modules/freetype2/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 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_FRAME_EXIT();
 107     return result;
 108   }
 109
 110
 111   static FT_Bool
 112   _tt_check_patents_in_table( FT_Face   face,
 113                               FT_ULong  tag )
 114   {
 115     FT_Stream              stream = face->stream;
 116     FT_Error               error;
 117     FT_Service_SFNT_Table  service;
 118     FT_Bool                result = FALSE;
 119
 120
 121     FT_FACE_FIND_SERVICE( face, service, SFNT_TABLE );
 122
 123     if ( service )
 124     {
 125       FT_ULong  offset, size;
 126
 127
 128       error = service->table_info( face, tag, &offset, &size );
 129       if ( error                    ||
 130            FT_STREAM_SEEK( offset ) )
 131         goto Exit;
 132
 133       result = _tt_check_patents_in_range( stream, size );
 134     }
 135
 136   Exit:
 137     return result;
 138   }
 139
 140
 141   static FT_Bool
 142   _tt_face_check_patents( FT_Face  face )
 143   {
 144     FT_Stream  stream = face->stream;
 145     FT_UInt    gindex;
 146     FT_Error   error;
 147     FT_Bool    result;
 148
 149     FT_Service_TTGlyf  service;
 150
 151
 152     result = _tt_check_patents_in_table( face, TTAG_fpgm );
 153     if ( result )
 154       goto Exit;
 155
 156     result = _tt_check_patents_in_table( face, TTAG_prep );
 157     if ( result )
 158       goto Exit;
 159
 160     FT_FACE_FIND_SERVICE( face, service, TT_GLYF );
 161     if ( service == NULL )
 162       goto Exit;
 163
 164     for ( gindex = 0; gindex < (FT_UInt)face->num_glyphs; gindex++ )
 165     {
 166       FT_ULong  offset, num_ins, size;
 167       FT_Int    num_contours;
 168
 169
 170       offset = service->get_location( face, gindex, &size );
 171       if ( size == 0 )
 172         continue;
 173
 174       if ( FT_STREAM_SEEK( offset )      ||
 175            FT_READ_SHORT( num_contours ) )
 176         continue;
 177
 178       if ( num_contours >= 0 )  /* simple glyph */
 179       {
 180         if ( FT_STREAM_SKIP( 8 + num_contours * 2 ) )
 181           continue;
 182       }
 183       else  /* compound glyph */
 184       {
 185         FT_Bool  has_instr = 0;
 186
 187
 188         if ( FT_STREAM_SKIP( 8 ) )
 189           continue;
 190
 191         /* now read each component */
 192         for (;;)
 193         {
 194           FT_UInt  flags, toskip;
 195
 196
 197           if( FT_READ_USHORT( flags ) )
 198             break;
 199
 200           toskip = 2 + 1 + 1;
 201
 202           if ( ( flags & ( 1 << 0 ) ) != 0 )       /* ARGS_ARE_WORDS */
 203             toskip += 2;
 204
 205           if ( ( flags & ( 1 << 3 ) ) != 0 )       /* WE_HAVE_A_SCALE */
 206             toskip += 2;
 207           else if ( ( flags & ( 1 << 6 ) ) != 0 )  /* WE_HAVE_X_Y_SCALE */
 208             toskip += 4;
 209           else if ( ( flags & ( 1 << 7 ) ) != 0 )  /* WE_HAVE_A_2x2 */
 210             toskip += 8;
 211
 212           if ( ( flags & ( 1 << 8 ) ) != 0 )       /* WE_HAVE_INSTRUCTIONS */
 213             has_instr = 1;
 214
 215           if ( FT_STREAM_SKIP( toskip ) )
 216             goto NextGlyph;
 217
 218           if ( ( flags & ( 1 << 5 ) ) == 0 )       /* MORE_COMPONENTS */
 219             break;
 220         }
 221
 222         if ( !has_instr )
 223           goto NextGlyph;
 224       }
 225
 226       if ( FT_READ_USHORT( num_ins ) )
 227         continue;
 228
 229       result = _tt_check_patents_in_range( stream, num_ins );
 230       if ( result )
 231         goto Exit;
 232
 233     NextGlyph:
 234       ;
 235     }
 236
 237   Exit:
 238     return result;
 239   }
 240
 241
 242   /* documentation is in freetype.h */
 243
 244   FT_EXPORT_DEF( FT_Bool )
 245   FT_Face_CheckTrueTypePatents( FT_Face  face )
 246   {
 247     FT_Bool  result = FALSE;
 248
 249
 250     if ( face && FT_IS_SFNT( face ) )
 251       result = _tt_face_check_patents( face );
 252
 253     return result;
 254   }
 255
 256
 257   /* documentation is in freetype.h */
 258
 259   FT_EXPORT_DEF( FT_Bool )
 260   FT_Face_SetUnpatentedHinting( FT_Face  face,
 261                                 FT_Bool  value )
 262   {
 263     FT_Bool  result = 0;
 264
 265
 266 #if defined( TT_CONFIG_OPTION_UNPATENTED_HINTING ) && \
 267     !defined( TT_CONFIG_OPTION_BYTECODE_INTEPRETER )
 268     if ( face && FT_IS_SFNT( face ) )
 269     {
 270       result = !face->internal->ignore_unpatented_hinter;
 271       face->internal->ignore_unpatented_hinter = !value;
 272     }
 273 #else
 274     FT_UNUSED( face );
 275     FT_UNUSED( value );
 276 #endif
 277
 278     return result;
 279   }
 280
 281 /* END */