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|
/***************************************************************************/
/* */
/* ftlru.c */
/* */
/* Simple LRU list-cache (body). */
/* */
/* Copyright 2000 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_H
#include FT_CACHE_INTERNAL_LRU_H
#include FT_LIST_H
#include FT_INTERNAL_OBJECTS_H
static
void lru_build_free_list( FT_LruNode nodes,
FT_UInt count,
FT_List free_list )
{
FT_LruNode node = nodes;
FT_LruNode limit = node + count;
free_list->head = free_list->tail = 0;
for ( ; node < limit; node++ )
FT_List_Add( free_list, (FT_ListNode)node );
}
FT_EXPORT_DEF( FT_Error ) FT_Lru_New( const FT_Lru_Class* clazz,
FT_UInt max_elements,
FT_Pointer user_data,
FT_Memory memory,
FT_Bool pre_alloc,
FT_Lru *anlru )
{
FT_Error error;
FT_Lru lru;
if ( !anlru )
return FT_Err_Invalid_Argument;
*anlru = 0;
if ( !ALLOC( lru, sizeof ( *lru ) ) )
{
if ( pre_alloc )
{
/* allocate static array of lru list nodes */
if ( ALLOC_ARRAY( lru->nodes, max_elements, FT_LruNodeRec ) )
{
FREE( lru );
goto Exit;
}
/* build the `free_nodes' list from the array */
lru_build_free_list( lru->nodes, max_elements, &lru->free_nodes );
}
/* initialize common fields */
lru->clazz = (FT_Lru_Class*)clazz;
lru->max_elements = max_elements;
lru->memory = memory;
lru->user_data = user_data;
*anlru = lru;
}
Exit:
return error;
}
FT_EXPORT_DEF( void ) FT_Lru_Reset( FT_Lru lru )
{
FT_ListNode node;
FT_Lru_Class* clazz;
FT_Memory memory;
if ( !lru )
return;
node = lru->elements.head;
clazz = lru->clazz;
memory = lru->memory;
while ( node )
{
FT_ListNode next = node->next;
clazz->done_element( lru, (FT_LruNode)node );
if ( !lru->nodes )
FREE( node );
node = next;
}
/* rebuild free list if necessary */
if ( lru->nodes )
lru_build_free_list( lru->nodes, lru->max_elements, &lru->free_nodes );
lru->elements.head = lru->elements.tail = 0;
lru->num_elements = 0;
}
FT_EXPORT_DEF( void ) FT_Lru_Done( FT_Lru lru )
{
FT_Memory memory;
if ( !lru )
return;
memory = lru->memory;
FT_Lru_Reset( lru );
FREE( lru->nodes );
FREE( lru );
}
FT_EXPORT_DEF( FT_Error ) FT_Lru_Lookup_Node( FT_Lru lru,
FT_LruKey key,
FT_LruNode *anode )
{
FT_Error error = 0;
FT_ListNode node;
FT_Lru_Class* clazz;
FT_LruNode found = 0;
FT_Memory memory;
if ( !lru || !key || !anode )
return FT_Err_Invalid_Argument;
node = lru->elements.head;
clazz = lru->clazz;
memory = lru->memory;
if ( clazz->compare_element )
{
for ( ; node; node = node->next )
if ( clazz->compare_element( (FT_LruNode)node, key ) )
{
found = (FT_LruNode)node;
break;
}
}
else
{
for ( ; node; node = node->next )
if ( ((FT_LruNode)node)->key == key )
{
found = (FT_LruNode)node;
break;
}
}
if ( !found )
{
/* we haven't found the relevant element. We will now try */
/* to create a new one. */
if ( lru->num_elements >= lru->max_elements )
{
/* this lru list is full; we will now flush */
/* the oldest node */
FT_LruNode lru_node;
node = lru->elements.tail;
lru_node = (FT_LruNode)node;
found = lru_node;
if ( clazz->flush_element )
error = clazz->flush_element( lru, lru_node, key );
else
{
clazz->done_element( lru, lru_node );
lru_node->key = key;
node->data = 0;
error = clazz->init_element( lru, lru_node );
}
if ( !error )
{
/* now, move element to top of list */
FT_List_Up( &lru->elements, node );
}
else
{
/* in case of error, the node must be discarded */
FT_List_Remove( &lru->elements, node );
lru->num_elements--;
if ( lru->nodes )
FT_List_Insert( &lru->free_nodes, node );
else
FREE( lru_node );
found = 0;
}
}
else
{
FT_LruNode lru_node;
/* create a new lru list node, then the element for it */
if ( lru->nodes )
{
node = lru->free_nodes.head;
lru_node = (FT_LruNode)node;
lru_node->key = key;
error = clazz->init_element( lru, lru_node );
if ( error )
goto Exit;
FT_List_Remove( &lru->free_nodes, node );
}
else
{
if ( ALLOC( lru_node, sizeof ( *lru_node ) ) )
goto Exit;
lru_node->key = key;
error = clazz->init_element( lru, lru_node );
if ( error )
{
FREE( lru_node );
goto Exit;
}
}
found = lru_node;
node = (FT_ListNode)lru_node;
FT_List_Insert( &lru->elements, node );
lru->num_elements++;
}
}
Exit:
*anode = found;
return error;
}
FT_EXPORT_DEF( FT_Error ) FT_Lru_Lookup( FT_Lru lru,
FT_LruKey key,
FT_Pointer *anobject )
{
FT_Error error;
FT_LruNode node;
/* check for valid `lru' and `key' delayed to FT_Lru_Lookup_Node() */
if ( !anobject )
return FT_Err_Invalid_Argument;
*anobject = 0;
error = FT_Lru_Lookup_Node( lru, key, &node );
if ( !error )
*anobject = node->root.data;
return error;
}
FT_EXPORT_DEF( void ) FT_Lru_Remove_Node( FT_Lru lru,
FT_LruNode node )
{
if ( !lru || !node )
return;
if ( lru->num_elements > 0 )
{
FT_List_Remove( &lru->elements, (FT_ListNode)node );
lru->clazz->done_element( lru, node );
if ( lru->nodes )
FT_List_Insert( &lru->free_nodes, (FT_ListNode)node );
else
{
FT_Memory memory = lru->memory;
FREE( node );
}
lru->num_elements--;
}
}
FT_EXPORT_DEF( void ) FT_Lru_Remove_Selection( FT_Lru lru,
FT_Lru_Selector selector,
FT_Pointer data )
{
if ( !lru || !selector )
return;
if ( lru->num_elements > 0 )
{
FT_ListNode node = lru->elements.head;
FT_ListNode next;
while ( node )
{
next = node->next;
if ( selector( lru, (FT_LruNode)node, data ) )
{
/* remove this element from the list, and destroy it */
FT_Lru_Remove_Node( lru, (FT_LruNode)node );
}
node = next;
}
}
}
/* END */
|
