ref: 03ceda9701cd8c08ea5b4ee0c2d558a98fc4ed7d
dir: /src/truetype/ttpload.c/
/****************************************************************************
*
* ttpload.c
*
* TrueType-specific tables loader (body).
*
* Copyright (C) 1996-2020 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/internal/ftdebug.h>
#include <freetype/internal/ftobjs.h>
#include <freetype/internal/ftstream.h>
#include <freetype/tttags.h>
#include "ttpload.h"
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
#include "ttgxvar.h"
#endif
#include "tterrors.h"
/**************************************************************************
*
* The macro FT_COMPONENT is used in trace mode. It is an implicit
* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
* messages during execution.
*/
#undef FT_COMPONENT
#define FT_COMPONENT ttpload
/**************************************************************************
*
* @Function:
* tt_face_load_loca
*
* @Description:
* Load the locations table.
*
* @InOut:
* face ::
* A handle to the target face object.
*
* @Input:
* stream ::
* The input stream.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_loca( TT_Face face,
FT_Stream stream )
{
FT_Error error;
FT_ULong table_len;
FT_Int shift;
/* we need the size of the `glyf' table for malformed `loca' tables */
error = face->goto_table( face, TTAG_glyf, stream, &face->glyf_len );
/* it is possible that a font doesn't have a glyf table at all */
/* or its size is zero */
if ( FT_ERR_EQ( error, Table_Missing ) )
{
face->glyf_len = 0;
face->glyf_offset = 0;
}
else if ( error )
goto Exit;
else
{
#ifdef FT_CONFIG_OPTION_INCREMENTAL
if ( face->root.internal->incremental_interface )
face->glyf_offset = 0;
else
#endif
face->glyf_offset = FT_STREAM_POS();
}
FT_TRACE2(( "Locations " ));
error = face->goto_table( face, TTAG_loca, stream, &table_len );
if ( error )
{
error = FT_THROW( Locations_Missing );
goto Exit;
}
if ( face->header.Index_To_Loc_Format != 0 )
{
shift = 2;
if ( table_len >= 0x40000L )
{
FT_TRACE2(( "table too large\n" ));
table_len = 0x3FFFFL;
}
face->num_locations = table_len >> shift;
}
else
{
shift = 1;
if ( table_len >= 0x20000L )
{
FT_TRACE2(( "table too large\n" ));
table_len = 0x1FFFFL;
}
face->num_locations = table_len >> shift;
}
if ( face->num_locations != (FT_ULong)face->root.num_glyphs + 1 )
{
FT_TRACE2(( "glyph count mismatch! loca: %ld, maxp: %ld\n",
face->num_locations - 1, face->root.num_glyphs ));
/* we only handle the case where `maxp' gives a larger value */
if ( face->num_locations <= (FT_ULong)face->root.num_glyphs )
{
FT_ULong new_loca_len =
( (FT_ULong)face->root.num_glyphs + 1 ) << shift;
TT_Table entry = face->dir_tables;
TT_Table limit = entry + face->num_tables;
FT_Long pos = (FT_Long)FT_STREAM_POS();
FT_Long dist = 0x7FFFFFFFL;
FT_Bool found = 0;
/* compute the distance to next table in font file */
for ( ; entry < limit; entry++ )
{
FT_Long diff = (FT_Long)entry->Offset - pos;
if ( diff > 0 && diff < dist )
{
dist = diff;
found = 1;
}
}
if ( !found )
{
/* `loca' is the last table */
dist = (FT_Long)stream->size - pos;
}
if ( new_loca_len <= (FT_ULong)dist )
{
face->num_locations = (FT_ULong)face->root.num_glyphs + 1;
table_len = new_loca_len;
FT_TRACE2(( "adjusting num_locations to %ld\n",
face->num_locations ));
}
else
{
face->root.num_glyphs = face->num_locations
? (FT_Long)face->num_locations - 1 : 0;
FT_TRACE2(( "adjusting num_glyphs to %ld\n",
face->root.num_glyphs ));
}
}
}
/*
* Extract the frame. We don't need to decompress it since
* we are able to parse it directly.
*/
if ( FT_FRAME_EXTRACT( table_len, face->glyph_locations ) )
goto Exit;
FT_TRACE2(( "loaded\n" ));
Exit:
return error;
}
FT_LOCAL_DEF( FT_ULong )
tt_face_get_location( TT_Face face,
FT_UInt gindex,
FT_UInt *asize )
{
FT_ULong pos1, pos2;
FT_Byte* p;
FT_Byte* p_limit;
pos1 = pos2 = 0;
if ( gindex < face->num_locations )
{
if ( face->header.Index_To_Loc_Format != 0 )
{
p = face->glyph_locations + gindex * 4;
p_limit = face->glyph_locations + face->num_locations * 4;
pos1 = FT_NEXT_ULONG( p );
pos2 = pos1;
if ( p + 4 <= p_limit )
pos2 = FT_NEXT_ULONG( p );
}
else
{
p = face->glyph_locations + gindex * 2;
p_limit = face->glyph_locations + face->num_locations * 2;
pos1 = FT_NEXT_USHORT( p );
pos2 = pos1;
if ( p + 2 <= p_limit )
pos2 = FT_NEXT_USHORT( p );
pos1 <<= 1;
pos2 <<= 1;
}
}
/* Check broken location data. */
if ( pos1 > face->glyf_len )
{
FT_TRACE1(( "tt_face_get_location:"
" too large offset (0x%08lx) found for glyph index %d,\n"
" "
" exceeding the end of `glyf' table (0x%08lx)\n",
pos1, gindex, face->glyf_len ));
*asize = 0;
return 0;
}
if ( pos2 > face->glyf_len )
{
/* We try to sanitize the last `loca' entry. */
if ( gindex == face->num_locations - 2 )
{
FT_TRACE1(( "tt_face_get_location:"
" too large size (%ld bytes) found for glyph index %d,\n"
" "
" truncating at the end of `glyf' table to %ld bytes\n",
pos2 - pos1, gindex, face->glyf_len - pos1 ));
pos2 = face->glyf_len;
}
else
{
FT_TRACE1(( "tt_face_get_location:"
" too large offset (0x%08lx) found for glyph index %d,\n"
" "
" exceeding the end of `glyf' table (0x%08lx)\n",
pos2, gindex + 1, face->glyf_len ));
*asize = 0;
return 0;
}
}
/* The `loca' table must be ordered; it refers to the length of */
/* an entry as the difference between the current and the next */
/* position. However, there do exist (malformed) fonts which */
/* don't obey this rule, so we are only able to provide an */
/* upper bound for the size. */
/* */
/* We get (intentionally) a wrong, non-zero result in case the */
/* `glyf' table is missing. */
if ( pos2 >= pos1 )
*asize = (FT_UInt)( pos2 - pos1 );
else
*asize = (FT_UInt)( face->glyf_len - pos1 );
return pos1;
}
FT_LOCAL_DEF( void )
tt_face_done_loca( TT_Face face )
{
FT_Stream stream = face->root.stream;
FT_FRAME_RELEASE( face->glyph_locations );
face->num_locations = 0;
}
/**************************************************************************
*
* @Function:
* tt_face_load_cvt
*
* @Description:
* Load the control value table into a face object.
*
* @InOut:
* face ::
* A handle to the target face object.
*
* @Input:
* stream ::
* A handle to the input stream.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_cvt( TT_Face face,
FT_Stream stream )
{
#ifdef TT_USE_BYTECODE_INTERPRETER
FT_Error error;
FT_Memory memory = stream->memory;
FT_ULong table_len;
FT_TRACE2(( "CVT " ));
error = face->goto_table( face, TTAG_cvt, stream, &table_len );
if ( error )
{
FT_TRACE2(( "is missing\n" ));
face->cvt_size = 0;
face->cvt = NULL;
error = FT_Err_Ok;
goto Exit;
}
face->cvt_size = table_len / 2;
if ( FT_NEW_ARRAY( face->cvt, face->cvt_size ) )
goto Exit;
if ( FT_FRAME_ENTER( face->cvt_size * 2L ) )
goto Exit;
{
FT_Int32* cur = face->cvt;
FT_Int32* limit = cur + face->cvt_size;
for ( ; cur < limit; cur++ )
*cur = FT_GET_SHORT() * 64;
}
FT_FRAME_EXIT();
FT_TRACE2(( "loaded\n" ));
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
if ( face->doblend )
error = tt_face_vary_cvt( face, stream );
#endif
Exit:
return error;
#else /* !TT_USE_BYTECODE_INTERPRETER */
FT_UNUSED( face );
FT_UNUSED( stream );
return FT_Err_Ok;
#endif
}
/**************************************************************************
*
* @Function:
* tt_face_load_fpgm
*
* @Description:
* Load the font program.
*
* @InOut:
* face ::
* A handle to the target face object.
*
* @Input:
* stream ::
* A handle to the input stream.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_fpgm( TT_Face face,
FT_Stream stream )
{
#ifdef TT_USE_BYTECODE_INTERPRETER
FT_Error error;
FT_ULong table_len;
FT_TRACE2(( "Font program " ));
/* The font program is optional */
error = face->goto_table( face, TTAG_fpgm, stream, &table_len );
if ( error )
{
face->font_program = NULL;
face->font_program_size = 0;
error = FT_Err_Ok;
FT_TRACE2(( "is missing\n" ));
}
else
{
face->font_program_size = table_len;
if ( FT_FRAME_EXTRACT( table_len, face->font_program ) )
goto Exit;
FT_TRACE2(( "loaded, %12ld bytes\n", face->font_program_size ));
}
Exit:
return error;
#else /* !TT_USE_BYTECODE_INTERPRETER */
FT_UNUSED( face );
FT_UNUSED( stream );
return FT_Err_Ok;
#endif
}
/**************************************************************************
*
* @Function:
* tt_face_load_prep
*
* @Description:
* Load the cvt program.
*
* @InOut:
* face ::
* A handle to the target face object.
*
* @Input:
* stream ::
* A handle to the input stream.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_prep( TT_Face face,
FT_Stream stream )
{
#ifdef TT_USE_BYTECODE_INTERPRETER
FT_Error error;
FT_ULong table_len;
FT_TRACE2(( "Prep program " ));
error = face->goto_table( face, TTAG_prep, stream, &table_len );
if ( error )
{
face->cvt_program = NULL;
face->cvt_program_size = 0;
error = FT_Err_Ok;
FT_TRACE2(( "is missing\n" ));
}
else
{
face->cvt_program_size = table_len;
if ( FT_FRAME_EXTRACT( table_len, face->cvt_program ) )
goto Exit;
FT_TRACE2(( "loaded, %12ld bytes\n", face->cvt_program_size ));
}
Exit:
return error;
#else /* !TT_USE_BYTECODE_INTERPRETER */
FT_UNUSED( face );
FT_UNUSED( stream );
return FT_Err_Ok;
#endif
}
/**************************************************************************
*
* @Function:
* tt_face_load_hdmx
*
* @Description:
* Load the `hdmx' table into the face object.
*
* @Input:
* face ::
* A handle to the target face object.
*
* stream ::
* A handle to the input stream.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_hdmx( TT_Face face,
FT_Stream stream )
{
FT_Error error;
FT_Memory memory = stream->memory;
FT_UInt nn, num_records;
FT_ULong table_size, record_size;
FT_Byte* p;
FT_Byte* limit;
/* this table is optional */
error = face->goto_table( face, TTAG_hdmx, stream, &table_size );
if ( error || table_size < 8 )
return FT_Err_Ok;
if ( FT_FRAME_EXTRACT( table_size, face->hdmx_table ) )
goto Exit;
p = face->hdmx_table;
limit = p + table_size;
/* Given that `hdmx' tables are losing its importance (for example, */
/* variation fonts introduced in OpenType 1.8 must not have this */
/* table) we no longer test for a correct `version' field. */
p += 2;
num_records = FT_NEXT_USHORT( p );
record_size = FT_NEXT_ULONG( p );
/* The maximum number of bytes in an hdmx device record is the */
/* maximum number of glyphs + 2; this is 0xFFFF + 2, thus */
/* explaining why `record_size' is a long (which we read as */
/* unsigned long for convenience). In practice, two bytes are */
/* sufficient to hold the size value. */
/* */
/* There are at least two fonts, HANNOM-A and HANNOM-B version */
/* 2.0 (2005), which get this wrong: The upper two bytes of */
/* the size value are set to 0xFF instead of 0x00. We catch */
/* and fix this. */
if ( record_size >= 0xFFFF0000UL )
record_size &= 0xFFFFU;
/* The limit for `num_records' is a heuristic value. */
if ( num_records > 255 ||
( num_records > 0 &&
( record_size > 0x10001L ||
record_size < 4 ) ) )
{
error = FT_THROW( Invalid_File_Format );
goto Fail;
}
if ( FT_NEW_ARRAY( face->hdmx_record_sizes, num_records ) )
goto Fail;
for ( nn = 0; nn < num_records; nn++ )
{
if ( p + record_size > limit )
break;
face->hdmx_record_sizes[nn] = p[0];
p += record_size;
}
face->hdmx_record_count = nn;
face->hdmx_table_size = table_size;
face->hdmx_record_size = record_size;
Exit:
return error;
Fail:
FT_FRAME_RELEASE( face->hdmx_table );
face->hdmx_table_size = 0;
goto Exit;
}
FT_LOCAL_DEF( void )
tt_face_free_hdmx( TT_Face face )
{
FT_Stream stream = face->root.stream;
FT_Memory memory = stream->memory;
FT_FREE( face->hdmx_record_sizes );
FT_FRAME_RELEASE( face->hdmx_table );
}
/**************************************************************************
*
* Return the advance width table for a given pixel size if it is found
* in the font's `hdmx' table (if any).
*/
FT_LOCAL_DEF( FT_Byte* )
tt_face_get_device_metrics( TT_Face face,
FT_UInt ppem,
FT_UInt gindex )
{
FT_UInt nn;
FT_Byte* result = NULL;
FT_ULong record_size = face->hdmx_record_size;
FT_Byte* record = FT_OFFSET( face->hdmx_table, 8 );
for ( nn = 0; nn < face->hdmx_record_count; nn++ )
if ( face->hdmx_record_sizes[nn] == ppem )
{
gindex += 2;
if ( gindex < record_size )
result = record + nn * record_size + gindex;
break;
}
return result;
}
/* END */