ref: 2de1b5630d7717f5fc5401a7ca3aa756d3c204fd
dir: /src/cache/ftccmap.c/
/****************************************************************************
*
* ftccmap.c
*
* FreeType CharMap cache (body)
*
* 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.
*
*/
#include <freetype/freetype.h>
#include <freetype/ftcache.h>
#include "ftcmanag.h"
#include <freetype/internal/ftmemory.h>
#include <freetype/internal/ftobjs.h>
#include <freetype/internal/ftdebug.h>
#include "ftccback.h"
#include "ftcerror.h"
#undef FT_COMPONENT
#define FT_COMPONENT cache
/**************************************************************************
*
* Each FTC_CMapNode contains a simple array to map a range of character
* codes to equivalent glyph indices.
*
* For now, the implementation is very basic: Each node maps a range of
* 128 consecutive character codes to their corresponding glyph indices.
*
* We could do more complex things, but I don't think it is really very
* useful.
*
*/
/* number of glyph indices / character code per node */
#define FTC_CMAP_INDICES_MAX 128
/* compute a query/node hash */
#define FTC_CMAP_HASH( faceid, index, charcode ) \
( FTC_FACE_ID_HASH( faceid ) + 211 * (index) + \
( (charcode) / FTC_CMAP_INDICES_MAX ) )
/* the charmap query */
typedef struct FTC_CMapQueryRec_
{
FTC_FaceID face_id;
FT_UInt cmap_index;
FT_UInt32 char_code;
} FTC_CMapQueryRec, *FTC_CMapQuery;
#define FTC_CMAP_QUERY( x ) ((FTC_CMapQuery)(x))
/* the cmap cache node */
typedef struct FTC_CMapNodeRec_
{
FTC_NodeRec node;
FTC_FaceID face_id;
FT_UInt cmap_index;
FT_UInt32 first; /* first character in node */
FT_UInt16 indices[FTC_CMAP_INDICES_MAX]; /* array of glyph indices */
} FTC_CMapNodeRec, *FTC_CMapNode;
#define FTC_CMAP_NODE( x ) ( (FTC_CMapNode)( x ) )
/* if (indices[n] == FTC_CMAP_UNKNOWN), we assume that the corresponding */
/* glyph indices haven't been queried through FT_Get_Glyph_Index() yet */
#define FTC_CMAP_UNKNOWN (FT_UInt16)~0
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** CHARMAP NODES *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
FT_CALLBACK_DEF( void )
ftc_cmap_node_free( FTC_Node ftcnode,
FTC_Cache cache )
{
FTC_CMapNode node = (FTC_CMapNode)ftcnode;
FT_Memory memory = cache->memory;
FT_FREE( node );
}
/* initialize a new cmap node */
FT_CALLBACK_DEF( FT_Error )
ftc_cmap_node_new( FTC_Node *ftcanode,
FT_Pointer ftcquery,
FTC_Cache cache )
{
FTC_CMapNode *anode = (FTC_CMapNode*)ftcanode;
FTC_CMapQuery query = (FTC_CMapQuery)ftcquery;
FT_Error error;
FT_Memory memory = cache->memory;
FTC_CMapNode node = NULL;
FT_UInt nn;
if ( !FT_NEW( node ) )
{
node->face_id = query->face_id;
node->cmap_index = query->cmap_index;
node->first = (query->char_code / FTC_CMAP_INDICES_MAX) *
FTC_CMAP_INDICES_MAX;
for ( nn = 0; nn < FTC_CMAP_INDICES_MAX; nn++ )
node->indices[nn] = FTC_CMAP_UNKNOWN;
}
*anode = node;
return error;
}
/* compute the weight of a given cmap node */
FT_CALLBACK_DEF( FT_Offset )
ftc_cmap_node_weight( FTC_Node cnode,
FTC_Cache cache )
{
FT_UNUSED( cnode );
FT_UNUSED( cache );
return sizeof ( *cnode );
}
/* compare a cmap node to a given query */
FT_CALLBACK_DEF( FT_Bool )
ftc_cmap_node_compare( FTC_Node ftcnode,
FT_Pointer ftcquery,
FTC_Cache cache,
FT_Bool* list_changed )
{
FTC_CMapNode node = (FTC_CMapNode)ftcnode;
FTC_CMapQuery query = (FTC_CMapQuery)ftcquery;
FT_UNUSED( cache );
if ( list_changed )
*list_changed = FALSE;
if ( node->face_id == query->face_id &&
node->cmap_index == query->cmap_index )
{
FT_UInt32 offset = (FT_UInt32)( query->char_code - node->first );
return FT_BOOL( offset < FTC_CMAP_INDICES_MAX );
}
return 0;
}
FT_CALLBACK_DEF( FT_Bool )
ftc_cmap_node_remove_faceid( FTC_Node ftcnode,
FT_Pointer ftcface_id,
FTC_Cache cache,
FT_Bool* list_changed )
{
FTC_CMapNode node = (FTC_CMapNode)ftcnode;
FTC_FaceID face_id = (FTC_FaceID)ftcface_id;
FT_UNUSED( cache );
if ( list_changed )
*list_changed = FALSE;
return FT_BOOL( node->face_id == face_id );
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** GLYPH IMAGE CACHE *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
static
const FTC_CacheClassRec ftc_cmap_cache_class =
{
ftc_cmap_node_new, /* FTC_Node_NewFunc node_new */
ftc_cmap_node_weight, /* FTC_Node_WeightFunc node_weight */
ftc_cmap_node_compare, /* FTC_Node_CompareFunc node_compare */
ftc_cmap_node_remove_faceid, /* FTC_Node_CompareFunc node_remove_faceid */
ftc_cmap_node_free, /* FTC_Node_FreeFunc node_free */
sizeof ( FTC_CacheRec ),
ftc_cache_init, /* FTC_Cache_InitFunc cache_init */
ftc_cache_done, /* FTC_Cache_DoneFunc cache_done */
};
/* documentation is in ftcache.h */
FT_EXPORT_DEF( FT_Error )
FTC_CMapCache_New( FTC_Manager manager,
FTC_CMapCache *acache )
{
return FTC_Manager_RegisterCache( manager,
&ftc_cmap_cache_class,
FTC_CACHE_P( acache ) );
}
/* documentation is in ftcache.h */
FT_EXPORT_DEF( FT_UInt )
FTC_CMapCache_Lookup( FTC_CMapCache cmap_cache,
FTC_FaceID face_id,
FT_Int cmap_index,
FT_UInt32 char_code )
{
FTC_Cache cache = FTC_CACHE( cmap_cache );
FTC_CMapQueryRec query;
FTC_Node node;
FT_Error error;
FT_UInt gindex = 0;
FT_Offset hash;
FT_Int no_cmap_change = 0;
if ( cmap_index < 0 )
{
/* Treat a negative cmap index as a special value, meaning that you */
/* don't want to change the FT_Face's character map through this */
/* call. This can be useful if the face requester callback already */
/* sets the face's charmap to the appropriate value. */
no_cmap_change = 1;
cmap_index = 0;
}
if ( !cache )
{
FT_TRACE0(( "FTC_CMapCache_Lookup: bad arguments, returning 0\n" ));
return 0;
}
query.face_id = face_id;
query.cmap_index = (FT_UInt)cmap_index;
query.char_code = char_code;
hash = FTC_CMAP_HASH( face_id, (FT_UInt)cmap_index, char_code );
#if 1
FTC_CACHE_LOOKUP_CMP( cache, ftc_cmap_node_compare, hash, &query,
node, error );
#else
error = FTC_Cache_Lookup( cache, hash, &query, &node );
#endif
if ( error )
goto Exit;
FT_ASSERT( (FT_UInt)( char_code - FTC_CMAP_NODE( node )->first ) <
FTC_CMAP_INDICES_MAX );
/* something rotten can happen with rogue clients */
if ( (FT_UInt)( char_code - FTC_CMAP_NODE( node )->first >=
FTC_CMAP_INDICES_MAX ) )
return 0; /* XXX: should return appropriate error */
gindex = FTC_CMAP_NODE( node )->indices[char_code -
FTC_CMAP_NODE( node )->first];
if ( gindex == FTC_CMAP_UNKNOWN )
{
FT_Face face;
gindex = 0;
error = FTC_Manager_LookupFace( cache->manager,
FTC_CMAP_NODE( node )->face_id,
&face );
if ( error )
goto Exit;
if ( (FT_UInt)cmap_index < (FT_UInt)face->num_charmaps )
{
FT_CharMap old, cmap = NULL;
old = face->charmap;
cmap = face->charmaps[cmap_index];
if ( old != cmap && !no_cmap_change )
FT_Set_Charmap( face, cmap );
gindex = FT_Get_Char_Index( face, char_code );
if ( old != cmap && !no_cmap_change )
FT_Set_Charmap( face, old );
}
FTC_CMAP_NODE( node )->indices[char_code -
FTC_CMAP_NODE( node )->first]
= (FT_UShort)gindex;
}
Exit:
return gindex;
}
/* END */