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/***************************************************************************/ |
/* */ |
/* ftpatent.c */ |
/* */ |
/* FreeType API for checking patented TrueType bytecode instructions */ |
/* (body). */ |
/* */ |
/* Copyright 2007, 2008, 2010 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. */ |
/* */ |
/***************************************************************************/ |
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#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 |
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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; |
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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; |
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case 0x40: |
if ( p + 1 >= end ) |
goto Exit; |
|
p += p[1] + 2; |
break; |
|
case 0x41: |
if ( p + 1 >= end ) |
goto Exit; |
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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_UNUSED( error ); |
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_Err_Ok; |
FT_Service_SFNT_Table service; |
FT_Bool result = FALSE; |
|
|
FT_FACE_FIND_SERVICE( face, service, SFNT_TABLE ); |
|
if ( service ) |
{ |
FT_UInt i = 0; |
FT_ULong tag_i = 0, offset_i = 0, length_i = 0; |
|
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for ( i = 0; !error && tag_i != tag ; i++ ) |
error = service->table_info( face, i, |
&tag_i, &offset_i, &length_i ); |
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if ( error || |
FT_STREAM_SEEK( offset_i ) ) |
goto Exit; |
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result = _tt_check_patents_in_range( stream, length_i ); |
} |
|
Exit: |
return result; |
} |
|
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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; |
|
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result = _tt_check_patents_in_table( face, TTAG_fpgm ); |
if ( result ) |
goto Exit; |
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result = _tt_check_patents_in_table( face, TTAG_prep ); |
if ( result ) |
goto Exit; |
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FT_FACE_FIND_SERVICE( face, service, TT_GLYF ); |
if ( service == NULL ) |
goto Exit; |
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for ( gindex = 0; gindex < (FT_UInt)face->num_glyphs; gindex++ ) |
{ |
FT_ULong offset, num_ins, size; |
FT_Int num_contours; |
|
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offset = service->get_location( face, gindex, &size ); |
if ( size == 0 ) |
continue; |
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if ( FT_STREAM_SEEK( offset ) || |
FT_READ_SHORT( num_contours ) ) |
continue; |
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if ( num_contours >= 0 ) /* simple glyph */ |
{ |
if ( FT_STREAM_SKIP( 8 + num_contours * 2 ) ) |
continue; |
} |
else /* compound glyph */ |
{ |
FT_Bool has_instr = 0; |
|
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if ( FT_STREAM_SKIP( 8 ) ) |
continue; |
|
/* now read each component */ |
for (;;) |
{ |
FT_UInt flags, toskip; |
|
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if( FT_READ_USHORT( flags ) ) |
break; |
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toskip = 2 + 1 + 1; |
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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; |
|
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if ( face && FT_IS_SFNT( face ) ) |
result = _tt_face_check_patents( face ); |
|
return result; |
} |
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/* documentation is in freetype.h */ |
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FT_EXPORT_DEF( FT_Bool ) |
FT_Face_SetUnpatentedHinting( FT_Face face, |
FT_Bool value ) |
{ |
FT_Bool result = FALSE; |
|
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#if defined( TT_CONFIG_OPTION_UNPATENTED_HINTING ) && \ |
!defined( TT_CONFIG_OPTION_BYTECODE_INTERPRETER ) |
if ( face && FT_IS_SFNT( face ) ) |
{ |
result = !face->internal->ignore_unpatented_hinter; |
face->internal->ignore_unpatented_hinter = !value; |
} |
#else |
FT_UNUSED( face ); |
FT_UNUSED( value ); |
#endif |
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return result; |
} |
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/* END */ |