ref: 6c2ab0977cd6d443fe845f88c9846bda2944622a
dir: /src/base/ftpatent.c/
/***************************************************************************/
/* */
/* ftpatent.c */
/* */
/* FreeType API for checking patented TrueType bytecode instructions */
/* (body). */
/* */
/* Copyright 2007 by David Turner. */
/* */
/* 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_FREETYPE_H
#include FT_TRUETYPE_TAGS_H
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_STREAM_H
#include FT_SERVICE_SFNT_H
#include FT_SERVICE_TRUETYPE_GLYF_H
static FT_Bool
_tt_check_patents_in_range( FT_Stream stream,
FT_ULong size )
{
FT_Bool result = FALSE;
FT_Error error;
FT_Bytes p, end;
if ( FT_FRAME_ENTER( size ) )
return 0;
p = stream->cursor;
end = p + size;
while ( p < end )
{
switch (p[0])
{
case 0x06: /* SPvTL // */
case 0x07: /* SPvTL + */
case 0x08: /* SFvTL // */
case 0x09: /* SFvTL + */
case 0x0A: /* SPvFS */
case 0x0B: /* SFvFS */
result = TRUE;
goto Exit;
case 0x40:
if ( p + 1 >= end )
goto Exit;
p += p[1] + 2;
break;
case 0x41:
if ( p + 1 >= end )
goto Exit;
p += p[1] * 2 + 2;
break;
case 0x71: /* DELTAP2 */
case 0x72: /* DELTAP3 */
case 0x73: /* DELTAC0 */
case 0x74: /* DELTAC1 */
case 0x75: /* DELTAC2 */
result = TRUE;
goto Exit;
case 0xB0:
case 0xB1:
case 0xB2:
case 0xB3:
case 0xB4:
case 0xB5:
case 0xB6:
case 0xB7:
p += ( p[0] - 0xB0 ) + 2;
break;
case 0xB8:
case 0xB9:
case 0xBA:
case 0xBB:
case 0xBC:
case 0xBD:
case 0xBE:
case 0xBF:
p += ( p[0] - 0xB8 ) * 2 + 3;
break;
default:
p += 1;
break;
}
}
Exit:
FT_FRAME_EXIT();
return result;
}
static FT_Bool
_tt_check_patents_in_table( FT_Face face,
FT_ULong tag )
{
FT_Stream stream = face->stream;
FT_Error error;
FT_Service_SFNT_Table service;
FT_Bool result = FALSE;
FT_FACE_FIND_SERVICE( face, service, SFNT_TABLE );
if ( service )
{
FT_ULong offset, size;
error = service->table_info( face, tag, &offset, &size );
if ( error ||
FT_STREAM_SEEK( offset ) )
goto Exit;
result = _tt_check_patents_in_range( stream, size );
}
Exit:
return result;
}
static FT_Bool
_tt_face_check_patents( FT_Face face )
{
FT_Stream stream = face->stream;
FT_UInt gindex;
FT_Error error;
FT_Bool result;
FT_Service_TTGlyf service;
result = _tt_check_patents_in_table( face, TTAG_fpgm );
if ( result )
goto Exit;
result = _tt_check_patents_in_table( face, TTAG_prep );
if ( result )
goto Exit;
FT_FACE_FIND_SERVICE( face, service, TT_GLYF );
if ( service == NULL )
goto Exit;
for ( gindex = 0; gindex < (FT_UInt)face->num_glyphs; gindex++ )
{
FT_ULong offset, num_ins, size;
FT_Int num_contours;
offset = service->get_location( face, gindex, &size );
if ( size == 0 )
continue;
if ( FT_STREAM_SEEK( offset ) ||
FT_READ_SHORT( num_contours ) )
continue;
if ( num_contours >= 0 ) /* simple glyph */
{
if ( FT_STREAM_SKIP( 8 + num_contours * 2 ) )
continue;
}
else /* compound glyph */
{
FT_Bool has_instr = 0;
if ( FT_STREAM_SKIP( 8 ) )
continue;
/* now read each component */
for (;;)
{
FT_UInt flags, toskip;
if( FT_READ_USHORT( flags ) )
break;
toskip = 2 + 1 + 1;
if ( ( flags & ( 1 << 0 ) ) != 0 ) /* ARGS_ARE_WORDS */
toskip += 2;
if ( ( flags & ( 1 << 3 ) ) != 0 ) /* WE_HAVE_A_SCALE */
toskip += 2;
else if ( ( flags & ( 1 << 6 ) ) != 0 ) /* WE_HAVE_X_Y_SCALE */
toskip += 4;
else if ( ( flags & ( 1 << 7 ) ) != 0 ) /* WE_HAVE_A_2x2 */
toskip += 8;
if ( ( flags & ( 1 << 8 ) ) != 0 ) /* WE_HAVE_INSTRUCTIONS */
has_instr = 1;
if ( FT_STREAM_SKIP( toskip ) )
goto NextGlyph;
if ( ( flags & ( 1 << 5 ) ) == 0 ) /* MORE_COMPONENTS */
break;
}
if ( !has_instr )
goto NextGlyph;
}
if ( FT_READ_USHORT( num_ins ) )
continue;
result = _tt_check_patents_in_range( stream, num_ins );
if ( result )
goto Exit;
NextGlyph:
;
}
Exit:
return result;
}
/* documentation is in freetype.h */
FT_EXPORT_DEF( FT_Bool )
FT_Face_CheckTrueTypePatents( FT_Face face )
{
FT_Bool result = FALSE;
if ( face && FT_IS_SFNT( face ) )
result = _tt_face_check_patents( face );
return result;
}
/* END */