ref: a48001361ce01b0b9c3b1408f02d89b5d5fc5642
dir: /src/cache/ftccache.c/
/***************************************************************************/
/* */
/* ftccache.c */
/* */
/* The FreeType internal cache interface (body). */
/* */
/* Copyright 2000-2001, 2002, 2003, 2004 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 "ftccback.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_MruNode_Prepend( (FTC_MruNode*)&manager->nodes_list,
(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 )
{
FTC_MruNode_Remove( (FTC_MruNode*)&manager->nodes_list,
(FTC_MruNode)node );
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_MruNode_Up( (FTC_MruNode*)&manager->nodes_list,
(FTC_MruNode)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_DEF( 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_LOCAL_DEF( FT_Error )
ftc_cache_init( FTC_Cache cache )
{
return FTC_Cache_Init( cache );
}
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_DEF( 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;
}
}
FT_LOCAL_DEF( void )
ftc_cache_done( FTC_Cache cache )
{
FTC_Cache_Done( cache );
}
static void
ftc_cache_add( FTC_Cache cache,
FT_UInt32 hash,
FTC_Node node )
{
node->hash = hash;
node->cache_index = (FT_UInt16) 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_EXPORT_DEF( FT_Error )
FTC_Cache_NewNode( FTC_Cache cache,
FT_UInt32 hash,
FT_Pointer query,
FTC_Node *anode )
{
FT_Error error;
FTC_Node node;
/*
* 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 FlushCache;
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;
FlushCache:
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;
}
}
goto AddNode;
}
FT_EXPORT_DEF( 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 );
}
*anode = node;
return error;
NewNode:
return FTC_Cache_NewNode( cache, hash, query, anode );
}
FT_EXPORT_DEF( void )
FTC_Cache_RemoveFaceID( FTC_Cache cache,
FTC_FaceID face_id )
{
FT_UFast i, count;
FTC_Manager manager = cache->manager;
FTC_Node frees = 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 = frees;
frees = node;
}
else
pnode = &node->link;
}
}
/* remove all nodes in the free list */
while ( frees )
{
FTC_Node node;
node = frees;
frees = 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 */