thirdparty/freetype-2.3.12/src/base/ftpatent.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ftpatent.c                                                             */
   4 /*                                                                         */
   5 /*    FreeType API for checking patented TrueType bytecode instructions    */
   6 /*    (body).                                                              */
   7 /*                                                                         */
   8 /*  Copyright 2007, 2008, 2010 by David Turner.                            */
   9 /*                                                                         */
  10 /*  This file is part of the FreeType project, and may only be used,       */
  11 /*  modified, and distributed under the terms of the FreeType project      */
  12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
  13 /*  this file you indicate that you have read the license and              */
  14 /*  understand and accept it fully.                                        */
  15 /*                                                                         */
  16 /***************************************************************************/
  17
  18 #include <ft2build.h>
  19 #include FT_FREETYPE_H
  20 #include FT_TRUETYPE_TAGS_H
  21 #include FT_INTERNAL_OBJECTS_H
  22 #include FT_INTERNAL_STREAM_H
  23 #include FT_SERVICE_SFNT_H
  24 #include FT_SERVICE_TRUETYPE_GLYF_H
  25
  26
  27   static FT_Bool
  28   _tt_check_patents_in_range( FT_Stream  stream,
  29                               FT_ULong   size )
  30   {
  31     FT_Bool   result = FALSE;
  32     FT_Error  error;
  33     FT_Bytes  p, end;
  34
  35
  36     if ( FT_FRAME_ENTER( size ) )
  37       return 0;
  38
  39     p   = stream->cursor;
  40     end = p + size;
  41
  42     while ( p < end )
  43     {
  44       switch (p[0])
  45       {
  46       case 0x06:  /* SPvTL // */
  47       case 0x07:  /* SPvTL +  */
  48       case 0x08:  /* SFvTL // */
  49       case 0x09:  /* SFvTL +  */
  50       case 0x0A:  /* SPvFS    */
  51       case 0x0B:  /* SFvFS    */
  52         result = TRUE;
  53         goto Exit;
  54
  55       case 0x40:
  56         if ( p + 1 >= end )
  57           goto Exit;
  58
  59         p += p[1] + 2;
  60         break;
  61
  62       case 0x41:
  63         if ( p + 1 >= end )
  64           goto Exit;
  65
  66         p += p[1] * 2 + 2;
  67         break;
  68
  69       case 0x71:  /* DELTAP2 */
  70       case 0x72:  /* DELTAP3 */
  71       case 0x73:  /* DELTAC0 */
  72       case 0x74:  /* DELTAC1 */
  73       case 0x75:  /* DELTAC2 */
  74         result = TRUE;
  75         goto Exit;
  76
  77       case 0xB0:
  78       case 0xB1:
  79       case 0xB2:
  80       case 0xB3:
  81       case 0xB4:
  82       case 0xB5:
  83       case 0xB6:
  84       case 0xB7:
  85         p += ( p[0] - 0xB0 ) + 2;
  86         break;
  87
  88       case 0xB8:
  89       case 0xB9:
  90       case 0xBA:
  91       case 0xBB:
  92       case 0xBC:
  93       case 0xBD:
  94       case 0xBE:
  95       case 0xBF:
  96         p += ( p[0] - 0xB8 ) * 2 + 3;
  97         break;
  98
  99       default:
 100         p += 1;
 101         break;
 102       }
 103     }
 104
 105   Exit:
 106     FT_UNUSED( error );
 107     FT_FRAME_EXIT();
 108     return result;
 109   }
 110
 111
 112   static FT_Bool
 113   _tt_check_patents_in_table( FT_Face   face,
 114                               FT_ULong  tag )
 115   {
 116     FT_Stream              stream = face->stream;
 117     FT_Error               error  = FT_Err_Ok;
 118     FT_Service_SFNT_Table  service;
 119     FT_Bool                result = FALSE;
 120
 121
 122     FT_FACE_FIND_SERVICE( face, service, SFNT_TABLE );
 123
 124     if ( service )
 125     {
 126       FT_UInt   i = 0;
 127       FT_ULong  tag_i = 0, offset_i = 0, length_i = 0;
 128
 129
 130       for ( i = 0; !error && tag_i != tag ; i++ )
 131         error = service->table_info( face, i,
 132                                      &tag_i, &offset_i, &length_i );
 133
 134       if ( error                      ||
 135            FT_STREAM_SEEK( offset_i ) )
 136         goto Exit;
 137
 138       result = _tt_check_patents_in_range( stream, length_i );
 139     }
 140
 141   Exit:
 142     return result;
 143   }
 144
 145
 146   static FT_Bool
 147   _tt_face_check_patents( FT_Face  face )
 148   {
 149     FT_Stream  stream = face->stream;
 150     FT_UInt    gindex;
 151     FT_Error   error;
 152     FT_Bool    result;
 153
 154     FT_Service_TTGlyf  service;
 155
 156
 157     result = _tt_check_patents_in_table( face, TTAG_fpgm );
 158     if ( result )
 159       goto Exit;
 160
 161     result = _tt_check_patents_in_table( face, TTAG_prep );
 162     if ( result )
 163       goto Exit;
 164
 165     FT_FACE_FIND_SERVICE( face, service, TT_GLYF );
 166     if ( service == NULL )
 167       goto Exit;
 168
 169     for ( gindex = 0; gindex < (FT_UInt)face->num_glyphs; gindex++ )
 170     {
 171       FT_ULong  offset, num_ins, size;
 172       FT_Int    num_contours;
 173
 174
 175       offset = service->get_location( face, gindex, &size );
 176       if ( size == 0 )
 177         continue;
 178
 179       if ( FT_STREAM_SEEK( offset )      ||
 180            FT_READ_SHORT( num_contours ) )
 181         continue;
 182
 183       if ( num_contours >= 0 )  /* simple glyph */
 184       {
 185         if ( FT_STREAM_SKIP( 8 + num_contours * 2 ) )
 186           continue;
 187       }
 188       else  /* compound glyph */
 189       {
 190         FT_Bool  has_instr = 0;
 191
 192
 193         if ( FT_STREAM_SKIP( 8 ) )
 194           continue;
 195
 196         /* now read each component */
 197         for (;;)
 198         {
 199           FT_UInt  flags, toskip;
 200
 201
 202           if( FT_READ_USHORT( flags ) )
 203             break;
 204
 205           toskip = 2 + 1 + 1;
 206
 207           if ( ( flags & ( 1 << 0 ) ) != 0 )       /* ARGS_ARE_WORDS */
 208             toskip += 2;
 209
 210           if ( ( flags & ( 1 << 3 ) ) != 0 )       /* WE_HAVE_A_SCALE */
 211             toskip += 2;
 212           else if ( ( flags & ( 1 << 6 ) ) != 0 )  /* WE_HAVE_X_Y_SCALE */
 213             toskip += 4;
 214           else if ( ( flags & ( 1 << 7 ) ) != 0 )  /* WE_HAVE_A_2x2 */
 215             toskip += 8;
 216
 217           if ( ( flags & ( 1 << 8 ) ) != 0 )       /* WE_HAVE_INSTRUCTIONS */
 218             has_instr = 1;
 219
 220           if ( FT_STREAM_SKIP( toskip ) )
 221             goto NextGlyph;
 222
 223           if ( ( flags & ( 1 << 5 ) ) == 0 )       /* MORE_COMPONENTS */
 224             break;
 225         }
 226
 227         if ( !has_instr )
 228           goto NextGlyph;
 229       }
 230
 231       if ( FT_READ_USHORT( num_ins ) )
 232         continue;
 233
 234       result = _tt_check_patents_in_range( stream, num_ins );
 235       if ( result )
 236         goto Exit;
 237
 238     NextGlyph:
 239       ;
 240     }
 241
 242   Exit:
 243     return result;
 244   }
 245
 246
 247   /* documentation is in freetype.h */
 248
 249   FT_EXPORT_DEF( FT_Bool )
 250   FT_Face_CheckTrueTypePatents( FT_Face  face )
 251   {
 252     FT_Bool  result = FALSE;
 253
 254
 255     if ( face && FT_IS_SFNT( face ) )
 256       result = _tt_face_check_patents( face );
 257
 258     return result;
 259   }
 260
 261
 262   /* documentation is in freetype.h */
 263
 264   FT_EXPORT_DEF( FT_Bool )
 265   FT_Face_SetUnpatentedHinting( FT_Face  face,
 266                                 FT_Bool  value )
 267   {
 268     FT_Bool  result = FALSE;
 269
 270
 271 #if defined( TT_CONFIG_OPTION_UNPATENTED_HINTING ) && \
 272     !defined( TT_CONFIG_OPTION_BYTECODE_INTEPRETER )
 273     if ( face && FT_IS_SFNT( face ) )
 274     {
 275       result = !face->internal->ignore_unpatented_hinter;
 276       face->internal->ignore_unpatented_hinter = !value;
 277     }
 278 #else
 279     FT_UNUSED( face );
 280     FT_UNUSED( value );
 281 #endif
 282
 283     return result;
 284   }
 285
 286 /* END */