| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkData_DEFINED |
| #define SkData_DEFINED |
| |
| #include <stdio.h> |
| |
| #include "include/core/SkRefCnt.h" |
| |
| class SkStream; |
| |
| /** |
| * SkData holds an immutable data buffer. Not only is the data immutable, |
| * but the actual ptr that is returned (by data() or bytes()) is guaranteed |
| * to always be the same for the life of this instance. |
| */ |
| class SK_API SkData final : public SkNVRefCnt<SkData> { |
| public: |
| /** |
| * Returns the number of bytes stored. |
| */ |
| size_t size() const { return fSize; } |
| |
| bool isEmpty() const { return 0 == fSize; } |
| |
| /** |
| * Returns the ptr to the data. |
| */ |
| const void* data() const { return fPtr; } |
| |
| /** |
| * Like data(), returns a read-only ptr into the data, but in this case |
| * it is cast to uint8_t*, to make it easy to add an offset to it. |
| */ |
| const uint8_t* bytes() const { |
| return reinterpret_cast<const uint8_t*>(fPtr); |
| } |
| |
| /** |
| * USE WITH CAUTION. |
| * This call will assert that the refcnt is 1, as a precaution against modifying the |
| * contents when another client/thread has access to the data. |
| */ |
| void* writable_data() { |
| if (fSize) { |
| // only assert we're unique if we're not empty |
| SkASSERT(this->unique()); |
| } |
| return const_cast<void*>(fPtr); |
| } |
| |
| /** |
| * Helper to copy a range of the data into a caller-provided buffer. |
| * Returns the actual number of bytes copied, after clamping offset and |
| * length to the size of the data. If buffer is NULL, it is ignored, and |
| * only the computed number of bytes is returned. |
| */ |
| size_t copyRange(size_t offset, size_t length, void* buffer) const; |
| |
| /** |
| * Returns true if these two objects have the same length and contents, |
| * effectively returning 0 == memcmp(...) |
| */ |
| bool equals(const SkData* other) const; |
| |
| /** |
| * Function that, if provided, will be called when the SkData goes out |
| * of scope, allowing for custom allocation/freeing of the data's contents. |
| */ |
| typedef void (*ReleaseProc)(const void* ptr, void* context); |
| |
| /** |
| * Create a new dataref by copying the specified data |
| */ |
| static sk_sp<SkData> MakeWithCopy(const void* data, size_t length); |
| |
| |
| /** |
| * Create a new data with uninitialized contents. The caller should call writable_data() |
| * to write into the buffer, but this must be done before another ref() is made. |
| */ |
| static sk_sp<SkData> MakeUninitialized(size_t length); |
| |
| /** |
| * Create a new data with zero-initialized contents. The caller should call writable_data() |
| * to write into the buffer, but this must be done before another ref() is made. |
| */ |
| static sk_sp<SkData> MakeZeroInitialized(size_t length); |
| |
| /** |
| * Create a new dataref by copying the specified c-string |
| * (a null-terminated array of bytes). The returned SkData will have size() |
| * equal to strlen(cstr) + 1. If cstr is NULL, it will be treated the same |
| * as "". |
| */ |
| static sk_sp<SkData> MakeWithCString(const char cstr[]); |
| |
| /** |
| * Create a new dataref, taking the ptr as is, and using the |
| * releaseproc to free it. The proc may be NULL. |
| */ |
| static sk_sp<SkData> MakeWithProc(const void* ptr, size_t length, ReleaseProc proc, void* ctx); |
| |
| /** |
| * Call this when the data parameter is already const and will outlive the lifetime of the |
| * SkData. Suitable for with const globals. |
| */ |
| static sk_sp<SkData> MakeWithoutCopy(const void* data, size_t length) { |
| return MakeWithProc(data, length, NoopReleaseProc, nullptr); |
| } |
| |
| /** |
| * Create a new dataref from a pointer allocated by malloc. The Data object |
| * takes ownership of that allocation, and will handling calling sk_free. |
| */ |
| static sk_sp<SkData> MakeFromMalloc(const void* data, size_t length); |
| |
| /** |
| * Create a new dataref the file with the specified path. |
| * If the file cannot be opened, this returns NULL. |
| */ |
| static sk_sp<SkData> MakeFromFileName(const char path[]); |
| |
| /** |
| * Create a new dataref from a stdio FILE. |
| * This does not take ownership of the FILE, nor close it. |
| * The caller is free to close the FILE at its convenience. |
| * The FILE must be open for reading only. |
| * Returns NULL on failure. |
| */ |
| static sk_sp<SkData> MakeFromFILE(FILE* f); |
| |
| /** |
| * Create a new dataref from a file descriptor. |
| * This does not take ownership of the file descriptor, nor close it. |
| * The caller is free to close the file descriptor at its convenience. |
| * The file descriptor must be open for reading only. |
| * Returns NULL on failure. |
| */ |
| static sk_sp<SkData> MakeFromFD(int fd); |
| |
| /** |
| * Attempt to read size bytes into a SkData. If the read succeeds, return the data, |
| * else return NULL. Either way the stream's cursor may have been changed as a result |
| * of calling read(). |
| */ |
| static sk_sp<SkData> MakeFromStream(SkStream*, size_t size); |
| |
| /** |
| * Create a new dataref using a subset of the data in the specified |
| * src dataref. |
| */ |
| static sk_sp<SkData> MakeSubset(const SkData* src, size_t offset, size_t length); |
| |
| /** |
| * Returns a new empty dataref (or a reference to a shared empty dataref). |
| * New or shared, the caller must see that unref() is eventually called. |
| */ |
| static sk_sp<SkData> MakeEmpty(); |
| |
| private: |
| friend class SkNVRefCnt<SkData>; |
| ReleaseProc fReleaseProc; |
| void* fReleaseProcContext; |
| const void* fPtr; |
| size_t fSize; |
| |
| SkData(const void* ptr, size_t size, ReleaseProc, void* context); |
| explicit SkData(size_t size); // inplace new/delete |
| ~SkData(); |
| |
| // Ensure the unsized delete is called. |
| void operator delete(void* p); |
| |
| // shared internal factory |
| static sk_sp<SkData> PrivateNewWithCopy(const void* srcOrNull, size_t length); |
| |
| static void NoopReleaseProc(const void*, void*); // {} |
| |
| using INHERITED = SkRefCnt; |
| }; |
| |
| #endif |