1 /**************************************************************************** 2 * 3 * ftccache.h 4 * 5 * FreeType internal cache interface (specification). 6 * 7 * Copyright 2000-2018 by 8 * David Turner, Robert Wilhelm, and Werner Lemberg. 9 * 10 * This file is part of the FreeType project, and may only be used, 11 * modified, and distributed under the terms of the FreeType project 12 * license, LICENSE.TXT. By continuing to use, modify, or distribute 13 * this file you indicate that you have read the license and 14 * understand and accept it fully. 15 * 16 */ 17 18 19 #ifndef FTCCACHE_H_ 20 #define FTCCACHE_H_ 21 22 23 #include "ftcmru.h" 24 25 FT_BEGIN_HEADER 26 27 #define FTC_FACE_ID_HASH( i ) \ 28 ( ( (FT_Offset)(i) >> 3 ) ^ ( (FT_Offset)(i) << 7 ) ) 29 30 /* handle to cache object */ 31 typedef struct FTC_CacheRec_* FTC_Cache; 32 33 /* handle to cache class */ 34 typedef const struct FTC_CacheClassRec_* FTC_CacheClass; 35 36 37 /*************************************************************************/ 38 /*************************************************************************/ 39 /***** *****/ 40 /***** CACHE NODE DEFINITIONS *****/ 41 /***** *****/ 42 /*************************************************************************/ 43 /*************************************************************************/ 44 45 /************************************************************************** 46 * 47 * Each cache controls one or more cache nodes. Each node is part of 48 * the global_lru list of the manager. Its `data' field however is used 49 * as a reference count for now. 50 * 51 * A node can be anything, depending on the type of information held by 52 * the cache. It can be an individual glyph image, a set of bitmaps 53 * glyphs for a given size, some metrics, etc. 54 * 55 */ 56 57 /* structure size should be 20 bytes on 32-bits machines */ 58 typedef struct FTC_NodeRec_ 59 { 60 FTC_MruNodeRec mru; /* circular mru list pointer */ 61 FTC_Node link; /* used for hashing */ 62 FT_Offset hash; /* used for hashing too */ 63 FT_UShort cache_index; /* index of cache the node belongs to */ 64 FT_Short ref_count; /* reference count for this node */ 65 66 } FTC_NodeRec; 67 68 69 #define FTC_NODE( x ) ( (FTC_Node)(x) ) 70 #define FTC_NODE_P( x ) ( (FTC_Node*)(x) ) 71 72 #define FTC_NODE_NEXT( x ) FTC_NODE( (x)->mru.next ) 73 #define FTC_NODE_PREV( x ) FTC_NODE( (x)->mru.prev ) 74 75 #ifdef FTC_INLINE 76 #define FTC_NODE_TOP_FOR_HASH( cache, hash ) \ 77 ( ( cache )->buckets + \ 78 ( ( ( ( hash ) & ( cache )->mask ) < ( cache )->p ) \ 79 ? ( ( hash ) & ( ( cache )->mask * 2 + 1 ) ) \ 80 : ( ( hash ) & ( cache )->mask ) ) ) 81 #else 82 FT_LOCAL( FTC_Node* ) 83 ftc_get_top_node_for_hash( FTC_Cache cache, 84 FT_Offset hash ); 85 #define FTC_NODE_TOP_FOR_HASH( cache, hash ) \ 86 ftc_get_top_node_for_hash( ( cache ), ( hash ) ) 87 #endif 88 89 90 /*************************************************************************/ 91 /*************************************************************************/ 92 /***** *****/ 93 /***** CACHE DEFINITIONS *****/ 94 /***** *****/ 95 /*************************************************************************/ 96 /*************************************************************************/ 97 98 /* initialize a new cache node */ 99 typedef FT_Error 100 (*FTC_Node_NewFunc)( FTC_Node *pnode, 101 FT_Pointer query, 102 FTC_Cache cache ); 103 104 typedef FT_Offset 105 (*FTC_Node_WeightFunc)( FTC_Node node, 106 FTC_Cache cache ); 107 108 /* compare a node to a given key pair */ 109 typedef FT_Bool 110 (*FTC_Node_CompareFunc)( FTC_Node node, 111 FT_Pointer key, 112 FTC_Cache cache, 113 FT_Bool* list_changed ); 114 115 116 typedef void 117 (*FTC_Node_FreeFunc)( FTC_Node node, 118 FTC_Cache cache ); 119 120 typedef FT_Error 121 (*FTC_Cache_InitFunc)( FTC_Cache cache ); 122 123 typedef void 124 (*FTC_Cache_DoneFunc)( FTC_Cache cache ); 125 126 127 typedef struct FTC_CacheClassRec_ 128 { 129 FTC_Node_NewFunc node_new; 130 FTC_Node_WeightFunc node_weight; 131 FTC_Node_CompareFunc node_compare; 132 FTC_Node_CompareFunc node_remove_faceid; 133 FTC_Node_FreeFunc node_free; 134 135 FT_Offset cache_size; 136 FTC_Cache_InitFunc cache_init; 137 FTC_Cache_DoneFunc cache_done; 138 139 } FTC_CacheClassRec; 140 141 142 /* each cache really implements a dynamic hash table to manage its nodes */ 143 typedef struct FTC_CacheRec_ 144 { 145 FT_UFast p; 146 FT_UFast mask; 147 FT_Long slack; 148 FTC_Node* buckets; 149 150 FTC_CacheClassRec clazz; /* local copy, for speed */ 151 152 FTC_Manager manager; 153 FT_Memory memory; 154 FT_UInt index; /* in manager's table */ 155 156 FTC_CacheClass org_class; /* original class pointer */ 157 158 } FTC_CacheRec; 159 160 161 #define FTC_CACHE( x ) ( (FTC_Cache)(x) ) 162 #define FTC_CACHE_P( x ) ( (FTC_Cache*)(x) ) 163 164 165 /* default cache initialize */ 166 FT_LOCAL( FT_Error ) 167 FTC_Cache_Init( FTC_Cache cache ); 168 169 /* default cache finalizer */ 170 FT_LOCAL( void ) 171 FTC_Cache_Done( FTC_Cache cache ); 172 173 /* Call this function to look up the cache. If no corresponding 174 * node is found, a new one is automatically created. This function 175 * is capable of flushing the cache adequately to make room for the 176 * new cache object. 177 */ 178 179 #ifndef FTC_INLINE 180 FT_LOCAL( FT_Error ) 181 FTC_Cache_Lookup( FTC_Cache cache, 182 FT_Offset hash, 183 FT_Pointer query, 184 FTC_Node *anode ); 185 #endif 186 187 FT_LOCAL( FT_Error ) 188 FTC_Cache_NewNode( FTC_Cache cache, 189 FT_Offset hash, 190 FT_Pointer query, 191 FTC_Node *anode ); 192 193 /* Remove all nodes that relate to a given face_id. This is useful 194 * when un-installing fonts. Note that if a cache node relates to 195 * the face_id but is locked (i.e., has `ref_count > 0'), the node 196 * will _not_ be destroyed, but its internal face_id reference will 197 * be modified. 198 * 199 * The final result will be that the node will never come back 200 * in further lookup requests, and will be flushed on demand from 201 * the cache normally when its reference count reaches 0. 202 */ 203 FT_LOCAL( void ) 204 FTC_Cache_RemoveFaceID( FTC_Cache cache, 205 FTC_FaceID face_id ); 206 207 208 #ifdef FTC_INLINE 209 210 #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \ 211 FT_BEGIN_STMNT \ 212 FTC_Node *_bucket, *_pnode, _node; \ 213 FTC_Cache _cache = FTC_CACHE(cache); \ 214 FT_Offset _hash = (FT_Offset)(hash); \ 215 FTC_Node_CompareFunc _nodcomp = (FTC_Node_CompareFunc)(nodecmp); \ 216 FT_Bool _list_changed = FALSE; \ 217 \ 218 \ 219 error = FT_Err_Ok; \ 220 node = NULL; \ 221 \ 222 /* Go to the `top' node of the list sharing same masked hash */ \ 223 _bucket = _pnode = FTC_NODE_TOP_FOR_HASH( _cache, _hash ); \ 224 \ 225 /* Look up a node with identical hash and queried properties. */ \ 226 /* NOTE: _nodcomp() may change the linked list to reduce memory. */ \ 227 for (;;) \ 228 { \ 229 _node = *_pnode; \ 230 if ( !_node ) \ 231 goto NewNode_; \ 232 \ 233 if ( _node->hash == _hash && \ 234 _nodcomp( _node, query, _cache, &_list_changed ) ) \ 235 break; \ 236 \ 237 _pnode = &_node->link; \ 238 } \ 239 \ 240 if ( _list_changed ) \ 241 { \ 242 /* Update _bucket by possibly modified linked list */ \ 243 _bucket = _pnode = FTC_NODE_TOP_FOR_HASH( _cache, _hash ); \ 244 \ 245 /* Update _pnode by possibly modified linked list */ \ 246 while ( *_pnode != _node ) \ 247 { \ 248 if ( !*_pnode ) \ 249 { \ 250 FT_ERROR(( "FTC_CACHE_LOOKUP_CMP: oops!!! node missing\n" )); \ 251 goto NewNode_; \ 252 } \ 253 else \ 254 _pnode = &((*_pnode)->link); \ 255 } \ 256 } \ 257 \ 258 /* Reorder the list to move the found node to the `top' */ \ 259 if ( _node != *_bucket ) \ 260 { \ 261 *_pnode = _node->link; \ 262 _node->link = *_bucket; \ 263 *_bucket = _node; \ 264 } \ 265 \ 266 /* Update MRU list */ \ 267 { \ 268 FTC_Manager _manager = _cache->manager; \ 269 void* _nl = &_manager->nodes_list; \ 270 \ 271 \ 272 if ( _node != _manager->nodes_list ) \ 273 FTC_MruNode_Up( (FTC_MruNode*)_nl, \ 274 (FTC_MruNode)_node ); \ 275 } \ 276 goto Ok_; \ 277 \ 278 NewNode_: \ 279 error = FTC_Cache_NewNode( _cache, _hash, query, &_node ); \ 280 \ 281 Ok_: \ 282 node = _node; \ 283 FT_END_STMNT 284 285 #else /* !FTC_INLINE */ 286 287 #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \ 288 FT_BEGIN_STMNT \ 289 error = FTC_Cache_Lookup( FTC_CACHE( cache ), hash, query, \ 290 (FTC_Node*)&(node) ); \ 291 FT_END_STMNT 292 293 #endif /* !FTC_INLINE */ 294 295 296 /* 297 * This macro, together with FTC_CACHE_TRYLOOP_END, defines a retry 298 * loop to flush the cache repeatedly in case of memory overflows. 299 * 300 * It is used when creating a new cache node, or within a lookup 301 * that needs to allocate data (e.g. the sbit cache lookup). 302 * 303 * Example: 304 * 305 * { 306 * FTC_CACHE_TRYLOOP( cache ) 307 * error = load_data( ... ); 308 * FTC_CACHE_TRYLOOP_END() 309 * } 310 * 311 */ 312 #define FTC_CACHE_TRYLOOP( cache ) \ 313 { \ 314 FTC_Manager _try_manager = FTC_CACHE( cache )->manager; \ 315 FT_UInt _try_count = 4; \ 316 \ 317 \ 318 for (;;) \ 319 { \ 320 FT_UInt _try_done; 321 322 323 #define FTC_CACHE_TRYLOOP_END( list_changed ) \ 324 if ( !error || FT_ERR_NEQ( error, Out_Of_Memory ) ) \ 325 break; \ 326 \ 327 _try_done = FTC_Manager_FlushN( _try_manager, _try_count ); \ 328 if ( _try_done > 0 && list_changed != NULL ) \ 329 *(FT_Bool*)( list_changed ) = TRUE; \ 330 \ 331 if ( _try_done == 0 ) \ 332 break; \ 333 \ 334 if ( _try_done == _try_count ) \ 335 { \ 336 _try_count *= 2; \ 337 if ( _try_count < _try_done || \ 338 _try_count > _try_manager->num_nodes ) \ 339 _try_count = _try_manager->num_nodes; \ 340 } \ 341 } \ 342 } 343 344 /* */ 345 346 FT_END_HEADER 347 348 349 #endif /* FTCCACHE_H_ */ 350 351 352 /* END */ 353