forked from minhngoc25a/freetype2
333 lines
15 KiB
C
333 lines
15 KiB
C
/***************************************************************************/
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/* */
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/* ftcmanag.h */
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/* */
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/* FreeType Cache Manager (specification). */
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/* */
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/* Copyright 2000-2001 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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/*************************************************************************/
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/* */
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/* A cache manager is in charge of the following: */
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/* */
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/* - Maintain a mapping between generic FTC_FaceIDs and live FT_Face */
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/* objects. The mapping itself is performed through a user-provided */
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/* callback. However, the manager maintains a small cache of FT_Face */
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/* & FT_Size objects in order to speed up things considerably. */
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/* */
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/* - Manage one or more cache objects. Each cache is in charge of */
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/* holding a varying number of `cache nodes'. Each cache node */
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/* represents a minimal amount of individually accessible cached */
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/* data. For example, a cache node can be an FT_Glyph image */
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/* containing a vector outline, or some glyph metrics, or anything */
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/* else. */
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/* */
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/* Each cache node has a certain size in bytes that is added to the */
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/* total amount of `cache memory' within the manager. */
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/* */
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/* All cache nodes are located in a global LRU list, where the oldest */
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/* node is at the tail of the list. */
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/* */
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/* Each node belongs to a single cache, and includes a reference */
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/* count to avoid destroying it (due to caching). */
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/* */
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/********* *********/
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/********* WARNING, THIS IS BETA CODE. *********/
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/********* *********/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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#ifndef __FTCMANAG_H__
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#define __FTCMANAG_H__
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#include <ft2build.h>
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#include FT_CACHE_H
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#include FT_CACHE_INTERNAL_LRU_H
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FT_BEGIN_HEADER
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/*************************************************************************/
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/* */
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/* <Section> */
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/* cache_subsystem */
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/* */
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/*************************************************************************/
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#define FTC_MAX_FACES_DEFAULT 2
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#define FTC_MAX_SIZES_DEFAULT 4
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#define FTC_MAX_BYTES_DEFAULT 100000L /* 200kByte by default! */
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/* maximum number of caches registered in a single manager */
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#define FTC_MAX_CACHES 16
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/* handle to cache object */
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typedef struct FTC_CacheRec_* FTC_Cache;
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/* handle to cache class */
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typedef const struct FTC_Cache_ClassRec_* FTC_Cache_Class;
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/* handle to cache node */
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typedef struct FTC_NodeRec_* FTC_Node;
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FTC_ManagerRec */
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/* */
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/* <Description> */
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/* The cache manager structure. */
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/* */
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/* <Fields> */
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/* library :: A handle to a FreeType library instance. */
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/* */
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/* faces_list :: The lru list of FT_Face objects in the cache. */
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/* */
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/* sizes_list :: The lru list of FT_Size objects in the cache. */
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/* */
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/* max_weight :: The maximum cache pool weight.. */
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/* */
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/* cur_weight :: The current cache pool weight. */
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/* */
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/* num_nodes :: The current number of nodes in the manager. */
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/* */
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/* nodes_list :: The global lru list of all cache nodes. */
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/* */
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/* caches :: A table of installed/registered cache objects. */
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/* */
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/* request_data :: User-provided data passed to the requester. */
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/* */
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/* request_face :: User-provided function used to implement a mapping */
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/* between abstract FTC_FaceIDs and real FT_Face */
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/* objects. */
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/* */
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typedef struct FTC_ManagerRec_
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{
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FT_Library library;
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FT_LruList faces_list;
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FT_LruList sizes_list;
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FT_ULong max_weight;
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FT_ULong cur_weight;
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FT_UInt num_nodes;
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FTC_Node nodes_list;
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FTC_Cache caches[FTC_MAX_CACHES];
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FT_Pointer request_data;
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FTC_Face_Requester request_face;
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} FTC_ManagerRec;
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Manager_Compress */
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/* */
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/* <Description> */
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/* This function is used to check the state of the cache manager if */
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/* its `num_bytes' field is greater than its `max_bytes' field. It */
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/* will flush as many old cache nodes as possible (ignoring cache */
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/* nodes with a non-zero reference count). */
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/* */
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/* <InOut> */
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/* manager :: A handle to the cache manager. */
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/* */
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/* <Note> */
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/* Client applications should not call this function directly. It is */
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/* normally invoked by specific cache implementations. */
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/* */
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/* The reason this function is exported is to allow client-specific */
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/* cache classes. */
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/* */
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FT_EXPORT( void )
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FTC_Manager_Compress( FTC_Manager manager );
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/*************************************************************************/
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/*************************************************************************/
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/***** *****/
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/***** CACHE NODE DEFINITIONS *****/
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/***** *****/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/* */
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/* Each cache controls one or more cache nodes. Each node is part of */
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/* the global_lru list of the manager. Its `data' field however is used */
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/* as a reference count for now. */
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/* */
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/* A node can be anything, depending on the type of information held by */
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/* the cache. It can be an individual glyph image, a set of bitmaps */
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/* glyphs for a given size, some metrics, etc. */
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/* */
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/* structure size should be 20 bytes on 32-bits machines */
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typedef struct FTC_NodeRec_
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{
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FTC_Node mru_next; /* circular mru list pointer */
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FTC_Node mru_prev; /* circular mru list pointer */
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FTC_Node link; /* used for hashing.. */
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FT_UInt32 hash; /* used for hashing too.. */
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FT_UShort cache_index; /* index of cache the node belongs to */
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FT_Short ref_count; /* reference count for this node.. */
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} FTC_NodeRec;
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#define FTC_NODE(x) ((FTC_Node)(x))
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#define FTC_NODE_P(x) ((FTC_Node*)(x))
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/* each cache really implements a dynamic hash table to manage its nodes */
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typedef struct FTC_CacheRec_
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{
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FTC_Manager manager;
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FT_Memory memory;
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FTC_Cache_Class clazz;
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FT_UInt cache_index; /* in manager's table */
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FT_Pointer cache_data; /* used by cache node methods */
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FT_UFast nodes;
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FT_UFast size;
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FTC_Node* buckets;
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} FTC_CacheRec;
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#define FTC_CACHE(x) ((FTC_Cache)(x))
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#define FTC_CACHE_P(x) ((FTC_Cache*)(x))
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/* initialize a given cache */
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typedef FT_Error
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(*FTC_Cache_InitFunc)( FTC_Cache cache );
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/* finalize a given cache */
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typedef void
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(*FTC_Cache_DoneFunc)( FTC_Cache cache );
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/* initialize a new cache node */
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typedef FT_Error
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(*FTC_Node_InitFunc)( FTC_Node node,
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FT_Pointer type,
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FTC_Cache cache );
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/* compute the weight of a given cache node */
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typedef FT_ULong
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(*FTC_Node_WeightFunc)( FTC_Node node,
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FTC_Cache cache );
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/* compare a node to a given key pair */
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typedef FT_Bool
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(*FTC_Node_CompareFunc)( FTC_Node node,
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FT_Pointer key,
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FTC_Cache cache );
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/* finalize a given cache node */
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typedef void
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(*FTC_Node_DoneFunc)( FTC_Node node,
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FTC_Cache cache );
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typedef struct FTC_Cache_ClassRec_
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{
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FT_UInt cache_size;
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FTC_Cache_InitFunc cache_init;
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FTC_Cache_DoneFunc cache_done;
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FT_UInt node_size;
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FTC_Node_InitFunc node_init;
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FTC_Node_WeightFunc node_weight;
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FTC_Node_CompareFunc node_compare;
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FTC_Node_DoneFunc node_done;
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} FTC_Cache_ClassRec;
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/* */
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#define FTC_CACHE_RESIZE_TEST(c) \
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( (c)->nodes*3 < (c)->size || \
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(c)->size*3 < (c)->nodes )
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/* this must be used internally for the moment */
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FT_EXPORT( FT_Error )
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FTC_Manager_Register_Cache( FTC_Manager manager,
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FTC_Cache_Class clazz,
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FTC_Cache *acache );
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/* can be used directory as FTC_Cache_DoneFunc, or called by custom */
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/* cache finalizers.. */
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FT_EXPORT( void )
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ftc_cache_done( FTC_Cache cache );
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/* initalize the hash table within the cache */
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FT_EXPORT( FT_Error )
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ftc_cache_init( FTC_Cache cache );
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/* can be used when FTC_CACHE_RESIZE_TEST returns TRUE after a node */
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/* insertion.. */
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FT_EXPORT(void)
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ftc_cache_resize( FTC_Cache cache );
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/* can be called when the key's hash value has been computed */
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FT_EXPORT(FT_Error)
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ftc_cache_lookup_node( FTC_Cache cache,
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FT_UFast key_hash,
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FT_Pointer key,
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FTC_Node *anode );
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/* can be called to increment a node's reference count */
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FT_EXPORT(void)
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ftc_node_ref( FTC_Node node,
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FTC_Cache cache );
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/* can be called to decrement a node's reference count */
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FT_EXPORT(void)
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ftc_node_unref( FTC_Node node,
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FTC_Cache cache );
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/* */
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FT_END_HEADER
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#endif /* __FTCMANAG_H__ */
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/* END */
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