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/***************************************************************************/
/* */
/* ftcmanag.h */
/* */
/* FreeType Cache Manager (specification). */
/* */
/* Copyright 2000-2001 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 <ft2build.h>
#include FT_CACHE_H
#include FT_CACHE_INTERNAL_LRU_H
FT_BEGIN_HEADER
/*************************************************************************/
/* */
/* <Section> */
/* cache_subsystem */
/* */
/*************************************************************************/
#define FTC_MAX_FACES_DEFAULT 2
#define FTC_MAX_SIZES_DEFAULT 4
#define FTC_MAX_BYTES_DEFAULT 100000L /* 200kByte by default! */
/* maximum number of caches registered in a single manager */
#define FTC_MAX_CACHES 16
/* handle to cache object */
typedef struct FTC_CacheRec_* FTC_Cache;
/* handle to cache class */
typedef const struct FTC_Cache_ClassRec_* FTC_Cache_Class;
/* handle to cache node */
typedef struct FTC_NodeRec_* FTC_Node;
/*************************************************************************/
/* */
/* <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_LruList faces_list;
FT_LruList sizes_list;
FT_ULong max_weight;
FT_ULong cur_weight;
FT_UInt num_nodes;
FTC_Node nodes_list;
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). */
/* */
/* <InOut> */
/* 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. */
/* */
/* structure size should be 20 bytes on 32-bits machines */
typedef struct FTC_NodeRec_
{
FTC_Node mru_next; /* circular mru list pointer */
FTC_Node mru_prev; /* circular mru list pointer */
FTC_Node link; /* used for hashing.. */
FT_UInt32 hash; /* used for hashing too.. */
FT_UShort cache_index; /* index of cache this node belongs to */
FT_Short ref_count; /* reference count for this node.. */
} FTC_NodeRec;
#define FTC_NODE(x) ((FTC_Node)(x))
#define FTC_NODE_P(x) ((FTC_Node*)(x))
/* each cache really implements a dynamic hash table to manage its nodes */
typedef struct FTC_CacheRec_
{
FTC_Manager manager;
FT_Memory memory;
FTC_Cache_Class clazz;
FT_UInt cache_index; /* in manager's table */
FT_Pointer cache_data; /* used by cache node methods */
FT_UFast nodes;
FT_UFast size;
FTC_Node* buckets;
} FTC_CacheRec;
#define FTC_CACHE(x) ((FTC_Cache)(x))
#define FTC_CACHE_P(x) ((FTC_Cache*)(x))
/* initialize a given cache */
typedef FT_Error
(*FTC_Cache_InitFunc)( FTC_Cache cache );
/* finalize a given cache */
typedef void
(*FTC_Cache_DoneFunc)( FTC_Cache cache );
/* initialize a new cache node */
typedef FT_Error
(*FTC_Node_InitFunc)( FTC_Node node,
FT_Pointer type,
FTC_Cache cache );
/* compute the weight of a given cache node */
typedef FT_ULong
(*FTC_Node_WeightFunc)( FTC_Node node,
FTC_Cache cache );
/* compare a node to a given key pair */
typedef FT_Bool
(*FTC_Node_CompareFunc)( FTC_Node node,
FT_Pointer key,
FTC_Cache cache );
/* finalize a given cache node */
typedef void
(*FTC_Node_DoneFunc)( FTC_Node node,
FTC_Cache cache );
typedef struct FTC_Cache_ClassRec_
{
FT_UInt cache_size;
FTC_Cache_InitFunc cache_init;
FTC_Cache_DoneFunc cache_done;
FT_UInt node_size;
FTC_Node_InitFunc node_init;
FTC_Node_WeightFunc node_weight;
FTC_Node_CompareFunc node_compare;
FTC_Node_DoneFunc node_done;
} FTC_Cache_ClassRec;
/* */
#define FTC_CACHE_RESIZE_TEST(c) \
( (c)->nodes*3 < (c)->size || \
(c)->size*3 < (c)->nodes )
/* this must be used internally for the moment */
FT_EXPORT( FT_Error )
FTC_Manager_Register_Cache( FTC_Manager manager,
FTC_Cache_Class clazz,
FTC_Cache *acache );
/* can be used directory as FTC_Cache_DoneFunc, or called by custom */
/* cache finalizers.. */
FT_EXPORT( void )
ftc_cache_done( FTC_Cache cache );
/* initalize the hash table within the cache */
FT_EXPORT( FT_Error )
ftc_cache_init( FTC_Cache cache );
/* can be used when FTC_CACHE_RESIZE_TEST returns TRUE after a node */
/* insertion.. */
FT_EXPORT(void)
ftc_cache_resize( FTC_Cache cache );
/* can be called when the key's hash value has been computed */
FT_EXPORT(FT_Error)
ftc_cache_lookup_node( FTC_Cache cache,
FT_UFast key_hash,
FT_Pointer key,
FTC_Node *anode );
/* can be called to increment a node's reference count */
FT_EXPORT(void)
ftc_node_ref( FTC_Node node,
FTC_Cache cache );
/* can be called to decrement a node's reference count */
FT_EXPORT(void)
ftc_node_unref( FTC_Node node,
FTC_Cache cache );
/* */
FT_END_HEADER
#endif /* __FTCMANAG_H__ */
/* END */
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