| /***************************************************************************/ |
| /* */ |
| /* ftcmanag.h */ |
| /* */ |
| /* FreeType Cache Manager (specification). */ |
| /* */ |
| /* Copyright 2000 by */ |
| /* David Turner, Robert Wilhelm, and Werner Lemberg. */ |
| /* */ |
| /* This file is part of the FreeType project, and may only be used, */ |
| /* modified, and distributed under the terms of the FreeType project */ |
| /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ |
| /* this file you indicate that you have read the license and */ |
| /* understand and accept it fully. */ |
| /* */ |
| /***************************************************************************/ |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* A cache manager is in charge of the following: */ |
| /* */ |
| /* - Maintain a mapping between generic FTC_FaceIDs and live FT_Face */ |
| /* objects. The mapping itself is performed through a user-provided */ |
| /* callback. However, the manager maintains a small cache of FT_Face */ |
| /* & FT_Size objects in order to speed up things considerably. */ |
| /* */ |
| /* - Manage one or more cache objects. Each cache is in charge of */ |
| /* holding a varying number of `cache nodes'. Each cache node */ |
| /* represents a minimal amount of individually accessible cached */ |
| /* data. For example, a cache node can be an FT_Glyph image */ |
| /* containing a vector outline, or some glyph metrics, or anything */ |
| /* else. */ |
| /* */ |
| /* Each cache node has a certain size in bytes that is added to the */ |
| /* total amount of `cache memory' within the manager. */ |
| /* */ |
| /* All cache nodes are located in a global LRU list, where the oldest */ |
| /* node is at the tail of the list. */ |
| /* */ |
| /* Each node belongs to a single cache, and includes a reference */ |
| /* count to avoid destroying it (due to caching). */ |
| /* */ |
| /*************************************************************************/ |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /********* *********/ |
| /********* WARNING, THIS IS BETA CODE. *********/ |
| /********* *********/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| |
| #ifndef FTCMANAG_H |
| #define FTCMANAG_H |
| |
| #include <freetype/ftcache.h> |
| #include <freetype/cache/ftlru.h> |
| |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| #define FTC_MAX_FACES_DEFAULT 2 |
| #define FTC_MAX_SIZES_DEFAULT 4 |
| #define FTC_MAX_BYTES_DEFAULT 200000 /* 200kByte by default! */ |
| |
| /* maximum number of caches registered in a single manager */ |
| #define FTC_MAX_CACHES 16 |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <Struct> */ |
| /* FTC_ManagerRec */ |
| /* */ |
| /* <Description> */ |
| /* The cache manager structure. */ |
| /* */ |
| /* <Fields> */ |
| /* library :: A handle to a FreeType library instance. */ |
| /* */ |
| /* faces_lru :: The lru list of FT_Face objects in the cache. */ |
| /* */ |
| /* sizes_lru :: The lru list of FT_Size objects in the cache. */ |
| /* */ |
| /* max_bytes :: The maximum number of bytes to be allocated in the */ |
| /* cache. This is only related to the byte size of */ |
| /* the nodes cached by the manager. */ |
| /* */ |
| /* num_bytes :: The current number of bytes allocated in the */ |
| /* cache. Only related to the byte size of cached */ |
| /* nodes. */ |
| /* */ |
| /* num_nodes :: The current number of nodes in the manager. */ |
| /* */ |
| /* global_lru :: The global lru list of all cache nodes. */ |
| /* */ |
| /* caches :: A table of installed/registered cache objects. */ |
| /* */ |
| /* request_data :: User-provided data passed to the requester. */ |
| /* */ |
| /* request_face :: User-provided function used to implement a mapping */ |
| /* between abstract FTC_FaceIDs and real FT_Face */ |
| /* objects. */ |
| /* */ |
| typedef struct FTC_ManagerRec_ |
| { |
| FT_Library library; |
| FT_Lru faces_lru; |
| FT_Lru sizes_lru; |
| |
| FT_ULong max_bytes; |
| FT_ULong num_bytes; |
| FT_UInt num_nodes; |
| FT_ListRec global_lru; |
| FTC_Cache caches[FTC_MAX_CACHES]; |
| |
| FT_Pointer request_data; |
| FTC_Face_Requester request_face; |
| |
| } FTC_ManagerRec; |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <Function> */ |
| /* FTC_Manager_Compress */ |
| /* */ |
| /* <Description> */ |
| /* This function is used to check the state of the cache manager if */ |
| /* its `num_bytes' field is greater than its `max_bytes' field. It */ |
| /* will flush as many old cache nodes as possible (ignoring cache */ |
| /* nodes with a non-zero reference count). */ |
| /* */ |
| /* <Input> */ |
| /* manager :: A handle to the cache manager. */ |
| /* */ |
| /* <Note> */ |
| /* Client applications should not call this function directly. It is */ |
| /* normally invoked by specific cache implementations. */ |
| /* */ |
| /* The reason this function is exported is to allow client-specific */ |
| /* cache classes. */ |
| /* */ |
| FT_EXPORT( void ) FTC_Manager_Compress( FTC_Manager manager ); |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** CACHE NODE DEFINITIONS *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* Each cache controls one or more cache nodes. Each node is part of */ |
| /* the global_lru list of the manager. Its `data' field however is used */ |
| /* as a reference count for now. */ |
| /* */ |
| /* A node can be anything, depending on the type of information held by */ |
| /* the cache. It can be an individual glyph image, a set of bitmaps */ |
| /* glyphs for a given size, some metrics, etc. */ |
| /* */ |
| |
| typedef FT_ListNodeRec FTC_CacheNodeRec; |
| typedef FTC_CacheNodeRec* FTC_CacheNode; |
| |
| |
| /* the field `cachenode.data' is typecast to this type */ |
| typedef struct FTC_CacheNode_Data_ |
| { |
| FT_UShort cache_index; |
| FT_Short ref_count; |
| |
| } FTC_CacheNode_Data; |
| |
| |
| /* return a pointer to FTC_CacheNode_Data contained in a */ |
| /* CacheNode's `data' field */ |
| #define FTC_CACHENODE_TO_DATA_P( n ) \ |
| ( (FTC_CacheNode_Data*)&(n)->data ) |
| |
| #define FTC_LIST_TO_CACHENODE( n ) ( (FTC_CacheNode)(n) ) |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <FuncType> */ |
| /* FTC_CacheNode_SizeFunc */ |
| /* */ |
| /* <Description> */ |
| /* A function used to compute the total size in bytes of a given */ |
| /* cache node. It is used by the cache manager to compute the number */ |
| /* of old nodes to flush when the cache is full. */ |
| /* */ |
| /* <Input> */ |
| /* node :: A handle to the target cache node. */ |
| /* */ |
| /* cache_data :: A generic pointer passed to the destructor. */ |
| /* */ |
| typedef FT_ULong (*FTC_CacheNode_SizeFunc)( FTC_CacheNode node, |
| FT_Pointer cache_data ); |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <FuncType> */ |
| /* FTC_CacheNode_DestroyFunc */ |
| /* */ |
| /* <Description> */ |
| /* A function used to destroy a given cache node. It is called by */ |
| /* the manager when the cache is full and old nodes need to be */ |
| /* flushed out. */ |
| /* */ |
| /* <Input> */ |
| /* node :: A handle to the target cache node. */ |
| /* */ |
| /* cache_data :: A generic pointer passed to the destructor. */ |
| /* */ |
| typedef void (*FTC_CacheNode_DestroyFunc)( FTC_CacheNode node, |
| FT_Pointer cache_data ); |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <Struct> */ |
| /* FTC_CacheNode_Class */ |
| /* */ |
| /* <Description> */ |
| /* A very simple structure used to describe a cache node's class to */ |
| /* the cache manager. */ |
| /* */ |
| /* <Fields> */ |
| /* size_node :: A function used to size the node. */ |
| /* */ |
| /* destroy_node :: A function used to destroy the node. */ |
| /* */ |
| /* <Note> */ |
| /* The cache node class doesn't include a `new_node' function because */ |
| /* the cache manager never allocates cache node directly; it */ |
| /* delegates this task to its cache objects. */ |
| /* */ |
| /* */ |
| typedef struct FTC_CacheNode_Class_ |
| { |
| FTC_CacheNode_SizeFunc size_node; |
| FTC_CacheNode_DestroyFunc destroy_node; |
| |
| } FTC_CacheNode_Class; |
| |
| |
| /*************************************************************************/ |
| /*************************************************************************/ |
| /***** *****/ |
| /***** CACHE DEFINITIONS *****/ |
| /***** *****/ |
| /*************************************************************************/ |
| /*************************************************************************/ |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <FuncType> */ |
| /* FTC_Cache_InitFunc */ |
| /* */ |
| /* <Description> */ |
| /* A function used to initialize a given cache object. */ |
| /* */ |
| /* <Input> */ |
| /* cache :: A handle to the new cache. */ |
| /* */ |
| typedef FT_Error (*FTC_Cache_InitFunc)( FTC_Cache cache ); |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <FuncType> */ |
| /* FTC_Cache_DoneFunc */ |
| /* */ |
| /* <Description> */ |
| /* A function to finalize a given cache object. */ |
| /* */ |
| /* <Input> */ |
| /* cache :: A handle to the target cache. */ |
| /* */ |
| typedef void (*FTC_Cache_DoneFunc)( FTC_Cache cache ); |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <Struct> */ |
| /* FTC_Cache_Class */ |
| /* */ |
| /* <Description> */ |
| /* A structure used to describe a given cache object class to the */ |
| /* cache manager. */ |
| /* */ |
| /* <Fields> */ |
| /* cache_byte_size :: The size of the cache object in bytes. */ |
| /* */ |
| /* init_cache :: The cache object initializer. */ |
| /* */ |
| /* done_cache :: The cache object finalizer. */ |
| /* */ |
| struct FTC_Cache_Class_ |
| { |
| FT_UInt cache_byte_size; |
| FTC_Cache_InitFunc init_cache; |
| FTC_Cache_DoneFunc done_cache; |
| }; |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <Struct> */ |
| /* FTC_CacheRec */ |
| /* */ |
| /* <Description> */ |
| /* A structure used to describe an abstract cache object. */ |
| /* */ |
| /* <Fields> */ |
| /* manager :: A handle to the parent cache manager. */ |
| /* */ |
| /* memory :: A handle to the memory manager. */ |
| /* */ |
| /* clazz :: A pointer to the cache class. */ |
| /* */ |
| /* node_clazz :: A pointer to the cache's node class. */ |
| /* */ |
| /* cache_index :: An index of the cache in the manager's table. */ |
| /* */ |
| /* cache_data :: Data passed to the cache node */ |
| /* constructor/finalizer. */ |
| /* */ |
| typedef struct FTC_CacheRec_ |
| { |
| FTC_Manager manager; |
| FT_Memory memory; |
| FTC_Cache_Class* clazz; |
| FTC_CacheNode_Class* node_clazz; |
| |
| FT_UInt cache_index; /* in manager's table */ |
| FT_Pointer cache_data; /* passed to cache node methods */ |
| |
| } FTC_CacheRec; |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| |
| #endif /* FTCMANAG_H */ |
| |
| |
| /* END */ |
