ref: 216e077600a58346bb022d8409fd82e9d914a10a
dir: /src/cache/ftccache.h/
/****************************************************************************
*
* ftccache.h
*
* FreeType internal cache interface (specification).
*
* Copyright (C) 2000-2020 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.
*
*/
#ifndef FTCCACHE_H_
#define FTCCACHE_H_
#include "ftcmru.h"
FT_BEGIN_HEADER
#define FTC_FACE_ID_HASH( i ) \
( ( (FT_Offset)(i) >> 3 ) ^ ( (FT_Offset)(i) << 7 ) )
/* handle to cache object */
typedef struct FTC_CacheRec_* FTC_Cache;
/* handle to cache class */
typedef const struct FTC_CacheClassRec_* FTC_CacheClass;
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** CACHE NODE DEFINITIONS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
/**************************************************************************
*
* Each cache controls one or more cache nodes. Each node is part of
* the global_lru list of the manager. Its `data' field however is used
* as a reference count for now.
*
* A node can be anything, depending on the type of information held by
* the cache. It can be an individual glyph image, a set of bitmaps
* glyphs for a given size, some metrics, etc.
*
*/
/* structure size should be 20 bytes on 32-bits machines */
typedef struct FTC_NodeRec_
{
FTC_MruNodeRec mru; /* circular mru list pointer */
FTC_Node link; /* used for hashing */
FT_Offset hash; /* used for hashing too */
FT_UShort cache_index; /* index of cache the node belongs to */
FT_Short ref_count; /* reference count for this node */
} FTC_NodeRec;
#define FTC_NODE( x ) ( (FTC_Node)(x) )
#define FTC_NODE_P( x ) ( (FTC_Node*)(x) )
#define FTC_NODE_NEXT( x ) FTC_NODE( (x)->mru.next )
#define FTC_NODE_PREV( x ) FTC_NODE( (x)->mru.prev )
#ifdef FTC_INLINE
#define FTC_NODE_TOP_FOR_HASH( cache, hash ) \
( ( cache )->buckets + \
( ( ( ( hash ) & ( cache )->mask ) < ( cache )->p ) \
? ( ( hash ) & ( ( cache )->mask * 2 + 1 ) ) \
: ( ( hash ) & ( cache )->mask ) ) )
#else
FT_LOCAL( FTC_Node* )
ftc_get_top_node_for_hash( FTC_Cache cache,
FT_Offset hash );
#define FTC_NODE_TOP_FOR_HASH( cache, hash ) \
ftc_get_top_node_for_hash( ( cache ), ( hash ) )
#endif
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** CACHE DEFINITIONS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
/* initialize a new cache node */
typedef FT_Error
(*FTC_Node_NewFunc)( FTC_Node *pnode,
FT_Pointer query,
FTC_Cache cache );
typedef FT_Offset
(*FTC_Node_WeightFunc)( FTC_Node node,
FTC_Cache cache );
/* compare a node to a given key pair */
typedef FT_Bool
(*FTC_Node_CompareFunc)( FTC_Node node,
FT_Pointer key,
FTC_Cache cache,
FT_Bool* list_changed );
typedef void
(*FTC_Node_FreeFunc)( FTC_Node node,
FTC_Cache cache );
typedef FT_Error
(*FTC_Cache_InitFunc)( FTC_Cache cache );
typedef void
(*FTC_Cache_DoneFunc)( FTC_Cache cache );
typedef struct FTC_CacheClassRec_
{
FTC_Node_NewFunc node_new;
FTC_Node_WeightFunc node_weight;
FTC_Node_CompareFunc node_compare;
FTC_Node_CompareFunc node_remove_faceid;
FTC_Node_FreeFunc node_free;
FT_Offset cache_size;
FTC_Cache_InitFunc cache_init;
FTC_Cache_DoneFunc cache_done;
} FTC_CacheClassRec;
/* each cache really implements a dynamic hash table to manage its nodes */
typedef struct FTC_CacheRec_
{
FT_UFast p;
FT_UFast mask;
FT_Long slack;
FTC_Node* buckets;
FTC_CacheClassRec clazz; /* local copy, for speed */
FTC_Manager manager;
FT_Memory memory;
FT_UInt index; /* in manager's table */
FTC_CacheClass org_class; /* original class pointer */
} FTC_CacheRec;
#define FTC_CACHE( x ) ( (FTC_Cache)(x) )
#define FTC_CACHE_P( x ) ( (FTC_Cache*)(x) )
/* default cache initialize */
FT_LOCAL( FT_Error )
FTC_Cache_Init( FTC_Cache cache );
/* default cache finalizer */
FT_LOCAL( void )
FTC_Cache_Done( FTC_Cache cache );
/* Call this function to look up the cache. If no corresponding
* node is found, a new one is automatically created. This function
* is capable of flushing the cache adequately to make room for the
* new cache object.
*/
#ifndef FTC_INLINE
FT_LOCAL( FT_Error )
FTC_Cache_Lookup( FTC_Cache cache,
FT_Offset hash,
FT_Pointer query,
FTC_Node *anode );
#endif
FT_LOCAL( FT_Error )
FTC_Cache_NewNode( FTC_Cache cache,
FT_Offset hash,
FT_Pointer query,
FTC_Node *anode );
/* Remove all nodes that relate to a given face_id. This is useful
* when un-installing fonts. Note that if a cache node relates to
* the face_id but is locked (i.e., has `ref_count > 0'), the node
* will _not_ be destroyed, but its internal face_id reference will
* be modified.
*
* The final result will be that the node will never come back
* in further lookup requests, and will be flushed on demand from
* the cache normally when its reference count reaches 0.
*/
FT_LOCAL( void )
FTC_Cache_RemoveFaceID( FTC_Cache cache,
FTC_FaceID face_id );
#ifdef FTC_INLINE
#define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
FT_BEGIN_STMNT \
FTC_Node *_bucket, *_pnode, _node; \
FTC_Cache _cache = FTC_CACHE(cache); \
FT_Offset _hash = (FT_Offset)(hash); \
FTC_Node_CompareFunc _nodcomp = (FTC_Node_CompareFunc)(nodecmp); \
FT_Bool _list_changed = FALSE; \
\
\
error = FT_Err_Ok; \
node = NULL; \
\
/* Go to the `top' node of the list sharing same masked hash */ \
_bucket = _pnode = FTC_NODE_TOP_FOR_HASH( _cache, _hash ); \
\
/* Look up a node with identical 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 && \
_nodcomp( _node, query, _cache, &_list_changed ) ) \
break; \
\
_pnode = &_node->link; \
} \
\
if ( _list_changed ) \
{ \
/* Update _bucket by possibly modified linked list */ \
_bucket = _pnode = FTC_NODE_TOP_FOR_HASH( _cache, _hash ); \
\
/* Update _pnode by possibly modified linked list */ \
while ( *_pnode != _node ) \
{ \
if ( !*_pnode ) \
{ \
FT_ERROR(( "FTC_CACHE_LOOKUP_CMP: 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; \
} \
\
/* Update MRU list */ \
{ \
FTC_Manager _manager = _cache->manager; \
void* _nl = &_manager->nodes_list; \
\
\
if ( _node != _manager->nodes_list ) \
FTC_MruNode_Up( (FTC_MruNode*)_nl, \
(FTC_MruNode)_node ); \
} \
goto Ok_; \
\
NewNode_: \
error = FTC_Cache_NewNode( _cache, _hash, query, &_node ); \
\
Ok_: \
node = _node; \
FT_END_STMNT
#else /* !FTC_INLINE */
#define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
FT_BEGIN_STMNT \
error = FTC_Cache_Lookup( FTC_CACHE( cache ), hash, query, \
(FTC_Node*)&(node) ); \
FT_END_STMNT
#endif /* !FTC_INLINE */
/*
* This macro, together with FTC_CACHE_TRYLOOP_END, defines a retry
* loop to flush the cache repeatedly in case of memory overflows.
*
* It is used when creating a new cache node, or within a lookup
* that needs to allocate data (e.g. the sbit cache lookup).
*
* Example:
*
* {
* FTC_CACHE_TRYLOOP( cache )
* error = load_data( ... );
* FTC_CACHE_TRYLOOP_END()
* }
*
*/
#define FTC_CACHE_TRYLOOP( cache ) \
{ \
FTC_Manager _try_manager = FTC_CACHE( cache )->manager; \
FT_UInt _try_count = 4; \
\
\
for (;;) \
{ \
FT_UInt _try_done;
#define FTC_CACHE_TRYLOOP_END( list_changed ) \
if ( !error || FT_ERR_NEQ( error, Out_Of_Memory ) ) \
break; \
\
_try_done = FTC_Manager_FlushN( _try_manager, _try_count ); \
if ( _try_done > 0 && list_changed != NULL ) \
*(FT_Bool*)( list_changed ) = TRUE; \
\
if ( _try_done == 0 ) \
break; \
\
if ( _try_done == _try_count ) \
{ \
_try_count *= 2; \
if ( _try_count < _try_done || \
_try_count > _try_manager->num_nodes ) \
_try_count = _try_manager->num_nodes; \
} \
} \
}
/* */
FT_END_HEADER
#endif /* FTCCACHE_H_ */
/* END */