1 /***************************************************************************/
5 /* FreeType internal cache interface (specification). */
7 /* Copyright 2000-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, */
9 /* David Turner, Robert Wilhelm, and Werner Lemberg. */
11 /* This file is part of the FreeType project, and may only be used, */
12 /* modified, and distributed under the terms of the FreeType project */
13 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */
14 /* this file you indicate that you have read the license and */
15 /* understand and accept it fully. */
17 /***************************************************************************/
20 #ifndef __FTCCACHE_H__
21 #define __FTCCACHE_H__
28 #define _FTC_FACE_ID_HASH( i ) \
29 ((FT_PtrDist)(( (FT_PtrDist)(i) >> 3 ) ^ ( (FT_PtrDist)(i) << 7 )))
31 /* handle to cache object */
32 typedef struct FTC_CacheRec_* FTC_Cache;
34 /* handle to cache class */
35 typedef const struct FTC_CacheClassRec_* FTC_CacheClass;
38 /*************************************************************************/
39 /*************************************************************************/
41 /***** CACHE NODE DEFINITIONS *****/
43 /*************************************************************************/
44 /*************************************************************************/
46 /*************************************************************************/
48 /* Each cache controls one or more cache nodes. Each node is part of */
49 /* the global_lru list of the manager. Its `data' field however is used */
50 /* as a reference count for now. */
52 /* A node can be anything, depending on the type of information held by */
53 /* the cache. It can be an individual glyph image, a set of bitmaps */
54 /* glyphs for a given size, some metrics, etc. */
56 /*************************************************************************/
58 /* structure size should be 20 bytes on 32-bits machines */
59 typedef struct FTC_NodeRec_
61 FTC_MruNodeRec mru; /* circular mru list pointer */
62 FTC_Node link; /* used for hashing */
63 FT_PtrDist hash; /* used for hashing too */
64 FT_UShort cache_index; /* index of cache the node belongs to */
65 FT_Short ref_count; /* reference count for this node */
70 #define FTC_NODE( x ) ( (FTC_Node)(x) )
71 #define FTC_NODE_P( x ) ( (FTC_Node*)(x) )
73 #define FTC_NODE__NEXT( x ) FTC_NODE( (x)->mru.next )
74 #define FTC_NODE__PREV( x ) FTC_NODE( (x)->mru.prev )
77 #define FTC_NODE__TOP_FOR_HASH( cache, hash ) \
78 ( ( cache )->buckets + \
79 ( ( ( ( hash ) & ( cache )->mask ) < ( cache )->p ) \
80 ? ( ( hash ) & ( ( cache )->mask * 2 + 1 ) ) \
81 : ( ( hash ) & ( cache )->mask ) ) )
84 ftc_get_top_node_for_hash( FTC_Cache cache,
86 #define FTC_NODE__TOP_FOR_HASH( cache, hash ) \
87 ftc_get_top_node_for_hash( ( cache ), ( hash ) )
90 #ifdef FT_CONFIG_OPTION_OLD_INTERNALS
92 ftc_node_destroy( FTC_Node node,
93 FTC_Manager manager );
97 /*************************************************************************/
98 /*************************************************************************/
100 /***** CACHE DEFINITIONS *****/
102 /*************************************************************************/
103 /*************************************************************************/
105 /* initialize a new cache node */
107 (*FTC_Node_NewFunc)( FTC_Node *pnode,
112 (*FTC_Node_WeightFunc)( FTC_Node node,
115 /* compare a node to a given key pair */
117 (*FTC_Node_CompareFunc)( FTC_Node node,
120 FT_Bool* list_changed );
124 (*FTC_Node_FreeFunc)( FTC_Node node,
128 (*FTC_Cache_InitFunc)( FTC_Cache cache );
131 (*FTC_Cache_DoneFunc)( FTC_Cache cache );
134 typedef struct FTC_CacheClassRec_
136 FTC_Node_NewFunc node_new;
137 FTC_Node_WeightFunc node_weight;
138 FTC_Node_CompareFunc node_compare;
139 FTC_Node_CompareFunc node_remove_faceid;
140 FTC_Node_FreeFunc node_free;
142 FT_Offset cache_size;
143 FTC_Cache_InitFunc cache_init;
144 FTC_Cache_DoneFunc cache_done;
149 /* each cache really implements a dynamic hash table to manage its nodes */
150 typedef struct FTC_CacheRec_
157 FTC_CacheClassRec clazz; /* local copy, for speed */
161 FT_UInt index; /* in manager's table */
163 FTC_CacheClass org_class; /* original class pointer */
168 #define FTC_CACHE( x ) ( (FTC_Cache)(x) )
169 #define FTC_CACHE_P( x ) ( (FTC_Cache*)(x) )
172 /* default cache initialize */
174 FTC_Cache_Init( FTC_Cache cache );
176 /* default cache finalizer */
178 FTC_Cache_Done( FTC_Cache cache );
180 /* Call this function to look up the cache. If no corresponding
181 * node is found, a new one is automatically created. This function
182 * is capable of flushing the cache adequately to make room for the
188 FTC_Cache_Lookup( FTC_Cache cache,
195 FTC_Cache_NewNode( FTC_Cache cache,
200 /* Remove all nodes that relate to a given face_id. This is useful
201 * when un-installing fonts. Note that if a cache node relates to
202 * the face_id but is locked (i.e., has `ref_count > 0'), the node
203 * will _not_ be destroyed, but its internal face_id reference will
206 * The final result will be that the node will never come back
207 * in further lookup requests, and will be flushed on demand from
208 * the cache normally when its reference count reaches 0.
211 FTC_Cache_RemoveFaceID( FTC_Cache cache,
212 FTC_FaceID face_id );
217 #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
219 FTC_Node *_bucket, *_pnode, _node; \
220 FTC_Cache _cache = FTC_CACHE(cache); \
221 FT_PtrDist _hash = (FT_PtrDist)(hash); \
222 FTC_Node_CompareFunc _nodcomp = (FTC_Node_CompareFunc)(nodecmp); \
223 FT_Bool _list_changed = FALSE; \
226 error = FTC_Err_Ok; \
229 /* Go to the `top' node of the list sharing same masked hash */ \
230 _bucket = _pnode = FTC_NODE__TOP_FOR_HASH( _cache, _hash ); \
232 /* Look up a node with identical hash and queried properties. */ \
233 /* NOTE: _nodcomp() may change the linked list to reduce memory. */ \
237 if ( _node == NULL ) \
240 if ( _node->hash == _hash && \
241 _nodcomp( _node, query, _cache, &_list_changed ) ) \
244 _pnode = &_node->link; \
247 if ( _list_changed ) \
249 /* Update _bucket by possibly modified linked list */ \
250 _bucket = _pnode = FTC_NODE__TOP_FOR_HASH( _cache, _hash ); \
252 /* Update _pnode by possibly modified linked list */ \
253 while ( *_pnode != _node ) \
255 if ( *_pnode == NULL ) \
257 FT_ERROR(( "FTC_CACHE_LOOKUP_CMP: oops!!! node missing\n" )); \
261 _pnode = &((*_pnode)->link); \
265 /* Reorder the list to move the found node to the `top' */ \
266 if ( _node != *_bucket ) \
268 *_pnode = _node->link; \
269 _node->link = *_bucket; \
273 /* Update MRU list */ \
275 FTC_Manager _manager = _cache->manager; \
276 void* _nl = &_manager->nodes_list; \
279 if ( _node != _manager->nodes_list ) \
280 FTC_MruNode_Up( (FTC_MruNode*)_nl, \
281 (FTC_MruNode)_node ); \
286 error = FTC_Cache_NewNode( _cache, _hash, query, &_node ); \
292 #else /* !FTC_INLINE */
294 #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
296 error = FTC_Cache_Lookup( FTC_CACHE( cache ), hash, query, \
297 (FTC_Node*)&(node) ); \
300 #endif /* !FTC_INLINE */
304 * This macro, together with FTC_CACHE_TRYLOOP_END, defines a retry
305 * loop to flush the cache repeatedly in case of memory overflows.
307 * It is used when creating a new cache node, or within a lookup
308 * that needs to allocate data (e.g. the sbit cache lookup).
313 * FTC_CACHE_TRYLOOP( cache )
314 * error = load_data( ... );
315 * FTC_CACHE_TRYLOOP_END()
319 #define FTC_CACHE_TRYLOOP( cache ) \
321 FTC_Manager _try_manager = FTC_CACHE( cache )->manager; \
322 FT_UInt _try_count = 4; \
330 #define FTC_CACHE_TRYLOOP_END( list_changed ) \
331 if ( !error || error != FTC_Err_Out_Of_Memory ) \
334 _try_done = FTC_Manager_FlushN( _try_manager, _try_count ); \
335 if ( _try_done > 0 && ( list_changed ) ) \
336 *(FT_Bool*)( list_changed ) = TRUE; \
338 if ( _try_done == 0 ) \
341 if ( _try_done == _try_count ) \
344 if ( _try_count < _try_done || \
345 _try_count > _try_manager->num_nodes ) \
346 _try_count = _try_manager->num_nodes; \
356 #endif /* __FTCCACHE_H__ */