/***************************************************************************/ /* */ /* 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 #include FT_CACHE_H #include FT_CACHE_INTERNAL_LRU_H FT_BEGIN_HEADER /*************************************************************************/ /* */ /*
*/ /* cache_subsystem */ /* */ /*************************************************************************/ #define FTC_MAX_FACES_DEFAULT 2 #define FTC_MAX_SIZES_DEFAULT 4 #define FTC_MAX_BYTES_DEFAULT 200000L /* 200kByte by default! */ /* maximum number of caches registered in a single manager */ #define FTC_MAX_CACHES 16 /*************************************************************************/ /* */ /* */ /* FTC_ManagerRec */ /* */ /* */ /* The cache manager structure. */ /* */ /* */ /* 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; /*************************************************************************/ /* */ /* */ /* FTC_Manager_Compress */ /* */ /* */ /* 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). */ /* */ /* */ /* manager :: A handle to the cache manager. */ /* */ /* */ /* 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) ) /*************************************************************************/ /* */ /* */ /* FTC_CacheNode_SizeFunc */ /* */ /* */ /* 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. */ /* */ /* */ /* node :: A handle to the target cache node. */ /* */ /* cache_data :: A generic pointer passed to the destructor. */ /* */ /* */ /* The size of a given cache node in bytes. */ /* */ typedef FT_ULong (*FTC_CacheNode_SizeFunc)( FTC_CacheNode node, FT_Pointer cache_data ); /*************************************************************************/ /* */ /* */ /* FTC_CacheNode_DestroyFunc */ /* */ /* */ /* 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. */ /* */ /* */ /* 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 ); /*************************************************************************/ /* */ /* */ /* FTC_CacheNode_Class */ /* */ /* */ /* A very simple structure used to describe a cache node's class to */ /* the cache manager. */ /* */ /* */ /* size_node :: A function used to size the node. */ /* */ /* destroy_node :: A function used to destroy the node. */ /* */ /* */ /* 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 *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* */ /* */ /* FTC_Cache_InitFunc */ /* */ /* */ /* A function used to initialize a given cache object. */ /* */ /* */ /* cache :: A handle to the new cache. */ /* */ typedef FT_Error (*FTC_Cache_InitFunc)( FTC_Cache cache ); /*************************************************************************/ /* */ /* */ /* FTC_Cache_DoneFunc */ /* */ /* */ /* A function to finalize a given cache object. */ /* */ /* */ /* cache :: A handle to the target cache. */ /* */ typedef void (*FTC_Cache_DoneFunc)( FTC_Cache cache ); /*************************************************************************/ /* */ /* */ /* FTC_Cache_Class */ /* */ /* */ /* A structure used to describe a given cache object class to the */ /* cache manager. */ /* */ /* */ /* 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; }; /*************************************************************************/ /* */ /* */ /* FTC_CacheRec */ /* */ /* */ /* A structure used to describe an abstract cache object. */ /* */ /* */ /* 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; /* */ FT_END_HEADER #endif /* __FTCMANAG_H__ */ /* END */