ftccache.c (13683B)
1 /**************************************************************************** 2 * 3 * ftccache.c 4 * 5 * The FreeType internal cache interface (body). 6 * 7 * Copyright (C) 2000-2025 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 #include "ftcmanag.h" 20 #include <freetype/internal/ftobjs.h> 21 #include <freetype/internal/ftdebug.h> 22 23 #include "ftccback.h" 24 #include "ftcerror.h" 25 26 #undef FT_COMPONENT 27 #define FT_COMPONENT cache 28 29 30 #define FTC_HASH_MAX_LOAD 2 31 #define FTC_HASH_MIN_LOAD 1 32 #define FTC_HASH_SUB_LOAD ( FTC_HASH_MAX_LOAD - FTC_HASH_MIN_LOAD ) 33 34 /* this one _must_ be a power of 2! */ 35 #define FTC_HASH_INITIAL_SIZE 8 36 37 38 /*************************************************************************/ 39 /*************************************************************************/ 40 /***** *****/ 41 /***** CACHE NODE DEFINITIONS *****/ 42 /***** *****/ 43 /*************************************************************************/ 44 /*************************************************************************/ 45 46 /* add a new node to the head of the manager's circular MRU list */ 47 static void 48 ftc_node_mru_link( FTC_Node node, 49 FTC_Manager manager ) 50 { 51 void *nl = &manager->nodes_list; 52 53 54 FTC_MruNode_Prepend( (FTC_MruNode*)nl, 55 (FTC_MruNode)node ); 56 manager->num_nodes++; 57 } 58 59 60 /* remove a node from the manager's MRU list */ 61 static void 62 ftc_node_mru_unlink( FTC_Node node, 63 FTC_Manager manager ) 64 { 65 void *nl = &manager->nodes_list; 66 67 68 FTC_MruNode_Remove( (FTC_MruNode*)nl, 69 (FTC_MruNode)node ); 70 manager->num_nodes--; 71 } 72 73 74 #ifndef FTC_INLINE 75 76 /* move a node to the head of the manager's MRU list */ 77 static void 78 ftc_node_mru_up( FTC_Node node, 79 FTC_Manager manager ) 80 { 81 FTC_MruNode_Up( (FTC_MruNode*)&manager->nodes_list, 82 (FTC_MruNode)node ); 83 } 84 85 86 /* get a top bucket for specified hash from cache, 87 * body for FTC_NODE_TOP_FOR_HASH( cache, hash ) 88 */ 89 FT_LOCAL_DEF( FTC_Node* ) 90 ftc_get_top_node_for_hash( FTC_Cache cache, 91 FT_Offset hash ) 92 { 93 FT_Offset idx; 94 95 96 idx = hash & cache->mask; 97 if ( idx >= cache->p ) 98 idx = hash & ( cache->mask >> 1 ); 99 100 return cache->buckets + idx; 101 } 102 103 #endif /* !FTC_INLINE */ 104 105 106 /* Note that this function cannot fail. If we cannot re-size the 107 * buckets array appropriately, we simply degrade the hash table's 108 * performance! 109 */ 110 static void 111 ftc_cache_resize( FTC_Cache cache ) 112 { 113 for (;;) 114 { 115 FTC_Node node, *pnode; 116 FT_UFast p = cache->p; 117 FT_UFast size = cache->mask + 1; /* available size */ 118 FT_UFast half = size >> 1; 119 120 121 /* do we need to expand the buckets array? */ 122 if ( cache->slack < 0 ) 123 { 124 FTC_Node new_list = NULL; 125 126 127 /* try to expand the buckets array _before_ splitting 128 * the bucket lists 129 */ 130 if ( p == size ) 131 { 132 FT_Memory memory = cache->memory; 133 FT_Error error; 134 135 136 /* if we can't expand the array, leave immediately */ 137 if ( FT_QRENEW_ARRAY( cache->buckets, size, size * 2 ) ) 138 break; 139 140 cache->mask = 2 * size - 1; 141 half = size; 142 } 143 144 /* the bucket to split */ 145 pnode = cache->buckets + p - half; 146 147 for (;;) 148 { 149 node = *pnode; 150 if ( !node ) 151 break; 152 153 if ( node->hash & half ) 154 { 155 *pnode = node->link; 156 node->link = new_list; 157 new_list = node; 158 } 159 else 160 pnode = &node->link; 161 } 162 163 cache->buckets[p] = new_list; 164 165 cache->slack += FTC_HASH_MAX_LOAD; 166 cache->p = p + 1; 167 168 FT_TRACE2(( "ftc_cache_resize: cache %u increased to %u hashes\n", 169 cache->index, cache->p )); 170 } 171 172 /* do we need to shrink the buckets array? */ 173 else if ( cache->slack > (FT_Long)p * FTC_HASH_SUB_LOAD ) 174 { 175 FTC_Node old_list = cache->buckets[--p]; 176 177 178 if ( p < FTC_HASH_INITIAL_SIZE ) 179 break; 180 181 if ( p == half ) 182 { 183 FT_Memory memory = cache->memory; 184 FT_Error error; 185 186 187 /* if we can't shrink the array, leave immediately */ 188 if ( FT_QRENEW_ARRAY( cache->buckets, size, half ) ) 189 break; 190 191 cache->mask = half - 1; 192 } 193 194 /* the bucket to merge */ 195 pnode = cache->buckets + p - half; 196 197 while ( *pnode ) 198 pnode = &(*pnode)->link; 199 200 *pnode = old_list; 201 202 cache->slack -= FTC_HASH_MAX_LOAD; 203 cache->p = p; 204 205 FT_TRACE2(( "ftc_cache_resize: cache %u decreased to %u hashes\n", 206 cache->index, cache->p )); 207 } 208 209 /* otherwise, the hash table is balanced */ 210 else 211 break; 212 } 213 } 214 215 216 /* remove a node from its cache's hash table */ 217 static void 218 ftc_node_hash_unlink( FTC_Node node0, 219 FTC_Cache cache ) 220 { 221 FTC_Node *pnode = FTC_NODE_TOP_FOR_HASH( cache, node0->hash ); 222 223 224 for (;;) 225 { 226 FTC_Node node = *pnode; 227 228 229 if ( !node ) 230 { 231 FT_TRACE0(( "ftc_node_hash_unlink: unknown node\n" )); 232 return; 233 } 234 235 if ( node == node0 ) 236 break; 237 238 pnode = &node->link; 239 } 240 241 *pnode = node0->link; 242 node0->link = NULL; 243 244 cache->slack++; 245 ftc_cache_resize( cache ); 246 } 247 248 249 /* add a node to the `top' of its cache's hash table */ 250 static void 251 ftc_node_hash_link( FTC_Node node, 252 FTC_Cache cache ) 253 { 254 FTC_Node *pnode = FTC_NODE_TOP_FOR_HASH( cache, node->hash ); 255 256 257 node->link = *pnode; 258 *pnode = node; 259 260 cache->slack--; 261 ftc_cache_resize( cache ); 262 } 263 264 265 /* remove a node from the cache manager */ 266 FT_LOCAL_DEF( void ) 267 ftc_node_destroy( FTC_Node node, 268 FTC_Manager manager ) 269 { 270 FTC_Cache cache; 271 272 273 #ifdef FT_DEBUG_ERROR 274 /* find node's cache */ 275 if ( node->cache_index >= manager->num_caches ) 276 { 277 FT_TRACE0(( "ftc_node_destroy: invalid node handle\n" )); 278 return; 279 } 280 #endif 281 282 cache = manager->caches[node->cache_index]; 283 284 #ifdef FT_DEBUG_ERROR 285 if ( !cache ) 286 { 287 FT_TRACE0(( "ftc_node_destroy: invalid node handle\n" )); 288 return; 289 } 290 #endif 291 292 manager->cur_weight -= cache->clazz.node_weight( node, cache ); 293 294 /* remove node from mru list */ 295 ftc_node_mru_unlink( node, manager ); 296 297 /* remove node from cache's hash table */ 298 ftc_node_hash_unlink( node, cache ); 299 300 /* now finalize it */ 301 cache->clazz.node_free( node, cache ); 302 303 #if 0 304 /* check, just in case of general corruption :-) */ 305 if ( manager->num_nodes == 0 ) 306 FT_TRACE0(( "ftc_node_destroy: invalid cache node count (%u)\n", 307 manager->num_nodes )); 308 #endif 309 } 310 311 312 /*************************************************************************/ 313 /*************************************************************************/ 314 /***** *****/ 315 /***** ABSTRACT CACHE CLASS *****/ 316 /***** *****/ 317 /*************************************************************************/ 318 /*************************************************************************/ 319 320 321 FT_LOCAL_DEF( FT_Error ) 322 ftc_cache_init( FTC_Cache cache ) 323 { 324 FT_Memory memory = cache->memory; 325 FT_Error error; 326 327 328 cache->p = FTC_HASH_INITIAL_SIZE; 329 cache->mask = FTC_HASH_INITIAL_SIZE - 1; 330 cache->slack = FTC_HASH_INITIAL_SIZE * FTC_HASH_MAX_LOAD; 331 332 FT_MEM_NEW_ARRAY( cache->buckets, FTC_HASH_INITIAL_SIZE ); 333 return error; 334 } 335 336 337 FT_LOCAL_DEF( FT_Error ) 338 FTC_Cache_Init( FTC_Cache cache ) 339 { 340 return ftc_cache_init( cache ); 341 } 342 343 344 FT_LOCAL_DEF( void ) 345 ftc_cache_done( FTC_Cache cache ) 346 { 347 FT_Memory memory = cache->memory; 348 349 350 if ( cache->buckets ) 351 { 352 FTC_Manager manager = cache->manager; 353 FT_UFast count = cache->p; 354 FT_UFast i; 355 356 357 for ( i = 0; i < count; i++ ) 358 { 359 FTC_Node node = cache->buckets[i], next; 360 361 362 while ( node ) 363 { 364 next = node->link; 365 node->link = NULL; 366 367 /* remove node from mru list */ 368 ftc_node_mru_unlink( node, manager ); 369 370 /* now finalize it */ 371 manager->cur_weight -= cache->clazz.node_weight( node, cache ); 372 373 cache->clazz.node_free( node, cache ); 374 node = next; 375 } 376 } 377 } 378 379 FT_FREE( cache->buckets ); 380 381 cache->p = 0; 382 cache->mask = 0; 383 cache->slack = 0; 384 } 385 386 387 FT_LOCAL_DEF( void ) 388 FTC_Cache_Done( FTC_Cache cache ) 389 { 390 ftc_cache_done( cache ); 391 } 392 393 394 static void 395 ftc_cache_add( FTC_Cache cache, 396 FT_Offset hash, 397 FTC_Node node ) 398 { 399 node->hash = hash; 400 node->cache_index = (FT_UShort)cache->index; 401 node->ref_count = 0; 402 403 ftc_node_hash_link( node, cache ); 404 ftc_node_mru_link( node, cache->manager ); 405 406 { 407 FTC_Manager manager = cache->manager; 408 409 410 manager->cur_weight += cache->clazz.node_weight( node, cache ); 411 412 if ( manager->cur_weight >= manager->max_weight ) 413 { 414 node->ref_count++; 415 FTC_Manager_Compress( manager ); 416 node->ref_count--; 417 } 418 } 419 } 420 421 422 FT_LOCAL_DEF( FT_Error ) 423 FTC_Cache_NewNode( FTC_Cache cache, 424 FT_Offset hash, 425 FT_Pointer query, 426 FTC_Node *anode ) 427 { 428 FT_Error error; 429 FTC_Node node; 430 431 432 /* 433 * We use the FTC_CACHE_TRYLOOP macros to support out-of-memory 434 * errors (OOM) correctly, i.e., by flushing the cache progressively 435 * in order to make more room. 436 */ 437 438 FTC_CACHE_TRYLOOP( cache ) 439 { 440 error = cache->clazz.node_new( &node, query, cache ); 441 } 442 FTC_CACHE_TRYLOOP_END( NULL ) 443 444 if ( error ) 445 node = NULL; 446 else 447 { 448 /* don't assume that the cache has the same number of buckets, since 449 * our allocation request might have triggered global cache flushing 450 */ 451 ftc_cache_add( cache, hash, node ); 452 } 453 454 *anode = node; 455 return error; 456 } 457 458 459 #ifndef FTC_INLINE 460 461 FT_LOCAL_DEF( FT_Error ) 462 FTC_Cache_Lookup( FTC_Cache cache, 463 FT_Offset hash, 464 FT_Pointer query, 465 FTC_Node *anode ) 466 { 467 FTC_Node* bucket; 468 FTC_Node* pnode; 469 FTC_Node node; 470 FT_Error error = FT_Err_Ok; 471 FT_Bool list_changed = FALSE; 472 473 FTC_Node_CompareFunc compare = cache->clazz.node_compare; 474 475 476 if ( !cache || !anode ) 477 return FT_THROW( Invalid_Argument ); 478 479 /* Go to the `top' node of the list sharing same masked hash */ 480 bucket = pnode = FTC_NODE_TOP_FOR_HASH( cache, hash ); 481 482 /* Lookup a node with exactly same hash and queried properties. */ 483 /* NOTE: _nodcomp() may change the linked list to reduce memory. */ 484 for (;;) 485 { 486 node = *pnode; 487 if ( !node ) 488 goto NewNode; 489 490 if ( node->hash == hash && 491 compare( node, query, cache, &list_changed ) ) 492 break; 493 494 pnode = &node->link; 495 } 496 497 if ( list_changed ) 498 { 499 /* Update bucket by modified linked list */ 500 bucket = pnode = FTC_NODE_TOP_FOR_HASH( cache, hash ); 501 502 /* Update pnode by modified linked list */ 503 while ( *pnode != node ) 504 { 505 if ( !*pnode ) 506 { 507 FT_ERROR(( "FTC_Cache_Lookup: oops!!! node missing\n" )); 508 goto NewNode; 509 } 510 else 511 pnode = &(*pnode)->link; 512 } 513 } 514 515 /* Reorder the list to move the found node to the `top' */ 516 if ( node != *bucket ) 517 { 518 *pnode = node->link; 519 node->link = *bucket; 520 *bucket = node; 521 } 522 523 /* move to head of MRU list */ 524 { 525 FTC_Manager manager = cache->manager; 526 527 528 if ( node != manager->nodes_list ) 529 ftc_node_mru_up( node, manager ); 530 } 531 *anode = node; 532 533 return error; 534 535 NewNode: 536 return FTC_Cache_NewNode( cache, hash, query, anode ); 537 } 538 539 #endif /* !FTC_INLINE */ 540 541 542 FT_LOCAL_DEF( void ) 543 FTC_Cache_RemoveFaceID( FTC_Cache cache, 544 FTC_FaceID face_id ) 545 { 546 FTC_Manager manager = cache->manager; 547 FT_UFast count = cache->p; 548 FT_UFast i; 549 550 551 for ( i = 0; i < count; i++ ) 552 { 553 FTC_Node* pnode = cache->buckets + i; 554 555 556 for (;;) 557 { 558 FTC_Node node = *pnode; 559 560 561 if ( !node ) 562 break; 563 564 if ( cache->clazz.node_remove_faceid( node, face_id, cache, NULL ) ) 565 { 566 *pnode = node->link; 567 568 manager->cur_weight -= cache->clazz.node_weight( node, cache ); 569 ftc_node_mru_unlink( node, manager ); 570 571 cache->clazz.node_free( node, cache ); 572 573 cache->slack++; 574 } 575 else 576 pnode = &node->link; 577 } 578 } 579 580 ftc_cache_resize( cache ); 581 } 582 583 584 /* END */