Edit
kc3-lang/freetype/src/cache/ftccache.c
Alexei Podtelezhnikov
- src/cache/ftccache.c
-
/**************************************************************************** * * ftccache.c * * The FreeType internal cache interface (body). * * Copyright (C) 2000-2024 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. * */ #include "ftcmanag.h" #include <freetype/internal/ftobjs.h> #include <freetype/internal/ftdebug.h> #include "ftccback.h" #include "ftcerror.h" #undef FT_COMPONENT #define FT_COMPONENT cache #define FTC_HASH_MAX_LOAD 2 #define FTC_HASH_MIN_LOAD 1 #define FTC_HASH_SUB_LOAD ( FTC_HASH_MAX_LOAD - FTC_HASH_MIN_LOAD ) /* this one _must_ be a power of 2! */ #define FTC_HASH_INITIAL_SIZE 8 /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** CACHE NODE DEFINITIONS *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* add a new node to the head of the manager's circular MRU list */ static void ftc_node_mru_link( FTC_Node node, FTC_Manager manager ) { void *nl = &manager->nodes_list; FTC_MruNode_Prepend( (FTC_MruNode*)nl, (FTC_MruNode)node ); manager->num_nodes++; } /* remove a node from the manager's MRU list */ static void ftc_node_mru_unlink( FTC_Node node, FTC_Manager manager ) { void *nl = &manager->nodes_list; FTC_MruNode_Remove( (FTC_MruNode*)nl, (FTC_MruNode)node ); manager->num_nodes--; } #ifndef FTC_INLINE /* move a node to the head of the manager's MRU list */ static void ftc_node_mru_up( FTC_Node node, FTC_Manager manager ) { FTC_MruNode_Up( (FTC_MruNode*)&manager->nodes_list, (FTC_MruNode)node ); } /* get a top bucket for specified hash from cache, * body for FTC_NODE_TOP_FOR_HASH( cache, hash ) */ FT_LOCAL_DEF( FTC_Node* ) ftc_get_top_node_for_hash( FTC_Cache cache, FT_Offset hash ) { FT_Offset idx; idx = hash & cache->mask; if ( idx >= cache->p ) idx = hash & ( cache->mask >> 1 ); return cache->buckets + idx; } #endif /* !FTC_INLINE */ /* Note that this function cannot fail. If we cannot re-size the * buckets array appropriately, we simply degrade the hash table's * performance! */ static void ftc_cache_resize( FTC_Cache cache ) { for (;;) { FTC_Node node, *pnode; FT_UFast p = cache->p; FT_UFast size = cache->mask + 1; /* available size */ FT_UFast half = size >> 1; /* do we need to expand the buckets array? */ if ( cache->slack < 0 ) { FTC_Node new_list = NULL; /* try to expand the buckets array _before_ splitting * the bucket lists */ if ( p == size ) { FT_Memory memory = cache->memory; FT_Error error; /* if we can't expand the array, leave immediately */ if ( FT_QRENEW_ARRAY( cache->buckets, size, size * 2 ) ) break; cache->mask = 2 * size - 1; half = size; } /* the bucket to split */ pnode = cache->buckets + p - half; for (;;) { node = *pnode; if ( !node ) break; if ( node->hash & half ) { *pnode = node->link; node->link = new_list; new_list = node; } else pnode = &node->link; } cache->buckets[p] = new_list; cache->slack += FTC_HASH_MAX_LOAD; cache->p = p + 1; FT_TRACE2(( "ftc_cache_resize: cache %u increased to %u hashes\n", cache->index, cache->p )); } /* do we need to shrink the buckets array? */ else if ( cache->slack > (FT_Long)p * FTC_HASH_SUB_LOAD ) { FTC_Node old_list = cache->buckets[--p]; if ( p < FTC_HASH_INITIAL_SIZE ) break; if ( p == half ) { FT_Memory memory = cache->memory; FT_Error error; /* if we can't shrink the array, leave immediately */ if ( FT_QRENEW_ARRAY( cache->buckets, size, half ) ) break; cache->mask = half - 1; } /* the bucket to merge */ pnode = cache->buckets + p - half; while ( *pnode ) pnode = &(*pnode)->link; *pnode = old_list; cache->slack -= FTC_HASH_MAX_LOAD; cache->p = p; FT_TRACE2(( "ftc_cache_resize: cache %u decreased to %u hashes\n", cache->index, cache->p )); } /* otherwise, the hash table is balanced */ else break; } } /* remove a node from its cache's hash table */ static void ftc_node_hash_unlink( FTC_Node node0, FTC_Cache cache ) { FTC_Node *pnode = FTC_NODE_TOP_FOR_HASH( cache, node0->hash ); for (;;) { FTC_Node node = *pnode; if ( !node ) { FT_TRACE0(( "ftc_node_hash_unlink: unknown node\n" )); return; } if ( node == node0 ) break; pnode = &node->link; } *pnode = node0->link; node0->link = NULL; cache->slack++; ftc_cache_resize( cache ); } /* add a node to the `top' of its cache's hash table */ static void ftc_node_hash_link( FTC_Node node, FTC_Cache cache ) { FTC_Node *pnode = FTC_NODE_TOP_FOR_HASH( cache, node->hash ); node->link = *pnode; *pnode = node; cache->slack--; ftc_cache_resize( cache ); } /* remove a node from the cache manager */ FT_LOCAL_DEF( void ) ftc_node_destroy( FTC_Node node, FTC_Manager manager ) { FTC_Cache cache; #ifdef FT_DEBUG_ERROR /* find node's cache */ if ( node->cache_index >= manager->num_caches ) { FT_TRACE0(( "ftc_node_destroy: invalid node handle\n" )); return; } #endif cache = manager->caches[node->cache_index]; #ifdef FT_DEBUG_ERROR if ( !cache ) { FT_TRACE0(( "ftc_node_destroy: invalid node handle\n" )); return; } #endif manager->cur_weight -= cache->clazz.node_weight( node, cache ); /* remove node from mru list */ ftc_node_mru_unlink( node, manager ); /* remove node from cache's hash table */ ftc_node_hash_unlink( node, cache ); /* now finalize it */ cache->clazz.node_free( node, cache ); #if 0 /* check, just in case of general corruption :-) */ if ( manager->num_nodes == 0 ) FT_TRACE0(( "ftc_node_destroy: invalid cache node count (%u)\n", manager->num_nodes )); #endif } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** ABSTRACT CACHE CLASS *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ FT_LOCAL_DEF( FT_Error ) ftc_cache_init( FTC_Cache cache ) { FT_Memory memory = cache->memory; FT_Error error; cache->p = FTC_HASH_INITIAL_SIZE; cache->mask = FTC_HASH_INITIAL_SIZE - 1; cache->slack = FTC_HASH_INITIAL_SIZE * FTC_HASH_MAX_LOAD; FT_MEM_NEW_ARRAY( cache->buckets, FTC_HASH_INITIAL_SIZE ); return error; } FT_LOCAL_DEF( FT_Error ) FTC_Cache_Init( FTC_Cache cache ) { return ftc_cache_init( cache ); } FT_LOCAL_DEF( void ) ftc_cache_done( FTC_Cache cache ) { FT_Memory memory = cache->memory; if ( cache->buckets ) { FTC_Manager manager = cache->manager; FT_UFast count = cache->p; FT_UFast i; for ( i = 0; i < count; i++ ) { FTC_Node node = cache->buckets[i], next; while ( node ) { next = node->link; node->link = NULL; /* remove node from mru list */ ftc_node_mru_unlink( node, manager ); /* now finalize it */ manager->cur_weight -= cache->clazz.node_weight( node, cache ); cache->clazz.node_free( node, cache ); node = next; } } } FT_FREE( cache->buckets ); cache->p = 0; cache->mask = 0; cache->slack = 0; } FT_LOCAL_DEF( void ) FTC_Cache_Done( FTC_Cache cache ) { ftc_cache_done( cache ); } static void ftc_cache_add( FTC_Cache cache, FT_Offset hash, FTC_Node node ) { node->hash = hash; node->cache_index = (FT_UShort)cache->index; node->ref_count = 0; ftc_node_hash_link( node, cache ); ftc_node_mru_link( node, cache->manager ); { FTC_Manager manager = cache->manager; manager->cur_weight += cache->clazz.node_weight( node, cache ); if ( manager->cur_weight >= manager->max_weight ) { node->ref_count++; FTC_Manager_Compress( manager ); node->ref_count--; } } } FT_LOCAL_DEF( FT_Error ) FTC_Cache_NewNode( FTC_Cache cache, FT_Offset hash, FT_Pointer query, FTC_Node *anode ) { FT_Error error; FTC_Node node; /* * We use the FTC_CACHE_TRYLOOP macros to support out-of-memory * errors (OOM) correctly, i.e., by flushing the cache progressively * in order to make more room. */ FTC_CACHE_TRYLOOP( cache ) { error = cache->clazz.node_new( &node, query, cache ); } FTC_CACHE_TRYLOOP_END( NULL ) if ( error ) node = NULL; else { /* don't assume that the cache has the same number of buckets, since * our allocation request might have triggered global cache flushing */ ftc_cache_add( cache, hash, node ); } *anode = node; return error; } #ifndef FTC_INLINE FT_LOCAL_DEF( FT_Error ) FTC_Cache_Lookup( FTC_Cache cache, FT_Offset hash, FT_Pointer query, FTC_Node *anode ) { FTC_Node* bucket; FTC_Node* pnode; FTC_Node node; FT_Error error = FT_Err_Ok; FT_Bool list_changed = FALSE; FTC_Node_CompareFunc compare = cache->clazz.node_compare; if ( !cache || !anode ) return FT_THROW( Invalid_Argument ); /* Go to the `top' node of the list sharing same masked hash */ bucket = pnode = FTC_NODE_TOP_FOR_HASH( cache, hash ); /* Lookup a node with exactly same hash and queried properties. */ /* NOTE: _nodcomp() may change the linked list to reduce memory. */ for (;;) { node = *pnode; if ( !node ) goto NewNode; if ( node->hash == hash && compare( node, query, cache, &list_changed ) ) break; pnode = &node->link; } if ( list_changed ) { /* Update bucket by modified linked list */ bucket = pnode = FTC_NODE_TOP_FOR_HASH( cache, hash ); /* Update pnode by modified linked list */ while ( *pnode != node ) { if ( !*pnode ) { FT_ERROR(( "FTC_Cache_Lookup: oops!!! node missing\n" )); goto NewNode; } else pnode = &(*pnode)->link; } } /* Reorder the list to move the found node to the `top' */ if ( node != *bucket ) { *pnode = node->link; node->link = *bucket; *bucket = node; } /* move to head of MRU list */ { FTC_Manager manager = cache->manager; if ( node != manager->nodes_list ) ftc_node_mru_up( node, manager ); } *anode = node; return error; NewNode: return FTC_Cache_NewNode( cache, hash, query, anode ); } #endif /* !FTC_INLINE */ FT_LOCAL_DEF( void ) FTC_Cache_RemoveFaceID( FTC_Cache cache, FTC_FaceID face_id ) { FTC_Manager manager = cache->manager; FT_UFast count = cache->p; FT_UFast i; for ( i = 0; i < count; i++ ) { FTC_Node* pnode = cache->buckets + i; for (;;) { FTC_Node node = *pnode; if ( !node ) break; if ( cache->clazz.node_remove_faceid( node, face_id, cache, NULL ) ) { *pnode = node->link; manager->cur_weight -= cache->clazz.node_weight( node, cache ); ftc_node_mru_unlink( node, manager ); cache->clazz.node_free( node, cache ); cache->slack++; } else pnode = &node->link; } } ftc_cache_resize( cache ); } /* END */