Edit
kc3-lang/freetype/src/cache/ftccache.c
David Turner
- src/cache/ftccache.c
-
/***************************************************************************/ /* */ /* ftccache.c */ /* */ /* The FreeType internal cache interface (body). */ /* */ /* Copyright 2000-2001, 2002, 2003 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 <ft2build.h> #include FT_CACHE_INTERNAL_MANAGER_H #include FT_INTERNAL_OBJECTS_H #include FT_INTERNAL_DEBUG_H #include "ftcerror.h" #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 ) { FTC_Node first = manager->nodes_list; if ( first ) { FTC_Node last = first->mru_prev; FT_ASSERT( last->mru_next == first ); node->mru_prev = last; node->mru_next = first; last->mru_next = node; first->mru_prev = node; } else { FT_ASSERT( manager->num_nodes == 0 ); node->mru_next = node; node->mru_prev = node; } manager->nodes_list = 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 ) { FTC_Node first = manager->nodes_list; FTC_Node prev = node->mru_prev; FTC_Node next = node->mru_next; FT_ASSERT( first != NULL && manager->num_nodes > 0 ); FT_ASSERT( next->mru_prev == node ); FT_ASSERT( prev->mru_next == node ); next->mru_prev = prev; prev->mru_next = next; if ( node == first ) { /* this is the last node in the list; update its head pointer */ if ( node == next ) manager->nodes_list = NULL; else manager->nodes_list = next; } node->mru_next = NULL; node->mru_prev = NULL; manager->num_nodes--; } /* 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_Node first = manager->nodes_list; if ( node != first ) { FTC_Node prev = node->mru_prev; FTC_Node next = node->mru_next; FTC_Node last; prev->mru_next = next; next->mru_prev = prev; last = first->mru_prev; node->mru_next = first; node->mru_prev = last; first->mru_prev = node; last->mru_next = node; manager->nodes_list = node; } } /* 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_UInt p = cache->p; FT_UInt mask = cache->mask; FT_UInt count = mask + p + 1; /* number of buckets */ /* do we need to shrink 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 >= mask ) { FT_Memory memory = cache->memory; /* if we can't expand the array, leave immediately */ if ( FT_MEM_RENEW_ARRAY( cache->buckets, (mask+1)*2, (mask+1)*4 ) ) break; } /* split a single bucket */ pnode = cache->buckets + p; for (;;) { node = *pnode; if ( node == NULL ) break; if ( node->hash & ( mask + 1 ) ) { *pnode = node->link; node->link = new_list; new_list = node; } else pnode = &node->link; } cache->buckets[p + mask + 1] = new_list; cache->slack += FTC_HASH_MAX_LOAD; if ( p >= mask ) { cache->mask = 2 * mask + 1; cache->p = 0; } else cache->p = p + 1; } /* do we need to expand the buckets array ? */ else if ( cache->slack > (FT_Long)count * FTC_HASH_SUB_LOAD ) { FT_UInt old_index = p + mask; FTC_Node* pold; if ( old_index + 1 <= FTC_HASH_INITIAL_SIZE ) break; if ( p == 0 ) { FT_Memory memory = cache->memory; /* if we can't shrink the array, leave immediately */ if ( FT_MEM_RENEW_ARRAY( cache->buckets, ( mask + 1 ) * 2, (mask+1) ) ) break; cache->mask >>= 1; p = cache->mask; } else p--; pnode = cache->buckets + p; while ( *pnode ) pnode = &(*pnode)->link; pold = cache->buckets + old_index; *pnode = *pold; *pold = NULL; cache->slack -= FTC_HASH_MAX_LOAD; cache->p = p; } else /* the hash table is balanced */ 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; FT_UInt idx; idx = (FT_UInt)( node0->hash & cache->mask ); if ( idx < cache->p ) idx = (FT_UInt)( node0->hash & ( 2 * cache->mask + 1 ) ); pnode = cache->buckets + idx; for (;;) { FTC_Node node = *pnode; if ( node == NULL ) { FT_ERROR(( "ftc_node_hash_unlink: unknown node!\n" )); return; } if ( node == node0 ) break; pnode = &(*pnode)->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; FT_UInt idx; idx = (FT_UInt)( node->hash & cache->mask ); if ( idx < cache->p ) idx = (FT_UInt)( node->hash & (2 * cache->mask + 1 ) ); pnode = cache->buckets + idx; node->link = *pnode; *pnode = node; cache->slack--; ftc_cache_resize( cache ); } /* remove a node from the cache manager */ FT_EXPORT_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_ERROR(( "ftc_node_destroy: invalid node handle\n" )); return; } #endif cache = manager->caches[ node->cache_index ]; #ifdef FT_DEBUG_ERROR if ( cache == NULL ) { FT_ERROR(( "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_ERROR(( "ftc_node_destroy: invalid cache node count! = %d\n", manager->num_nodes )); #endif } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** ABSTRACT CACHE CLASS *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ FT_EXPORT( FT_Error ) FTC_Cache_Init( FTC_Cache cache ) { FT_Memory memory = cache->memory; cache->p = 0; cache->mask = FTC_HASH_INITIAL_SIZE - 1; cache->slack = FTC_HASH_INITIAL_SIZE * FTC_HASH_MAX_LOAD; return ( FT_MEM_NEW_ARRAY( cache->buckets, FTC_HASH_INITIAL_SIZE * 2 ) ); } FT_EXPORT_DEF( void ) FTC_Cache_Clear( FTC_Cache cache ) { if ( cache ) { FTC_Manager manager = cache->manager; FT_UFast i; FT_UInt count; count = cache->p + cache->mask + 1; for ( i = 0; i < count; i++ ) { FTC_Node *pnode = cache->buckets + i, next, node = *pnode; 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; } cache->buckets[i] = NULL; } ftc_cache_resize( cache ); } } FT_EXPORT( void ) FTC_Cache_Done( FTC_Cache cache ) { if ( cache->memory ) { FT_Memory memory = cache->memory; FTC_Cache_Clear( cache ); FT_FREE( cache->buckets ); cache->mask = 0; cache->p = 0; cache->slack = 0; cache->memory = NULL; } } static void ftc_cache_add( FTC_Cache cache, FT_UInt32 hash, FTC_Node node ) { node->hash = hash; 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_EXPORT( FT_Error ) FTC_Cache_Lookup( FTC_Cache cache, FT_UInt32 hash, FT_Pointer query, FTC_Node *anode ) { FT_UFast idx; FTC_Node* bucket; FTC_Node* pnode; FTC_Node node; FT_Error error = 0; FTC_Node_CompareFunc compare = cache->clazz.node_compare; if ( cache == NULL || anode == NULL ) return FT_Err_Invalid_Argument; idx = hash & cache->mask; if ( idx < cache->p ) idx = hash & ( cache->mask * 2 + 1 ); bucket = cache->buckets + idx; pnode = bucket; for (;;) { node = *pnode; if ( node == NULL ) goto NewNode; if ( node->hash == hash && compare( node, query, cache ) ) break; pnode = &node->link; } 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 ); } goto Exit; NewNode: /* * try to allocate a new cache node. Note that in case of * out-of-memory error (OOM), we'll flush the cache a bit, * then try again. * * on each try, the "tries" variable gives the number * of old nodes we want to flush from the manager's global list * before the next allocation attempt. it barely doubles on * each iteration * */ error = cache->clazz.node_new( &node, query, cache ); if ( !error ) goto AddNode; node = NULL; if ( error != FT_Err_Out_Of_Memory ) goto Exit; { FTC_Manager manager = cache->manager; FT_UInt count, tries = 1; for (;;) { error = cache->clazz.node_new( &node, query, cache ); if ( !error ) break; node = NULL; if ( error != FT_Err_Out_Of_Memory ) goto Exit; count = FTC_Manager_FlushN( manager, tries ); if ( count == 0 ) goto Exit; if ( count == tries ) { count = tries*2; if ( count < tries || count > manager->num_nodes ) count = manager->num_nodes; } tries = count; } } AddNode: /* 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 ); Exit: *anode = node; return error; } FT_EXPORT( void ) FTC_Cache_RemoveFaceID( FTC_Cache cache, FTC_FaceID face_id ) { FT_UFast i, count; FTC_Manager manager = cache->manager; FTC_Node free = NULL; count = cache->p + cache->mask; for ( i = 0; i < count; i++ ) { FTC_Node* bucket = cache->buckets + i; FTC_Node* pnode = bucket; for ( ;; ) { FTC_Node node = *pnode; if ( node == NULL ) break; if ( cache->clazz.node_remove_faceid( node, face_id, cache ) ) { *pnode = node->link; node->link = free; free = node; } else pnode = &node->link; } } /* remove all nodes in the free list */ while ( free ) { FTC_Node node; node = free; free = 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 ++; } ftc_cache_resize( cache ); } /* END */