateInfo::pVulkanFunctions.
*/
#if !defined(VMA_STATIC_VULKAN_FUNCTIONS) && !defined(VK_NO_PROTOTYPES)
#define VMA_STATIC_VULKAN_FUNCTIONS 1
#endif

// Define this macro to 1 to make the library use STL containers instead of its own implementation.
//#define VMA_USE_STL_CONTAINERS 1

/* Set this macro to 1 to make the library including and using STL containers:
std::pair, std::vector, std::list, std::unordered_map.

Set it to 0 or undefined to make the library using its own implementation of
the containers.
*/
#if VMA_USE_STL_CONTAINERS
   #define VMA_USE_STL_VECTOR 1
   #define VMA_USE_STL_UNORDERED_MAP 1
   #define VMA_USE_STL_LIST 1
#endif

#if VMA_USE_STL_VECTOR
   #include <vector>
#endif

#if VMA_USE_STL_UNORDERED_MAP
   #include <unordered_map>
#endif

#if VMA_USE_STL_LIST
   #include <list>
#endif

/*
Following headers are used in this CONFIGURATION section only, so feel free to
remove them if not needed.
*/
#include <cassert> // for assert
#include <algorithm> // for min, max
#include <mutex> // for std::mutex
#include <atomic> // for std::atomic

#if !defined(_WIN32) && !defined(__APPLE__)
    #include <malloc.h> // for aligned_alloc()
#endif

#ifndef VMA_NULL
   // Value used as null pointer. Define it to e.g.: nullptr, NULL, 0, (void*)0.
   #define VMA_NULL   nullptr
#endif

#if defined(__APPLE__) || defined(__ANDROID__)
#include <cstdlib>
void *aligned_alloc(size_t alignment, size_t size)
{
    // alignment must be >= sizeof(void*)
    if(alignment < sizeof(void*))
    {
        alignment = sizeof(void*);
    }

    void *pointer;
    if(posix_memalign(&pointer, alignment, size) == 0)
        return pointer;
    return VMA_NULL;
}
#endif

// Normal assert to check for programmer's errors, especially in Debug configuration.
#ifndef VMA_ASSERT
   #ifdef _DEBUG
       #define VMA_ASSERT(expr)         assert(expr)
   #else
       #define VMA_ASSERT(expr)
   #endif
#endif

// Assert that will be called very often, like inside data structures e.g. operator[].
// Making it non-empty can make program slow.
#ifndef VMA_HEAVY_ASSERT
   #ifdef _DEBUG
       #define VMA_HEAVY_ASSERT(expr)   //VMA_ASSERT(expr)
   #else
       #define VMA_HEAVY_ASSERT(expr)
   #endif
#endif

#ifndef VMA_ALIGN_OF
   #define VMA_ALIGN_OF(type)       (__alignof(type))
#endif

#ifndef VMA_SYSTEM_ALIGNED_MALLOC
   #if defined(_WIN32)
       #define VMA_SYSTEM_ALIGNED_MALLOC(size, alignment)   (_aligned_malloc((size), (alignment)))
   #else
       #define VMA_SYSTEM_ALIGNED_MALLOC(size, alignment)   (aligned_alloc((alignment), (size) ))
   #endif
#endif

#ifndef VMA_SYSTEM_FREE
   #if defined(_WIN32)
       #define VMA_SYSTEM_FREE(ptr)   _aligned_free(ptr)
   #else
       #define VMA_SYSTEM_FREE(ptr)   free(ptr)
   #endif
#endif

#ifndef VMA_MIN
   #define VMA_MIN(v1, v2)    (std::min((v1), (v2)))
#endif

#ifndef VMA_MAX
   #define VMA_MAX(v1, v2)    (std::max((v1), (v2)))
#endif

#ifndef VMA_SWAP
   #define VMA_SWAP(v1, v2)   std::swap((v1), (v2))
#endif

#ifndef VMA_SORT
   #define VMA_SORT(beg, end, cmp)  std::sort(beg, end, cmp)
#endif

#ifndef VMA_DEBUG_LOG
   #define VMA_DEBUG_LOG(format, ...)
   /*
   #define VMA_DEBUG_LOG(format, ...) do { \
       printf(format, __VA_ARGS__); \
       printf("\n"); \
   } while(false)
   */
#endif

// Define this macro to 1 to enable functions: vmaBuildStatsString, vmaFreeStatsString.
#if VMA_STATS_STRING_ENABLED
   static inline void VmaUint32ToStr(char* outStr, size_t strLen, uint32_t num)
   {
       snprintf(outStr, strLen, "%u", static_cast<unsigned int>(num));
   }
   static inline void VmaUint64ToStr(char* outStr, size_t strLen, uint64_t num)
   {
       snprintf(outStr, strLen, "%llu", static_cast<unsigned long long>(num));
   }
   static inline void VmaPtrToStr(char* outStr, size_t strLen, const void* ptr)
   {
       snprintf(outStr, strLen, "%p", ptr);
   }
#endif

#ifndef VMA_MUTEX
   class VmaMutex
   {
   public:
       VmaMutex() { }
       ~VmaMutex() { }
       void Lock() { m_Mutex.lock(); }
       void Unlock() { m_Mutex.unlock(); }
   private:
       std::mutex m_Mutex;
   };
   #define VMA_MUTEX VmaMutex
#endif

/*
If providing your own implementation, you need to implement a subset of std::atomic:

- Constructor(uint32_t desired)
- uint32_t load() const
- void store(uint32_t desired)
- bool compare_exchange_weak(uint32_t& expected, uint32_t desired)
*/
#ifndef VMA_ATOMIC_UINT32
   #define VMA_ATOMIC_UINT32 std::atomic<uint32_t>
#endif

#ifndef VMA_BEST_FIT
   /**
   Main parameter for function assessing how good is a free suballocation for a new
   allocation request.

   - Set to 1 to use Best-Fit algorithm - prefer smaller blocks, as close to the
     size of requested allocations as possible.
   - Set to 0 to use Worst-Fit algorithm - prefer larger blocks, as large as
     possible.

   Experiments in special testing environment showed that Best-Fit algorithm is
   better.
   */
   #define VMA_BEST_FIT (1)
#endif

#ifndef VMA_DEBUG_ALWAYS_DEDICATED_MEMORY
   /**
   Every allocation will have its own memory block.
   Define to 1 for debugging purposes only.
   */
   #define VMA_DEBUG_ALWAYS_DEDICATED_MEMORY (0)
#endif

#ifndef VMA_DEBUG_ALIGNMENT
   /**
   Minimum alignment of all suballocations, in bytes.
   Set to more than 1 for debugging purposes only. Must be power of two.
   */
   #define VMA_DEBUG_ALIGNMENT (1)
#endif

#ifndef VMA_DEBUG_MARGIN
   /**
   Minimum margin between suballocations, in bytes.
   Set nonzero for debugging purposes only.
   */
   #define VMA_DEBUG_MARGIN (0)
#endif

#ifndef VMA_DEBUG_GLOBAL_MUTEX
   /**
   Set this to 1 for debugging purposes only, to enable single mutex protecting all
   entry calls to the library. Can be useful for debugging multithreading issues.
   */
   #define VMA_DEBUG_GLOBAL_MUTEX (0)
#endif

#ifndef VMA_DEBUG_MIN_BUFFER_IMAGE_GRANULARITY
   /**
   Minimum value for VkPhysicalDeviceLimits::bufferImageGranularity.
   Set to more than 1 for debugging purposes only. Must be power of two.
   */
   #define VMA_DEBUG_MIN_BUFFER_IMAGE_GRANULARITY (1)
#endif

#ifndef VMA_SMALL_HEAP_MAX_SIZE
   /// Maximum size of a memory heap in Vulkan to consider it "small".
   #define VMA_SMALL_HEAP_MAX_SIZE (1024ull * 1024 * 1024)
#endif

#ifndef VMA_DEFAULT_LARGE_HEAP_BLOCK_SIZE
   /// Default size of a block allocated as single VkDeviceMemory from a "large" heap.
   #define VMA_DEFAULT_LARGE_HEAP_BLOCK_SIZE (256ull * 1024 * 1024)
#endif

static const uint32_t VMA_FRAME_INDEX_LOST = UINT32_MAX;

/*******************************************************************************
END OF CONFIGURATION
*/

static VkAllocationCallbacks VmaEmptyAllocationCallbacks = {
    VMA_NULL, VMA_NULL, VMA_NULL, VMA_NULL, VMA_NULL, VMA_NULL };

// Returns number of bits set to 1 in (v).
static inline uint32_t VmaCountBitsSet(uint32_t v)
{
	uint32_t c = v - ((v >> 1) & 0x55555555);
	c = ((c >>  2) & 0x33333333) + (c & 0x33333333);
	c = ((c >>  4) + c) & 0x0F0F0F0F;
	c = ((c >>  8) + c) & 0x00FF00FF;
	c = ((c >> 16) + c) & 0x0000FFFF;
	return c;
}

// Aligns given value up to nearest multiply of align value. For example: VmaAlignUp(11, 8) = 16.
// Use types like uint32_t, uint64_t as T.
template <typename T>
static inline T VmaAlignUp(T val, T align)
{
	return (val + align - 1) / align * align;
}

// Division with mathematical rounding to nearest number.
template <typename T>
inline T VmaRoundDiv(T x, T y)
{
	return (x + (y / (T)2)) / y;
}

#ifndef VMA_SORT

template<typename Iterator, typename Compare>
Iterator VmaQuickSortPartition(Iterator beg, Iterator end, Compare cmp)
{
    Iterator centerValue = end; --centerValue;
    Iterator insertIndex = beg;
    for(Iterator memTypeIndex = beg; memTypeIndex < centerValue; ++memTypeIndex)
    {
        if(cmp(*memTypeIndex, *centerValue))
        {
            if(insertIndex != memTypeIndex)
            {
                VMA_SWAP(*memTypeIndex, *insertIndex);
            }
            ++insertIndex;
        }
    }
    if(insertIndex != centerValue)
    {
        VMA_SWAP(*insertIndex, *centerValue);
    }
    return insertIndex;
}

template<typename Iterator, typename Compare>
void VmaQuickSort(Iterator beg, Iterator end, Compare cmp)
{
    if(beg < end)
    {
        Iterator it = VmaQuickSortPartition<Iterator, Compare>(beg, end, cmp);
        VmaQuickSort<Iterator, Compare>(beg, it, cmp);
        VmaQuickSort<Iterator, Compare>(it + 1, end, cmp);
    }
}

#define VMA_SORT(beg, end, cmp) VmaQuickSort(beg, end, cmp)

#endif // #ifndef VMA_SORT

/*
Returns true if two memory blocks occupy overlapping pages.
ResourceA must be in less memory offset than ResourceB.

Algorithm is based on "Vulkan 1.0.39 - A Specification (with all registered Vulkan extensions)"
chapter 11.6 "Resource Memory Association", paragraph "Buffer-Image Granularity".
*/
static inline bool VmaBlocksOnSamePage(
    VkDeviceSize resourceAOffset,
    VkDeviceSize resourceASize,
    VkDeviceSize resourceBOffset,
    VkDeviceSize pageSize)
{
    VMA_ASSERT(resourceAOffset + resourceASize <= resourceBOffset && resourceASize > 0 && pageSize > 0);
    VkDeviceSize resourceAEnd = resourceAOffset + resourceASize - 1;
    VkDeviceSize resourceAEndPage = resourceAEnd & ~(pageSize - 1);
    VkDeviceSize resourceBStart = resourceBOffset;
    VkDeviceSize resourceBStartPage = resourceBStart & ~(pageSize - 1);
    return resourceAEndPage == resourceBStartPage;
}

enum VmaSuballocationType
{
    VMA_SUBALLOCATION_TYPE_FREE = 0,
    VMA_SUBALLOCATION_TYPE_UNKNOWN = 1,
    VMA_SUBALLOCATION_TYPE_BUFFER = 2,
    VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN = 3,
    VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR = 4,
    VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL = 5,
    VMA_SUBALLOCATION_TYPE_MAX_ENUM = 0x7FFFFFFF
};

/*
Returns true if given suballocation types could conflict and must respect
VkPhysicalDeviceLimits::bufferImageGranularity. They conflict if one is buffer
or linear image and another one is optimal image. If type is unknown, behave
conservatively.
*/
static inline bool VmaIsBufferImageGranularityConflict(
    VmaSuballocationType suballocType1,
    VmaSuballocationType suballocType2)
{
    if(suballocType1 > suballocType2)
    {
        VMA_SWAP(suballocType1, suballocType2);
    }
    
    switch(suballocType1)
    {
    case VMA_SUBALLOCATION_TYPE_FREE:
        return false;
    case VMA_SUBALLOCATION_TYPE_UNKNOWN:
        return true;
    case VMA_SUBALLOCATION_TYPE_BUFFER:
        return
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN ||
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL;
    case VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN:
        return
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN ||
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR ||
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL;
    case VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR:
        return
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL;
    case VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL:
        return false;
    default:
        VMA_ASSERT(0);
        return true;
    }
}

// Helper RAII class to lock a mutex in constructor and unlock it in destructor (at the end of scope).
struct VmaMutexLock
{
public:
    VmaMutexLock(VMA_MUTEX& mutex, bool useMutex) :
        m_pMutex(useMutex ? &mutex : VMA_NULL)
    {
        if(m_pMutex)
        {
            m_pMutex->Lock();
        }
    }
    
    ~VmaMutexLock()
    {
        if(m_pMutex)
        {
            m_pMutex->Unlock();
        }
    }

private:
    VMA_MUTEX* m_pMutex;
};

#if VMA_DEBUG_GLOBAL_MUTEX
    static VMA_MUTEX gDebugGlobalMutex;
    #define VMA_DEBUG_GLOBAL_MUTEX_LOCK VmaMutexLock debugGlobalMutexLock(gDebugGlobalMutex, true);
#else
    #define VMA_DEBUG_GLOBAL_MUTEX_LOCK
#endif

// Minimum size of a free suballocation to register it in the free suballocation collection.
static const VkDeviceSize VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER = 16;

/*
Performs binary search and returns iterator to first element that is greater or
equal to (key), according to comparison (cmp).

Cmp should return true if first argument is less than second argument.

Returned value is the found element, if present in the collection or place where
new element with value (key) should be inserted.
*/
template <typename IterT, typename KeyT, typename CmpT>
static IterT VmaBinaryFindFirstNotLess(IterT beg, IterT end, const KeyT &key, CmpT cmp)
{
   size_t down = 0, up = (end - beg);
   while(down < up)
   {
      const size_t mid = (down + up) / 2;
      if(cmp(*(beg+mid), key))
      {
         down = mid + 1;
      }
      else
      {
         up = mid;
      }
   }
   return beg + down;
}

////////////////////////////////////////////////////////////////////////////////
// Memory allocation

static void* VmaMalloc(const VkAllocationCallbacks* pAllocationCallbacks, size_t size, size_t alignment)
{
    if((pAllocationCallbacks != VMA_NULL) &&
        (pAllocationCallbacks->pfnAllocation != VMA_NULL))
    {
        return (*pAllocationCallbacks->pfnAllocation)(
            pAllocationCallbacks->pUserData,
            size,
            alignment,
            VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
    }
    else
    {
        return VMA_SYSTEM_ALIGNED_MALLOC(size, alignment);
    }
}

static void VmaFree(const VkAllocationCallbacks* pAllocationCallbacks, void* ptr)
{
    if((pAllocationCallbacks != VMA_NULL) &&
        (pAllocationCallbacks->pfnFree != VMA_NULL))
    {
        (*pAllocationCallbacks->pfnFree)(pAllocationCallbacks->pUserData, ptr);
    }
    else
    {
        VMA_SYSTEM_FREE(ptr);
    }
}

template<typename T>
static T* VmaAllocate(const VkAllocationCallbacks* pAllocationCallbacks)
{
    return (T*)VmaMalloc(pAllocationCallbacks, sizeof(T), VMA_ALIGN_OF(T));
}

template<typename T>
static T* VmaAllocateArray(const VkAllocationCallbacks* pAllocationCallbacks, size_t count)
{
    return (T*)VmaMalloc(pAllocationCallbacks, sizeof(T) * count, VMA_ALIGN_OF(T));
}

#define vma_new(allocator, type)   new(VmaAllocate<type>(allocator))(type)

#define vma_new_array(allocator, type, count)   new(VmaAllocateArray<type>((allocator), (count)))(type)

template<typename T>
static void vma_delete(const VkAllocationCallbacks* pAllocationCallbacks, T* ptr)
{
    ptr->~T();
    VmaFree(pAllocationCallbacks, ptr);
}

template<typename T>
static void vma_delete_array(const VkAllocationCallbacks* pAllocationCallbacks, T* ptr, size_t count)
{
    if(ptr != VMA_NULL)
    {
        for(size_t i = count; i--; )
        {
            ptr[i].~T();
        }
        VmaFree(pAllocationCallbacks, ptr);
    }
}

// STL-compatible allocator.
template<typename T>
class VmaStlAllocator
{
public:
    const VkAllocationCallbacks* const m_pCallbacks;
    typedef T value_type;
    
    VmaStlAllocator(const VkAllocationCallbacks* pCallbacks) : m_pCallbacks(pCallbacks) { }
    template<typename U> VmaStlAllocator(const VmaStlAllocator<U>& src) : m_pCallbacks(src.m_pCallbacks) { }

    T* allocate(size_t n) { return VmaAllocateArray<T>(m_pCallbacks, n); }
    void deallocate(T* p, size_t n) { VmaFree(m_pCallbacks, p); }

    template<typename U>
    bool operator==(const VmaStlAllocator<U>& rhs) const
    {
        return m_pCallbacks == rhs.m_pCallbacks;
    }
    template<typename U>
    bool operator!=(const VmaStlAllocator<U>& rhs) const
    {
        return m_pCallbacks != rhs.m_pCallbacks;
    }

    VmaStlAllocator& operator=(const VmaStlAllocator& x) = delete;
};

#if VMA_USE_STL_VECTOR

#define VmaVector std::vector

template<typename T, typename allocatorT>
static void VmaVectorInsert(std::vector<T, allocatorT>& vec, size_t index, const T& item)
{
    vec.insert(vec.begin() + index, item);
}

template<typename T, typename allocatorT>
static void VmaVectorRemove(std::vector<T, allocatorT>& vec, size_t index)
{
    vec.erase(vec.begin() + index);
}

#else // #if VMA_USE_STL_VECTOR

/* Class with interface compatible with subset of std::vector.
T must be POD because constructors and destructors are not called and memcpy is
used for these objects. */
template<typename T, typename AllocatorT>
class VmaVector
{
public:
    typedef T value_type;

    VmaVector(const AllocatorT& allocator) :
        m_Allocator(allocator),
        m_pArray(VMA_NULL),
        m_Count(0),
        m_Capacity(0)
    {
    }

    VmaVector(size_t count, const AllocatorT& allocator) :
        m_Allocator(allocator),
        m_pArray(count ? (T*)VmaAllocateArray<T>(allocator.m_pCallbacks, count) : VMA_NULL),
        m_Count(count),
        m_Capacity(count)
    {
    }
    
    VmaVector(const VmaVector<T, AllocatorT>& src) :
        m_Allocator(src.m_Allocator),
        m_pArray(src.m_Count ? (T*)VmaAllocateArray<T>(src.m_Allocator.m_pCallbacks, src.m_Count) : VMA_NULL),
        m_Count(src.m_Count),
        m_Capacity(src.m_Count)
    {
        if(m_Count != 0)
        {
            memcpy(m_pArray, src.m_pArray, m_Count * sizeof(T));
        }
    }
    
    ~VmaVector()
    {
        VmaFree(m_Allocator.m_pCallbacks, m_pArray);
    }

    VmaVector& operator=(const VmaVector<T, AllocatorT>& rhs)
    {
        if(&rhs != this)
        {
            resize(rhs.m_Count);
            if(m_Count != 0)
            {
                memcpy(m_pArray, rhs.m_pArray, m_Count * sizeof(T));
            }
        }
        return *this;
    }
    
    bool empty() const { return m_Count == 0; }
    size_t size() const { return m_Count; }
    T* data() { return m_pArray; }
    const T* data() const { return m_pArray; }
    
    T& operator[](size_t index)
    {
        VMA_HEAVY_ASSERT(index < m_Count);
        return m_pArray[index];
    }
    const T& operator[](size_t index) const
    {
        VMA_HEAVY_ASSERT(index < m_Count);
        return m_pArray[index];
    }

    T& front()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[0];
    }
    const T& front() const
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[0];
    }
    T& back()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[m_Count - 1];
    }
    const T& back() const
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[m_Count - 1];
    }

    void reserve(size_t newCapacity, bool freeMemory = false)
    {
        newCapacity = VMA_MAX(newCapacity, m_Count);
        
        if((newCapacity < m_Capacity) && !freeMemory)
        {
            newCapacity = m_Capacity;
        }
        
        if(newCapacity != m_Capacity)
        {
            T* const newArray = newCapacity ? VmaAllocateArray<T>(m_Allocator, newCapacity) : VMA_NULL;
            if(m_Count != 0)
            {
                memcpy(newArray, m_pArray, m_Count * sizeof(T));
            }
            VmaFree(m_Allocator.m_pCallbacks, m_pArray);
            m_Capacity = newCapacity;
            m_pArray = newArray;
        }
    }

    void resize(size_t newCount, bool freeMemory = false)
    {
        size_t newCapacity = m_Capacity;
        if(newCount > m_Capacity)
        {
            newCapacity = VMA_MAX(newCount, VMA_MAX(m_Capacity * 3 / 2, (size_t)8));
        }
        else if(freeMemory)
        {
            newCapacity = newCount;
        }

        if(newCapacity != m_Capacity)
        {
            T* const newArray = newCapacity ? VmaAllocateArray<T>(m_Allocator.m_pCallbacks, newCapacity) : VMA_NULL;
            const size_t elementsToCopy = VMA_MIN(m_Count, newCount);
            if(elementsToCopy != 0)
            {
                memcpy(newArray, m_pArray, elementsToCopy * sizeof(T));
            }
            VmaFree(m_Allocator.m_pCallbacks, m_pArray);
            m_Capacity = newCapacity;
            m_pArray = newArray;
        }

        m_Count = newCount;
    }

    void clear(bool freeMemory = false)
    {
        resize(0, freeMemory);
    }

    void insert(size_t index, const T& src)
    {
        VMA_HEAVY_ASSERT(index <= m_Count);
        const size_t oldCount = size();
        resize(oldCount + 1);
        if(index < oldCount)
        {
            memmove(m_pArray + (index + 1), m_pArray + index, (oldCount - index) * sizeof(T));
        }
        m_pArray[index] = src;
    }

    void remove(size_t index)
    {
        VMA_HEAVY_ASSERT(index < m_Count);
        const size_t oldCount = size();
        if(index < oldCount - 1)
        {
            memmove(m_pArray + index, m_pArray + (index + 1), (oldCount - index - 1) * sizeof(T));
        }
        resize(oldCount - 1);
    }

    void push_back(const T& src)
    {
        const size_t newIndex = size();
        resize(newIndex + 1);
        m_pArray[newIndex] = src;
    }

    void pop_back()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        resize(size() - 1);
    }

    void push_front(const T& src)
    {
        insert(0, src);
    }

    void pop_front()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        remove(0);
    }

    typedef T* iterator;

    iterator begin() { return m_pArray; }
    iterator end() { return m_pArray + m_Count; }

private:
    AllocatorT m_Allocator;
    T* m_pArray;
    size_t m_Count;
    size_t m_Capacity;
};

template<typename T, typename allocatorT>
static void VmaVectorInsert(VmaVector<T, allocatorT>& vec, size_t index, const T& item)
{
    vec.insert(index, item);
}

template<typename T, typename allocatorT>
static void VmaVectorRemove(VmaVector<T, allocatorT>& vec, size_t index)
{
    vec.remove(index);
}

#endif // #if VMA_USE_STL_VECTOR

template<typename CmpLess, typename VectorT>
size_t VmaVectorInsertSorted(VectorT& vector, const typename VectorT::value_type& value)
{
    const size_t indexToInsert = VmaBinaryFindFirstNotLess(
        vector.data(),
        vector.data() + vector.size(),
        value,
        CmpLess()) - vector.data();
    VmaVectorInsert(vector, indexToInsert, value);
    return indexToInsert;
}

template<typename CmpLess, typename VectorT>
bool VmaVectorRemoveSorted(VectorT& vector, const typename VectorT::value_type& value)
{
    CmpLess comparator;
    typename VectorT::iterator it = VmaBinaryFindFirstNotLess(
        vector.begin(),
        vector.end(),
        value,
        comparator);
    if((it != vector.end()) && !comparator(*it, value) && !comparator(value, *it))
    {
        size_t indexToRemove = it - vector.begin();
        VmaVectorRemove(vector, indexToRemove);
        return true;
    }
    return false;
}

template<typename CmpLess, typename VectorT>
size_t VmaVectorFindSorted(const VectorT& vector, const typename VectorT::value_type& value)
{
    CmpLess comparator;
    typename VectorT::iterator it = VmaBinaryFindFirstNotLess(
        vector.data(),
        vector.data() + vector.size(),
        value,
        comparator);
    if(it != vector.size() && !comparator(*it, value) && !comparator(value, *it))
    {
        return it - vector.begin();
    }
    else
    {
        return vector.size();
    }
}

////////////////////////////////////////////////////////////////////////////////
// class VmaPoolAllocator

/*
Allocator for objects of type T using a list of arrays (pools) to speed up
allocation. Number of elements that can be allocated is not bounded because
allocator can create multiple blocks.
*/
template<typename T>
class VmaPoolAllocator
{
public:
    VmaPoolAllocator(const VkAllocationCallbacks* pAllocationCallbacks, size_t itemsPerBlock);
    ~VmaPoolAllocator();
    void Clear();
    T* Alloc();
    void Free(T* ptr);

private:
    union Item
    {
        uint32_t NextFreeIndex;
        T Value;
    };

    struct ItemBlock
    {
        Item* pItems;
        uint32_t FirstFreeIndex;
    };
    
    const VkAllocationCallbacks* m_pAllocationCallbacks;
    size_t m_ItemsPerBlock;
    VmaVector< ItemBlock, VmaStlAllocator<ItemBlock> > m_ItemBlocks;

    ItemBlock& CreateNewBlock();
};

template<typename T>
VmaPoolAllocator<T>::VmaPoolAllocator(const VkAllocationCallbacks* pAllocationCallbacks, size_t itemsPerBlock) :
    m_pAllocationCallbacks(pAllocationCallbacks),
    m_ItemsPerBlock(itemsPerBlock),
    m_ItemBlocks(VmaStlAllocator<ItemBlock>(pAllocationCallbacks))
{
    VMA_ASSERT(itemsPerBlock > 0);
}

template<typename T>
VmaPoolAllocator<T>::~VmaPoolAllocator()
{
    Clear();
}

template<typename T>
void VmaPoolAllocator<T>::Clear()
{
    for(size_t i = m_ItemBlocks.size(); i--; )
        vma_delete_array(m_pAllocationCallbacks, m_ItemBlocks[i].pItems, m_ItemsPerBlock);
    m_ItemBlocks.clear();
}

template<typename T>
T* VmaPoolAllocator<T>::Alloc()
{
    for(size_t i = m_ItemBlocks.size(); i--; )
    {
        ItemBlock& block = m_ItemBlocks[i];
        // This block has some free items: Use first one.
        if(block.FirstFreeIndex != UINT32_MAX)
        {
            Item* const pItem = &block.pItems[block.FirstFreeIndex];
            block.FirstFreeIndex = pItem->NextFreeIndex;
            return &pItem->Value;
        }
    }

    // No block has free item: Create new one and use it.
    ItemBlock& newBlock = CreateNewBlock();
    Item* const pItem = &newBlock.pItems[0];
    newBlock.FirstFreeIndex = pItem->NextFreeIndex;
    return &pItem->Value;
}

template<typename T>
void VmaPoolAllocator<T>::Free(T* ptr)
{
    // Search all memory blocks to find ptr.
    for(size_t i = 0; i < m_ItemBlocks.size(); ++i)
    {
        ItemBlock& block = m_ItemBlocks[i];
        
        // Casting to union.
        Item* pItemPtr;
        memcpy(&pItemPtr, &ptr, sizeof(pItemPtr));
        
        // Check if pItemPtr is in address range of this block.
        if((pItemPtr >= block.pItems) && (pItemPtr < block.pItems + m_ItemsPerBlock))
        {
            const uint32_t index = static_cast<uint32_t>(pItemPtr - block.pItems);
            pItemPtr->NextFreeIndex = block.FirstFreeIndex;
            block.FirstFreeIndex = index;
            return;
        }
    }
    VMA_ASSERT(0 && "Pointer doesn't belong to this memory pool.");
}

template<typename T>
typename VmaPoolAllocator<T>::ItemBlock& VmaPoolAllocator<T>::CreateNewBlock()
{
    ItemBlock newBlock = {
        vma_new_array(m_pAllocationCallbacks, Item, m_ItemsPerBlock), 0 };

    m_ItemBlocks.push_back(newBlock);

    // Setup singly-linked list of all free items in this block.
    for(uint32_t i = 0; i < m_ItemsPerBlock - 1; ++i)
        newBlock.pItems[i].NextFreeIndex = i + 1;
    newBlock.pItems[m_ItemsPerBlock - 1].NextFreeIndex = UINT32_MAX;
    return m_ItemBlocks.back();
}

////////////////////////////////////////////////////////////////////////////////
// class VmaRawList, VmaList

#if VMA_USE_STL_LIST

#define VmaList std::list

#else // #if VMA_USE_STL_LIST

template<typename T>
struct VmaListItem
{
    VmaListItem* pPrev;
    VmaListItem* pNext;
    T Value;
};

// Doubly linked list.
template<typename T>
class VmaRawList
{
public:
    typedef VmaListItem<T> ItemType;

    VmaRawList(const VkAllocationCallbacks* pAllocationCallbacks);
    ~VmaRawList();
    void Clear();

    size_t GetCount() const { return m_Count; }
    bool IsEmpty() const { return m_Count == 0; }

    ItemType* Front() { return m_pFront; }
    const ItemType* Front() const { return m_pFront; }
    ItemType* Back() { return m_pBack; }
    const ItemType* Back() const { return m_pBack; }

    ItemType* PushBack();
    ItemType* PushFront();
    ItemType* PushBack(const T& value);
    ItemType* PushFront(const T& value);
    void PopBack();
    void PopFront();
    
    // Item can be null - it means PushBack.
    ItemType* InsertBefore(ItemType* pItem);
    // Item can be null - it means PushFront.
    ItemType* InsertAfter(ItemType* pItem);

    ItemType* InsertBefore(ItemType* pItem, const T& value);
    ItemType* InsertAfter(ItemType* pItem, const T& value);

    void Remove(ItemType* pItem);

private:
    const VkAllocationCallbacks* const m_pAllocationCallbacks;
    VmaPoolAllocator<ItemType> m_ItemAllocator;
    ItemType* m_pFront;
    ItemType* m_pBack;
    size_t m_Count;

    // Declared not defined, to block copy constructor and assignment operator.
    VmaRawList(const VmaRawList<T>& src);
    VmaRawList<T>& operator=(const VmaRawList<T>& rhs);
};

template<typename T>
VmaRawList<T>::VmaRawList(const VkAllocationCallbacks* pAllocationCallbacks) :
    m_pAllocationCallbacks(pAllocationCallbacks),
    m_ItemAllocator(pAllocationCallbacks, 128),
    m_pFront(VMA_NULL),
    m_pBack(VMA_NULL),
    m_Count(0)
{
}

template<typename T>
VmaRawList<T>::~VmaRawList()
{
    // Intentionally not calling Clear, because that would be unnecessary
    // computations to return all items to m_ItemAllocator as free.
}

template<typename T>
void VmaRawList<T>::Clear()
{
    if(IsEmpty() == false)
    {
        ItemType* pItem = m_pBack;
        while(pItem != VMA_NULL)
        {
            ItemType* const pPrevItem = pItem->pPrev;
            m_ItemAllocator.Free(pItem);
            pItem = pPrevItem;
        }
        m_pFront = VMA_NULL;
        m_pBack = VMA_NULL;
        m_Count = 0;
    }
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushBack()
{
    ItemType* const pNewItem = m_ItemAllocator.Alloc();
    pNewItem->pNext = VMA_NULL;
    if(IsEmpty())
    {
        pNewItem->pPrev = VMA_NULL;
        m_pFront = pNewItem;
        m_pBack = pNewItem;
        m_Count = 1;
    }
    else
    {
        pNewItem->pPrev = m_pBack;
        m_pBack->pNext = pNewItem;
        m_pBack = pNewItem;
        ++m_Count;
    }
    return pNewItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushFront()
{
    ItemType* const pNewItem = m_ItemAllocator.Alloc();
    pNewItem->pPrev = VMA_NULL;
    if(IsEmpty())
    {
        pNewItem->pNext = VMA_NULL;
        m_pFront = pNewItem;
        m_pBack = pNewItem;
        m_Count = 1;
    }
    else
    {
        pNewItem->pNext = m_pFront;
        m_pFront->pPrev = pNewItem;
        m_pFront = pNewItem;
        ++m_Count;
    }
    return pNewItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushBack(const T& value)
{
    ItemType* const pNewItem = PushBack();
    pNewItem->Value = value;
    return pNewItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushFront(const T& value)
{
    ItemType* const pNewItem = PushFront();
    pNewItem->Value = value;
    return pNewItem;
}

template<typename T>
void VmaRawList<T>::PopBack()
{
    VMA_HEAVY_ASSERT(m_Count > 0);
    ItemType* const pBackItem = m_pBack;
    ItemType* const pPrevItem = pBackItem->pPrev;
    if(pPrevItem != VMA_NULL)
    {
        pPrevItem->pNext = VMA_NULL;
    }
    m_pBack = pPrevItem;
    m_ItemAllocator.Free(pBackItem);
    --m_Count;
}

template<typename T>
void VmaRawList<T>::PopFront()
{
    VMA_HEAVY_ASSERT(m_Count > 0);
    ItemType* const pFrontItem = m_pFront;
    ItemType* const pNextItem = pFrontItem->pNext;
    if(pNextItem != VMA_NULL)
    {
        pNextItem->pPrev = VMA_NULL;
    }
    m_pFront = pNextItem;
    m_ItemAllocator.Free(pFrontItem);
    --m_Count;
}

template<typename T>
void VmaRawList<T>::Remove(ItemType* pItem)
{
    VMA_HEAVY_ASSERT(pItem != VMA_NULL);
    VMA_HEAVY_ASSERT(m_Count > 0);

    if(pItem->pPrev != VMA_NULL)
    {
        pItem->pPrev->pNext = pItem->pNext;
    }
    else
    {
        VMA_HEAVY_ASSERT(m_pFront == pItem);
        m_pFront = pItem->pNext;
    }

    if(pItem->pNext != VMA_NULL)
    {
        pItem->pNext->pPrev = pItem->pPrev;
    }
    else
    {
        VMA_HEAVY_ASSERT(m_pBack == pItem);
        m_pBack = pItem->pPrev;
    }

    m_ItemAllocator.Free(pItem);
    --m_Count;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertBefore(ItemType* pItem)
{
    if(pItem != VMA_NULL)
    {
        ItemType* const prevItem = pItem->pPrev;
        ItemType* const newItem = m_ItemAllocator.Alloc();
        newItem->pPrev = prevItem;
        newItem->pNext = pItem;
        pItem->pPrev = newItem;
        if(prevItem != VMA_NULL)
        {
            prevItem->pNext = newItem;
        }
        else
        {
            VMA_HEAVY_ASSERT(m_pFront == pItem);
            m_pFront = newItem;
        }
        ++m_Count;
        return newItem;
    }
    else
        return PushBack();
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertAfter(ItemType* pItem)
{
    if(pItem != VMA_NULL)
    {
        ItemType* const nextItem = pItem->pNext;
        ItemType* const newItem = m_ItemAllocator.Alloc();
        newItem->pNext = nextItem;
        newItem->pPrev = pItem;
        pItem->pNext = newItem;
        if(nextItem != VMA_NULL)
        {
            nextItem->pPrev = newItem;
        }
        else
        {
            VMA_HEAVY_ASSERT(m_pBack == pItem);
            m_pBack = newItem;
        }
        ++m_Count;
        return newItem;
    }
    else
        return PushFront();
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertBefore(ItemType* pItem, const T& value)
{
    ItemType* const newItem = InsertBefore(pItem);
    newItem->Value = value;
    return newItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertAfter(ItemType* pItem, const T& value)
{
    ItemType* const newItem = InsertAfter(pItem);
    newItem->Value = value;
    return newItem;
}

template<typename T, typename AllocatorT>
class VmaList
{
public:
    class iterator
    {
    public:
        iterator() :
            m_pList(VMA_NULL),
            m_pItem(VMA_NULL)
        {
        }

        T& operator*() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return m_pItem->Value;
        }
        T* operator->() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return &m_pItem->Value;
        }

        iterator& operator++()
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            m_pItem = m_pItem->pNext;
            return *this;
        }
        iterator& operator--()
        {
            if(m_pItem != VMA_NULL)
            {
                m_pItem = m_pItem->pPrev;
            }
            else
            {
                VMA_HEAVY_ASSERT(!m_pList->IsEmpty());
                m_pItem = m_pList->Back();
            }
            return *this;
        }

        iterator operator++(int)
        {
            iterator result = *this;
            ++*this;
            return result;
        }
        iterator operator--(int)
        {
            iterator result = *this;
            --*this;
            return result;
        }

        bool operator==(const iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem == rhs.m_pItem;
        }
        bool operator!=(const iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem != rhs.m_pItem;
        }
        
    private:
        VmaRawList<T>* m_pList;
        VmaListItem<T>* m_pItem;

        iterator(VmaRawList<T>* pList, VmaListItem<T>* pItem) :
            m_pList(pList),
            m_pItem(pItem)
        {
        }

        friend class VmaList<T, AllocatorT>;
    };

    class const_iterator
    {
    public:
        const_iterator() :
            m_pList(VMA_NULL),
            m_pItem(VMA_NULL)
        {
        }

        const_iterator(const iterator& src) :
            m_pList(src.m_pList),
            m_pItem(src.m_pItem)
        {
        }
        
        const T& operator*() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return m_pItem->Value;
        }
        const T* operator->() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return &m_pItem->Value;
        }

        const_iterator& operator++()
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            m_pItem = m_pItem->pNext;
            return *this;
        }
        const_iterator& operator--()
        {
            if(m_pItem != VMA_NULL)
            {
                m_pItem = m_pItem->pPrev;
            }
            else
            {
                VMA_HEAVY_ASSERT(!m_pList->IsEmpty());
                m_pItem = m_pList->Back();
            }
            return *this;
        }

        const_iterator operator++(int)
        {
            const_iterator result = *this;
            ++*this;
            return result;
        }
        const_iterator operator--(int)
        {
            const_iterator result = *this;
            --*this;
            return result;
        }

        bool operator==(const const_iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem == rhs.m_pItem;
        }
        bool operator!=(const const_iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem != rhs.m_pItem;
        }
        
    private:
        const_iterator(const VmaRawList<T>* pList, const VmaListItem<T>* pItem) :
            m_pList(pList),
            m_pItem(pItem)
        {
        }

        const VmaRawList<T>* m_pList;
        const VmaListItem<T>* m_pItem;

        friend class VmaList<T, AllocatorT>;
    };

    VmaList(const AllocatorT& allocator) : m_RawList(allocator.m_pCallbacks) { }

    bool empty() const { return m_RawList.IsEmpty(); }
    size_t size() const { return m_RawList.GetCount(); }

    iterator begin() { return iterator(&m_RawList, m_RawList.Front()); }
    iterator end() { return iterator(&m_RawList, VMA_NULL); }

    const_iterator cbegin() const { return const_iterator(&m_RawList, m_RawList.Front()); }
    const_iterator cend() const { return const_iterator(&m_RawList, VMA_NULL); }

    void clear() { m_RawList.Clear(); }
    void push_back(const T& value) { m_RawList.PushBack(value); }
    void erase(iterator it) { m_RawList.Remove(it.m_pItem); }
    iterator insert(iterator it, const T& value) { return iterator(&m_RawList, m_RawList.InsertBefore(it.m_pItem, value)); }

private:
    VmaRawList<T> m_RawList;
};

#endif // #if VMA_USE_STL_LIST

////////////////////////////////////////////////////////////////////////////////
// class VmaMap

// Unused in this version.
#if 0

#if VMA_USE_STL_UNORDERED_MAP

#define VmaPair std::pair

#define VMA_MAP_TYPE(KeyT, ValueT) \
    std::unordered_map< KeyT, ValueT, std::hash<KeyT>, std::equal_to<KeyT>, VmaStlAllocator< std::pair<KeyT, ValueT> > >

#else // #if VMA_USE_STL_UNORDERED_MAP

template<typename T1, typename T2>
struct VmaPair
{
    T1 first;
    T2 second;

    VmaPair() : first(), second() { }
    VmaPair(const T1& firstSrc, const T2& secondSrc) : first(firstSrc), second(secondSrc) { }
};

/* Class compatible with subset of interface of std::unordered_map.
KeyT, ValueT must be POD because they will be stored in VmaVector.
*/
template<typename KeyT, typename ValueT>
class VmaMap
{
public:
    typedef VmaPair<KeyT, ValueT> PairType;
    typedef PairType* iterator;

    VmaMap(const VmaStlAllocator<PairType>& allocator) : m_Vector(allocator) { }

    iterator begin() { return m_Vector.begin(); }
    iterator end() { return m_Vector.end(); }

    void insert(const PairType& pair);
    iterator find(const KeyT& key);
    void erase(iterator it);
    
private:
    VmaVector< PairType, VmaStlAllocator<PairType> > m_Vector;
};

#define VMA_MAP_TYPE(KeyT, ValueT) VmaMap<KeyT, ValueT>

template<typename FirstT, typename SecondT>
struct VmaPairFirstLess
{
    bool operator()(const VmaPair<FirstT, SecondT>& lhs, const VmaPair<FirstT, SecondT>& rhs) const
    {
        return lhs.first < rhs.first;
    }
    bool operator()(const VmaPair<FirstT, SecondT>& lhs, const FirstT& rhsFirst) const
    {
        return lhs.first < rhsFirst;
    }
};

template<typename KeyT, typename ValueT>
void VmaMap<KeyT, ValueT>::insert(const PairType& pair)
{
    const size_t indexToInsert = VmaBinaryFindFirstNotLess(
        m_Vector.data(),
        m_Vector.data() + m_Vector.size(),
        pair,
        VmaPairFirstLess<KeyT, ValueT>()) - m_Vector.data();
    VmaVectorInsert(m_Vector, indexToInsert, pair);
}

template<typename KeyT, typename ValueT>
VmaPair<KeyT, ValueT>* VmaMap<KeyT, ValueT>::find(const KeyT& key)
{
    PairType* it = VmaBinaryFindFirstNotLess(
        m_Vector.data(),
        m_Vector.data() + m_Vector.size(),
        key,
        VmaPairFirstLess<KeyT, ValueT>());
    if((it != m_Vector.end()) && (it->first == key))
    {
        return it;
    }
    else
    {
        return m_Vector.end();
    }
}

template<typename KeyT, typename ValueT>
void VmaMap<KeyT, ValueT>::erase(iterator it)
{
    VmaVectorRemove(m_Vector, it - m_Vector.begin());
}

#endif // #if VMA_USE_STL_UNORDERED_MAP

#endif // #if 0

////////////////////////////////////////////////////////////////////////////////

class VmaDeviceMemoryBlock;

struct VmaAllocation_T
{
private:
    static const uint8_t MAP_COUNT_FLAG_PERSISTENT_MAP = 0x80;

    enum FLAGS
    {
        FLAG_USER_DATA_STRING = 0x01,
    };

public:
    enum ALLOCATION_TYPE
    {
        ALLOCATION_TYPE_NONE,
        ALLOCATION_TYPE_BLOCK,
        ALLOCATION_TYPE_DEDICATED,
    };

    VmaAllocation_T(uint32_t currentFrameIndex, bool userDataString) :
        m_Alignment(1),
        m_Size(0),
        m_pUserData(VMA_NULL),
        m_LastUseFrameIndex(currentFrameIndex),
        m_Type((uint8_t)ALLOCATION_TYPE_NONE),
        m_SuballocationType((uint8_t)VMA_SUBALLOCATION_TYPE_UNKNOWN),
        m_MapCount(0),
        m_Flags(userDataString ? (uint8_t)FLAG_USER_DATA_STRING : 0)
    {
    }

    ~VmaAllocation_T()
    {
        VMA_ASSERT((m_MapCount & ~MAP_COUNT_FLAG_PERSISTENT_MAP) == 0 && "Allocation was not unmapped before destruction.");

        // Check if owned string was freed.
        VMA_ASSERT(m_pUserData == VMA_NULL);
    }

    void InitBlockAllocation(
        VmaPool hPool,
        VmaDeviceMemoryBlock* block,
        VkDeviceSize offset,
        VkDeviceSize alignment,
        VkDeviceSize size,
        VmaSuballocationType suballocationType,
        bool mapped,
        bool canBecomeLost)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_NONE);
        VMA_ASSERT(block != VMA_NULL);
        m_Type = (uint8_t)ALLOCATION_TYPE_BLOCK;
        m_Alignment = alignment;
        m_Size = size;
        m_MapCount = mapped ? MAP_COUNT_FLAG_PERSISTENT_MAP : 0;
        m_SuballocationType = (uint8_t)suballocationType;
        m_BlockAllocation.m_hPool = hPool;
        m_BlockAllocation.m_Block = block;
        m_BlockAllocation.m_Offset = offset;
        m_BlockAllocation.m_CanBecomeLost = canBecomeLost;
    }

    void InitLost()
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_NONE);
        VMA_ASSERT(m_LastUseFrameIndex.load() == VMA_FRAME_INDEX_LOST);
        m_Type = (uint8_t)ALLOCATION_TYPE_BLOCK;
        m_BlockAllocation.m_hPool = VK_NULL_HANDLE;
        m_BlockAllocation.m_Block = VMA_NULL;
        m_BlockAllocation.m_Offset = 0;
        m_BlockAllocation.m_CanBecomeLost = true;
    }

    void ChangeBlockAllocation(
        VmaAllocator hAllocator,
        VmaDeviceMemoryBlock* block,
        VkDeviceSize offset);

    // pMappedData not null means allocation is created with MAPPED flag.
    void InitDedicatedAllocation(
        uint32_t memoryTypeIndex,
        VkDeviceMemory hMemory,
        VmaSuballocationType suballocationType,
        void* pMappedData,
        VkDeviceSize size)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_NONE);
        VMA_ASSERT(hMemory != VK_NULL_HANDLE);
        m_Type = (uint8_t)ALLOCATION_TYPE_DEDICATED;
        m_Alignment = 0;
        m_Size = size;
        m_SuballocationType = (uint8_t)suballocationType;
        m_MapCount = (pMappedData != VMA_NULL) ? MAP_COUNT_FLAG_PERSISTENT_MAP : 0;
        m_DedicatedAllocation.m_MemoryTypeIndex = memoryTypeIndex;
        m_DedicatedAllocation.m_hMemory = hMemory;
        m_DedicatedAllocation.m_pMappedData = pMappedData;
    }

    ALLOCATION_TYPE GetType() const { return (ALLOCATION_TYPE)m_Type; }
    VkDeviceSize GetAlignment() const { return m_Alignment; }
    VkDeviceSize GetSize() const { return m_Size; }
    bool IsUserDataString() const { return (m_Flags & FLAG_USER_DATA_STRING) != 0; }
    void* GetUserData() const { return m_pUserData; }
    void SetUserData(VmaAllocator hAllocator, void* pUserData);
    VmaSuballocationType GetSuballocationType() const { return (VmaSuballocationType)m_SuballocationType; }

    VmaDeviceMemoryBlock* GetBlock() const
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_BLOCK);
        return m_BlockAllocation.m_Block;
    }
    VkDeviceSize GetOffset() const;
    VkDeviceMemory GetMemory() const;
    uint32_t GetMemoryTypeIndex() const;
    bool IsPersistentMap() const { return (m_MapCount & MAP_COUNT_FLAG_PERSISTENT_MAP) != 0; }
    void* GetMappedData() const;
    bool CanBecomeLost() const;
    VmaPool GetPool() const;
    
    uint32_t GetLastUseFrameIndex() const
    {
        return m_LastUseFrameIndex.load();
    }
    bool CompareExchangeLastUseFrameIndex(uint32_t& expected, uint32_t desired)
    {
        return m_LastUseFrameIndex.compare_exchange_weak(expected, desired);
    }
    /*
    - If hAllocation.LastUseFrameIndex + frameInUseCount < allocator.CurrentFrameIndex,
      makes it lost by setting LastUseFrameIndex = VMA_FRAME_INDEX_LOST and returns true.
    - Else, returns false.
    
    If hAllocation is already lost, assert - you should not call it then.
    If hAllocation was not created with CAN_BECOME_LOST_BIT, assert.
    */
    bool MakeLost(uint32_t currentFrameIndex, uint32_t frameInUseCount);

    void DedicatedAllocCalcStatsInfo(VmaStatInfo& outInfo)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_DEDICATED);
        outInfo.blockCount = 1;
        outInfo.allocationCount = 1;
        outInfo.unusedRangeCount = 0;
        outInfo.usedBytes = m_Size;
        outInfo.unusedBytes = 0;
        outInfo.allocationSizeMin = outInfo.allocationSizeMax = m_Size;
        outInfo.unusedRangeSizeMin = UINT64_MAX;
        outInfo.unusedRangeSizeMax = 0;
    }

    void BlockAllocMap();
    void BlockAllocUnmap();
    VkResult DedicatedAllocMap(VmaAllocator hAllocator, void** ppData);
    void DedicatedAllocUnmap(VmaAllocator hAllocator);

private:
    VkDeviceSize m_Alignment;
    VkDeviceSize m_Size;
    void* m_pUserData;
    VMA_ATOMIC_UINT32 m_LastUseFrameIndex;
    uint8_t m_Type; // ALLOCATION_TYPE
    uint8_t m_SuballocationType; // VmaSuballocationType
    // Bit 0x80 is set when allocation was created with VMA_ALLOCATION_CREATE_MAPPED_BIT.
    // Bits with mask 0x7F are reference counter for vmaMapMemory()/vmaUnmapMemory().
    uint8_t m_MapCount;
    uint8_t m_Flags; // enum FLAGS

    // Allocation out of VmaDeviceMemoryBlock.
    struct BlockAllocation
    {
        VmaPool m_hPool; // Null if belongs to general memory.
        VmaDeviceMemoryBlock* m_Block;
        VkDeviceSize m_Offset;
        bool m_CanBecomeLost;
    };

    // Allocation for an object that has its own private VkDeviceMemory.
    struct DedicatedAllocation
    {
        uint32_t m_MemoryTypeIndex;
        VkDeviceMemory m_hMemory;
        void* m_pMappedData; // Not null means memory is mapped.
    };

    union
    {
        // Allocation out of VmaDeviceMemoryBlock.
        BlockAllocation m_BlockAllocation;
        // Allocation for an object that has its own private VkDeviceMemory.
        DedicatedAllocation m_DedicatedAllocation;
    };

    void FreeUserDataString(VmaAllocator hAllocator);
};

/*
Represents a region of VmaDeviceMemoryBlock that is either assigned and returned as
allocated memory block or free.
*/
struct VmaSuballocation
{
    VkDeviceSize offset;
    VkDeviceSize size;
    VmaAllocation hAllocation;
    VmaSuballocationType type;
};

typedef VmaList< VmaSuballocation, VmaStlAllocator<VmaSuballocation> > VmaSuballocationList;

// Cost of one additional allocation lost, as equivalent in bytes.
static const VkDeviceSize VMA_LOST_ALLOCATION_COST = 1048576;

/*
Parameters of planned allocation inside a VmaDeviceMemoryBlock.

If canMakeOtherLost was false:
- item points to a FREE suballocation.
- itemsToMakeLostCount is 0.

If canMakeOtherLost was true:
- item points to first of sequence of suballocations, which are either FREE,
  or point to VmaAllocations that can become lost.
- itemsToMakeLostCount is the number of VmaAllocations that need to be made lost for
  the requested allocation to succeed.
*/
struct VmaAllocationRequest
{
    VkDeviceSize offset;
    VkDeviceSize sumFreeSize; // Sum size of free items that overlap with proposed allocation.
    VkDeviceSize sumItemSize; // Sum size of items to make lost that overlap with proposed allocation.
    VmaSuballocationList::iterator item;
    size_t itemsToMakeLostCount;

    VkDeviceSize CalcCost() const
    {
        return sumItemSize + itemsToMakeLostCount * VMA_LOST_ALLOCATION_COST;
    }
};

/*
Data structure used for bookkeeping of allocations and unused ranges of memory
in a single VkDeviceMemory block.
*/
class VmaBlockMetadata
{
public:
    VmaBlockMetadata(VmaAllocator hAllocator);
    ~VmaBlockMetadata();
    void Init(VkDeviceSize size);

    // Validates all data structures inside this object. If not valid, returns false.
    bool Validate() const;
    VkDeviceSize GetSize() const { return m_Size; }
    size_t GetAllocationCount() const { return m_Suballocations.size() - m_FreeCount; }
    VkDeviceSize GetSumFreeSize() const { return m_SumFreeSize; }
    VkDeviceSize GetUnusedRangeSizeMax() const;
    // Returns true if this block is empty - contains only single free suballocation.
    bool IsEmpty() const;

    void CalcAllocationStatInfo(VmaStatInfo& outInfo) const;
    void AddPoolStats(VmaPoolStats& inoutStats) const;

#if VMA_STATS_STRING_ENABLED
    void PrintDetailedMap(class VmaJsonWriter& json) const;
#endif

    // Creates trivial request for case when block is empty.
    void CreateFirstAllocationRequest(VmaAllocationRequest* pAllocationRequest);

    // Tries to find a place for suballocation with given parameters inside this block.
    // If succeeded, fills pAllocationRequest and returns true.
    // If failed, returns false.
    bool CreateAllocationRequest(
        uint32_t currentFrameIndex,
        uint32_t frameInUseCount,
        VkDeviceSize bufferImageGranularity,
        VkDeviceSize allocSize,
        VkDeviceSize allocAlignment,
        VmaSuballocationType allocType,
        bool canMakeOtherLost,
        VmaAllocationRequest* pAllocationRequest);

    bool MakeRequestedAllocationsLost(
        uint32_t currentFrameIndex,
        uint32_t frameInUseCount,
        VmaAllocationRequest* pAllocationRequest);

    uint32_t MakeAllocationsLost(uint32_t currentFrameIndex, uint32_t frameInUseCount);

    // Makes actual allocation based on request. Request must already be checked and valid.
    void Alloc(
        const VmaAllocationRequest& request,
        VmaSuballocationType type,
        VkDeviceSize allocSize,
        VmaAllocation hAllocation);

    // Frees suballocation assigned to given memory region.
    void Free(const VmaAllocation allocation);
    void FreeAtOffset(VkDeviceSize offset);

private:
    VkDeviceSize m_Size;
    uint32_t m_FreeCount;
    VkDeviceSize m_SumFreeSize;
    VmaSuballocationList m_Suballocations;
    // Suballocations that are free and have size greater than certain threshold.
    // Sorted by size, ascending.
    VmaVector< VmaSuballocationList::iterator, VmaStlAllocator< VmaSuballocationList::iterator > > m_FreeSuballocationsBySize;

    bool ValidateFreeSuballocationList() const;

    // Checks if requested suballocation with given parameters can be placed in given pFreeSuballocItem.
    // If yes, fills pOffset and returns true. If no, returns false.
    bool CheckAllocation(
        uint32_t currentFrameIndex,
        uint32_t frameInUseCount,
        VkDeviceSize bufferImageGranularity,
        VkDeviceSize allocSize,
        VkDeviceSize allocAlignment,
        VmaSuballocationType allocType,
        VmaSuballocationList::const_iterator suballocItem,
        bool canMakeOtherLost,
        VkDeviceSize* pOffset,
        size_t* itemsToMakeLostCount,
        VkDeviceSize* pSumFreeSize,
        VkDeviceSize* pSumItemSize) const;
    // Given free suballocation, it merges it with following one, which must also be free.
    void MergeFreeWithNext(VmaSuballocationList::iterator item);
    // Releases given suballocation, making it free.
    // Merges it with adjacent free suballocations if applicable.
    // Returns iterator to new free suballocation at this place.
    VmaSuballocationList::iterator FreeSuballocation(VmaSuballocationList::iterator suballocItem);
    // Given free suballocation, it inserts it into sorted list of
    // m_FreeSuballocationsBySize if it's suitable.
    void RegisterFreeSuballocation(VmaSuballocationList::iterator item);
    // Given free suballocation, it removes it from sorted list of
    // m_FreeSuballocationsBySize if it's suitable.
    void UnregisterFreeSuballocation(VmaSuballocationList::iterator item);
};

/*
Represents a single block of device memory (`VkDeviceMemory`) with all the
data about its regions (aka suballocations, #VmaAllocation), assigned and free.

Thread-safety: This class must be externally synchronized.
*/
class VmaDeviceMemoryBlock
{
public:
    VmaBlockMetadata m_Metadata;

    VmaDeviceMemoryBlock(VmaAllocator hAllocator);

    ~VmaDeviceMemoryBlock()
    {
        VMA_ASSERT(m_MapCount == 0 && "VkDeviceMemory block is being destroyed while it is still mapped.");
        VMA_ASSERT(m_hMemory == VK_NULL_HANDLE);
    }

    // Always call after construction.
    void Init(
        uint32_t newMemoryTypeIndex,
        VkDeviceMemory newMemory,
        VkDeviceSize newSize);
    // Always call before destruction.
    void Destroy(VmaAllocator allocator);
    
    VkDeviceMemory GetDeviceMemory() const { return m_hMemory; }
    uint32_t GetMemoryTypeIndex() const { return m_MemoryTypeIndex; }
    void* GetMappedData() const { return m_pMappedData; }

    // Validates all data structures inside this object. If not valid, returns false.
    bool Validate() const;

    // ppData can be null.
    VkResult Map(VmaAllocator hAllocator, uint32_t count, void** ppData);
    void Unmap(VmaAllocator hAllocator, uint32_t count);

    VkResult BindBufferMemory(
        const VmaAllocator hAllocator,
        const VmaAllocation hAllocation,
        VkBuffer hBuffer);
    VkResult BindImageMemory(
        const VmaAllocator hAllocator,
        const VmaAllocation hAllocation,
        VkImage hImage);

private:
    uint32_t m_MemoryTypeIndex;
    VkDeviceMemory m_hMemory;

    // Protects access to m_hMemory so it's not used by multiple threads simultaneously, e.g. vkMapMemory, vkBindBufferMemory.
    // Also protects m_MapCount, m_pMappedData.
    VMA_MUTEX m_Mutex;
    uint32_t m_MapCount;
    void* m_pMappedData;
};

struct VmaPointerLess
{
    bool operator()(const void* lhs, const void* rhs) const
    {
        return lhs < rhs;
    }
};

class VmaDefragmentator;

/*
Sequence of VmaDeviceMemoryBlock. Represents memory blocks allocated for a specific
Vulkan memory type.

Synchronized internally with a mutex.
*/
struct VmaBlockVector
{
    VmaBlockVector(
        VmaAllocator hAllocator,
        uint32_t memoryTypeIndex,
        VkDeviceSize preferredBlockSize,
        size_t minBlockCount,
        size_t maxBlockCount,
        VkDeviceSize bufferImageGranularity,
        uint32_t frameInUseCount,
        bool isCustomPool);
    ~VmaBlockVector();

    VkResult CreateMinBlocks();

    uint32_t GetMemoryTypeIndex() const { return m_MemoryTypeIndex; }
    VkDeviceSize GetPreferredBlockSize() const { return m_PreferredBlockSize; }
    VkDeviceSize GetBufferImageGranularity() const { return m_BufferImageGranularity; }
    uint32_t GetFrameInUseCount() const { return m_FrameInUseCount; }

    void GetPoolStats(VmaPoolStats* pStats);

    bool IsEmpty() const { return m_Blocks.empty(); }

    VkResult Allocate(
        VmaPool hCurrentPool,
        uint32_t currentFrameIndex,
        const VkMemoryRequirements& vkMemReq,
        const VmaAllocationCreateInfo& createInfo,
        VmaSuballocationType suballocType,
        VmaAllocation* pAllocation);

    void Free(
        VmaAllocation hAllocation);

    // Adds statistics of this BlockVector to pStats.
    void AddStats(VmaStats* pStats);

#if VMA_STATS_STRING_ENABLED
    void PrintDetailedMap(class VmaJsonWriter& json);
#endif

    void MakePoolAllocationsLost(
        uint32_t currentFrameIndex,
        size_t* pLostAllocationCount);

    VmaDefragmentator* EnsureDefragmentator(
        VmaAllocator hAllocator,
        uint32_t currentFrameIndex);

    VkResult Defragment(
        VmaDefragmentationStats* pDefragmentationStats,
        VkDeviceSize& maxBytesToMove,
        uint32_t& maxAllocationsToMove);

    void DestroyDefragmentator();

private:
    friend class VmaDefragmentator;

    const VmaAllocator m_hAllocator;
    const uint32_t m_MemoryTypeIndex;
    const VkDeviceSize m_PreferredBlockSize;
    const size_t m_MinBlockCount;
    const size_t m_MaxBlockCount;
    const VkDeviceSize m_BufferImageGranularity;
    const uint32_t m_FrameInUseCount;
    const bool m_IsCustomPool;
    VMA_MUTEX m_Mutex;
    // Incrementally sorted by sumFreeSize, ascending.
    VmaVector< VmaDeviceMemoryBlock*, VmaStlAllocator<VmaDeviceMemoryBlock*> > m_Blocks;
    /* There can be at most one allocation that is completely empty - a
    hysteresis to avoid pessimistic case of alternating creation and destruction
    of a VkDeviceMemory. */
    bool m_HasEmptyBlock;
    VmaDefragmentator* m_pDefragmentator;

    size_t CalcMaxBlockSize() const;

    // Finds and removes given block from vector.
    void Remove(VmaDeviceMemoryBlock* pBlock);

    // Performs single step in sorting m_Blocks. They may not be fully sorted
    // after this call.
    void IncrementallySortBlocks();

    VkResult CreateBlock(VkDeviceSize blockSize, size_t* pNewBlockIndex);
};

struct VmaPool_T
{
public:
    VmaBlockVector m_BlockVector;

    // Takes ownership.
    VmaPool_T(
        VmaAllocator hAllocator,
        const VmaPoolCreateInfo& createInfo);
    ~VmaPool_T();

    VmaBlockVector& GetBlockVector() { return m_BlockVector; }

#if VMA_STATS_STRING_ENABLED
    //void PrintDetailedMap(class VmaStringBuilder& sb);
#endif
};

class VmaDefragmentator
{
    const VmaAllocator m_hAllocator;
    VmaBlockVector* const m_pBlockVector;
    uint32_t m_CurrentFrameIndex;
    VkDeviceSize m_BytesMoved;
    uint32_t m_AllocationsMoved;

    struct AllocationInfo
    {
        VmaAllocation m_hAllocation;
        VkBool32* m_pChanged;

        AllocationInfo() :
            m_hAllocation(VK_NULL_HANDLE),
            m_pChanged(VMA_NULL)
        {
        }
    };

    struct AllocationInfoSizeGreater
    {
        bool operator()(const AllocationInfo& lhs, const AllocationInfo& rhs) const
        {
            return lhs.m_hAllocation->GetSize() > rhs.m_hAllocation->GetSize();
        }
    };

    // Used between AddAllocation and Defragment.
    VmaVector< AllocationInfo, VmaStlAllocator<AllocationInfo> > m_Allocations;

    struct BlockInfo
    {
        VmaDeviceMemoryBlock* m_pBlock;
        bool m_HasNonMovableAllocations;
        VmaVector< AllocationInfo, VmaStlAllocator<AllocationInfo> > m_Allocations;

        BlockInfo(const VkAllocationCallbacks* pAllocationCallbacks) :
            m_pBlock(VMA_NULL),
            m_HasNonMovableAllocations(true),
            m_Allocations(pAllocationCallbacks),
            m_pMappedDataForDefragmentation(VMA_NULL)
        {
        }

        void CalcHasNonMovableAllocations()
        {
            const size_t blockAllocCount = m_pBlock->m_Metadata.GetAllocationCount();
            const size_t defragmentAllocCount = m_Allocations.size();
            m_HasNonMovableAllocations = blockAllocCount != defragmentAllocCount;
        }

        void SortAllocationsBySizeDescecnding()
        {
            VMA_SORT(m_Allocations.begin(), m_Allocations.end(), AllocationInfoSizeGreater());
        }

        VkResult EnsureMapping(VmaAllocator hAllocator, void** ppMappedData);
        void Unmap(VmaAllocator hAllocator);

    private:
        // Not null if mapped for defragmentation only, not originally mapped.
        void* m_pMappedDataForDefragmentation;
    };

    struct BlockPointerLess
    {
        bool operator()(const BlockInfo* pLhsBlockInfo, const VmaDeviceMemoryBlock* pRhsBlock) const
        {
            return pLhsBlockInfo->m_pBlock < pRhsBlock;
        }
        bool operator()(const BlockInfo* pLhsBlockInfo, const BlockInfo* pRhsBlockInfo) const
        {
            return pLhsBlockInfo->m_pBlock < pRhsBlockInfo->m_pBlock;
        }
    };

    // 1. Blocks with some non-movable allocations go first.
    // 2. Blocks with smaller sumFreeSize go first.
    struct BlockInfoCompareMoveDestination
    {
        bool operator()(const BlockInfo* pLhsBlockInfo, const BlockInfo* pRhsBlockInfo) const
        {
            if(pLhsBlockInfo->m_HasNonMovableAllocations && !pRhsBlockInfo->m_HasNonMovableAllocations)
            {
                return true;
            }
            if(!pLhsBlockInfo->m_HasNonMovableAllocations && pRhsBlockInfo->m_HasNonMovableAllocations)
            {
                return false;
            }
            if(pLhsBlockInfo->m_pBlock->m_Metadata.GetSumFreeSize() < pRhsBlockInfo->m_pBlock->m_Metadata.GetSumFreeSize())
            {
                return true;
            }
            return false;
        }
    };

    typedef VmaVector< BlockInfo*, VmaStlAllocator<BlockInfo*> > BlockInfoVector;
    BlockInfoVector m_Blocks;

    VkResult DefragmentRound(
        VkDeviceSize maxBytesToMove,
        uint32_t maxAllocationsToMove);

    static bool MoveMakesSense(
        size_t dstBlockIndex, VkDeviceSize dstOffset,
        size_t srcBlockIndex, VkDeviceSize srcOffset);

public:
    VmaDefragmentator(
        VmaAllocator hAllocator,
        VmaBlockVector* pBlockVector,
        uint32_t currentFrameIndex);

    ~VmaDefragmentator();

    VkDeviceSize GetBytesMoved() const { return m_BytesMoved; }
    uint32_t GetAllocationsMoved() const { return m_AllocationsMoved; }

    void AddAllocation(VmaAllocation hAlloc, VkBool32* pChanged);

    VkResult Defragment(
        VkDeviceSize maxBytesToMove,
        uint32_t maxAllocationsToMove);
};

// Main allocator object.
struct VmaAllocator_T
{
    bool m_UseMutex;
    bool m_UseKhrDedicatedAllocation;
    VkDevice m_hDevice;
    bool m_AllocationCallbacksSpecified;
    VkAllocationCallbacks m_AllocationCallbacks;
    VmaDeviceMemoryCallbacks m_DeviceMemoryCallbacks;
    
    // Number of bytes free out of limit, or VK_WHOLE_SIZE if not limit for that heap.
    VkDeviceSize m_HeapSizeLimit[VK_MAX_MEMORY_HEAPS];
    VMA_MUTEX m_HeapSizeLimitMutex;

    VkPhysicalDeviceProperties m_PhysicalDeviceProperties;
    VkPhysicalDeviceMemoryProperties m_MemProps;

    // Default pools.
    VmaBlockVector* m_pBlockVectors[VK_MAX_MEMORY_TYPES];

    // Each vector is sorted by memory (handle value).
    typedef VmaVector< VmaAllocation, VmaStlAllocator<VmaAllocation> > AllocationVectorType;
    AllocationVectorType* m_pDedicatedAllocations[VK_MAX_MEMORY_TYPES];
    VMA_MUTEX m_DedicatedAllocationsMutex[VK_MAX_MEMORY_TYPES];

    VmaAllocator_T(const VmaAllocatorCreateInfo* pCreateInfo);
    ~VmaAllocator_T();

    const VkAllocationCallbacks* GetAllocationCallbacks() const
    {
        return m_AllocationCallbacksSpecified ? &m_AllocationCallbacks : 0;
    }
    const VmaVulkanFunctions& GetVulkanFunctions() const
    {
        return m_VulkanFunctions;
    }

    VkDeviceSize GetBufferImageGranularity() const
    {
        return VMA_MAX(
            static_cast<VkDeviceSize>(VMA_DEBUG_MIN_BUFFER_IMAGE_GRANULARITY),
            m_PhysicalDeviceProperties.limits.bufferImageGranularity);
    }

    uint32_t GetMemoryHeapCount() const { return m_MemProps.memoryHeapCount; }
    uint32_t GetMemoryTypeCount() const { return m_MemProps.memoryTypeCount; }

    uint32_t MemoryTypeIndexToHeapIndex(uint32_t memTypeIndex) const
    {
        VMA_ASSERT(memTypeIndex < m_MemProps.memoryTypeCount);
        return m_MemProps.memoryTypes[memTypeIndex].heapIndex;
    }

    void GetBufferMemoryRequirements(
        VkBuffer hBuffer,
        VkMemoryRequirements& memReq,
        bool& requiresDedicatedAllocation,
        bool& prefersDedicatedAllocation) const;
    void GetImageMemoryRequirements(
        VkImage hImage,
        VkMemoryRequirements& memReq,
        bool& requiresDedicatedAllocation,
        bool& prefersDedicatedAllocation) const;

    // Main allocation function.
    VkResult AllocateMemory(
        const VkMemoryRequirements& vkMemReq,
        bool requiresDedicatedAllocation,
        bool prefersDedicatedAllocation,
        VkBuffer dedicatedBuffer,
        VkImage dedicatedImage,
        const VmaAllocationCreateInfo& createInfo,
        VmaSuballocationType suballocType,
        VmaAllocation* pAllocation);

    // Main deallocation function.
    void FreeMemory(const VmaAllocation allocation);

    void CalculateStats(VmaStats* pStats);

#if VMA_STATS_STRING_ENABLED
    void PrintDetailedMap(class VmaJsonWriter& json);
#endif

    VkResult Defragment(
        VmaAllocation* pAllocations,
        size_t allocationCount,
        VkBool32* pAllocationsChanged,
        const VmaDefragmentationInfo* pDefragmentationInfo,
        VmaDefragmentationStats* pDefragmentationStats);

    void GetAllocationInfo(VmaAllocation hAllocation, VmaAllocationInfo* pAllocationInfo);
    bool TouchAllocation(VmaAllocation hAllocation);

    VkResult CreatePool(const VmaPoolCreateInfo* pCreateInfo, VmaPool* pPool);
    void DestroyPool(VmaPool pool);
    void GetPoolStats(VmaPool pool, VmaPoolStats* pPoolStats);

    void SetCurrentFrameIndex(uint32_t frameIndex);

    void MakePoolAllocationsLost(
        VmaPool hPool,
        size_t* pLostAllocationCount);

    void CreateLostAllocation(VmaAllocation* pAllocation);

    VkResult AllocateVulkanMemory(const VkMemoryAllocateInfo* pAllocateInfo, VkDeviceMemory* pMemory);
    void FreeVulkanMemory(uint32_t memoryType, VkDeviceSize size, VkDeviceMemory hMemory);

    VkResult Map(VmaAllocation hAllocation, void** ppData);
    void Unmap(VmaAllocation hAllocation);

    VkResult BindBufferMemory(VmaAllocation hAllocation, VkBuffer hBuffer);
    VkResult BindImageMemory(VmaAllocation hAllocation, VkImage hImage);

private:
    VkDeviceSize m_PreferredLargeHeapBlockSize;

    VkPhysicalDevice m_PhysicalDevice;
    VMA_ATOMIC_UINT32 m_CurrentFrameIndex;
    
    VMA_MUTEX m_PoolsMutex;
    // Protected by m_PoolsMutex. Sorted by pointer value.
    VmaVector<VmaPool, VmaStlAllocator<VmaPool> > m_Pools;

    VmaVulkanFunctions m_VulkanFunctions;

    void ImportVulkanFunctions(const VmaVulkanFunctions* pVulkanFunctions);

    VkDeviceSize CalcPreferredBlockSize(uint32_t memTypeIndex);

    VkResult AllocateMemoryOfType(
        const VkMemoryRequirements& vkMemReq,
        bool dedicatedAllocation,
        VkBuffer dedicatedBuffer,
        VkImage dedicatedImage,
        const VmaAllocationCreateInfo& createInfo,
        uint32_t memTypeIndex,
        VmaSuballocationType suballocType,
        VmaAllocation* pAllocation);

    // Allocates and registers new VkDeviceMemory specifically for single allocation.
    VkResult AllocateDedicatedMemory(
        VkDeviceSize size,
        VmaSuballocationType suballocType,
        uint32_t memTypeIndex,
        bool map,
        bool isUserDataString,
        void* pUserData,
        VkBuffer dedicatedBuffer,
        VkImage dedicatedImage,
        VmaAllocation* pAllocation);

    // Tries to free pMemory as Dedicated Memory. Returns true if found and freed.
    void FreeDedicatedMemory(VmaAllocation allocation);
};

////////////////////////////////////////////////////////////////////////////////
// Memory allocation #2 after VmaAllocator_T definition

static void* VmaMalloc(VmaAllocator hAllocator, size_t size, size_t alignment)
{
    return VmaMalloc(&hAllocator->m_AllocationCallbacks, size, alignment);
}

static void VmaFree(VmaAllocator hAllocator, void* ptr)
{
    VmaFree(&hAllocator->m_AllocationCallbacks, ptr);
}

template<typename T>
static T* VmaAllocate(VmaAllocator hAllocator)
{
    return (T*)VmaMalloc(hAllocator, sizeof(T), VMA_ALIGN_OF(T));
}

template<typename T>
static T* VmaAllocateArray(VmaAllocator hAllocator, size_t count)
{
    return (T*)VmaMalloc(hAllocator, sizeof(T) * count, VMA_ALIGN_OF(T));
}

template<typename T>
static void vma_delete(VmaAllocator hAllocator, T* ptr)
{
    if(ptr != VMA_NULL)
    {
        ptr->~T();
        VmaFree(hAllocator, ptr);
    }
}

template<typename T>
static void vma_delete_array(VmaAllocator hAllocator, T* ptr, size_t count)
{
    if(ptr != VMA_NULL)
    {
        for(size_t i = count; i--; )
            ptr[i].~T();
        VmaFree(hAllocator, ptr);
    }
}

////////////////////////////////////////////////////////////////////////////////
// VmaStringBuilder

#if VMA_STATS_STRING_ENABLED

class VmaStringBuilder
{
public:
    VmaStringBuilder(VmaAllocator alloc) : m_Data(VmaStlAllocator<char>(alloc->GetAllocationCallbacks())) { }
    size_t GetLength() const { return m_Data.size(); }
    const char* GetData() const { return m_Data.data(); }

    void Add(char ch) { m_Data.push_back(ch); }
    void Add(const char* pStr);
    void AddNewLine() { Add('\n'); }
    void AddNumber(uint32_t num);
    void AddNumber(uint64_t num);
    void AddPointer(const void* ptr);

private:
    VmaVector< char, VmaStlAllocator<char> > m_Data;
};

void VmaStringBuilder::Add(const char* pStr)
{
    const size_t strLen = strlen(pStr);
    if(strLen > 0)
    {
        const size_t oldCount = m_Data.size();
        m_Data.resize(oldCount + strLen);
        memcpy(m_Data.data() + oldCount, pStr, strLen);
    }
}

void VmaStringBuilder::AddNumber(uint32_t num)
{
    char buf[11];
    VmaUint32ToStr(buf, sizeof(buf), num);
    Add(buf);
}

void VmaStringBuilder::AddNumber(uint64_t num)
{
    char buf[21];
    VmaUint64ToStr(buf, sizeof(buf), num);
    Add(buf);
}

void VmaStringBuilder::AddPointer(const void* ptr)
{
    char buf[21];
    VmaPtrToStr(buf, sizeof(buf), ptr);
    Add(buf);
}

#endif // #if VMA_STATS_STRING_ENABLED

////////////////////////////////////////////////////////////////////////////////
// VmaJsonWriter

#if VMA_STATS_STRING_ENABLED

class VmaJsonWriter
{
public:
    VmaJsonWriter(const VkAllocationCallbacks* pAllocationCallbacks, VmaStringBuilder& sb);
    ~VmaJsonWriter();

    void BeginObject(bool singleLine = false);
    void EndObject();
    
    void BeginArray(bool singleLine = false);
    void EndArray();
    
    void WriteString(const char* pStr);
    void BeginString(const char* pStr = VMA_NULL);
    void ContinueString(const char* pStr);
    void ContinueString(uint32_t n);
    void ContinueString(uint64_t n);
    void ContinueString_Pointer(const void* ptr);
    void EndString(const char* pStr = VMA_NULL);
    
    void WriteNumber(uint32_t n);
    void WriteNumber(uint64_t n);
    void WriteBool(bool b);
    void WriteNull();

private:
    static const char* const INDENT;

    enum COLLECTION_TYPE
    {
        COLLECTION_TYPE_OBJECT,
        COLLECTION_TYPE_ARRAY,
    };
    struct StackItem
    {
        COLLECTION_TYPE type;
        uint32_t valueCount;
        bool singleLineMode;
    };

    VmaStringBuilder& m_SB;
    VmaVector< StackItem, VmaStlAllocator<StackItem> > m_Stack;
    bool m_InsideString;

    void BeginValue(bool isString);
    void WriteIndent(bool oneLess = false);
};

const char* const VmaJsonWriter::INDENT = "  ";

VmaJsonWriter::VmaJsonWriter(const VkAllocationCallbacks* pAllocationCallbacks, VmaStringBuilder& sb) :
    m_SB(sb),
    m_Stack(VmaStlAllocator<StackItem>(pAllocationCallbacks)),
    m_InsideString(false)
{
}

VmaJsonWriter::~VmaJsonWriter()
{
    VMA_ASSERT(!m_InsideString);
    VMA_ASSERT(m_Stack.empty());
}

void VmaJsonWriter::BeginObject(bool singleLine)
{
    VMA_ASSERT(!m_InsideString);

    BeginValue(false);
    m_SB.Add('{');

    StackItem item;
    item.type = COLLECTION_TYPE_OBJECT;
    item.valueCount = 0;
    item.singleLineMode = singleLine;
    m_Stack.push_back(item);
}

void VmaJsonWriter::EndObject()
{
    VMA_ASSERT(!m_InsideString);

    WriteIndent(true);
    m_SB.Add('}');

    VMA_ASSERT(!m_Stack.empty() && m_Stack.back().type == COLLECTION_TYPE_OBJECT);
    m_Stack.pop_back();
}

void VmaJsonWriter::BeginArray(bool singleLine)
{
    VMA_ASSERT(!m_InsideString);

    BeginValue(false);
    m_SB.Add('[');

    StackItem item;
    item.type = COLLECTION_TYPE_ARRAY;
    item.valueCount = 0;
    item.singleLineMode = singleLine;
    m_Stack.push_back(item);
}

void VmaJsonWriter::EndArray()
{
    VMA_ASSERT(!m_InsideString);

    WriteIndent(true);
    m_SB.Add(']');

    VMA_ASSERT(!m_Stack.empty() && m_Stack.back().type == COLLECTION_TYPE_ARRAY);
    m_Stack.pop_back();
}

void VmaJsonWriter::WriteString(const char* pStr)
{
    BeginString(pStr);
    EndString();
}

void VmaJsonWriter::BeginString(const char* pStr)
{
    VMA_ASSERT(!m_InsideString);

    BeginValue(true);
    m_SB.Add('"');
    m_InsideString = true;
    if(pStr != VMA_NULL && pStr[0] != '\0')
    {
        ContinueString(pStr);
    }
}

void VmaJsonWriter::ContinueString(const char* pStr)
{
    VMA_ASSERT(m_InsideString);

    const size_t strLen = strlen(pStr);
    for(size_t i = 0; i < strLen; ++i)
    {
        char ch = pStr[i];
        if(ch == '\'')
        {
            m_SB.Add("\\\\");
        }
        else if(ch == '"')
        {
            m_SB.Add("\\\"");
        }
        else if(ch >= 32)
        {
            m_SB.Add(ch);
        }
        else switch(ch)
        {
        case '\b':
            m_SB.Add("\\b");
            break;
        case '\f':
            m_SB.Add("\\f");
            break;
        case '\n':
            m_SB.Add("\\n");
            break;
        case '\r':
            m_SB.Add("\\r");
            break;
        case '\t':
            m_SB.Add("\\t");
            break;
        default:
            VMA_ASSERT(0 && "Character not currently supported.");
            break;
        }
    }
}

void VmaJsonWriter::ContinueString(uint32_t n)
{
    VMA_ASSERT(m_InsideString);
    m_SB.AddNumber(n);
}

void VmaJsonWriter::ContinueString(uint64_t n)
{
    VMA_ASSERT(m_InsideString);
    m_SB.AddNumber(n);
}

void VmaJsonWriter::ContinueString_Pointer(const void* ptr)
{
    VMA_ASSERT(m_InsideString);
    m_SB.AddPointer(ptr);
}

void VmaJsonWriter::EndString(const char* pStr)
{
    VMA_ASSERT(m_InsideString);
    if(pStr != VMA_NULL && pStr[0] != '\0')
    {
        ContinueString(pStr);
    }
    m_SB.Add('"');
    m_InsideString = false;
}

void VmaJsonWriter::WriteNumber(uint32_t n)
{
    VMA_ASSERT(!m_InsideString);
    BeginValue(false);
    m_SB.AddNumber(n);
}

void VmaJsonWriter::WriteNumber(uint64_t n)
{
    VMA_ASSERT(!m_InsideString);
    BeginValue(false);
    m_SB.AddNumber(n);
}

void VmaJsonWriter::WriteBool(bool b)
{
    VMA_ASSERT(!m_InsideString);
    BeginValue(false);
    m_SB.Add(b ? "true" : "false");
}

void VmaJsonWriter::WriteNull()
{
    VMA_ASSERT(!m_InsideString);
    BeginValue(false);
    m_SB.Add("null");
}

void VmaJsonWriter::BeginValue(bool isString)
{
    if(!m_Stack.empty())
    {
        StackItem& currItem = m_Stack.back();
        if(currItem.type == COLLECTION_TYPE_OBJECT &&
            currItem.valueCount % 2 == 0)
        {
            VMA_ASSERT(isString);
        }

        if(currItem.type == COLLECTION_TYPE_OBJECT &&
            currItem.valueCount % 2 != 0)
        {
            m_SB.Add(": ");
        }
        else if(currItem.valueCount > 0)
        {
            m_SB.Add(", ");
            WriteIndent();
        }
        else
        {
            WriteIndent();
        }
        ++currItem.valueCount;
    }
}

void VmaJsonWriter::WriteIndent(bool oneLess)
{
    if(!m_Stack.empty() && !m_Stack.back().singleLineMode)
    {
        m_SB.AddNewLine();
        
        size_t count = m_Stack.size();
        if(count > 0 && oneLess)
        {
            --count;
        }
        for(size_t i = 0; i < count; ++i)
        {
            m_SB.Add(INDENT);
        }
    }
}

#endif // #if VMA_STATS_STRING_ENABLED

////////////////////////////////////////////////////////////////////////////////

void VmaAllocation_T::SetUserData(VmaAllocator hAllocator, void* pUserData)
{
    if(IsUserDataString())
    {
        VMA_ASSERT(pUserData == VMA_NULL || pUserData != m_pUserData);

        FreeUserDataString(hAllocator);

        if(pUserData != VMA_NULL)
        {
            const char* const newStrSrc = (char*)pUserData;
            const size_t newStrLen = strlen(newStrSrc);
            char* const newStrDst = vma_new_array(hAllocator, char, newStrLen + 1);
            memcpy(newStrDst, newStrSrc, newStrLen + 1);
            m_pUserData = newStrDst;
        }
    }
    else
    {
        m_pUserData = pUserData;
    }
}

void VmaAllocation_T::ChangeBlockAllocation(
    VmaAllocator hAllocator,
    VmaDeviceMemoryBlock* block,
    VkDeviceSize offset)
{
    VMA_ASSERT(block != VMA_NULL);
    VMA_ASSERT(m_Type == ALLOCATION_TYPE_BLOCK);

    // Move mapping reference counter from old block to new block.
    if(block != m_BlockAllocation.m_Block)
    {
        uint32_t mapRefCount = m_MapCount & ~MAP_COUNT_FLAG_PERSISTENT_MAP;
        if(IsPersistentMap())
            ++mapRefCount;
        m_BlockAllocation.m_Block->Unmap(hAllocator, mapRefCount);
        block->Map(hAllocator, mapRefCount, VMA_NULL);
    }

    m_BlockAllocation.m_Block = block;
    m_BlockAllocation.m_Offset = offset;
}

VkDeviceSize VmaAllocation_T::GetOffset() const
{
    switch(m_Type)
    {
    case ALLOCATION_TYPE_BLOCK:
        return m_BlockAllocation.m_Offset;
    case ALLOCATION_TYPE_DEDICATED:
        return 0;
    default:
        VMA_ASSERT(0);
        return 0;
    }
}

VkDeviceMemory VmaAllocation_T::GetMemory() const
{
    switch(m_Type)
    {
    case ALLOCATION_TYPE_BLOCK:
        return m_BlockAllocation.m_Block->GetDeviceMemory();
    case ALLOCATION_TYPE_DEDICATED:
        return m_DedicatedAllocation.m_hMemory;
    default:
        VMA_ASSERT(0);
        return VK_NULL_HANDLE;
    }
}

uint32_t VmaAllocation_T::GetMemoryTypeIndex() const
{
    switch(m_Type)
    {
    case ALLOCATION_TYPE_BLOCK:
        return m_BlockAllocation.m_Block->GetMemoryTypeIndex();
    case ALLOCATION_TYPE_DEDICATED:
        return m_DedicatedAllocation.m_MemoryTypeIndex;
    default:
        VMA_ASSERT(0);
        return UINT32_MAX;
    }
}

void* VmaAllocation_T::GetMappedData() const
{
    switch(m_Type)
    {
    case ALLOCATION_TYPE_BLOCK:
        if(m_MapCount != 0)
        {
            void* pBlockData = m_BlockAllocation.m_Block->GetMappedData();
            VMA_ASSERT(pBlockData != VMA_NULL);
            return (char*)pBlockData + m_BlockAllocation.m_Offset;
        }
        else
        {
            return VMA_NULL;
        }
        break;
    case ALLOCATION_TYPE_DEDICATED:
        VMA_ASSERT((m_DedicatedAllocation.m_pMappedData != VMA_NULL) == (m_MapCount != 0));
        return m_DedicatedAllocation.m_pMappedData;
    default:
        VMA_ASSERT(0);
        return VMA_NULL;
    }
}

bool VmaAllocation_T::CanBecomeLost() const
{
    switch(m_Type)
    {
    case ALLOCATION_TYPE_BLOCK:
        return m_BlockAllocation.m_CanBecomeLost;
    case ALLOCATION_TYPE_DEDICATED:
        return false;
    default:
        VMA_ASSERT(0);
        return false;
    }
}

VmaPool VmaAllocation_T::GetPool() const
{
    VMA_ASSERT(m_Type == ALLOCATION_TYPE_BLOCK);
    return m_BlockAllocation.m_hPool;
}

bool VmaAllocation_T::MakeLost(uint32_t currentFrameIndex, uint32_t frameInUseCount)
{
    VMA_ASSERT(CanBecomeLost());

    /*
    Warning: This is a carefully designed algorithm.
    Do not modify unless you really know what you're doing :)
    */
    uint32_t localLastUseFrameIndex = GetLastUseFrameIndex();
    for(;;)
    {
        if(localLastUseFrameIndex == VMA_FRAME_INDEX_LOST)
        {
            VMA_ASSERT(0);
            return false;
        }
        else if(localLastUseFrameIndex + frameInUseCount >= currentFrameIndex)
        {
            return false;
        }
        else // Last use time earlier than current time.
        {
            if(CompareExchangeLastUseFrameIndex(localLastUseFrameIndex, VMA_FRAME_INDEX_LOST))
            {
                // Setting hAllocation.LastUseFrameIndex atomic to VMA_FRAME_INDEX_LOST is enough to mark it as LOST.
                // Calling code just needs to unregister this allocation in owning VmaDeviceMemoryBlock.
                return true;
            }
        }
    }
}

void VmaAllocation_T::FreeUserDataString(VmaAllocator hAllocator)
{
    VMA_ASSERT(IsUserDataString());
    if(m_pUserData != VMA_NULL)
    {
        char* const oldStr = (char*)m_pUserData;
        const size_t oldStrLen = strlen(oldStr);
        vma_delete_array(hAllocator, oldStr, oldStrLen + 1);
        m_pUserData = VMA_NULL;
    }
}

void VmaAllocation_T::BlockAllocMap()
{
    VMA_ASSERT(GetType() == ALLOCATION_TYPE_BLOCK);

    if((m_MapCount & ~MAP_COUNT_FLAG_PERSISTENT_MAP) < 0x7F)
    {
        ++m_MapCount;
    }
    else
    {
        VMA_ASSERT(0 && "Allocation mapped too many times simultaneously.");
    }
}

void VmaAllocation_T::BlockAllocUnmap()
{
    VMA_ASSERT(GetType() == ALLOCATION_TYPE_BLOCK);

    if((m_MapCount & ~MAP_COUNT_FLAG_PERSISTENT_MAP) != 0)
    {
        --m_MapCount;
    }
    else
    {
        VMA_ASSERT(0 && "Unmapping allocation not previously mapped.");
    }
}

VkResult VmaAllocation_T::DedicatedAllocMap(VmaAllocator hAllocator, void** ppData)
{
    VMA_ASSERT(GetType() == ALLOCATION_TYPE_DEDICATED);

    if(m_MapCount != 0)
    {
        if((m_MapCount & ~MAP_COUNT_FLAG_PERSISTENT_MAP) < 0x7F)
        {
            VMA_ASSERT(m_DedicatedAllocation.m_pMappedData != VMA_NULL);
            *ppData = m_DedicatedAllocation.m_pMappedData;
            ++m_MapCount;
            return VK_SUCCESS;
        }
        else
        {
            VMA_ASSERT(0 && "Dedicated allocation mapped too many times simultaneously.");
            return VK_ERROR_MEMORY_MAP_FAILED;
        }
    }
    else
    {
        VkResult result = (*hAllocator->GetVulkanFunctions().vkMapMemory)(
            hAllocator->m_hDevice,
            m_DedicatedAllocation.m_hMemory,
            0, // offset
            VK_WHOLE_SIZE,
            0, // flags
            ppData);
        if(result == VK_SUCCESS)
        {
            m_DedicatedAllocation.m_pMappedData = *ppData;
            m_MapCount = 1;
        }
        return result;
    }
}

void VmaAllocation_T::DedicatedAllocUnmap(VmaAllocator hAllocator)
{
    VMA_ASSERT(GetType() == ALLOCATION_TYPE_DEDICATED);

    if((m_MapCount & ~MAP_COUNT_FLAG_PERSISTENT_MAP) != 0)
    {
        --m_MapCount;
        if(m_MapCount == 0)
        {
            m_DedicatedAllocation.m_pMappedData = VMA_NULL;
            (*hAllocator->GetVulkanFunctions().vkUnmapMemory)(
                hAllocator->m_hDevice,
                m_DedicatedAllocation.m_hMemory);
        }
    }
    else
    {
        VMA_ASSERT(0 && "Unmapping dedicated allocation not previously mapped.");
    }
}

#if VMA_STATS_STRING_ENABLED

// Correspond to values of enum VmaSuballocationType.
static const char* VMA_SUBALLOCATION_TYPE_NAMES[] = {
    "FREE",
    "UNKNOWN",
    "BUFFER",
    "IMAGE_UNKNOWN",
    "IMAGE_LINEAR",
    "IMAGE_OPTIMAL",
};

static void VmaPrintStatInfo(VmaJsonWriter& json, const VmaStatInfo& stat)
{
    json.BeginObject();

    json.WriteString("Blocks");
    json.WriteNumber(stat.blockCount);

    json.WriteString("Allocations");
    json.WriteNumber(stat.allocationCount);

    json.WriteString("UnusedRanges");
    json.WriteNumber(stat.unusedRangeCount);

    json.WriteString("UsedBytes");
    json.WriteNumber(stat.usedBytes);

    json.WriteString("UnusedBytes");
    json.WriteNumber(stat.unusedBytes);

    if(stat.allocationCount > 1)
    {
        json.WriteString("AllocationSize");
        json.BeginObject(true);
        json.WriteString("Min");
        json.WriteNumber(stat.allocationSizeMin);
        json.WriteString("Avg");
        json.WriteNumber(stat.allocationSizeAvg);
        json.WriteString("Max");
        json.WriteNumber(stat.allocationSizeMax);
        json.EndObject();
    }

    if(stat.unusedRangeCount > 1)
    {
        json.WriteString("UnusedRangeSize");
        json.BeginObject(true);
        json.WriteString("Min");
        json.WriteNumber(stat.unusedRangeSizeMin);
        json.WriteString("Avg");
        json.WriteNumber(stat.unusedRangeSizeAvg);
        json.WriteString("Max");
        json.WriteNumber(stat.unusedRangeSizeMax);
        json.EndObject();
    }

    json.EndObject();
}

#endif // #if VMA_STATS_STRING_ENABLED

struct VmaSuballocationItemSizeLess
{
    bool operator()(
        const VmaSuballocationList::iterator lhs,
        const VmaSuballocationList::iterator rhs) const
    {
        return lhs->size < rhs->size;
    }
    bool operator()(
        const VmaSuballocationList::iterator lhs,
        VkDeviceSize rhsSize) const
    {
        return lhs->size < rhsSize;
    }
};

////////////////////////////////////////////////////////////////////////////////
// class VmaBlockMetadata

VmaBlockMetadata::VmaBlockMetadata(VmaAllocator hAllocator) :
    m_Size(0),
    m_FreeCount(0),
    m_SumFreeSize(0),
    m_Suballocations(VmaStlAllocator<VmaSuballocation>(hAllocator->GetAllocationCallbacks())),
    m_FreeSuballocationsBySize(VmaStlAllocator<VmaSuballocationList::iterator>(hAllocator->GetAllocationCallbacks()))
{
}

VmaBlockMetadata::~VmaBlockMetadata()
{
}

void VmaBlockMetadata::Init(VkDeviceSize size)
{
    m_Size = size;
    m_FreeCount = 1;
    m_SumFreeSize = size;

    VmaSuballocation suballoc = {};
    suballoc.offset = 0;
    suballoc.size = size;
    suballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
    suballoc.hAllocation = VK_NULL_HANDLE;

    m_Suballocations.push_back(suballoc);
    VmaSuballocationList::iterator suballocItem = m_Suballocations.end();
    --suballocItem;
    m_FreeSuballocationsBySize.push_back(suballocItem);
}

bool VmaBlockMetadata::Validate() const
{
    if(m_Suballocations.empty())
    {
        return false;
    }
    
    // Expected offset of new suballocation as calculates from previous ones.
    VkDeviceSize calculatedOffset = 0;
    // Expected number of free suballocations as calculated from traversing their list.
    uint32_t calculatedFreeCount = 0;
    // Expected sum size of free suballocations as calculated from traversing their list.
    VkDeviceSize calculatedSumFreeSize = 0;
    // Expected number of free suballocations that should be registered in
    // m_FreeSuballocationsBySize calculated from traversing their list.
    size_t freeSuballocationsToRegister = 0;
    // True if previous visisted suballocation was free.
    bool prevFree = false;

    for(VmaSuballocationList::const_iterator suballocItem = m_Suballocations.cbegin();
        suballocItem != m_Suballocations.cend();
        ++suballocItem)
    {
        const VmaSuballocation& subAlloc = *suballocItem;
        
        // Actual offset of this suballocation doesn't match expected one.
        if(subAlloc.offset != calculatedOffset)
        {
            return false;
        }

        const bool currFree = (subAlloc.type == VMA_SUBALLOCATION_TYPE_FREE);
        // Two adjacent free suballocations are invalid. They should be merged.
        if(prevFree && currFree)
        {
            return false;
        }

        if(currFree != (subAlloc.hAllocation == VK_NULL_HANDLE))
        {
            return false;
        }

        if(currFree)
        {
            calculatedSumFreeSize += subAlloc.size;
            ++calculatedFreeCount;
            if(subAlloc.size >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
            {
                ++freeSuballocationsToRegister;
            }
        }
        else
        {
            if(subAlloc.hAllocation->GetOffset() != subAlloc.offset)
            {
                return false;
            }
            if(subAlloc.hAllocation->GetSize() != subAlloc.size)
            {
                return false;
            }
        }

        calculatedOffset += subAlloc.size;
        prevFree = currFree;
    }

    // Number of free suballocations registered in m_FreeSuballocationsBySize doesn't
    // match expected one.
    if(m_FreeSuballocationsBySize.size() != freeSuballocationsToRegister)
    {
        return false;
    }

    VkDeviceSize lastSize = 0;
    for(size_t i = 0; i < m_FreeSuballocationsBySize.size(); ++i)
    {
        VmaSuballocationList::iterator suballocItem = m_FreeSuballocationsBySize[i];
        
        // Only free suballocations can be registered in m_FreeSuballocationsBySize.
        if(suballocItem->type != VMA_SUBALLOCATION_TYPE_FREE)
        {
            return false;
        }
        // They must be sorted by size ascending.
        if(suballocItem->size < lastSize)
        {
            return false;
        }

        lastSize = suballocItem->size;
    }

    // Check if totals match calculacted values.
    if(!ValidateFreeSuballocationList() ||
        (calculatedOffset != m_Size) ||
        (calculatedSumFreeSize != m_SumFreeSize) ||
        (calculatedFreeCount != m_FreeCount))
    {
        return false;
    }

    return true;
}

VkDeviceSize VmaBlockMetadata::GetUnusedRangeSizeMax() const
{
    if(!m_FreeSuballocationsBySize.empty())
    {
        return m_FreeSuballocationsBySize.back()->size;
    }
    else
    {
        return 0;
    }
}

bool VmaBlockMetadata::IsEmpty() const
{
    return (m_Suballocations.size() == 1) && (m_FreeCount == 1);
}

void VmaBlockMetadata::CalcAllocationStatInfo(VmaStatInfo& outInfo) const
{
    outInfo.blockCount = 1;

    const uint32_t rangeCount = (uint32_t)m_Suballocations.size();
    outInfo.allocationCount = rangeCount - m_FreeCount;
    outInfo.unusedRangeCount = m_FreeCount;
    
    outInfo.unusedBytes = m_SumFreeSize;
    outInfo.usedBytes = m_Size - outInfo.unusedBytes;

    outInfo.allocationSizeMin = UINT64_MAX;
    outInfo.allocationSizeMax = 0;
    outInfo.unusedRangeSizeMin = UINT64_MAX;
    outInfo.unusedRangeSizeMax = 0;

    for(VmaSuballocationList::const_iterator suballocItem = m_Suballocations.cbegin();
        suballocItem != m_Suballocations.cend();
        ++suballocItem)
    {
        const VmaSuballocation& suballoc = *suballocItem;
        if(suballoc.type != VMA_SUBALLOCATION_TYPE_FREE)
        {
            outInfo.allocationSizeMin = VMA_MIN(outInfo.allocationSizeMin, suballoc.size);
            outInfo.allocationSizeMax = VMA_MAX(outInfo.allocationSizeMax, suballoc.size);
        }
        else
        {
            outInfo.unusedRangeSizeMin = VMA_MIN(outInfo.unusedRangeSizeMin, suballoc.size);
            outInfo.unusedRangeSizeMax = VMA_MAX(outInfo.unusedRangeSizeMax, suballoc.size);
        }
    }
}

void VmaBlockMetadata::AddPoolStats(VmaPoolStats& inoutStats) const
{
    const uint32_t rangeCount = (uint32_t)m_Suballocations.size();

    inoutStats.size += m_Size;
    inoutStats.unusedSize += m_SumFreeSize;
    inoutStats.allocationCount += rangeCount - m_FreeCount;
    inoutStats.unusedRangeCount += m_FreeCount;
    inoutStats.unusedRangeSizeMax = VMA_MAX(inoutStats.unusedRangeSizeMax, GetUnusedRangeSizeMax());
}

#if VMA_STATS_STRING_ENABLED

void VmaBlockMetadata::PrintDetailedMap(class VmaJsonWriter& json) const
{
    json.BeginObject();

    json.WriteString("TotalBytes");
    json.WriteNumber(m_Size);

    json.WriteString("UnusedBytes");
    json.WriteNumber(m_SumFreeSize);

    json.WriteString("Allocations");
    json.WriteNumber((uint64_t)m_Suballocations.size() - m_FreeCount);

    json.WriteString("UnusedRanges");
    json.WriteNumber(m_FreeCount);

    json.WriteString("Suballocations");
    json.BeginArray();
    size_t i = 0;
    for(VmaSuballocationList::const_iterator suballocItem = m_Suballocations.cbegin();
        suballocItem != m_Suballocations.cend();
        ++suballocItem, ++i)
    {
        json.BeginObject(true);
        
        json.WriteString("Type");
        json.WriteString(VMA_SUBALLOCATION_TYPE_NAMES[suballocItem->type]);

        json.WriteString("Size");
        json.WriteNumber(suballocItem->size);

        json.WriteString("Offset");
        json.WriteNumber(suballocItem->offset);

        if(suballocItem->type != VMA_SUBALLOCATION_TYPE_FREE)
        {
            const void* pUserData = suballocItem->hAllocation->GetUserData();
            if(pUserData != VMA_NULL)
            {
                json.WriteString("UserData");
                if(suballocItem->hAllocation->IsUserDataString())
                {
                    json.WriteString((const char*)pUserData);
                }
                else
                {
                    json.BeginString();
                    json.ContinueString_Pointer(pUserData);
                    json.EndString();
                }
            }
        }

        json.EndObject();
    }
    json.EndArray();

    json.EndObject();
}

#endif // #if VMA_STATS_STRING_ENABLED

/*
How many suitable free suballocations to analyze before choosing best one.
- Set to 1 to use First-Fit algorithm - first suitable free suballocation will
  be chosen.
- Set to UINT32_MAX to use Best-Fit/Worst-Fit algorithm - all suitable free
  suballocations will be analized and best one will be chosen.
- Any other value is also acceptable.
*/
//static const uint32_t MAX_SUITABLE_SUBALLOCATIONS_TO_CHECK = 8;

void VmaBlockMetadata::CreateFirstAllocationRequest(VmaAllocationRequest* pAllocationRequest)
{
    VMA_ASSERT(IsEmpty());
    pAllocationRequest->offset = 0;
    pAllocationRequest->sumFreeSize = m_SumFreeSize;
    pAllocationRequest->sumItemSize = 0;
    pAllocationRequest->item = m_Suballocations.begin();
    pAllocationRequest->itemsToMakeLostCount = 0;
}

bool VmaBlockMetadata::CreateAllocationRequest(
    uint32_t currentFrameIndex,
    uint32_t frameInUseCount,
    VkDeviceSize bufferImageGranularity,
    VkDeviceSize allocSize,
    VkDeviceSize allocAlignment,
    VmaSuballocationType allocType,
    bool canMakeOtherLost,
    VmaAllocationRequest* pAllocationRequest)
{
    VMA_ASSERT(allocSize > 0);
    VMA_ASSERT(allocType != VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(pAllocationRequest != VMA_NULL);
    VMA_HEAVY_ASSERT(Validate());

    // There is not enough total free space in this block to fullfill the request: Early return.
    if(canMakeOtherLost == false && m_SumFreeSize < allocSize)
    {
        return false;
    }

    // New algorithm, efficiently searching freeSuballocationsBySize.
    const size_t freeSuballocCount = m_FreeSuballocationsBySize.size();
    if(freeSuballocCount > 0)
    {
        if(VMA_BEST_FIT)
        {
            // Find first free suballocation with size not less than allocSize.
            VmaSuballocationList::iterator* const it = VmaBinaryFindFirstNotLess(
                m_FreeSuballocationsBySize.data(),
                m_FreeSuballocationsBySize.data() + freeSuballocCount,
                allocSize,
                VmaSuballocationItemSizeLess());
            size_t index = it - m_FreeSuballocationsBySize.data();
            for(; index < freeSuballocCount; ++index)
            {
                if(CheckAllocation(
                    currentFrameIndex,
                    frameInUseCount,
                    bufferImageGranularity,
                    allocSize,
                    allocAlignment,
                    allocType,
                    m_FreeSuballocationsBySize[index],
                    false, // canMakeOtherLost
                    &pAllocationRequest->offset,
                    &pAllocationRequest->itemsToMakeLostCount,
                    &pAllocationRequest->sumFreeSize,
                    &pAllocationRequest->sumItemSize))
                {
                    pAllocationRequest->item = m_FreeSuballocationsBySize[index];
                    return true;
                }
            }
        }
        else
        {
            // Search staring from biggest suballocations.
            for(size_t index = freeSuballocCount; index--; )
            {
                if(CheckAllocation(
                    currentFrameIndex,
                    frameInUseCount,
                    bufferImageGranularity,
                    allocSize,
                    allocAlignment,
                    allocType,
                    m_FreeSuballocationsBySize[index],
                    false, // canMakeOtherLost
                    &pAllocationRequest->offset,
                    &pAllocationRequest->itemsToMakeLostCount,
                    &pAllocationRequest->sumFreeSize,
                    &pAllocationRequest->sumItemSize))
                {
                    pAllocationRequest->item = m_FreeSuballocationsBySize[index];
                    return true;
                }
            }
        }
    }

    if(canMakeOtherLost)
    {
        // Brute-force algorithm. TODO: Come up with something better.

        pAllocationRequest->sumFreeSize = VK_WHOLE_SIZE;
        pAllocationRequest->sumItemSize = VK_WHOLE_SIZE;

        VmaAllocationRequest tmpAllocRequest = {};
        for(VmaSuballocationList::iterator suballocIt = m_Suballocations.begin();
            suballocIt != m_Suballocations.end();
            ++suballocIt)
        {
            if(suballocIt->type == VMA_SUBALLOCATION_TYPE_FREE ||
                suballocIt->hAllocation->CanBecomeLost())
            {
                if(CheckAllocation(
                    currentFrameIndex,
                    frameInUseCount,
                    bufferImageGranularity,
                    allocSize,
                    allocAlignment,
                    allocType,
                    suballocIt,
                    canMakeOtherLost,
                    &tmpAllocRequest.offset,
                    &tmpAllocRequest.itemsToMakeLostCount,
                    &tmpAllocRequest.sumFreeSize,
                    &tmpAllocRequest.sumItemSize))
                {
                    tmpAllocRequest.item = suballocIt;

                    if(tmpAllocRequest.CalcCost() < pAllocationRequest->CalcCost())
                    {
                        *pAllocationRequest = tmpAllocRequest;
                    }
                }
            }
        }

        if(pAllocationRequest->sumItemSize != VK_WHOLE_SIZE)
        {
            return true;
        }
    }

    return false;
}

bool VmaBlockMetadata::MakeRequestedAllocationsLost(
    uint32_t currentFrameIndex,
    uint32_t frameInUseCount,
    VmaAllocationRequest* pAllocationRequest)
{
    while(pAllocationRequest->itemsToMakeLostCount > 0)
    {
        if(pAllocationRequest->item->type == VMA_SUBALLOCATION_TYPE_FREE)
        {
            ++pAllocationRequest->item;
        }
        VMA_ASSERT(pAllocationRequest->item != m_Suballocations.end());
        VMA_ASSERT(pAllocationRequest->item->hAllocation != VK_NULL_HANDLE);
        VMA_ASSERT(pAllocationRequest->item->hAllocation->CanBecomeLost());
        if(pAllocationRequest->item->hAllocation->MakeLost(currentFrameIndex, frameInUseCount))
        {
            pAllocationRequest->item = FreeSuballocation(pAllocationRequest->item);
            --pAllocationRequest->itemsToMakeLostCount;
        }
        else
        {
            return false;
        }
    }

    VMA_HEAVY_ASSERT(Validate());
    VMA_ASSERT(pAllocationRequest->item != m_Suballocations.end());
    VMA_ASSERT(pAllocationRequest->item->type == VMA_SUBALLOCATION_TYPE_FREE);
    
    return true;
}

uint32_t VmaBlockMetadata::MakeAllocationsLost(uint32_t currentFrameIndex, uint32_t frameInUseCount)
{
    uint32_t lostAllocationCount = 0;
    for(VmaSuballocationList::iterator it = m_Suballocations.begin();
        it != m_Suballocations.end();
        ++it)
    {
        if(it->type != VMA_SUBALLOCATION_TYPE_FREE &&
            it->hAllocation->CanBecomeLost() &&
            it->hAllocation->MakeLost(currentFrameIndex, frameInUseCount))
        {
            it = FreeSuballocation(it);
            ++lostAllocationCount;
        }
    }
    return lostAllocationCount;
}

void VmaBlockMetadata::Alloc(
    const VmaAllocationRequest& request,
    VmaSuballocationType type,
    VkDeviceSize allocSize,
    VmaAllocation hAllocation)
{
    VMA_ASSERT(request.item != m_Suballocations.end());
    VmaSuballocation& suballoc = *request.item;
    // Given suballocation is a free block.
    VMA_ASSERT(suballoc.type == VMA_SUBALLOCATION_TYPE_FREE);
    // Given offset is inside this suballocation.
    VMA_ASSERT(request.offset >= suballoc.offset);
    const VkDeviceSize paddingBegin = request.offset - suballoc.offset;
    VMA_ASSERT(suballoc.size >= paddingBegin + allocSize);
    const VkDeviceSize paddingEnd = suballoc.size - paddingBegin - allocSize;

    // Unregister this free suballocation from m_FreeSuballocationsBySize and update
    // it to become used.
    UnregisterFreeSuballocation(request.item);

    suballoc.offset = request.offset;
    suballoc.size = allocSize;
    suballoc.type = type;
    suballoc.hAllocation = hAllocation;

    // If there are any free bytes remaining at the end, insert new free suballocation after current one.
    if(paddingEnd)
    {
        VmaSuballocation paddingSuballoc = {};
        paddingSuballoc.offset = request.offset + allocSize;
        paddingSuballoc.size = paddingEnd;
        paddingSuballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
        VmaSuballocationList::iterator next = request.item;
        ++next;
        const VmaSuballocationList::iterator paddingEndItem =
            m_Suballocations.insert(next, paddingSuballoc);
        RegisterFreeSuballocation(paddingEndItem);
    }

    // If there are any free bytes remaining at the beginning, insert new free suballocation before current one.
    if(paddingBegin)
    {
        VmaSuballocation paddingSuballoc = {};
        paddingSuballoc.offset = request.offset - paddingBegin;
        paddingSuballoc.size = paddingBegin;
        paddingSuballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
        const VmaSuballocationList::iterator paddingBeginItem =
            m_Suballocations.insert(request.item, paddingSuballoc);
        RegisterFreeSuballocation(paddingBeginItem);
    }

    // Update totals.
    m_FreeCount = m_FreeCount - 1;
    if(paddingBegin > 0)
    {
        ++m_FreeCount;
    }
    if(paddingEnd > 0)
    {
        ++m_FreeCount;
    }
    m_SumFreeSize -= allocSize;
}

void VmaBlockMetadata::Free(const VmaAllocation allocation)
{
    for(VmaSuballocationList::iterator suballocItem = m_Suballocations.begin();
        suballocItem != m_Suballocations.end();
        ++suballocItem)
    {
        VmaSuballocation& suballoc = *suballocItem;
        if(suballoc.hAllocation == allocation)
        {
            FreeSuballocation(suballocItem);
            VMA_HEAVY_ASSERT(Validate());
            return;
        }
    }
    VMA_ASSERT(0 && "Not found!");
}

void VmaBlockMetadata::FreeAtOffset(VkDeviceSize offset)
{
    for(VmaSuballocationList::iterator suballocItem = m_Suballocations.begin();
        suballocItem != m_Suballocations.end();
        ++suballocItem)
    {
        VmaSuballocation& suballoc = *suballocItem;
        if(suballoc.offset == offset)
        {
            FreeSuballocation(suballocItem);
            return;
        }
    }
    VMA_ASSERT(0 && "Not found!");
}

bool VmaBlockMetadata::ValidateFreeSuballocationList() const
{
    VkDeviceSize lastSize = 0;
    for(size_t i = 0, count = m_FreeSuballocationsBySize.size(); i < count; ++i)
    {
        const VmaSuballocationList::iterator it = m_FreeSuballocationsBySize[i];

        if(it->type != VMA_SUBALLOCATION_TYPE_FREE)
        {
            VMA_ASSERT(0);
            return false;
        }
        if(it->size < VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
        {
            VMA_ASSERT(0);
            return false;
        }
        if(it->size < lastSize)
        {
            VMA_ASSERT(0);
            return false;
        }

        lastSize = it->size;
    }
    return true;
}

bool VmaBlockMetadata::CheckAllocation(
    uint32_t currentFrameIndex,
    uint32_t frameInUseCount,
    VkDeviceSize bufferImageGranularity,
    VkDeviceSize allocSize,
    VkDeviceSize allocAlignment,
    VmaSuballocationType allocType,
    VmaSuballocationList::const_iterator suballocItem,
    bool canMakeOtherLost,
    VkDeviceSize* pOffset,
    size_t* itemsToMakeLostCount,
    VkDeviceSize* pSumFreeSize,
    VkDeviceSize* pSumItemSize) const
{
    VMA_ASSERT(allocSize > 0);
    VMA_ASSERT(allocType != VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(suballocItem != m_Suballocations.cend());
    VMA_ASSERT(pOffset != VMA_NULL);
    
    *itemsToMakeLostCount = 0;
    *pSumFreeSize = 0;
    *pSumItemSize = 0;

    if(canMakeOtherLost)
    {
        if(suballocItem->type == VMA_SUBALLOCATION_TYPE_FREE)
        {
            *pSumFreeSize = suballocItem->size;
        }
        else
        {
            if(suballocItem->hAllocation->CanBecomeLost() &&
                suballocItem->hAllocation->GetLastUseFrameIndex() + frameInUseCount < currentFrameIndex)
            {
                ++*itemsToMakeLostCount;
                *pSumItemSize = suballocItem->size;
            }
            else
            {
                return false;
            }
        }

        // Remaining size is too small for this request: Early return.
        if(m_Size - suballocItem->offset < allocSize)
        {
            return false;
        }

        // Start from offset equal to beginning of this suballocation.
        *pOffset = suballocItem->offset;
    
        // Apply VMA_DEBUG_MARGIN at the beginning.
        if((VMA_DEBUG_MARGIN > 0) && suballocItem != m_Suballocations.cbegin())
        {
            *pOffset += VMA_DEBUG_MARGIN;
        }
    
        // Apply alignment.
        const VkDeviceSize alignment = VMA_MAX(allocAlignment, static_cast<VkDeviceSize>(VMA_DEBUG_ALIGNMENT));
        *pOffset = VmaAlignUp(*pOffset, alignment);

        // Check previous suballocations for BufferImageGranularity conflicts.
        // Make bigger alignment if necessary.
        if(bufferImageGranularity > 1)
        {
            bool bufferImageGranularityConflict = false;
            VmaSuballocationList::const_iterator prevSuballocItem = suballocItem;
            while(prevSuballocItem != m_Suballocations.cbegin())
            {
                --prevSuballocItem;
                const VmaSuballocation& prevSuballoc = *prevSuballocItem;
                if(VmaBlocksOnSamePage(prevSuballoc.offset, prevSuballoc.size, *pOffset, bufferImageGranularity))
                {
                    if(VmaIsBufferImageGranularityConflict(prevSuballoc.type, allocType))
                    {
                        bufferImageGranularityConflict = true;
                        break;
                    }
                }
                else
                    // Already on previous page.
                    break;
            }
            if(bufferImageGranularityConflict)
            {
                *pOffset = VmaAlignUp(*pOffset, bufferImageGranularity);
            }
        }
    
        // Now that we have final *pOffset, check if we are past suballocItem.
        // If yes, return false - this function should be called for another suballocItem as starting point.
        if(*pOffset >= suballocItem->offset + suballocItem->size)
        {
            return false;
        }
    
        // Calculate padding at the beginning based on current offset.
        const VkDeviceSize paddingBegin = *pOffset - suballocItem->offset;

        // Calculate required margin at the end if this is not last suballocation.
        VmaSuballocationList::const_iterator next = suballocItem;
        ++next;
        const VkDeviceSize requiredEndMargin =
            (next != m_Suballocations.cend()) ? VMA_DEBUG_MARGIN : 0;

        const VkDeviceSize totalSize = paddingBegin + allocSize + requiredEndMargin;
        // Another early return check.
        if(suballocItem->offset + totalSize > m_Size)
        {
            return false;
        }

        // Advance lastSuballocItem until desired size is reached.
        // Update itemsToMakeLostCount.
        VmaSuballocationList::const_iterator lastSuballocItem = suballocItem;
        if(totalSize > suballocItem->size)
        {
            VkDeviceSize remainingSize = totalSize - suballocItem->size;
            while(remainingSize > 0)
            {
                ++lastSuballocItem;
                if(lastSuballocItem == m_Suballocations.cend())
                {
                    return false;
                }
                if(lastSuballocItem->type == VMA_SUBALLOCATION_TYPE_FREE)
                {
                    *pSumFreeSize += lastSuballocItem->size;
                }
                else
                {
                    VMA_ASSERT(lastSuballocItem->hAllocation != VK_NULL_HANDLE);
                    if(lastSuballocItem->hAllocation->CanBecomeLost() &&
                        lastSuballocItem->hAllocation->GetLastUseFrameIndex() + frameInUseCount < currentFrameIndex)
                    {
                        ++*itemsToMakeLostCount;
                        *pSumItemSize += lastSuballocItem->size;
                    }
                    else
                    {
                        return false;
                    }
                }
                remainingSize = (lastSuballocItem->size < remainingSize) ?
                    remainingSize - lastSuballocItem->size : 0;
            }
        }

        // Check next suballocations for BufferImageGranularity conflicts.
        // If conflict exists, we must mark more allocations lost or fail.
        if(bufferImageGranularity > 1)
        {
            VmaSuballocationList::const_iterator nextSuballocItem = lastSuballocItem;
            ++nextSuballocItem;
            while(nextSuballocItem != m_Suballocations.cend())
            {
                const VmaSuballocation& nextSuballoc = *nextSuballocItem;
                if(VmaBlocksOnSamePage(*pOffset, allocSize, nextSuballoc.offset, bufferImageGranularity))
                {
                    if(VmaIsBufferImageGranularityConflict(allocType, nextSuballoc.type))
                    {
                        VMA_ASSERT(nextSuballoc.hAllocation != VK_NULL_HANDLE);
                        if(nextSuballoc.hAllocation->CanBecomeLost() &&
                            nextSuballoc.hAllocation->GetLastUseFrameIndex() + frameInUseCount < currentFrameIndex)
                        {
                            ++*itemsToMakeLostCount;
                        }
                        else
                        {
                            return false;
                        }
                    }
                }
                else
                {
                    // Already on next page.
                    break;
                }
                ++nextSuballocItem;
            }
        }
    }
    else
    {
        const VmaSuballocation& suballoc = *suballocItem;
        VMA_ASSERT(suballoc.type == VMA_SUBALLOCATION_TYPE_FREE);

        *pSumFreeSize = suballoc.size;

        // Size of this suballocation is too small for this request: Early return.
        if(suballoc.size < allocSize)
        {
            return false;
        }

        // Start from offset equal to beginning of this suballocation.
        *pOffset = suballoc.offset;
    
        // Apply VMA_DEBUG_MARGIN at the beginning.
        if((VMA_DEBUG_MARGIN > 0) && suballocItem != m_Suballocations.cbegin())
        {
            *pOffset += VMA_DEBUG_MARGIN;
        }
    
        // Apply alignment.
        const VkDeviceSize alignment = VMA_MAX(allocAlignment, static_cast<VkDeviceSize>(VMA_DEBUG_ALIGNMENT));
        *pOffset = VmaAlignUp(*pOffset, alignment);
    
        // Check previous suballocations for BufferImageGranularity conflicts.
        // Make bigger alignment if necessary.
        if(bufferImageGranularity > 1)
        {
            bool bufferImageGranularityConflict = false;
            VmaSuballocationList::const_iterator prevSuballocItem = suballocItem;
            while(prevSuballocItem != m_Suballocations.cbegin())
            {
                --prevSuballocItem;
                const VmaSuballocation& prevSuballoc = *prevSuballocItem;
                if(VmaBlocksOnSamePage(prevSuballoc.offset, prevSuballoc.size, *pOffset, bufferImageGranularity))
                {
                    if(VmaIsBufferImageGranularityConflict(prevSuballoc.type, allocType))
                    {
                        bufferImageGranularityConflict = true;
                        break;
                    }
                }
                else
                    // Already on previous page.
                    break;
            }
            if(bufferImageGranularityConflict)
            {
                *pOffset = VmaAlignUp(*pOffset, bufferImageGranularity);
            }
        }
    
        // Calculate padding at the beginning based on current offset.
        const VkDeviceSize paddingBegin = *pOffset - suballoc.offset;

        // Calculate required margin at the end if this is not last suballocation.
        VmaSuballocationList::const_iterator next = suballocItem;
        ++next;
        const VkDeviceSize requiredEndMargin =
            (next != m_Suballocations.cend()) ? VMA_DEBUG_MARGIN : 0;

        // Fail if requested size plus margin before and after is bigger than size of this suballocation.
        if(paddingBegin + allocSize + requiredEndMargin > suballoc.size)
        {
            return false;
        }

        // Check next suballocations for BufferImageGranularity conflicts.
        // If conflict exists, allocation cannot be made here.
        if(bufferImageGranularity > 1)
        {
            VmaSuballocationList::const_iterator nextSuballocItem = suballocItem;
            ++nextSuballocItem;
            while(nextSuballocItem != m_Suballocations.cend())
            {
                const VmaSuballocation& nextSuballoc = *nextSuballocItem;
                if(VmaBlocksOnSamePage(*pOffset, allocSize, nextSuballoc.offset, bufferImageGranularity))
                {
                    if(VmaIsBufferImageGranularityConflict(allocType, nextSuballoc.type))
                    {
                        return false;
                    }
                }
                else
                {
                    // Already on next page.
                    break;
                }
                ++nextSuballocItem;
            }
        }
    }

    // All tests passed: Success. pOffset is already filled.
    return true;
}

void VmaBlockMetadata::MergeFreeWithNext(VmaSuballocationList::iterator item)
{
    VMA_ASSERT(item != m_Suballocations.end());
    VMA_ASSERT(item->type == VMA_SUBALLOCATION_TYPE_FREE);
    
    VmaSuballocationList::iterator nextItem = item;
    ++nextItem;
    VMA_ASSERT(nextItem != m_Suballocations.end());
    VMA_ASSERT(nextItem->type == VMA_SUBALLOCATION_TYPE_FREE);

    item->size += nextItem->size;
    --m_FreeCount;
    m_Suballocations.erase(nextItem);
}

VmaSuballocationList::iterator VmaBlockMetadata::FreeSuballocation(VmaSuballocationList::iterator suballocItem)
{
    // Change this suballocation to be marked as free.
    VmaSuballocation& suballoc = *suballocItem;
    suballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
    suballoc.hAllocation = VK_NULL_HANDLE;
    
    // Update totals.
    ++m_FreeCount;
    m_SumFreeSize += suballoc.size;

    // Merge with previous and/or next suballocation if it's also free.
    bool mergeWithNext = false;
    bool mergeWithPrev = false;
    
    VmaSuballocationList::iterator nextItem = suballocItem;
    ++nextItem;
    if((nextItem != m_Suballocations.end()) && (nextItem->type == VMA_SUBALLOCATION_TYPE_FREE))
    {
        mergeWithNext = true;
    }

    VmaSuballocationList::iterator prevItem = suballocItem;
    if(suballocItem != m_Suballocations.begin())
    {
        --prevItem;
        if(prevItem->type == VMA_SUBALLOCATION_TYPE_FREE)
        {
            mergeWithPrev = true;
        }
    }

    if(mergeWithNext)
    {
        UnregisterFreeSuballocation(nextItem);
        MergeFreeWithNext(suballocItem);
    }

    if(mergeWithPrev)
    {
        UnregisterFreeSuballocation(prevItem);
        MergeFreeWithNext(prevItem);
        RegisterFreeSuballocation(prevItem);
        return prevItem;
    }
    else
    {
        RegisterFreeSuballocation(suballocItem);
        return suballocItem;
    }
}

void VmaBlockMetadata::RegisterFreeSuballocation(VmaSuballocationList::iterator item)
{
    VMA_ASSERT(item->type == VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(item->size > 0);

    // You may want to enable this validation at the beginning or at the end of
    // this function, depending on what do you want to check.
    VMA_HEAVY_ASSERT(ValidateFreeSuballocationList());

    if(item->size >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
    {
        if(m_FreeSuballocationsBySize.empty())
        {
            m_FreeSuballocationsBySize.push_back(item);
        }
        else
        {
            VmaVectorInsertSorted<VmaSuballocationItemSizeLess>(m_FreeSuballocationsBySize, item);
        }
    }

    //VMA_HEAVY_ASSERT(ValidateFreeSuballocationList());
}


void VmaBlockMetadata::UnregisterFreeSuballocation(VmaSuballocationList::iterator item)
{
    VMA_ASSERT(item->type == VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(item->size > 0);

    // You may want to enable this validation at the beginning or at the end of
    // this function, depending on what do you want to check.
    VMA_HEAVY_ASSERT(ValidateFreeSuballocationList());

    if(item->size >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
    {
        VmaSuballocationList::iterator* const it = VmaBinaryFindFirstNotLess(
            m_FreeSuballocationsBySize.data(),
            m_FreeSuballocationsBySize.data() + m_FreeSuballocationsBySize.size(),
            item,
            VmaSuballocationItemSizeLess());
        for(size_t index = it - m_FreeSuballocationsBySize.data();
            index < m_FreeSuballocationsBySize.size();
            ++index)
        {
            if(m_FreeSuballocationsBySize[index] == item)
            {
                VmaVectorRemove(m_FreeSuballocationsBySize, index);
                return;
            }
            VMA_ASSERT((m_FreeSuballocationsBySize[index]->size == item->size) && "Not found.");
        }
        VMA_ASSERT(0 && "Not found.");
    }

    //VMA_HEAVY_ASSERT(ValidateFreeSuballocationList());
}

////////////////////////////////////////////////////////////////////////////////
// class VmaDeviceMemoryBlock

VmaDeviceMemoryBlock::VmaDeviceMemoryBlock(VmaAllocator hAllocator) :
    m_Metadata(hAllocator),
    m_MemoryTypeIndex(UINT32_MAX),
    m_hMemory(VK_NULL_HANDLE),
    m_MapCount(0),
    m_pMappedData(VMA_NULL)
{
}

void VmaDeviceMemoryBlock::Init(
    uint32_t newMemoryTypeIndex,
    VkDeviceMemory newMemory,
    VkDeviceSize newSize)
{
    VMA_ASSERT(m_hMemory == VK_NULL_HANDLE);

    m_MemoryTypeIndex = newMemoryTypeIndex;
    m_hMemory = newMemory;

    m_Metadata.Init(newSize);
}

void VmaDeviceMemoryBlock::Destroy(VmaAllocator allocator)
{
    // This is the most important assert in the entire library.
    // Hitting it means you have some memory leak - unreleased VmaAllocation objects.
    VMA_ASSERT(m_Metadata.IsEmpty() && "Some allocations were not freed before destruction of this memory block!");
    
    VMA_ASSERT(m_hMemory != VK_NULL_HANDLE);
    allocator->FreeVulkanMemory(m_MemoryTypeIndex, m_Metadata.GetSize(), m_hMemory);
    m_hMemory = VK_NULL_HANDLE;
}

bool VmaDeviceMemoryBlock::Validate() const
{
    if((m_hMemory == VK_NULL_HANDLE) ||
        (m_Metadata.GetSize() == 0))
    {
        return false;
    }
    
    return m_Metadata.Validate();
}

VkResult VmaDeviceMemoryBlock::Map(VmaAllocator hAllocator, uint32_t count, void** ppData)
{
    if(count == 0)
    {
        return VK_SUCCESS;
    }

    VmaMutexLock lock(m_Mutex, hAllocator->m_UseMutex);
    if(m_MapCount != 0)
    {
        m_MapCount += count;
        VMA_ASSERT(m_pMappedData != VMA_NULL);
        if(ppData != VMA_NULL)
        {
            *ppData = m_pMappedData;
        }
        return VK_SUCCESS;
    }
    else
    {
        VkResult result = (*hAllocator->GetVulkanFunctions().vkMapMemory)(
            hAllocator->m_hDevice,
            m_hMemory,
            0, // offset
            VK_WHOLE_SIZE,
            0, // flags
            &m_pMappedData);
        if(result == VK_SUCCESS)
        {
            if(ppData != VMA_NULL)
            {
                *ppData = m_pMappedData;
            }
            m_MapCount = count;
        }
        return result;
    }
}

void VmaDeviceMemoryBlock::Unmap(VmaAllocator hAllocator, uint32_t count)
{
    if(count == 0)
    {
        return;
    }

    VmaMutexLock lock(m_Mutex, hAllocator->m_UseMutex);
    if(m_MapCount >= count)
    {
        m_MapCount -= count;
        if(m_MapCount == 0)
        {
            m_pMappedData = VMA_NULL;
            (*hAllocator->GetVulkanFunctions().vkUnmapMemory)(hAllocator->m_hDevice, m_hMemory);
        }
    }
    else
    {
        VMA_ASSERT(0 && "VkDeviceMemory block is being unmapped while it was not previously mapped.");
    }
}

VkResult VmaDeviceMemoryBlock::BindBufferMemory(
    const VmaAllocator hAllocator,
    const VmaAllocation hAllocation,
    VkBuffer hBuffer)
{
    VMA_ASSERT(hAllocation->GetType() == VmaAllocation_T::ALLOCATION_TYPE_BLOCK &&
        hAllocation->GetBlock() == this);
    // This lock is important so that we don't call vkBind... and/or vkMap... simultaneously on the same VkDeviceMemory from multiple threads.
    VmaMutexLock lock(m_Mutex, hAllocator->m_UseMutex);
    return hAllocator->GetVulkanFunctions().vkBindBufferMemory(
        hAllocator->m_hDevice,
        hBuffer,
        m_hMemory,
        hAllocation->GetOffset());
}

VkResult VmaDeviceMemoryBlock::BindImageMemory(
    const VmaAllocator hAllocator,
    const VmaAllocation hAllocation,
    VkImage hImage)
{
    VMA_ASSERT(hAllocation->GetType() == VmaAllocation_T::ALLOCATION_TYPE_BLOCK &&
        hAllocation->GetBlock() == this);
    // This lock is important so that we don't call vkBind... and/or vkMap... simultaneously on the same VkDeviceMemory from multiple threads.
    VmaMutexLock lock(m_Mutex, hAllocator->m_UseMutex);
    return hAllocator->GetVulkanFunctions().vkBindImageMemory(
        hAllocator->m_hDevice,
        hImage,
        m_hMemory,
        hAllocation->GetOffset());
}

static void InitStatInfo(VmaStatInfo& outInfo)
{
    memset(&outInfo, 0, sizeof(outInfo));
    outInfo.allocationSizeMin = UINT64_MAX;
    outInfo.unusedRangeSizeMin = UINT64_MAX;
}

// Adds statistics srcInfo into inoutInfo, like: inoutInfo += srcInfo.
static void VmaAddStatInfo(VmaStatInfo& inoutInfo, const VmaStatInfo& srcInfo)
{
    inoutInfo.blockCount += srcInfo.blockCount;
    inoutInfo.allocationCount += srcInfo.allocationCount;
    inoutInfo.unusedRangeCount += srcInfo.unusedRangeCount;
    inoutInfo.usedBytes += srcInfo.usedBytes;
    inoutInfo.unusedBytes += srcInfo.unusedBytes;
    inoutInfo.allocationSizeMin = VMA_MIN(inoutInfo.allocationSizeMin, srcInfo.allocationSizeMin);
    inoutInfo.allocationSizeMax = VMA_MAX(inoutInfo.allocationSizeMax, srcInfo.allocationSizeMax);
    inoutInfo.unusedRangeSizeMin = VMA_MIN(inoutInfo.unusedRangeSizeMin, srcInfo.unusedRangeSizeMin);
    inoutInfo.unusedRangeSizeMax = VMA_MAX(inoutInfo.unusedRangeSizeMax, srcInfo.unusedRangeSizeMax);
}

static void VmaPostprocessCalcStatInfo(VmaStatInfo& inoutInfo)
{
    inoutInfo.allocationSizeAvg = (inoutInfo.allocationCount > 0) ?
        VmaRoundDiv<VkDeviceSize>(inoutInfo.usedBytes, inoutInfo.allocationCount) : 0;
    inoutInfo.unusedRangeSizeAvg = (inoutInfo.unusedRangeCount > 0) ?
        VmaRoundDiv<VkDeviceSize>(inoutInfo.unusedBytes, inoutInfo.unusedRangeCount) : 0;
}

VmaPool_T::VmaPool_T(
    VmaAllocator hAllocator,
    const VmaPoolCreateInfo& createInfo) :
    m_BlockVector(
        hAllocator,
        createInfo.memoryTypeIndex,
        createInfo.blockSize,
        createInfo.minBlockCount,
        createInfo.maxBlockCount,
        (createInfo.flags & VMA_POOL_CREATE_IGNORE_BUFFER_IMAGE_GRANULARITY_BIT) != 0 ? 1 : hAllocator->GetBufferImageGranularity(),
        createInfo.frameInUseCount,
        true) // isCustomPool
{
}

VmaPool_T::~VmaPool_T()
{
}

#if VMA_STATS_STRING_ENABLED

#endif // #if VMA_STATS_STRING_ENABLED

VmaBlockVector::VmaBlockVector(
    VmaAllocator hAllocator,
    uint32_t memoryTypeIndex,
    VkDeviceSize preferredBlockSize,
    size_t minBlockCount,
    size_t maxBlockCount,
    VkDeviceSize bufferImageGranularity,
    uint32_t frameInUseCount,
    bool isCustomPool) :
    m_hAllocator(hAllocator),
    m_MemoryTypeIndex(memoryTypeIndex),
    m_PreferredBlockSize(preferredBlockSize),
    m_MinBlockCount(minBlockCount),
    m_MaxBlockCount(maxBlockCount),
    m_BufferImageGranularity(bufferImageGranularity),
    m_FrameInUseCount(frameInUseCount),
    m_IsCustomPool(isCustomPool),
    m_Blocks(VmaStlAllocator<VmaDeviceMemoryBlock*>(hAllocator->GetAllocationCallbacks())),
    m_HasEmptyBlock(false),
    m_pDefragmentator(VMA_NULL)
{
}

VmaBlockVector::~VmaBlockVector()
{
    VMA_ASSERT(m_pDefragmentator == VMA_NULL);

    for(size_t i = m_Blocks.size(); i--; )
    {
        m_Blocks[i]->Destroy(m_hAllocator);
        vma_delete(m_hAllocator, m_Blocks[i]);
    }
}

VkResult VmaBlockVector::CreateMinBlocks()
{
    for(size_t i = 0; i < m_MinBlockCount; ++i)
    {
        VkResult res = CreateBlock(m_PreferredBlockSize, VMA_NULL);
        if(res != VK_SUCCESS)
        {
            return res;
        }
    }
    return VK_SUCCESS;
}

void VmaBlockVector::GetPoolStats(VmaPoolStats* pStats)
{
    pStats->size = 0;
    pStats->unusedSize = 0;
    pStats->allocationCount = 0;
    pStats->unusedRangeCount = 0;
    pStats->unusedRangeSizeMax = 0;

    VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);

    for(uint32_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex)
    {
        const VmaDeviceMemoryBlock* const pBlock = m_Blocks[blockIndex];
        VMA_ASSERT(pBlock);
        VMA_HEAVY_ASSERT(pBlock->Validate());
        pBlock->m_Metadata.AddPoolStats(*pStats);
    }
}

static const uint32_t VMA_ALLOCATION_TRY_COUNT = 32;

VkResult VmaBlockVector::Allocate(
    VmaPool hCurrentPool,
    uint32_t currentFrameIndex,
    const VkMemoryRequirements& vkMemReq,
    const VmaAllocationCreateInfo& createInfo,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    const bool mapped = (createInfo.flags & VMA_ALLOCATION_CREATE_MAPPED_BIT) != 0;
    const bool isUserDataString = (createInfo.flags & VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT) != 0;

    VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);

    // 1. Search existing allocations. Try to allocate without making other allocations lost.
    // Forward order in m_Blocks - prefer blocks with smallest amount of free space.
    for(size_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex )
    {
        VmaDeviceMemoryBlock* const pCurrBlock = m_Blocks[blockIndex];
        VMA_ASSERT(pCurrBlock);
        VmaAllocationRequest currRequest = {};
        if(pCurrBlock->m_Metadata.CreateAllocationRequest(
            currentFrameIndex,
            m_FrameInUseCount,
            m_BufferImageGranularity,
            vkMemReq.size,
            vkMemReq.alignment,
            suballocType,
            false, // canMakeOtherLost
            &currRequest))
        {
            // Allocate from pCurrBlock.
            VMA_ASSERT(currRequest.itemsToMakeLostCount == 0);

            if(mapped)
            {
                VkResult res = pCurrBlock->Map(m_hAllocator, 1, VMA_NULL);
                if(res != VK_SUCCESS)
                {
                    return res;
                }
            }
            
            // We no longer have an empty Allocation.
            if(pCurrBlock->m_Metadata.IsEmpty())
            {
                m_HasEmptyBlock = false;
            }
            
            *pAllocation = vma_new(m_hAllocator, VmaAllocation_T)(currentFrameIndex, isUserDataString);
            pCurrBlock->m_Metadata.Alloc(currRequest, suballocType, vkMemReq.size, *pAllocation);
            (*pAllocation)->InitBlockAllocation(
                hCurrentPool,
                pCurrBlock,
                currRequest.offset,
                vkMemReq.alignment,
                vkMemReq.size,
                suballocType,
                mapped,
                (createInfo.flags & VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT) != 0);
            VMA_HEAVY_ASSERT(pCurrBlock->Validate());
            VMA_DEBUG_LOG("    Returned from existing allocation #%u", (uint32_t)blockIndex);
            (*pAllocation)->SetUserData(m_hAllocator, createInfo.pUserData);
            return VK_SUCCESS;
        }
    }

    const bool canCreateNewBlock =
        ((createInfo.flags & VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT) == 0) &&
        (m_Blocks.size() < m_MaxBlockCount);

    // 2. Try to create new block.
    if(canCreateNewBlock)
    {
        // Calculate optimal size for new block.
        VkDeviceSize newBlockSize = m_PreferredBlockSize;
        uint32_t newBlockSizeShift = 0;
        const uint32_t NEW_BLOCK_SIZE_SHIFT_MAX = 3;

        // Allocating blocks of other sizes is allowed only in default pools.
        // In custom pools block size is fixed.
        if(m_IsCustomPool == false)
        {
            // Allocate 1/8, 1/4, 1/2 as first blocks.
            const VkDeviceSize maxExistingBlockSize = CalcMaxBlockSize();
            for(uint32_t i = 0; i < NEW_BLOCK_SIZE_SHIFT_MAX; ++i)
            {
                const VkDeviceSize smallerNewBlockSize = newBlockSize / 2;
                if(smallerNewBlockSize > maxExistingBlockSize && smallerNewBlockSize >= vkMemReq.size * 2)
                {
                    newBlockSize = smallerNewBlockSize;
                    ++newBlockSizeShift;
                }
                else
                {
                    break;
                }
            }
        }

        size_t newBlockIndex = 0;
        VkResult res = CreateBlock(newBlockSize, &newBlockIndex);
        // Allocation of this size failed? Try 1/2, 1/4, 1/8 of m_PreferredBlockSize.
        if(m_IsCustomPool == false)
        {
            while(res < 0 && newBlockSizeShift < NEW_BLOCK_SIZE_SHIFT_MAX)
            {
                const VkDeviceSize smallerNewBlockSize = newBlockSize / 2;
                if(smallerNewBlockSize >= vkMemReq.size)
                {
                    newBlockSize = smallerNewBlockSize;
                    ++newBlockSizeShift;
                    res = CreateBlock(newBlockSize, &newBlockIndex);
                }
                else
                {
                    break;
                }
            }
        }

        if(res == VK_SUCCESS)
        {
            VmaDeviceMemoryBlock* const pBlock = m_Blocks[newBlockIndex];
            VMA_ASSERT(pBlock->m_Metadata.GetSize() >= vkMemReq.size);

            if(mapped)
            {
                res = pBlock->Map(m_hAllocator, 1, VMA_NULL);
                if(res != VK_SUCCESS)
                {
                    return res;
                }
            }

            // Allocate from pBlock. Because it is empty, dstAllocRequest can be trivially filled.
            VmaAllocationRequest allocRequest;
            pBlock->m_Metadata.CreateFirstAllocationRequest(&allocRequest);
            *pAllocation = vma_new(m_hAllocator, VmaAllocation_T)(currentFrameIndex, isUserDataString);
            pBlock->m_Metadata.Alloc(allocRequest, suballocType, vkMemReq.size, *pAllocation);
            (*pAllocation)->InitBlockAllocation(
                hCurrentPool,
                pBlock,
                allocRequest.offset,
                vkMemReq.alignment,
                vkMemReq.size,
                suballocType,
                mapped,
                (createInfo.flags & VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT) != 0);
            VMA_HEAVY_ASSERT(pBlock->Validate());
            VMA_DEBUG_LOG("    Created new allocation Size=%llu", allocInfo.allocationSize);
            (*pAllocation)->SetUserData(m_hAllocator, createInfo.pUserData);
            return VK_SUCCESS;
        }
    }

    const bool canMakeOtherLost = (createInfo.flags & VMA_ALLOCATION_CREATE_CAN_MAKE_OTHER_LOST_BIT) != 0;

    // 3. Try to allocate from existing blocks with making other allocations lost.
    if(canMakeOtherLost)
    {
        uint32_t tryIndex = 0;
        for(; tryIndex < VMA_ALLOCATION_TRY_COUNT; ++tryIndex)
        {
            VmaDeviceMemoryBlock* pBestRequestBlock = VMA_NULL;
            VmaAllocationRequest bestRequest = {};
            VkDeviceSize bestRequestCost = VK_WHOLE_SIZE;

            // 1. Search existing allocations.
            // Forward order in m_Blocks - prefer blocks with smallest amount of free space.
            for(size_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex )
            {
                VmaDeviceMemoryBlock* const pCurrBlock = m_Blocks[blockIndex];
                VMA_ASSERT(pCurrBlock);
                VmaAllocationRequest currRequest = {};
                if(pCurrBlock->m_Metadata.CreateAllocationRequest(
                    currentFrameIndex,
                    m_FrameInUseCount,
                    m_BufferImageGranularity,
                    vkMemReq.size,
                    vkMemReq.alignment,
                    suballocType,
                    canMakeOtherLost,
                    &currRequest))
                {
                    const VkDeviceSize currRequestCost = currRequest.CalcCost();
                    if(pBestRequestBlock == VMA_NULL ||
                        currRequestCost < bestRequestCost)
                    {
                        pBestRequestBlock = pCurrBlock;
                        bestRequest = currRequest;
                        bestRequestCost = currRequestCost;

                        if(bestRequestCost == 0)
                        {
                            break;
                        }
                    }
                }
            }

            if(pBestRequestBlock != VMA_NULL)
            {
                if(mapped)
                {
                    VkResult res = pBestRequestBlock->Map(m_hAllocator, 1, VMA_NULL);
                    if(res != VK_SUCCESS)
                    {
                        return res;
                    }
                }

                if(pBestRequestBlock->m_Metadata.MakeRequestedAllocationsLost(
                    currentFrameIndex,
                    m_FrameInUseCount,
                    &bestRequest))
                {
                    // We no longer have an empty Allocation.
                    if(pBestRequestBlock->m_Metadata.IsEmpty())
                    {
                        m_HasEmptyBlock = false;
                    }
                    // Allocate from this pBlock.
                    *pAllocation = vma_new(m_hAllocator, VmaAllocation_T)(currentFrameIndex, isUserDataString);
                    pBestRequestBlock->m_Metadata.Alloc(bestRequest, suballocType, vkMemReq.size, *pAllocation);
                    (*pAllocation)->InitBlockAllocation(
                        hCurrentPool,
                        pBestRequestBlock,
                        bestRequest.offset,
                        vkMemReq.alignment,
                        vkMemReq.size,
                        suballocType,
                        mapped,
                        (createInfo.flags & VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT) != 0);
                    VMA_HEAVY_ASSERT(pBestRequestBlock->Validate());
                    VMA_DEBUG_LOG("    Returned from existing allocation #%u", (uint32_t)blockIndex);
                    (*pAllocation)->SetUserData(m_hAllocator, createInfo.pUserData);
                    return VK_SUCCESS;
                }
                // else: Some allocations must have been touched while we are here. Next try.
            }
            else
            {
                // Could not find place in any of the blocks - break outer loop.
                break;
            }
        }
        /* Maximum number of tries exceeded - a very unlike event when many other
        threads are simultaneously touching allocations making it impossible to make
        lost at the same time as we try to allocate. */
        if(tryIndex == VMA_ALLOCATION_TRY_COUNT)
        {
            return VK_ERROR_TOO_MANY_OBJECTS;
        }
    }

    return VK_ERROR_OUT_OF_DEVICE_MEMORY;
}

void VmaBlockVector::Free(
    VmaAllocation hAllocation)
{
    VmaDeviceMemoryBlock* pBlockToDelete = VMA_NULL;

    // Scope for lock.
    {
        VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);

        VmaDeviceMemoryBlock* pBlock = hAllocation->GetBlock();

        if(hAllocation->IsPersistentMap())
        {
            pBlock->Unmap(m_hAllocator, 1);
        }

        pBlock->m_Metadata.Free(hAllocation);
        VMA_HEAVY_ASSERT(pBlock->Validate());

        VMA_DEBUG_LOG("  Freed from MemoryTypeIndex=%u", memTypeIndex);

        // pBlock became empty after this deallocation.
        if(pBlock->m_Metadata.IsEmpty())
        {
            // Already has empty Allocation. We don't want to have two, so delete this one.
            if(m_HasEmptyBlock && m_Blocks.size() > m_MinBlockCount)
            {
                pBlockToDelete = pBlock;
                Remove(pBlock);
            }
            // We now have first empty Allocation.
            else
            {
                m_HasEmptyBlock = true;
            }
        }
        // pBlock didn't become empty, but we have another empty block - find and free that one.
        // (This is optional, heuristics.)
        else if(m_HasEmptyBlock)
        {
            VmaDeviceMemoryBlock* pLastBlock = m_Blocks.back();
            if(pLastBlock->m_Metadata.IsEmpty() && m_Blocks.size() > m_MinBlockCount)
            {
                pBlockToDelete = pLastBlock;
                m_Blocks.pop_back();
                m_HasEmptyBlock = false;
            }
        }

        IncrementallySortBlocks();
    }

    // Destruction of a free Allocation. Deferred until this point, outside of mutex
    // lock, for performance reason.
    if(pBlockToDelete != VMA_NULL)
    {
        VMA_DEBUG_LOG("    Deleted empty allocation");
        pBlockToDelete->Destroy(m_hAllocator);
        vma_delete(m_hAllocator, pBlockToDelete);
    }
}

size_t VmaBlockVector::CalcMaxBlockSize() const
{
    size_t result = 0;
    for(size_t i = m_Blocks.size(); i--; )
    {
        result = VMA_MAX((uint64_t)result, (uint64_t)m_Blocks[i]->m_Metadata.GetSize());
        if(result >= m_PreferredBlockSize)
        {
            break;
        }
    }
    return result;
}

void VmaBlockVector::Remove(VmaDeviceMemoryBlock* pBlock)
{
    for(uint32_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex)
    {
        if(m_Blocks[blockIndex] == pBlock)
        {
            VmaVectorRemove(m_Blocks, blockIndex);
            return;
        }
    }
    VMA_ASSERT(0);
}

void VmaBlockVector::IncrementallySortBlocks()
{
    // Bubble sort only until first swap.
    for(size_t i = 1; i < m_Blocks.size(); ++i)
    {
        if(m_Blocks[i - 1]->m_Metadata.GetSumFreeSize() > m_Blocks[i]->m_Metadata.GetSumFreeSize())
        {
            VMA_SWAP(m_Blocks[i - 1], m_Blocks[i]);
            return;
        }
    }
}

VkResult VmaBlockVector::CreateBlock(VkDeviceSize blockSize, size_t* pNewBlockIndex)
{
    VkMemoryAllocateInfo allocInfo = { VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
    allocInfo.memoryTypeIndex = m_MemoryTypeIndex;
    allocInfo.allocationSize = blockSize;
    VkDeviceMemory mem = VK_NULL_HANDLE;
    VkResult res = m_hAllocator->AllocateVulkanMemory(&allocInfo, &mem);
    if(res < 0)
    {
        return res;
    }

    // New VkDeviceMemory successfully created.

    // Create new Allocation for it.
    VmaDeviceMemoryBlock* const pBlock = vma_new(m_hAllocator, VmaDeviceMemoryBlock)(m_hAllocator);
    pBlock->Init(
        m_MemoryTypeIndex,
        mem,
        allocInfo.allocationSize);

    m_Blocks.push_back(pBlock);
    if(pNewBlockIndex != VMA_NULL)
    {
        *pNewBlockIndex = m_Blocks.size() - 1;
    }

    return VK_SUCCESS;
}

#if VMA_STATS_STRING_ENABLED

void VmaBlockVector::PrintDetailedMap(class VmaJsonWriter& json)
{
    VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);

    json.BeginObject();

    if(m_IsCustomPool)
    {
        json.WriteString("MemoryTypeIndex");
        json.WriteNumber(m_MemoryTypeIndex);

        json.WriteString("BlockSize");
        json.WriteNumber(m_PreferredBlockSize);

        json.WriteString("BlockCount");
        json.BeginObject(true);
        if(m_MinBlockCount > 0)
        {
            json.WriteString("Min");
            json.WriteNumber((uint64_t)m_MinBlockCount);
        }
        if(m_MaxBlockCount < SIZE_MAX)
        {
            json.WriteString("Max");
            json.WriteNumber((uint64_t)m_MaxBlockCount);
        }
        json.WriteString("Cur");
        json.WriteNumber((uint64_t)m_Blocks.size());
        json.EndObject();

        if(m_FrameInUseCount > 0)
        {
            json.WriteString("FrameInUseCount");
            json.WriteNumber(m_FrameInUseCount);
        }
    }
    else
    {
        json.WriteString("PreferredBlockSize");
        json.WriteNumber(m_PreferredBlockSize);
    }

    json.WriteString("Blocks");
    json.BeginArray();
    for(size_t i = 0; i < m_Blocks.size(); ++i)
    {
        m_Blocks[i]->m_Metadata.PrintDetailedMap(json);
    }
    json.EndArray();

    json.EndObject();
}

#endif // #if VMA_STATS_STRING_ENABLED

VmaDefragmentator* VmaBlockVector::EnsureDefragmentator(
    VmaAllocator hAllocator,
    uint32_t currentFrameIndex)
{
    if(m_pDefragmentator == VMA_NULL)
    {
        m_pDefragmentator = vma_new(m_hAllocator, VmaDefragmentator)(
            hAllocator,
            this,
            currentFrameIndex);
    }

    return m_pDefragmentator;
}

VkResult VmaBlockVector::Defragment(
    VmaDefragmentationStats* pDefragmentationStats,
    VkDeviceSize& maxBytesToMove,
    uint32_t& maxAllocationsToMove)
{
    if(m_pDefragmentator == VMA_NULL)
    {
        return VK_SUCCESS;
    }

    VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);

    // Defragment.
    VkResult result = m_pDefragmentator->Defragment(maxBytesToMove, maxAllocationsToMove);

    // Accumulate statistics.
    if(pDefragmentationStats != VMA_NULL)
    {
        const VkDeviceSize bytesMoved = m_pDefragmentator->GetBytesMoved();
        const uint32_t allocationsMoved = m_pDefragmentator->GetAllocationsMoved();
        pDefragmentationStats->bytesMoved += bytesMoved;
        pDefragmentationStats->allocationsMoved += allocationsMoved;
        VMA_ASSERT(bytesMoved <= maxBytesToMove);
        VMA_ASSERT(allocationsMoved <= maxAllocationsToMove);
        maxBytesToMove -= bytesMoved;
        maxAllocationsToMove -= allocationsMoved;
    }
    
    // Free empty blocks.
    m_HasEmptyBlock = false;
    for(size_t blockIndex = m_Blocks.size(); blockIndex--; )
    {
        VmaDeviceMemoryBlock* pBlock = m_Blocks[blockIndex];
        if(pBlock->m_Metadata.IsEmpty())
        {
            if(m_Blocks.size() > m_MinBlockCount)
            {
                if(pDefragmentationStats != VMA_NULL)
                {
                    ++pDefragmentationStats->deviceMemoryBlocksFreed;
                    pDefragmentationStats->bytesFreed += pBlock->m_Metadata.GetSize();
                }

                VmaVectorRemove(m_Blocks, blockIndex);
                pBlock->Destroy(m_hAllocator);
                vma_delete(m_hAllocator, pBlock);
            }
            else
            {
                m_HasEmptyBlock = true;
            }
        }
    }

    return result;
}

void VmaBlockVector::DestroyDefragmentator()
{
    if(m_pDefragmentator != VMA_NULL)
    {
        vma_delete(m_hAllocator, m_pDefragmentator);
        m_pDefragmentator = VMA_NULL;
    }
}

void VmaBlockVector::MakePoolAllocationsLost(
    uint32_t currentFrameIndex,
    size_t* pLostAllocationCount)
{
    VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);
    size_t lostAllocationCount = 0;
    for(uint32_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex)
    {
        VmaDeviceMemoryBlock* const pBlock = m_Blocks[blockIndex];
        VMA_ASSERT(pBlock);
        lostAllocationCount += pBlock->m_Metadata.MakeAllocationsLost(currentFrameIndex, m_FrameInUseCount);
    }
    if(pLostAllocationCount != VMA_NULL)
    {
        *pLostAllocationCount = lostAllocationCount;
    }
}

void VmaBlockVector::AddStats(VmaStats* pStats)
{
    const uint32_t memTypeIndex = m_MemoryTypeIndex;
    const uint32_t memHeapIndex = m_hAllocator->MemoryTypeIndexToHeapIndex(memTypeIndex);

    VmaMutexLock lock(m_Mutex, m_hAllocator->m_UseMutex);

    for(uint32_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex)
    {
        const VmaDeviceMemoryBlock* const pBlock = m_Blocks[blockIndex];
        VMA_ASSERT(pBlock);
        VMA_HEAVY_ASSERT(pBlock->Validate());
        VmaStatInfo allocationStatInfo;
        pBlock->m_Metadata.CalcAllocationStatInfo(allocationStatInfo);
        VmaAddStatInfo(pStats->total, allocationStatInfo);
        VmaAddStatInfo(pStats->memoryType[memTypeIndex], allocationStatInfo);
        VmaAddStatInfo(pStats->memoryHeap[memHeapIndex], allocationStatInfo);
    }
}

////////////////////////////////////////////////////////////////////////////////
// VmaDefragmentator members definition

VmaDefragmentator::VmaDefragmentator(
    VmaAllocator hAllocator,
    VmaBlockVector* pBlockVector,
    uint32_t currentFrameIndex) :
    m_hAllocator(hAllocator),
    m_pBlockVector(pBlockVector),
    m_CurrentFrameIndex(currentFrameIndex),
    m_BytesMoved(0),
    m_AllocationsMoved(0),
    m_Allocations(VmaStlAllocator<AllocationInfo>(hAllocator->GetAllocationCallbacks())),
    m_Blocks(VmaStlAllocator<BlockInfo*>(hAllocator->GetAllocationCallbacks()))
{
}

VmaDefragmentator::~VmaDefragmentator()
{
    for(size_t i = m_Blocks.size(); i--; )
    {
        vma_delete(m_hAllocator, m_Blocks[i]);
    }
}

void VmaDefragmentator::AddAllocation(VmaAllocation hAlloc, VkBool32* pChanged)
{
    AllocationInfo allocInfo;
    allocInfo.m_hAllocation = hAlloc;
    allocInfo.m_pChanged = pChanged;
    m_Allocations.push_back(allocInfo);
}

VkResult VmaDefragmentator::BlockInfo::EnsureMapping(VmaAllocator hAllocator, void** ppMappedData)
{
    // It has already been mapped for defragmentation.
    if(m_pMappedDataForDefragmentation)
    {
        *ppMappedData = m_pMappedDataForDefragmentation;
        return VK_SUCCESS;
    }
            
    // It is originally mapped.
    if(m_pBlock->GetMappedData())
    {
        *ppMappedData = m_pBlock->GetMappedData();
        return VK_SUCCESS;
    }
            
    // Map on first usage.
    VkResult res = m_pBlock->Map(hAllocator, 1, &m_pMappedDataForDefragmentation);
    *ppMappedData = m_pMappedDataForDefragmentation;
    return res;
}

void VmaDefragmentator::BlockInfo::Unmap(VmaAllocator hAllocator)
{
    if(m_pMappedDataForDefragmentation != VMA_NULL)
    {
        m_pBlock->Unmap(hAllocator, 1);
    }
}

VkResult VmaDefragmentator::DefragmentRound(
    VkDeviceSize maxBytesToMove,
    uint32_t maxAllocationsToMove)
{
    if(m_Blocks.empty())
    {
        return VK_SUCCESS;
    }

    size_t srcBlockIndex = m_Blocks.size() - 1;
    size_t srcAllocIndex = SIZE_MAX;
    for(;;)
    {
        // 1. Find next allocation to move.
        // 1.1. Start from last to first m_Blocks - they are sorted from most "destination" to most "source".
        // 1.2. Then start from last to first m_Allocations - they are sorted from largest to smallest.
        while(srcAllocIndex >= m_Blocks[srcBlockIndex]->m_Allocations.size())
        {
            if(m_Blocks[srcBlockIndex]->m_Allocations.empty())
            {
                // Finished: no more allocations to process.
                if(srcBlockIndex == 0)
                {
                    return VK_SUCCESS;
                }
                else
                {
                    --srcBlockIndex;
                    srcAllocIndex = SIZE_MAX;
                }
            }
            else
            {
                srcAllocIndex = m_Blocks[srcBlockIndex]->m_Allocations.size() - 1;
            }
        }
        
        BlockInfo* pSrcBlockInfo = m_Blocks[srcBlockIndex];
        AllocationInfo& allocInfo = pSrcBlockInfo->m_Allocations[srcAllocIndex];

        const VkDeviceSize size = allocInfo.m_hAllocation->GetSize();
        const VkDeviceSize srcOffset = allocInfo.m_hAllocation->GetOffset();
        const VkDeviceSize alignment = allocInfo.m_hAllocation->GetAlignment();
        const VmaSuballocationType suballocType = allocInfo.m_hAllocation->GetSuballocationType();

        // 2. Try to find new place for this allocation in preceding or current block.
        for(size_t dstBlockIndex = 0; dstBlockIndex <= srcBlockIndex; ++dstBlockIndex)
        {
            BlockInfo* pDstBlockInfo = m_Blocks[dstBlockIndex];
            VmaAllocationRequest dstAllocRequest;
            if(pDstBlockInfo->m_pBlock->m_Metadata.CreateAllocationRequest(
                m_CurrentFrameIndex,
                m_pBlockVector->GetFrameInUseCount(),
                m_pBlockVector->GetBufferImageGranularity(),
                size,
                alignment,
                suballocType,
                false, // canMakeOtherLost
                &dstAllocRequest) &&
            MoveMakesSense(
                dstBlockIndex, dstAllocRequest.offset, srcBlockIndex, srcOffset))
            {
                VMA_ASSERT(dstAllocRequest.itemsToMakeLostCount == 0);

                // Reached limit on number of allocations or bytes to move.
                if((m_AllocationsMoved + 1 > maxAllocationsToMove) ||
                    (m_BytesMoved + size > maxBytesToMove))
                {
                    return VK_INCOMPLETE;
                }

                void* pDstMappedData = VMA_NULL;
                VkResult res = pDstBlockInfo->EnsureMapping(m_hAllocator, &pDstMappedData);
                if(res != VK_SUCCESS)
                {
                    return res;
                }

                void* pSrcMappedData = VMA_NULL;
                res = pSrcBlockInfo->EnsureMapping(m_hAllocator, &pSrcMappedData);
                if(res != VK_SUCCESS)
                {
                    return res;
                }
                
                // THE PLACE WHERE ACTUAL DATA COPY HAPPENS.
                memcpy(
                    reinterpret_cast<char*>(pDstMappedData) + dstAllocRequest.offset,
                    reinterpret_cast<char*>(pSrcMappedData) + srcOffset,
                    static_cast<size_t>(size));
                
                pDstBlockInfo->m_pBlock->m_Metadata.Alloc(dstAllocRequest, suballocType, size, allocInfo.m_hAllocation);
                pSrcBlockInfo->m_pBlock->m_Metadata.FreeAtOffset(srcOffset);
                
                allocInfo.m_hAllocation->ChangeBlockAllocation(m_hAllocator, pDstBlockInfo->m_pBlock, dstAllocRequest.offset);

                if(allocInfo.m_pChanged != VMA_NULL)
                {
                    *allocInfo.m_pChanged = VK_TRUE;
                }

                ++m_AllocationsMoved;
                m_BytesMoved += size;

                VmaVectorRemove(pSrcBlockInfo->m_Allocations, srcAllocIndex);

                break;
            }
        }

        // If not processed, this allocInfo remains in pBlockInfo->m_Allocations for next round.

        if(srcAllocIndex > 0)
        {
            --srcAllocIndex;
        }
        else
        {
            if(srcBlockIndex > 0)
            {
                --srcBlockIndex;
                srcAllocIndex = SIZE_MAX;
            }
            else
            {
                return VK_SUCCESS;
            }
        }
    }
}

VkResult VmaDefragmentator::Defragment(
    VkDeviceSize maxBytesToMove,
    uint32_t maxAllocationsToMove)
{
    if(m_Allocations.empty())
    {
        return VK_SUCCESS;
    }

    // Create block info for each block.
    const size_t blockCount = m_pBlockVector->m_Blocks.size();
    for(size_t blockIndex = 0; blockIndex < blockCount; ++blockIndex)
    {
        BlockInfo* pBlockInfo = vma_new(m_hAllocator, BlockInfo)(m_hAllocator->GetAllocationCallbacks());
        pBlockInfo->m_pBlock = m_pBlockVector->m_Blocks[blockIndex];
        m_Blocks.push_back(pBlockInfo);
    }

    // Sort them by m_pBlock pointer value.
    VMA_SORT(m_Blocks.begin(), m_Blocks.end(), BlockPointerLess());

    // Move allocation infos from m_Allocations to appropriate m_Blocks[memTypeIndex].m_Allocations.
    for(size_t blockIndex = 0, allocCount = m_Allocations.size(); blockIndex < allocCount; ++blockIndex)
    {
        AllocationInfo& allocInfo = m_Allocations[blockIndex];
        // Now as we are inside VmaBlockVector::m_Mutex, we can make final check if this allocation was not lost.
        if(allocInfo.m_hAllocation->GetLastUseFrameIndex() != VMA_FRAME_INDEX_LOST)
        {
            VmaDeviceMemoryBlock* pBlock = allocInfo.m_hAllocation->GetBlock();
            BlockInfoVector::iterator it = VmaBinaryFindFirstNotLess(m_Blocks.begin(), m_Blocks.end(), pBlock, BlockPointerLess());
            if(it != m_Blocks.end() && (*it)->m_pBlock == pBlock)
            {
                (*it)->m_Allocations.push_back(allocInfo);
            }
            else
            {
                VMA_ASSERT(0);
            }
        }
    }
    m_Allocations.clear();

    for(size_t blockIndex = 0; blockIndex < blockCount; ++blockIndex)
    {
        BlockInfo* pBlockInfo = m_Blocks[blockIndex];
        pBlockInfo->CalcHasNonMovableAllocations();
        pBlockInfo->SortAllocationsBySizeDescecnding();
    }

    // Sort m_Blocks this time by the main criterium, from most "destination" to most "source" blocks.
    VMA_SORT(m_Blocks.begin(), m_Blocks.end(), BlockInfoCompareMoveDestination());

    // Execute defragmentation rounds (the main part).
    VkResult result = VK_SUCCESS;
    for(size_t round = 0; (round < 2) && (result == VK_SUCCESS); ++round)
    {
        result = DefragmentRound(maxBytesToMove, maxAllocationsToMove);
    }

    // Unmap blocks that were mapped for defragmentation.
    for(size_t blockIndex = 0; blockIndex < blockCount; ++blockIndex)
    {
        m_Blocks[blockIndex]->Unmap(m_hAllocator);
    }

    return result;
}

bool VmaDefragmentator::MoveMakesSense(
        size_t dstBlockIndex, VkDeviceSize dstOffset,
        size_t srcBlockIndex, VkDeviceSize srcOffset)
{
    if(dstBlockIndex < srcBlockIndex)
    {
        return true;
    }
    if(dstBlockIndex > srcBlockIndex)
    {
        return false;
    }
    if(dstOffset < srcOffset)
    {
        return true;
    }
    return false;
}

////////////////////////////////////////////////////////////////////////////////
// VmaAllocator_T

VmaAllocator_T::VmaAllocator_T(const VmaAllocatorCreateInfo* pCreateInfo) :
    m_UseMutex((pCreateInfo->flags & VMA_ALLOCATOR_CREATE_EXTERNALLY_SYNCHRONIZED_BIT) == 0),
    m_UseKhrDedicatedAllocation((pCreateInfo->flags & VMA_ALLOCATOR_CREATE_KHR_DEDICATED_ALLOCATION_BIT) != 0),
    m_hDevice(pCreateInfo->device),
    m_AllocationCallbacksSpecified(pCreateInfo->pAllocationCallbacks != VMA_NULL),
    m_AllocationCallbacks(pCreateInfo->pAllocationCallbacks ?
        *pCreateInfo->pAllocationCallbacks : VmaEmptyAllocationCallbacks),
    m_PreferredLargeHeapBlockSize(0),
    m_PhysicalDevice(pCreateInfo->physicalDevice),
    m_CurrentFrameIndex(0),
    m_Pools(VmaStlAllocator<VmaPool>(GetAllocationCallbacks()))
{
    VMA_ASSERT(pCreateInfo->physicalDevice && pCreateInfo->device);    

    memset(&m_DeviceMemoryCallbacks, 0 ,sizeof(m_DeviceMemoryCallbacks));
    memset(&m_MemProps, 0, sizeof(m_MemProps));
    memset(&m_PhysicalDeviceProperties, 0, sizeof(m_PhysicalDeviceProperties));
        
    memset(&m_pBlockVectors, 0, sizeof(m_pBlockVectors));
    memset(&m_pDedicatedAllocations, 0, sizeof(m_pDedicatedAllocations));

    for(uint32_t i = 0; i < VK_MAX_MEMORY_HEAPS; ++i)
    {
        m_HeapSizeLimit[i] = VK_WHOLE_SIZE;
    }

    if(pCreateInfo->pDeviceMemoryCallbacks != VMA_NULL)
    {
        m_DeviceMemoryCallbacks.pfnAllocate = pCreateInfo->pDeviceMemoryCallbacks->pfnAllocate;
        m_DeviceMemoryCallbacks.pfnFree = pCreateInfo->pDeviceMemoryCallbacks->pfnFree;
    }

    ImportVulkanFunctions(pCreateInfo->pVulkanFunctions);

    (*m_VulkanFunctions.vkGetPhysicalDeviceProperties)(m_PhysicalDevice, &m_PhysicalDeviceProperties);
    (*m_VulkanFunctions.vkGetPhysicalDeviceMemoryProperties)(m_PhysicalDevice, &m_MemProps);

    m_PreferredLargeHeapBlockSize = (pCreateInfo->preferredLargeHeapBlockSize != 0) ?
        pCreateInfo->preferredLargeHeapBlockSize : static_cast<VkDeviceSize>(VMA_DEFAULT_LARGE_HEAP_BLOCK_SIZE);

    if(pCreateInfo->pHeapSizeLimit != VMA_NULL)
    {
        for(uint32_t heapIndex = 0; heapIndex < GetMemoryHeapCount(); ++heapIndex)
        {
            const VkDeviceSize limit = pCreateInfo->pHeapSizeLimit[heapIndex];
            if(limit != VK_WHOLE_SIZE)
            {
                m_HeapSizeLimit[heapIndex] = limit;
                if(limit < m_MemProps.memoryHeaps[heapIndex].size)
                {
                    m_MemProps.memoryHeaps[heapIndex].size = limit;
                }
            }
        }
    }

    for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        const VkDeviceSize preferredBlockSize = CalcPreferredBlockSize(memTypeIndex);

        m_pBlockVectors[memTypeIndex] = vma_new(this, VmaBlockVector)(
            this,
            memTypeIndex,
            preferredBlockSize,
            0,
            SIZE_MAX,
            GetBufferImageGranularity(),
            pCreateInfo->frameInUseCount,
            false); // isCustomPool
        // No need to call m_pBlockVectors[memTypeIndex][blockVectorTypeIndex]->CreateMinBlocks here,
        // becase minBlockCount is 0.
        m_pDedicatedAllocations[memTypeIndex] = vma_new(this, AllocationVectorType)(VmaStlAllocator<VmaAllocation>(GetAllocationCallbacks()));
    }
}

VmaAllocator_T::~VmaAllocator_T()
{
    VMA_ASSERT(m_Pools.empty());

    for(size_t i = GetMemoryTypeCount(); i--; )
    {
        vma_delete(this, m_pDedicatedAllocations[i]);
        vma_delete(this, m_pBlockVectors[i]);
    }
}

void VmaAllocator_T::ImportVulkanFunctions(const VmaVulkanFunctions* pVulkanFunctions)
{
#if VMA_STATIC_VULKAN_FUNCTIONS == 1
    m_VulkanFunctions.vkGetPhysicalDeviceProperties = &vkGetPhysicalDeviceProperties;
    m_VulkanFunctions.vkGetPhysicalDeviceMemoryProperties = &vkGetPhysicalDeviceMemoryProperties;
    m_VulkanFunctions.vkAllocateMemory = &vkAllocateMemory;
    m_VulkanFunctions.vkFreeMemory = &vkFreeMemory;
    m_VulkanFunctions.vkMapMemory = &vkMapMemory;
    m_VulkanFunctions.vkUnmapMemory = &vkUnmapMemory;
    m_VulkanFunctions.vkBindBufferMemory = &vkBindBufferMemory;
    m_VulkanFunctions.vkBindImageMemory = &vkBindImageMemory;
    m_VulkanFunctions.vkGetBufferMemoryRequirements = &vkGetBufferMemoryRequirements;
    m_VulkanFunctions.vkGetImageMemoryRequirements = &vkGetImageMemoryRequirements;
    m_VulkanFunctions.vkCreateBuffer = &vkCreateBuffer;
    m_VulkanFunctions.vkDestroyBuffer = &vkDestroyBuffer;
    m_VulkanFunctions.vkCreateImage = &vkCreateImage;
    m_VulkanFunctions.vkDestroyImage = &vkDestroyImage;
    if(m_UseKhrDedicatedAllocation)
    {
        m_VulkanFunctions.vkGetBufferMemoryRequirements2KHR =
            (PFN_vkGetBufferMemoryRequirements2KHR)vkGetDeviceProcAddr(m_hDevice, "vkGetBufferMemoryRequirements2KHR");
        m_VulkanFunctions.vkGetImageMemoryRequirements2KHR =
            (PFN_vkGetImageMemoryRequirements2KHR)vkGetDeviceProcAddr(m_hDevice, "vkGetImageMemoryRequirements2KHR");
    }
#endif // #if VMA_STATIC_VULKAN_FUNCTIONS == 1

#define VMA_COPY_IF_NOT_NULL(funcName) \
    if(pVulkanFunctions->funcName != VMA_NULL) m_VulkanFunctions.funcName = pVulkanFunctions->funcName;

    if(pVulkanFunctions != VMA_NULL)
    {
        VMA_COPY_IF_NOT_NULL(vkGetPhysicalDeviceProperties);
        VMA_COPY_IF_NOT_NULL(vkGetPhysicalDeviceMemoryProperties);
        VMA_COPY_IF_NOT_NULL(vkAllocateMemory);
        VMA_COPY_IF_NOT_NULL(vkFreeMemory);
        VMA_COPY_IF_NOT_NULL(vkMapMemory);
        VMA_COPY_IF_NOT_NULL(vkUnmapMemory);
        VMA_COPY_IF_NOT_NULL(vkBindBufferMemory);
        VMA_COPY_IF_NOT_NULL(vkBindImageMemory);
        VMA_COPY_IF_NOT_NULL(vkGetBufferMemoryRequirements);
        VMA_COPY_IF_NOT_NULL(vkGetImageMemoryRequirements);
        VMA_COPY_IF_NOT_NULL(vkCreateBuffer);
        VMA_COPY_IF_NOT_NULL(vkDestroyBuffer);
        VMA_COPY_IF_NOT_NULL(vkCreateImage);
        VMA_COPY_IF_NOT_NULL(vkDestroyImage);
        VMA_COPY_IF_NOT_NULL(vkGetBufferMemoryRequirements2KHR);
        VMA_COPY_IF_NOT_NULL(vkGetImageMemoryRequirements2KHR);
    }

#undef VMA_COPY_IF_NOT_NULL

    // If these asserts are hit, you must either #define VMA_STATIC_VULKAN_FUNCTIONS 1
    // or pass valid pointers as VmaAllocatorCreateInfo::pVulkanFunctions.
    VMA_ASSERT(m_VulkanFunctions.vkGetPhysicalDeviceProperties != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkGetPhysicalDeviceMemoryProperties != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkAllocateMemory != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkFreeMemory != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkMapMemory != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkUnmapMemory != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkBindBufferMemory != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkBindImageMemory != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkGetBufferMemoryRequirements != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkGetImageMemoryRequirements != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkCreateBuffer != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkDestroyBuffer != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkCreateImage != VMA_NULL);
    VMA_ASSERT(m_VulkanFunctions.vkDestroyImage != VMA_NULL);
    if(m_UseKhrDedicatedAllocation)
    {
        VMA_ASSERT(m_VulkanFunctions.vkGetBufferMemoryRequirements2KHR != VMA_NULL);
        VMA_ASSERT(m_VulkanFunctions.vkGetImageMemoryRequirements2KHR != VMA_NULL);
    }
}

VkDeviceSize VmaAllocator_T::CalcPreferredBlockSize(uint32_t memTypeIndex)
{
    const uint32_t heapIndex = MemoryTypeIndexToHeapIndex(memTypeIndex);
    const VkDeviceSize heapSize = m_MemProps.memoryHeaps[heapIndex].size;
    const bool isSmallHeap = heapSize <= VMA_SMALL_HEAP_MAX_SIZE;
    return isSmallHeap ? (heapSize / 8) : m_PreferredLargeHeapBlockSize;
}

VkResult VmaAllocator_T::AllocateMemoryOfType(
    const VkMemoryRequirements& vkMemReq,
    bool dedicatedAllocation,
    VkBuffer dedicatedBuffer,
    VkImage dedicatedImage,
    const VmaAllocationCreateInfo& createInfo,
    uint32_t memTypeIndex,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(pAllocation != VMA_NULL);
    VMA_DEBUG_LOG("  AllocateMemory: MemoryTypeIndex=%u, Size=%llu", memTypeIndex, vkMemReq.size);

    VmaAllocationCreateInfo finalCreateInfo = createInfo;

    // If memory type is not HOST_VISIBLE, disable MAPPED.
    if((finalCreateInfo.flags & VMA_ALLOCATION_CREATE_MAPPED_BIT) != 0 &&
        (m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) == 0)
    {
        finalCreateInfo.flags &= ~VMA_ALLOCATION_CREATE_MAPPED_BIT;
    }

    VmaBlockVector* const blockVector = m_pBlockVectors[memTypeIndex];
    VMA_ASSERT(blockVector);

    const VkDeviceSize preferredBlockSize = blockVector->GetPreferredBlockSize();
    bool preferDedicatedMemory =
        VMA_DEBUG_ALWAYS_DEDICATED_MEMORY ||
        dedicatedAllocation ||
        // Heuristics: Allocate dedicated memory if requested size if greater than half of preferred block size.
        vkMemReq.size > preferredBlockSize / 2;

    if(preferDedicatedMemory &&
        (finalCreateInfo.flags & VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT) == 0 &&
        finalCreateInfo.pool == VK_NULL_HANDLE)
    {
        finalCreateInfo.flags |= VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT;
    }

    if((finalCreateInfo.flags & VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT) != 0)
    {
        if((finalCreateInfo.flags & VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT) != 0)
        {
            return VK_ERROR_OUT_OF_DEVICE_MEMORY;
        }
        else
        {
            return AllocateDedicatedMemory(
                vkMemReq.size,
                suballocType,
                memTypeIndex,
                (finalCreateInfo.flags & VMA_ALLOCATION_CREATE_MAPPED_BIT) != 0,
                (finalCreateInfo.flags & VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT) != 0,
                finalCreateInfo.pUserData,
                dedicatedBuffer,
                dedicatedImage,
                pAllocation);
        }
    }
    else
    {
        VkResult res = blockVector->Allocate(
            VK_NULL_HANDLE, // hCurrentPool
            m_CurrentFrameIndex.load(),
            vkMemReq,
            finalCreateInfo,
            suballocType,
            pAllocation);
        if(res == VK_SUCCESS)
        {
            return res;
        }

        // 5. Try dedicated memory.
        if((finalCreateInfo.flags & VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT) != 0)
        {
            return VK_ERROR_OUT_OF_DEVICE_MEMORY;
        }
        else
        {
            res = AllocateDedicatedMemory(
                vkMemReq.size,
                suballocType,
                memTypeIndex,
                (finalCreateInfo.flags & VMA_ALLOCATION_CREATE_MAPPED_BIT) != 0,
                (finalCreateInfo.flags & VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT) != 0,
                finalCreateInfo.pUserData,
                dedicatedBuffer,
                dedicatedImage,
                pAllocation);
            if(res == VK_SUCCESS)
            {
                // Succeeded: AllocateDedicatedMemory function already filld pMemory, nothing more to do here.
                VMA_DEBUG_LOG("    Allocated as DedicatedMemory");
                return VK_SUCCESS;
            }
            else
            {
                // Everything failed: Return error code.
                VMA_DEBUG_LOG("    vkAllocateMemory FAILED");
                return res;
            }
        }
    }
}

VkResult VmaAllocator_T::AllocateDedicatedMemory(
    VkDeviceSize size,
    VmaSuballocationType suballocType,
    uint32_t memTypeIndex,
    bool map,
    bool isUserDataString,
    void* pUserData,
    VkBuffer dedicatedBuffer,
    VkImage dedicatedImage,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(pAllocation);

    VkMemoryAllocateInfo allocInfo = { VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
    allocInfo.memoryTypeIndex = memTypeIndex;
    allocInfo.allocationSize = size;

    VkMemoryDedicatedAllocateInfoKHR dedicatedAllocInfo = { VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR };
    if(m_UseKhrDedicatedAllocation)
    {
        if(dedicatedBuffer != VK_NULL_HANDLE)
        {
            VMA_ASSERT(dedicatedImage == VK_NULL_HANDLE);
            dedicatedAllocInfo.buffer = dedicatedBuffer;
            allocInfo.pNext = &dedicatedAllocInfo;
        }
        else if(dedicatedImage != VK_NULL_HANDLE)
        {
            dedicatedAllocInfo.image = dedicatedImage;
            allocInfo.pNext = &dedicatedAllocInfo;
        }
    }

    // Allocate VkDeviceMemory.
    VkDeviceMemory hMemory = VK_NULL_HANDLE;
    VkResult res = AllocateVulkanMemory(&allocInfo, &hMemory);
    if(res < 0)
    {
        VMA_DEBUG_LOG("    vkAllocateMemory FAILED");
        return res;
    }

    void* pMappedData = VMA_NULL;
    if(map)
    {
        res = (*m_VulkanFunctions.vkMapMemory)(
            m_hDevice,
            hMemory,
            0,
            VK_WHOLE_SIZE,
            0,
            &pMappedData);
        if(res < 0)
        {
            VMA_DEBUG_LOG("    vkMapMemory FAILED");
            FreeVulkanMemory(memTypeIndex, size, hMemory);
            return res;
        }
    }

    *pAllocation = vma_new(this, VmaAllocation_T)(m_CurrentFrameIndex.load(), isUserDataString);
    (*pAllocation)->InitDedicatedAllocation(memTypeIndex, hMemory, suballocType, pMappedData, size);
    (*pAllocation)->SetUserData(this, pUserData);

    // Register it in m_pDedicatedAllocations.
    {
        VmaMutexLock lock(m_DedicatedAllocationsMutex[memTypeIndex], m_UseMutex);
        AllocationVectorType* pDedicatedAllocations = m_pDedicatedAllocations[memTypeIndex];
        VMA_ASSERT(pDedicatedAllocations);
        VmaVectorInsertSorted<VmaPointerLess>(*pDedicatedAllocations, *pAllocation);
    }

    VMA_DEBUG_LOG("    Allocated DedicatedMemory MemoryTypeIndex=#%u", memTypeIndex);

    return VK_SUCCESS;
}

void VmaAllocator_T::GetBufferMemoryRequirements(
    VkBuffer hBuffer,
    VkMemoryRequirements& memReq,
    bool& requiresDedicatedAllocation,
    bool& prefersDedicatedAllocation) const
{
    if(m_UseKhrDedicatedAllocation)
    {
        VkBufferMemoryRequirementsInfo2KHR memReqInfo = { VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2_KHR };
        memReqInfo.buffer = hBuffer;

        VkMemoryDedicatedRequirementsKHR memDedicatedReq = { VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR };

        VkMemoryRequirements2KHR memReq2 = { VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2_KHR };
        memReq2.pNext = &memDedicatedReq;

        (*m_VulkanFunctions.vkGetBufferMemoryRequirements2KHR)(m_hDevice, &memReqInfo, &memReq2);

        memReq = memReq2.memoryRequirements;
        requiresDedicatedAllocation = (memDedicatedReq.requiresDedicatedAllocation != VK_FALSE);
        prefersDedicatedAllocation  = (memDedicatedReq.prefersDedicatedAllocation  != VK_FALSE);
    }
    else
    {
        (*m_VulkanFunctions.vkGetBufferMemoryRequirements)(m_hDevice, hBuffer, &memReq);
        requiresDedicatedAllocation = false;
        prefersDedicatedAllocation  = false;
    }
}

void VmaAllocator_T::GetImageMemoryRequirements(
    VkImage hImage,
    VkMemoryRequirements& memReq,
    bool& requiresDedicatedAllocation,
    bool& prefersDedicatedAllocation) const
{
    if(m_UseKhrDedicatedAllocation)
    {
        VkImageMemoryRequirementsInfo2KHR memReqInfo = { VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2_KHR };
        memReqInfo.image = hImage;

        VkMemoryDedicatedRequirementsKHR memDedicatedReq = { VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR };

        VkMemoryRequirements2KHR memReq2 = { VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2_KHR };
        memReq2.pNext = &memDedicatedReq;

        (*m_VulkanFunctions.vkGetImageMemoryRequirements2KHR)(m_hDevice, &memReqInfo, &memReq2);

        memReq = memReq2.memoryRequirements;
        requiresDedicatedAllocation = (memDedicatedReq.requiresDedicatedAllocation != VK_FALSE);
        prefersDedicatedAllocation  = (memDedicatedReq.prefersDedicatedAllocation  != VK_FALSE);
    }
    else
    {
        (*m_VulkanFunctions.vkGetImageMemoryRequirements)(m_hDevice, hImage, &memReq);
        requiresDedicatedAllocation = false;
        prefersDedicatedAllocation  = false;
    }
}

VkResult VmaAllocator_T::AllocateMemory(
    const VkMemoryRequirements& vkMemReq,
    bool requiresDedicatedAllocation,
    bool prefersDedicatedAllocation,
    VkBuffer dedicatedBuffer,
    VkImage dedicatedImage,
    const VmaAllocationCreateInfo& createInfo,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    if((createInfo.flags & VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT) != 0 &&
        (createInfo.flags & VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT) != 0)
    {
        VMA_ASSERT(0 && "Specifying VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT together with VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT makes no sense.");
        return VK_ERROR_OUT_OF_DEVICE_MEMORY;
    }
    if((createInfo.flags & VMA_ALLOCATION_CREATE_MAPPED_BIT) != 0 &&
        (createInfo.flags & VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT) != 0)
    {
        VMA_ASSERT(0 && "Specifying VMA_ALLOCATION_CREATE_MAPPED_BIT together with VMA_ALLOCATION_CREATE_CAN_BECOME_LOST_BIT is invalid.");
        return VK_ERROR_OUT_OF_DEVICE_MEMORY;
    }
    if(requiresDedicatedAllocation)
    {
        if((createInfo.flags & VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT) != 0)
        {
            VMA_ASSERT(0 && "VMA_ALLOCATION_CREATE_NEVER_ALLOCATE_BIT specified while dedicated allocation is required.");
            return VK_ERROR_OUT_OF_DEVICE_MEMORY;
        }
        if(createInfo.pool != VK_NULL_HANDLE)
        {
            VMA_ASSERT(0 && "Pool specified while dedicated allocation is required.");
            return VK_ERROR_OUT_OF_DEVICE_MEMORY;
        }
    }
    if((createInfo.pool != VK_NULL_HANDLE) &&
        ((createInfo.flags & (VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT)) != 0))
    {
        VMA_ASSERT(0 && "Specifying VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT when pool != null is invalid.");
        return VK_ERROR_OUT_OF_DEVICE_MEMORY;
    }

    if(createInfo.pool != VK_NULL_HANDLE)
    {
        return createInfo.pool->m_BlockVector.Allocate(
            createInfo.pool,
            m_CurrentFrameIndex.load(),
            vkMemReq,
            createInfo,
            suballocType,
            pAllocation);
    }
    else
    {
        // Bit mask of memory Vulkan types acceptable for this allocation.
        uint32_t memoryTypeBits = vkMemReq.memoryTypeBits;
        uint32_t memTypeIndex = UINT32_MAX;
        VkResult res = vmaFindMemoryTypeIndex(this, memoryTypeBits, &createInfo, &memTypeIndex);
        if(res == VK_SUCCESS)
        {
            res = AllocateMemoryOfType(
                vkMemReq,
                requiresDedicatedAllocation || prefersDedicatedAllocation,
                dedicatedBuffer,
                dedicatedImage,
                createInfo,
                memTypeIndex,
                suballocType,
                pAllocation);
            // Succeeded on first try.
            if(res == VK_SUCCESS)
            {
                return res;
            }
            // Allocation from this memory type failed. Try other compatible memory types.
            else
            {
                for(;;)
                {
                    // Remove old memTypeIndex from list of possibilities.
                    memoryTypeBits &= ~(1u << memTypeIndex);
                    // Find alternative memTypeIndex.
                    res = vmaFindMemoryTypeIndex(this, memoryTypeBits, &createInfo, &memTypeIndex);
                    if(res == VK_SUCCESS)
                    {
                        res = AllocateMemoryOfType(
                            vkMemReq,
                            requiresDedicatedAllocation || prefersDedicatedAllocation,
                            dedicatedBuffer,
                            dedicatedImage,
                            createInfo,
                            memTypeIndex,
                            suballocType,
                            pAllocation);
                        // Allocation from this alternative memory type succeeded.
                        if(res == VK_SUCCESS)
                        {
                            return res;
                        }
                        // else: Allocation from this memory type failed. Try next one - next loop iteration.
                    }
                    // No other matching memory type index could be found.
                    else
                    {
                        // Not returning res, which is VK_ERROR_FEATURE_NOT_PRESENT, because we already failed to allocate once.
                        return VK_ERROR_OUT_OF_DEVICE_MEMORY;
                    }
                }
            }
        }
        // Can't find any single memory type maching requirements. res is VK_ERROR_FEATURE_NOT_PRESENT.
        else
            return res;
    }
}

void VmaAllocator_T::FreeMemory(const VmaAllocation allocation)
{
    VMA_ASSERT(allocation);

    if(allocation->CanBecomeLost() == false ||
        allocation->GetLastUseFrameIndex() != VMA_FRAME_INDEX_LOST)
    {
        switch(allocation->GetType())
        {
        case VmaAllocation_T::ALLOCATION_TYPE_BLOCK:
            {
                VmaBlockVector* pBlockVector = VMA_NULL;
                VmaPool hPool = allocation->GetPool();
                if(hPool != VK_NULL_HANDLE)
                {
                    pBlockVector = &hPool->m_BlockVector;
                }
                else
                {
                    const uint32_t memTypeIndex = allocation->GetMemoryTypeIndex();
                    pBlockVector = m_pBlockVectors[memTypeIndex];
                }
                pBlockVector->Free(allocation);
            }
            break;
        case VmaAllocation_T::ALLOCATION_TYPE_DEDICATED:
            FreeDedicatedMemory(allocation);
            break;
        default:
            VMA_ASSERT(0);
        }
    }

    allocation->SetUserData(this, VMA_NULL);
    vma_delete(this, allocation);
}

void VmaAllocator_T::CalculateStats(VmaStats* pStats)
{
    // Initialize.
    InitStatInfo(pStats->total);
    for(size_t i = 0; i < VK_MAX_MEMORY_TYPES; ++i)
        InitStatInfo(pStats->memoryType[i]);
    for(size_t i = 0; i < VK_MAX_MEMORY_HEAPS; ++i)
        InitStatInfo(pStats->memoryHeap[i]);
    
    // Process default pools.
    for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        VmaBlockVector* const pBlockVector = m_pBlockVectors[memTypeIndex];
        VMA_ASSERT(pBlockVector);
        pBlockVector->AddStats(pStats);
    }

    // Process custom pools.
    {
        VmaMutexLock lock(m_PoolsMutex, m_UseMutex);
        for(size_t poolIndex = 0, poolCount = m_Pools.size(); poolIndex < poolCount; ++poolIndex)
        {
            m_Pools[poolIndex]->GetBlockVector().AddStats(pStats);
        }
    }

    // Process dedicated allocations.
    for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        const uint32_t memHeapIndex = MemoryTypeIndexToHeapIndex(memTypeIndex);
        VmaMutexLock dedicatedAllocationsLock(m_DedicatedAllocationsMutex[memTypeIndex], m_UseMutex);
        AllocationVectorType* const pDedicatedAllocVector = m_pDedicatedAllocations[memTypeIndex];
        VMA_ASSERT(pDedicatedAllocVector);
        for(size_t allocIndex = 0, allocCount = pDedicatedAllocVector->size(); allocIndex < allocCount; ++allocIndex)
        {
            VmaStatInfo allocationStatInfo;
            (*pDedicatedAllocVector)[allocIndex]->DedicatedAllocCalcStatsInfo(allocationStatInfo);
            VmaAddStatInfo(pStats->total, allocationStatInfo);
            VmaAddStatInfo(pStats->memoryType[memTypeIndex], allocationStatInfo);
            VmaAddStatInfo(pStats->memoryHeap[memHeapIndex], allocationStatInfo);
        }
    }

    // Postprocess.
    VmaPostprocessCalcStatInfo(pStats->total);
    for(size_t i = 0; i < GetMemoryTypeCount(); ++i)
        VmaPostprocessCalcStatInfo(pStats->memoryType[i]);
    for(size_t i = 0; i < GetMemoryHeapCount(); ++i)
        VmaPostprocessCalcStatInfo(pStats->memoryHeap[i]);
}

static const uint32_t VMA_VENDOR_ID_AMD = 4098;

VkResult VmaAllocator_T::Defragment(
    VmaAllocation* pAllocations,
    size_t allocationCount,
    VkBool32* pAllocationsChanged,
    const VmaDefragmentationInfo* pDefragmentationInfo,
    VmaDefragmentationStats* pDefragmentationStats)
{
    if(pAllocationsChanged != VMA_NULL)
    {
        memset(pAllocationsChanged, 0, sizeof(*pAllocationsChanged));
    }
    if(pDefragmentationStats != VMA_NULL)
    {
        memset(pDefragmentationStats, 0, sizeof(*pDefragmentationStats));
    }

    const uint32_t currentFrameIndex = m_CurrentFrameIndex.load();

    VmaMutexLock poolsLock(m_PoolsMutex, m_UseMutex);

    const size_t poolCount = m_Pools.size();

    // Dispatch pAllocations among defragmentators. Create them in BlockVectors when necessary.
    for(size_t allocIndex = 0; allocIndex < allocationCount; ++allocIndex)
    {
        VmaAllocation hAlloc = pAllocations[allocIndex];
        VMA_ASSERT(hAlloc);
        const uint32_t memTypeIndex = hAlloc->GetMemoryTypeIndex();
        // DedicatedAlloc cannot be defragmented.
        if((hAlloc->GetType() == VmaAllocation_T::ALLOCATION_TYPE_BLOCK) &&
            // Only HOST_VISIBLE memory types can be defragmented.
            ((m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0) &&
            // Lost allocation cannot be defragmented.
            (hAlloc->GetLastUseFrameIndex() != VMA_FRAME_INDEX_LOST))
        {
            VmaBlockVector* pAllocBlockVector = VMA_NULL;

            const VmaPool hAllocPool = hAlloc->GetPool();
            // This allocation belongs to custom pool.
            if(hAllocPool != VK_NULL_HANDLE)
            {
                pAllocBlockVector = &hAllocPool->GetBlockVector();
            }
            // This allocation belongs to general pool.
            else
            {
                pAllocBlockVector = m_pBlockVectors[memTypeIndex];
            }

            VmaDefragmentator* const pDefragmentator = pAllocBlockVector->EnsureDefragmentator(this, currentFrameIndex);

            VkBool32* const pChanged = (pAllocationsChanged != VMA_NULL) ?
                &pAllocationsChanged[allocIndex] : VMA_NULL;
            pDefragmentator->AddAllocation(hAlloc, pChanged);
        }
    }

    VkResult result = VK_SUCCESS;

    // ======== Main processing.

    VkDeviceSize maxBytesToMove = SIZE_MAX;
    uint32_t maxAllocationsToMove = UINT32_MAX;
    if(pDefragmentationInfo != VMA_NULL)
    {
        maxBytesToMove = pDefragmentationInfo->maxBytesToMove;
        maxAllocationsToMove = pDefragmentationInfo->maxAllocationsToMove;
    }

    // Process standard memory.
    for(uint32_t memTypeIndex = 0;
        (memTypeIndex < GetMemoryTypeCount()) && (result == VK_SUCCESS);
        ++memTypeIndex)
    {
        // Only HOST_VISIBLE memory types can be defragmented.
        if((m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
        {
            result = m_pBlockVectors[memTypeIndex]->Defragment(
                pDefragmentationStats,
                maxBytesToMove,
                maxAllocationsToMove);
        }
    }

    // Process custom pools.
    for(size_t poolIndex = 0; (poolIndex < poolCount) && (result == VK_SUCCESS); ++poolIndex)
    {
        result = m_Pools[poolIndex]->GetBlockVector().Defragment(
            pDefragmentationStats,
            maxBytesToMove,
            maxAllocationsToMove);
    }

    // ========  Destroy defragmentators.

    // Process custom pools.
    for(size_t poolIndex = poolCount; poolIndex--; )
    {
        m_Pools[poolIndex]->GetBlockVector().DestroyDefragmentator();
    }

    // Process standard memory.
    for(uint32_t memTypeIndex = GetMemoryTypeCount(); memTypeIndex--; )
    {
        if((m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
        {
            m_pBlockVectors[memTypeIndex]->DestroyDefragmentator();
        }
    }

    return result;
}

void VmaAllocator_T::GetAllocationInfo(VmaAllocation hAllocation, VmaAllocationInfo* pAllocationInfo)
{
    if(hAllocation->CanBecomeLost())
    {
        /*
        Warning: This is a carefully designed algorithm.
        Do not modify unless you really know what you're doing :)
        */
        uint32_t localCurrFrameIndex = m_CurrentFrameIndex.load();
        uint32_t localLastUseFrameIndex = hAllocation->GetLastUseFrameIndex();
        for(;;)
        {
            if(localLastUseFrameIndex == VMA_FRAME_INDEX_LOST)
            {
                pAllocationInfo->memoryType = UINT32_MAX;
                pAllocationInfo->deviceMemory = VK_NULL_HANDLE;
                pAllocationInfo->offset = 0;
                pAllocationInfo->size = hAllocation->GetSize();
                pAllocationInfo->pMappedData = VMA_NULL;
                pAllocationInfo->pUserData = hAllocation->GetUserData();
                return;
            }
            else if(localLastUseFrameIndex == localCurrFrameIndex)
            {
                pAllocationInfo->memoryType = hAllocation->GetMemoryTypeIndex();
                pAllocationInfo->deviceMemory = hAllocation->GetMemory();
                pAllocationInfo->offset = hAllocation->GetOffset();
                pAllocationInfo->size = hAllocation->GetSize();
                pAllocationInfo->pMappedData = VMA_NULL;
                pAllocationInfo->pUserData = hAllocation->GetUserData();
                return;
            }
            else // Last use time earlier than current time.
            {
                if(hAllocation->CompareExchangeLastUseFrameIndex(localLastUseFrameIndex, localCurrFrameIndex))
                {
                    localLastUseFrameIndex = localCurrFrameIndex;
                }
            }
        }
    }
    else
    {
        pAllocationInfo->memoryType = hAllocation->GetMemoryTypeIndex();
        pAllocationInfo->deviceMemory = hAllocation->GetMemory();
        pAllocationInfo->offset = hAllocation->GetOffset();
        pAllocationInfo->size = hAllocation->GetSize();
        pAllocationInfo->pMappedData = hAllocation->GetMappedData();
        pAllocationInfo->pUserData = hAllocation->GetUserData();
    }
}

bool VmaAllocator_T::TouchAllocation(VmaAllocation hAllocation)
{
    // This is a stripped-down version of VmaAllocator_T::GetAllocationInfo.
    if(hAllocation->CanBecomeLost())
    {
        uint32_t localCurrFrameIndex = m_CurrentFrameIndex.load();
        uint32_t localLastUseFrameIndex = hAllocation->GetLastUseFrameIndex();
        for(;;)
        {
            if(localLastUseFrameIndex == VMA_FRAME_INDEX_LOST)
            {
                return false;
            }
            else if(localLastUseFrameIndex == localCurrFrameIndex)
            {
                return true;
            }
            else // Last use time earlier than current time.
            {
                if(hAllocation->CompareExchangeLastUseFrameIndex(localLastUseFrameIndex, localCurrFrameIndex))
                {
                    localLastUseFrameIndex = localCurrFrameIndex;
                }
            }
        }
    }
    else
    {
        return true;
    }
}

VkResult VmaAllocator_T::CreatePool(const VmaPoolCreateInfo* pCreateInfo, VmaPool* pPool)
{
    VMA_DEBUG_LOG("  CreatePool: MemoryTypeIndex=%u", pCreateInfo->memoryTypeIndex);

    VmaPoolCreateInfo newCreateInfo = *pCreateInfo;

    if(newCreateInfo.maxBlockCount == 0)
    {
        newCreateInfo.maxBlockCount = SIZE_MAX;
    }
    if(newCreateInfo.blockSize == 0)
    {
        newCreateInfo.blockSize = CalcPreferredBlockSize(newCreateInfo.memoryTypeIndex);
    }

    *pPool = vma_new(this, VmaPool_T)(this, newCreateInfo);

    VkResult res = (*pPool)->m_BlockVector.CreateMinBlocks();
    if(res != VK_SUCCESS)
    {
        vma_delete(this, *pPool);
        *pPool = VMA_NULL;
        return res;
    }

    // Add to m_Pools.
    {
        VmaMutexLock lock(m_PoolsMutex, m_UseMutex);
        VmaVectorInsertSorted<VmaPointerLess>(m_Pools, *pPool);
    }

    return VK_SUCCESS;
}

void VmaAllocator_T::DestroyPool(VmaPool pool)
{
    // Remove from m_Pools.
    {
        VmaMutexLock lock(m_PoolsMutex, m_UseMutex);
        bool success = VmaVectorRemoveSorted<VmaPointerLess>(m_Pools, pool);
        VMA_ASSERT(success && "Pool not found in Allocator.");
    }

    vma_delete(this, pool);
}

void VmaAllocator_T::GetPoolStats(VmaPool pool, VmaPoolStats* pPoolStats)
{
    pool->m_BlockVector.GetPoolStats(pPoolStats);
}

void VmaAllocator_T::SetCurrentFrameIndex(uint32_t frameIndex)
{
    m_CurrentFrameIndex.store(frameIndex);
}

void VmaAllocator_T::MakePoolAllocationsLost(
    VmaPool hPool,
    size_t* pLostAllocationCount)
{
    hPool->m_BlockVector.MakePoolAllocationsLost(
        m_CurrentFrameIndex.load(),
        pLostAllocationCount);
}

void VmaAllocator_T::CreateLostAllocation(VmaAllocation* pAllocation)
{
    *pAllocation = vma_new(this, VmaAllocation_T)(VMA_FRAME_INDEX_LOST, false);
    (*pAllocation)->InitLost();
}

VkResult VmaAllocator_T::AllocateVulkanMemory(const VkMemoryAllocateInfo* pAllocateInfo, VkDeviceMemory* pMemory)
{
    const uint32_t heapIndex = MemoryTypeIndexToHeapIndex(pAllocateInfo->memoryTypeIndex);

    VkResult res;
    if(m_HeapSizeLimit[heapIndex] != VK_WHOLE_SIZE)
    {
        VmaMutexLock lock(m_HeapSizeLimitMutex, m_UseMutex);
        if(m_HeapSizeLimit[heapIndex] >= pAllocateInfo->allocationSize)
        {
            res = (*m_VulkanFunctions.vkAllocateMemory)(m_hDevice, pAllocateInfo, GetAllocationCallbacks(), pMemory);
            if(res == VK_SUCCESS)
            {
                m_HeapSizeLimit[heapIndex] -= pAllocateInfo->allocationSize;
            }
        }
        else
        {
            res = VK_ERROR_OUT_OF_DEVICE_MEMORY;
        }
    }
    else
    {
        res = (*m_VulkanFunctions.vkAllocateMemory)(m_hDevice, pAllocateInfo, GetAllocationCallbacks(), pMemory);
    }

    if(res == VK_SUCCESS && m_DeviceMemoryCallbacks.pfnAllocate != VMA_NULL)
    {
        (*m_DeviceMemoryCallbacks.pfnAllocate)(this, pAllocateInfo->memoryTypeIndex, *pMemory, pAllocateInfo->allocationSize);
    }

    return res;
}

void VmaAllocator_T::FreeVulkanMemory(uint32_t memoryType, VkDeviceSize size, VkDeviceMemory hMemory)
{
    if(m_DeviceMemoryCallbacks.pfnFree != VMA_NULL)
    {
        (*m_DeviceMemoryCallbacks.pfnFree)(this, memoryType, hMemory, size);
    }

    (*m_VulkanFunctions.vkFreeMemory)(m_hDevice, hMemory, GetAllocationCallbacks());

    const uint32_t heapIndex = MemoryTypeIndexToHeapIndex(memoryType);
    if(m_HeapSizeLimit[heapIndex] != VK_WHOLE_SIZE)
    {
        VmaMutexLock lock(m_HeapSizeLimitMutex, m_UseMutex);
        m_HeapSizeLimit[heapIndex] += size;
    }
}

VkResult VmaAllocator_T::Map(VmaAllocation hAllocation, void** ppData)
{
    if(hAllocation->CanBecomeLost())
    {
        return VK_ERROR_MEMORY_MAP_FAILED;
    }

    switch(hAllocation->GetType())
    {
    case VmaAllocation_T::ALLOCATION_TYPE_BLOCK:
        {
            VmaDeviceMemoryBlock* const pBlock = hAllocation->GetBlock();
            char *pBytes = VMA_NULL;
            VkResult res = pBlock->Map(this, 1, (void**)&pBytes);
            if(res == VK_SUCCESS)
            {
                *ppData = pBytes + (ptrdiff_t)hAllocation->GetOffset();
                hAllocation->BlockAllocMap();
            }
            return res;
        }
    case VmaAllocation_T::ALLOCATION_TYPE_DEDICATED:
        return hAllocation->DedicatedAllocMap(this, ppData);
    default:
        VMA_ASSERT(0);
        return VK_ERROR_MEMORY_MAP_FAILED;
    }
}

void VmaAllocator_T::Unmap(VmaAllocation hAllocation)
{
    switch(hAllocation->GetType())
    {
    case VmaAllocation_T::ALLOCATION_TYPE_BLOCK:
        {
            VmaDeviceMemoryBlock* const pBlock = hAllocation->GetBlock();
            hAllocation->BlockAllocUnmap();
            pBlock->Unmap(this, 1);
        }
        break;
    case VmaAllocation_T::ALLOCATION_TYPE_DEDICATED:
        hAllocation->DedicatedAllocUnmap(this);
        break;
    default:
        VMA_ASSERT(0);
    }
}

VkResult VmaAllocator_T::BindBufferMemory(VmaAllocation hAllocation, VkBuffer hBuffer)
{
    VkResult res = VK_SUCCESS;
    switch(hAllocation->GetType())
    {
    case VmaAllocation_T::ALLOCATION_TYPE_DEDICATED:
        res = GetVulkanFunctions().vkBindBufferMemory(
            m_hDevice,
            hBuffer,
            hAllocation->GetMemory(),
            0); //memoryOffset
        break;
    case VmaAllocation_T::ALLOCATION_TYPE_BLOCK:
    {
        VmaDeviceMemoryBlock* pBlock = hAllocation->GetBlock();
        VMA_ASSERT(pBlock && "Binding buffer to allocation that doesn't belong to any block. Is the allocation lost?");
        res = pBlock->BindBufferMemory(this, hAllocation, hBuffer);
        break;
    }
    default:
        VMA_ASSERT(0);
    }
    return res;
}

VkResult VmaAllocator_T::BindImageMemory(VmaAllocation hAllocation, VkImage hImage)
{
    VkResult res = VK_SUCCESS;
    switch(hAllocation->GetType())
    {
    case VmaAllocation_T::ALLOCATION_TYPE_DEDICATED:
        res = GetVulkanFunctions().vkBindImageMemory(
            m_hDevice,
            hImage,
            hAllocation->GetMemory(),
            0); //memoryOffset
        break;
    case VmaAllocation_T::ALLOCATION_TYPE_BLOCK:
    {
        VmaDeviceMemoryBlock* pBlock = hAllocation->GetBlock();
        VMA_ASSERT(pBlock && "Binding image to allocation that doesn't belong to any block. Is the allocation lost?");
        res = pBlock->BindImageMemory(this, hAllocation, hImage);
        break;
    }
    default:
        VMA_ASSERT(0);
    }
    return res;
}

void VmaAllocator_T::FreeDedicatedMemory(VmaAllocation allocation)
{
    VMA_ASSERT(allocation && allocation->GetType() == VmaAllocation_T::ALLOCATION_TYPE_DEDICATED);

    const uint32_t memTypeIndex = allocation->GetMemoryTypeIndex();
    {
        VmaMutexLock lock(m_DedicatedAllocationsMutex[memTypeIndex], m_UseMutex);
        AllocationVectorType* const pDedicatedAllocations = m_pDedicatedAllocations[memTypeIndex];
        VMA_ASSERT(pDedicatedAllocations);
        bool success = VmaVectorRemoveSorted<VmaPointerLess>(*pDedicatedAllocations, allocation);
        VMA_ASSERT(success);
    }

    VkDeviceMemory hMemory = allocation->GetMemory();
    
    if(allocation->GetMappedData() != VMA_NULL)
    {
        (*m_VulkanFunctions.vkUnmapMemory)(m_hDevice, hMemory);
    }
    
    FreeVulkanMemory(memTypeIndex, allocation->GetSize(), hMemory);

    VMA_DEBUG_LOG("    Freed DedicatedMemory MemoryTypeIndex=%u", memTypeIndex);
}

#if VMA_STATS_STRING_ENABLED

void VmaAllocator_T::PrintDetailedMap(VmaJsonWriter& json)
{
    bool dedicatedAllocationsStarted = false;
    for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        VmaMutexLock dedicatedAllocationsLock(m_DedicatedAllocationsMutex[memTypeIndex], m_UseMutex);
        AllocationVectorType* const pDedicatedAllocVector = m_pDedicatedAllocations[memTypeIndex];
        VMA_ASSERT(pDedicatedAllocVector);
        if(pDedicatedAllocVector->empty() == false)
        {
            if(dedicatedAllocationsStarted == false)
            {
                dedicatedAllocationsStarted = true;
                json.WriteString("DedicatedAllocations");
                json.BeginObject();
            }

            json.BeginString("Type ");
            json.ContinueString(memTypeIndex);
            json.EndString();
                
            json.BeginArray();

            for(size_t i = 0; i < pDedicatedAllocVector->size(); ++i)
            {
                const VmaAllocation hAlloc = (*pDedicatedAllocVector)[i];
                json.BeginObject(true);
                    
                json.WriteString("Type");
                json.WriteString(VMA_SUBALLOCATION_TYPE_NAMES[hAlloc->GetSuballocationType()]);

                json.WriteString("Size");
                json.WriteNumber(hAlloc->GetSize());

                const void* pUserData = hAlloc->GetUserData();
                if(pUserData != VMA_NULL)
                {
                    json.WriteString("UserData");
                    if(hAlloc->IsUserDataString())
                    {
                        json.WriteString((const char*)pUserData);
                    }
                    else
                    {
                        json.BeginString();
                        json.ContinueString_Pointer(pUserData);
                        json.EndString();
                    }
                }

                json.EndObject();
            }

            json.EndArray();
        }
    }
    if(dedicatedAllocationsStarted)
    {
        json.EndObject();
    }

    {
        bool allocationsStarted = false;
        for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
        {
            if(m_pBlockVectors[memTypeIndex]->IsEmpty() == false)
            {
                if(allocationsStarted == false)
                {
                    allocationsStarted = true;
                    json.WriteString("DefaultPools");
                    json.BeginObject();
                }

                json.BeginString("Type ");
                json.ContinueString(memTypeIndex);
                json.EndString();

                m_pBlockVectors[memTypeIndex]->PrintDetailedMap(json);
            }
        }
        if(allocationsStarted)
        {
            json.EndObject();
        }
    }

    {
        VmaMutexLock lock(m_PoolsMutex, m_UseMutex);
        const size_t poolCount = m_Pools.size();
        if(poolCount > 0)
        {
            json.WriteString("Pools");
            json.BeginArray();
            for(size_t poolIndex = 0; poolIndex < poolCount; ++poolIndex)
            {
                m_Pools[poolIndex]->m_BlockVector.PrintDetailedMap(json);
            }
            json.EndArray();
        }
    }
}

#endif // #if VMA_STATS_STRING_ENABLED

static VkResult AllocateMemoryForImage(
    VmaAllocator allocator,
    VkImage image,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(allocator && (image != VK_NULL_HANDLE) && pAllocationCreateInfo && pAllocation);
    
    VkMemoryRequirements vkMemReq = {};
    bool requiresDedicatedAllocation = false;
    bool prefersDedicatedAllocation  = false;
    allocator->GetImageMemoryRequirements(image, vkMemReq,
        requiresDedicatedAllocation, prefersDedicatedAllocation);

    return allocator->AllocateMemory(
        vkMemReq,
        requiresDedicatedAllocation,
        prefersDedicatedAllocation,
        VK_NULL_HANDLE, // dedicatedBuffer
        image, // dedicatedImage
        *pAllocationCreateInfo,
        suballocType,
        pAllocation);
}

////////////////////////////////////////////////////////////////////////////////
// Public interface

VkResult vmaCreateAllocator(
    const VmaAllocatorCreateInfo* pCreateInfo,
    VmaAllocator* pAllocator)
{
    VMA_ASSERT(pCreateInfo && pAllocator);
    VMA_DEBUG_LOG("vmaCreateAllocator");
    *pAllocator = vma_new(pCreateInfo->pAllocationCallbacks, VmaAllocator_T)(pCreateInfo);
    return VK_SUCCESS;
}

void vmaDestroyAllocator(
    VmaAllocator allocator)
{
    if(allocator != VK_NULL_HANDLE)
    {
        VMA_DEBUG_LOG("vmaDestroyAllocator");
        VkAllocationCallbacks allocationCallbacks = allocator->m_AllocationCallbacks;
        vma_delete(&allocationCallbacks, allocator);
    }
}

void vmaGetPhysicalDeviceProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceProperties **ppPhysicalDeviceProperties)
{
    VMA_ASSERT(allocator && ppPhysicalDeviceProperties);
    *ppPhysicalDeviceProperties = &allocator->m_PhysicalDeviceProperties;
}

void vmaGetMemoryProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceMemoryProperties** ppPhysicalDeviceMemoryProperties)
{
    VMA_ASSERT(allocator && ppPhysicalDeviceMemoryProperties);
    *ppPhysicalDeviceMemoryProperties = &allocator->m_MemProps;
}

void vmaGetMemoryTypeProperties(
    VmaAllocator allocator,
    uint32_t memoryTypeIndex,
    VkMemoryPropertyFlags* pFlags)
{
    VMA_ASSERT(allocator && pFlags);
    VMA_ASSERT(memoryTypeIndex < allocator->GetMemoryTypeCount());
    *pFlags = allocator->m_MemProps.memoryTypes[memoryTypeIndex].propertyFlags;
}

void vmaSetCurrentFrameIndex(
    VmaAllocator allocator,
    uint32_t frameIndex)
{
    VMA_ASSERT(allocator);
    VMA_ASSERT(frameIndex != VMA_FRAME_INDEX_LOST);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->SetCurrentFrameIndex(frameIndex);
}

void vmaCalculateStats(
    VmaAllocator allocator,
    VmaStats* pStats)
{
    VMA_ASSERT(allocator && pStats);
    VMA_DEBUG_GLOBAL_MUTEX_LOCK
    allocator->CalculateStats(pStats);
}

#if VMA_STATS_STRING_ENABLED

void vmaBuildStatsString(
    VmaAllocator allocator,
    char** ppStatsString,
    VkBool32 detailedMap)
{
    VMA_ASSERT(allocator && ppStatsString);
    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    VmaStringBuilder sb(allocator);
    {
        VmaJsonWriter json(allocator->GetAllocationCallbacks(), sb);
        json.BeginObject();

        VmaStats stats;
        allocator->CalculateStats(&stats);

        json.WriteString("Total");
        VmaPrintStatInfo(json, stats.total);
    
        for(uint32_t heapIndex = 0; heapIndex < allocator->GetMemoryHeapCount(); ++heapIndex)
        {
            json.BeginString("Heap ");
            json.ContinueString(heapIndex);
            json.EndString();
            json.BeginObject();

            json.WriteString("Size");
            json.WriteNumber(allocator->m_MemProps.memoryHeaps[heapIndex].size);

            json.WriteString("Flags");
            json.BeginArray(true);
            if((allocator->m_MemProps.memoryHeaps[heapIndex].flags & VK_MEMORY_HEAP_DEVICE_LOCAL_BIT) != 0)
            {
                json.WriteString("DEVICE_LOCAL");
            }
            json.EndArray();

            if(stats.memoryHeap[heapIndex].blockCount > 0)
            {
                json.WriteString("Stats");
                VmaPrintStatInfo(json, stats.memoryHeap[heapIndex]);
            }

            for(uint32_t typeIndex = 0; typeIndex < allocator->GetMemoryTypeCount(); ++typeIndex)
            {
                if(allocator->MemoryTypeIndexToHeapIndex(typeIndex) == heapIndex)
                {
                    json.BeginString("Type ");
                    json.ContinueString(typeIndex);
                    json.EndString();

                    json.BeginObject();

                    json.WriteString("Flags");
                    json.BeginArray(true);
                    VkMemoryPropertyFlags flags = allocator->m_MemProps.memoryTypes[typeIndex].propertyFlags;
                    if((flags & VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT) != 0)
                    {
                        json.WriteString("DEVICE_LOCAL");
                    }
                    if((flags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
                    {
                        json.WriteString("HOST_VISIBLE");
                    }
                    if((flags & VK_MEMORY_PROPERTY_HOST_COHERENT_BIT) != 0)
                    {
                        json.WriteString("HOST_COHERENT");
                    }
                    if((flags & VK_MEMORY_PROPERTY_HOST_CACHED_BIT) != 0)
                    {
                        json.WriteString("HOST_CACHED");
                    }
                    if((flags & VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT) != 0)
                    {
                        json.WriteString("LAZILY_ALLOCATED");
                    }
                    json.EndArray();

                    if(stats.memoryType[typeIndex].blockCount > 0)
                    {
                        json.WriteString("Stats");
                        VmaPrintStatInfo(json, stats.memoryType[typeIndex]);
                    }

                    json.EndObject();
                }
            }

            json.EndObject();
        }
        if(detailedMap == VK_TRUE)
        {
            allocator->PrintDetailedMap(json);
        }

        json.EndObject();
    }

    const size_t len = sb.GetLength();
    char* const pChars = vma_new_array(allocator, char, len + 1);
    if(len > 0)
    {
        memcpy(pChars, sb.GetData(), len);
    }
    pChars[len] = '\0';
    *ppStatsString = pChars;
}

void vmaFreeStatsString(
    VmaAllocator allocator,
    char* pStatsString)
{
    if(pStatsString != VMA_NULL)
    {
        VMA_ASSERT(allocator);
        size_t len = strlen(pStatsString);
        vma_delete_array(allocator, pStatsString, len + 1);
    }
}

#endif // #if VMA_STATS_STRING_ENABLED

/*
This function is not protected by any mutex because it just reads immutable data.
*/
VkResult vmaFindMemoryTypeIndex(
    VmaAllocator allocator,
    uint32_t memoryTypeBits,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    uint32_t* pMemoryTypeIndex)
{
    VMA_ASSERT(allocator != VK_NULL_HANDLE);
    VMA_ASSERT(pAllocationCreateInfo != VMA_NULL);
    VMA_ASSERT(pMemoryTypeIndex != VMA_NULL);

    if(pAllocationCreateInfo->memoryTypeBits != 0)
    {
        memoryTypeBits &= pAllocationCreateInfo->memoryTypeBits;
    }
    
    uint32_t requiredFlags = pAllocationCreateInfo->requiredFlags;
    uint32_t preferredFlags = pAllocationCreateInfo->preferredFlags;

    // Convert usage to requiredFlags and preferredFlags.
    switch(pAllocationCreateInfo->usage)
    {
    case VMA_MEMORY_USAGE_UNKNOWN:
        break;
    case VMA_MEMORY_USAGE_GPU_ONLY:
        preferredFlags |= VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
        break;
    case VMA_MEMORY_USAGE_CPU_ONLY:
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
        break;
    case VMA_MEMORY_USAGE_CPU_TO_GPU:
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT;
        preferredFlags |= VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
        break;
    case VMA_MEMORY_USAGE_GPU_TO_CPU:
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT;
        preferredFlags |= VK_MEMORY_PROPERTY_HOST_COHERENT_BIT | VK_MEMORY_PROPERTY_HOST_CACHED_BIT;
        break;
    default:
        break;
    }

    *pMemoryTypeIndex = UINT32_MAX;
    uint32_t minCost = UINT32_MAX;
    for(uint32_t memTypeIndex = 0, memTypeBit = 1;
        memTypeIndex < allocator->GetMemoryTypeCount();
        ++memTypeIndex, memTypeBit <<= 1)
    {
        // This memory type is acceptable according to memoryTypeBits bitmask.
        if((memTypeBit & memoryTypeBits) != 0)
        {
            const VkMemoryPropertyFlags currFlags =
                allocator->m_MemProps.memoryTypes[memTypeIndex].propertyFlags;
            // This memory type contains requiredFlags.
            if((requiredFlags & ~currFlags) == 0)
            {
                // Calculate cost as number of bits from preferredFlags not present in this memory type.
                uint32_t currCost = VmaCountBitsSet(preferredFlags & ~currFlags);
                // Remember memory type with lowest cost.
                if(currCost < minCost)
                {
                    *pMemoryTypeIndex = memTypeIndex;
                    if(currCost == 0)
                    {
                        return VK_SUCCESS;
                    }
                    minCost = currCost;
                }
            }
        }
    }
    return (*pMemoryTypeIndex != UINT32_MAX) ? VK_SUCCESS : VK_ERROR_FEATURE_NOT_PRESENT;
}

VkResult vmaFindMemoryTypeIndexForBufferInfo(
    VmaAllocator allocator,
    const VkBufferCreateInfo* pBufferCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    uint32_t* pMemoryTypeIndex)
{
    VMA_ASSERT(allocator != VK_NULL_HANDLE);
    VMA_ASSERT(pBufferCreateInfo != VMA_NULL);
    VMA_ASSERT(pAllocationCreateInfo != VMA_NULL);
    VMA_ASSERT(pMemoryTypeIndex != VMA_NULL);

    const VkDevice hDev = allocator->m_hDevice;
    VkBuffer hBuffer = VK_NULL_HANDLE;
    VkResult res = allocator->GetVulkanFunctions().vkCreateBuffer(
        hDev, pBufferCreateInfo, allocator->GetAllocationCallbacks(), &hBuffer);
    if(res == VK_SUCCESS)
    {
        VkMemoryRequirements memReq = {};
        allocator->GetVulkanFunctions().vkGetBufferMemoryRequirements(
            hDev, hBuffer, &memReq);

        res = vmaFindMemoryTypeIndex(
            allocator,
            memReq.memoryTypeBits,
            pAllocationCreateInfo,
            pMemoryTypeIndex);

        allocator->GetVulkanFunctions().vkDestroyBuffer(
            hDev, hBuffer, allocator->GetAllocationCallbacks());
    }
    return res;
}

VkResult vmaFindMemoryTypeIndexForImageInfo(
    VmaAllocator allocator,
    const VkImageCreateInfo* pImageCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    uint32_t* pMemoryTypeIndex)
{
    VMA_ASSERT(allocator != VK_NULL_HANDLE);
    VMA_ASSERT(pImageCreateInfo != VMA_NULL);
    VMA_ASSERT(pAllocationCreateInfo != VMA_NULL);
    VMA_ASSERT(pMemoryTypeIndex != VMA_NULL);

    const VkDevice hDev = allocator->m_hDevice;
    VkImage hImage = VK_NULL_HANDLE;
    VkResult res = allocator->GetVulkanFunctions().vkCreateImage(
        hDev, pImageCreateInfo, allocator->GetAllocationCallbacks(), &hImage);
    if(res == VK_SUCCESS)
    {
        VkMemoryRequirements memReq = {};
        allocator->GetVulkanFunctions().vkGetImageMemoryRequirements(
            hDev, hImage, &memReq);

        res = vmaFindMemoryTypeIndex(
            allocator,
            memReq.memoryTypeBits,
            pAllocationCreateInfo,
            pMemoryTypeIndex);

        allocator->GetVulkanFunctions().vkDestroyImage(
            hDev, hImage, allocator->GetAllocationCallbacks());
    }
    return res;
}

VkResult vmaCreatePool(
	VmaAllocator allocator,
	const VmaPoolCreateInfo* pCreateInfo,
	VmaPool* pPool)
{
    VMA_ASSERT(allocator && pCreateInfo && pPool);

    VMA_DEBUG_LOG("vmaCreatePool");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->CreatePool(pCreateInfo, pPool);
}

void vmaDestroyPool(
    VmaAllocator allocator,
    VmaPool pool)
{
    VMA_ASSERT(allocator);

    if(pool == VK_NULL_HANDLE)
    {
        return;
    }

    VMA_DEBUG_LOG("vmaDestroyPool");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->DestroyPool(pool);
}

void vmaGetPoolStats(
    VmaAllocator allocator,
    VmaPool pool,
    VmaPoolStats* pPoolStats)
{
    VMA_ASSERT(allocator && pool && pPoolStats);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->GetPoolStats(pool, pPoolStats);
}

void vmaMakePoolAllocationsLost(
    VmaAllocator allocator,
    VmaPool pool,
    size_t* pLostAllocationCount)
{
    VMA_ASSERT(allocator && pool);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->MakePoolAllocationsLost(pool, pLostAllocationCount);
}

VkResult vmaAllocateMemory(
    VmaAllocator allocator,
    const VkMemoryRequirements* pVkMemoryRequirements,
    const VmaAllocationCreateInfo* pCreateInfo,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && pVkMemoryRequirements && pCreateInfo && pAllocation);

    VMA_DEBUG_LOG("vmaAllocateMemory");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

	VkResult result = allocator->AllocateMemory(
        *pVkMemoryRequirements,
        false, // requiresDedicatedAllocation
        false, // prefersDedicatedAllocation
        VK_NULL_HANDLE, // dedicatedBuffer
        VK_NULL_HANDLE, // dedicatedImage
        *pCreateInfo,
        VMA_SUBALLOCATION_TYPE_UNKNOWN,
        pAllocation);

    if(pAllocationInfo && result == VK_SUCCESS)
    {
        allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
    }

	return result;
}

VkResult vmaAllocateMemoryForBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    const VmaAllocationCreateInfo* pCreateInfo,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && buffer != VK_NULL_HANDLE && pCreateInfo && pAllocation);

    VMA_DEBUG_LOG("vmaAllocateMemoryForBuffer");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    VkMemoryRequirements vkMemReq = {};
    bool requiresDedicatedAllocation = false;
    bool prefersDedicatedAllocation = false;
    allocator->GetBufferMemoryRequirements(buffer, vkMemReq,
        requiresDedicatedAllocation,
        prefersDedicatedAllocation);

    VkResult result = allocator->AllocateMemory(
        vkMemReq,
        requiresDedicatedAllocation,
        prefersDedicatedAllocation,
        buffer, // dedicatedBuffer
        VK_NULL_HANDLE, // dedicatedImage
        *pCreateInfo,
        VMA_SUBALLOCATION_TYPE_BUFFER,
        pAllocation);

    if(pAllocationInfo && result == VK_SUCCESS)
    {
        allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
    }

	return result;
}

VkResult vmaAllocateMemoryForImage(
    VmaAllocator allocator,
    VkImage image,
    const VmaAllocationCreateInfo* pCreateInfo,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && image != VK_NULL_HANDLE && pCreateInfo && pAllocation);

    VMA_DEBUG_LOG("vmaAllocateMemoryForImage");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    VkResult result = AllocateMemoryForImage(
        allocator,
        image,
        pCreateInfo,
        VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN,
        pAllocation);

    if(pAllocationInfo && result == VK_SUCCESS)
    {
        allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
    }

	return result;
}

void vmaFreeMemory(
    VmaAllocator allocator,
    VmaAllocation allocation)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_LOG("vmaFreeMemory");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->FreeMemory(allocation);
}

void vmaGetAllocationInfo(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && allocation && pAllocationInfo);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->GetAllocationInfo(allocation, pAllocationInfo);
}

VkBool32 vmaTouchAllocation(
    VmaAllocator allocator,
    VmaAllocation allocation)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->TouchAllocation(allocation);
}

void vmaSetAllocationUserData(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void* pUserData)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocation->SetUserData(allocator, pUserData);
}

void vmaCreateLostAllocation(
    VmaAllocator allocator,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(allocator && pAllocation);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK;

    allocator->CreateLostAllocation(pAllocation);
}

VkResult vmaMapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void** ppData)
{
    VMA_ASSERT(allocator && allocation && ppData);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->Map(allocation, ppData);
}

void vmaUnmapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->Unmap(allocation);
}

VkResult vmaDefragment(
    VmaAllocator allocator,
    VmaAllocation* pAllocations,
    size_t allocationCount,
    VkBool32* pAllocationsChanged,
    const VmaDefragmentationInfo *pDefragmentationInfo,
    VmaDefragmentationStats* pDefragmentationStats)
{
    VMA_ASSERT(allocator && pAllocations);

    VMA_DEBUG_LOG("vmaDefragment");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->Defragment(pAllocations, allocationCount, pAllocationsChanged, pDefragmentationInfo, pDefragmentationStats);
}

VkResult vmaBindBufferMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VkBuffer buffer)
{
    VMA_ASSERT(allocator && allocation && buffer);

    VMA_DEBUG_LOG("vmaBindBufferMemory");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->BindBufferMemory(allocation, buffer);
}

VkResult vmaBindImageMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VkImage image)
{
    VMA_ASSERT(allocator && allocation && image);

    VMA_DEBUG_LOG("vmaBindImageMemory");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->BindImageMemory(allocation, image);
}

VkResult vmaCreateBuffer(
    VmaAllocator allocator,
    const VkBufferCreateInfo* pBufferCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    VkBuffer* pBuffer,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && pBufferCreateInfo && pAllocationCreateInfo && pBuffer && pAllocation);
    
    VMA_DEBUG_LOG("vmaCreateBuffer");
    
    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    *pBuffer = VK_NULL_HANDLE;
    *pAllocation = VK_NULL_HANDLE;

    // 1. Create VkBuffer.
    VkResult res = (*allocator->GetVulkanFunctions().vkCreateBuffer)(
        allocator->m_hDevice,
        pBufferCreateInfo,
        allocator->GetAllocationCallbacks(),
        pBuffer);
    if(res >= 0)
    {
        // 2. vkGetBufferMemoryRequirements.
        VkMemoryRequirements vkMemReq = {};
        bool requiresDedicatedAllocation = false;
        bool prefersDedicatedAllocation  = false;
        allocator->GetBufferMemoryRequirements(*pBuffer, vkMemReq,
            requiresDedicatedAllocation, prefersDedicatedAllocation);

         // Make sure alignment requirements for specific buffer usages reported
         // in Physical Device Properties are included in alignment reported by memory requirements.
        if((pBufferCreateInfo->usage & VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT) != 0)
        {
           VMA_ASSERT(vkMemReq.alignment %
              allocator->m_PhysicalDeviceProperties.limits.minTexelBufferOffsetAlignment == 0);
        }
        if((pBufferCreateInfo->usage & VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT) != 0)
        {
           VMA_ASSERT(vkMemReq.alignment %
              allocator->m_PhysicalDeviceProperties.limits.minUniformBufferOffsetAlignment == 0);
        }
        if((pBufferCreateInfo->usage & VK_BUFFER_USAGE_STORAGE_BUFFER_BIT) != 0)
        {
           VMA_ASSERT(vkMemReq.alignment %
              allocator->m_PhysicalDeviceProperties.limits.minStorageBufferOffsetAlignment == 0);
        }

        // 3. Allocate memory using allocator.
        res = allocator->AllocateMemory(
            vkMemReq,
            requiresDedicatedAllocation,
            prefersDedicatedAllocation,
            *pBuffer, // dedicatedBuffer
            VK_NULL_HANDLE, // dedicatedImage
            *pAllocationCreateInfo,
            VMA_SUBALLOCATION_TYPE_BUFFER,
            pAllocation);
        if(res >= 0)
        {
            // 3. Bind buffer with memory.
            res = allocator->BindBufferMemory(*pAllocation, *pBuffer);
            if(res >= 0)
            {
                // All steps succeeded.
                if(pAllocationInfo != VMA_NULL)
                {
                    allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
                }
                return VK_SUCCESS;
            }
            allocator->FreeMemory(*pAllocation);
            *pAllocation = VK_NULL_HANDLE;
            (*allocator->GetVulkanFunctions().vkDestroyBuffer)(allocator->m_hDevice, *pBuffer, allocator->GetAllocationCallbacks());
            *pBuffer = VK_NULL_HANDLE;
            return res;
        }
        (*allocator->GetVulkanFunctions().vkDestroyBuffer)(allocator->m_hDevice, *pBuffer, allocator->GetAllocationCallbacks());
        *pBuffer = VK_NULL_HANDLE;
        return res;
    }
    return res;
}

void vmaDestroyBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    VmaAllocation allocation)
{
    if(buffer != VK_NULL_HANDLE)
    {
        VMA_ASSERT(allocator);

        VMA_DEBUG_LOG("vmaDestroyBuffer");

        VMA_DEBUG_GLOBAL_MUTEX_LOCK

        (*allocator->GetVulkanFunctions().vkDestroyBuffer)(allocator->m_hDevice, buffer, allocator->GetAllocationCallbacks());
        
        allocator->FreeMemory(allocation);
    }
}

VkResult vmaCreateImage(
    VmaAllocator allocator,
    const VkImageCreateInfo* pImageCreateInfo,
    const VmaAllocationCreateInfo* pAllocationCreateInfo,
    VkImage* pImage,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && pImageCreateInfo && pAllocationCreateInfo && pImage && pAllocation);

    VMA_DEBUG_LOG("vmaCreateImage");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    *pImage = VK_NULL_HANDLE;
    *pAllocation = VK_NULL_HANDLE;

    // 1. Create VkImage.
    VkResult res = (*allocator->GetVulkanFunctions().vkCreateImage)(
        allocator->m_hDevice,
        pImageCreateInfo,
        allocator->GetAllocationCallbacks(),
        pImage);
    if(res >= 0)
    {
        VmaSuballocationType suballocType = pImageCreateInfo->tiling == VK_IMAGE_TILING_OPTIMAL ?
            VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL :
            VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR;
        
        // 2. Allocate memory using allocator.
        res = AllocateMemoryForImage(allocator, *pImage, pAllocationCreateInfo, suballocType, pAllocation);
        if(res >= 0)
        {
            // 3. Bind image with memory.
            res = allocator->BindImageMemory(*pAllocation, *pImage);
            if(res >= 0)
            {
                // All steps succeeded.
                if(pAllocationInfo != VMA_NULL)
                {
                    allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
                }
                return VK_SUCCESS;
            }
            allocator->FreeMemory(*pAllocation);
            *pAllocation = VK_NULL_HANDLE;
            (*allocator->GetVulkanFunctions().vkDestroyImage)(allocator->m_hDevice, *pImage, allocator->GetAllocationCallbacks());
            *pImage = VK_NULL_HANDLE;
            return res;
        }
        (*allocator->GetVulkanFunctions().vkDestroyImage)(allocator->m_hDevice, *pImage, allocator->GetAllocationCallbacks());
        *pImage = VK_NULL_HANDLE;
        return res;
    }
    return res;
}

void vmaDestroyImage(
    VmaAllocator allocator,
    VkImage image,
    VmaAllocation allocation)
{
    if(image != VK_NULL_HANDLE)
    {
        VMA_ASSERT(allocator);

        VMA_DEBUG_LOG("vmaDestroyImage");

        VMA_DEBUG_GLOBAL_MUTEX_LOCK

        (*allocator->GetVulkanFunctions().vkDestroyImage)(allocator->m_hDevice, image, allocator->GetAllocationCallbacks());

        allocator->FreeMemory(allocation);
    }
}

#endif // #ifdef VMA_IMPLEMENTATION