src/gxvalid/gxvprop.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  gxvprop.c                                                              */
   4 /*                                                                         */
   5 /*    TrueTypeGX/AAT prop table validation (body).                         */
   6 /*                                                                         */
   7 /*  Copyright 2004, 2005 by suzuki toshiya, Masatake YAMATO, Red Hat K.K., */
   8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
   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 /***************************************************************************/
  19 /*                                                                         */
  20 /* gxvalid is derived from both gxlayout module and otvalid module.        */
  21 /* Development of gxlayout is supported by the Information-technology      */
  22 /* Promotion Agency(IPA), Japan.                                           */
  23 /*                                                                         */
  24 /***************************************************************************/
  25
  26
  27 #include "gxvalid.h"
  28 #include "gxvcommn.h"
  29
  30
  31   /*************************************************************************/
  32   /*                                                                       */
  33   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  34   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  35   /* messages during execution.                                            */
  36   /*                                                                       */
  37 #undef  FT_COMPONENT
  38 #define FT_COMPONENT  trace_gxvprop
  39
  40
  41   /*************************************************************************/
  42   /*************************************************************************/
  43   /*****                                                               *****/
  44   /*****                      Data and Types                           *****/
  45   /*****                                                               *****/
  46   /*************************************************************************/
  47   /*************************************************************************/
  48
  49 #define GXV_PROP_HEADER_SIZE  ( 4 + 2 + 2 )
  50 #define GXV_PROP_SIZE_MIN     GXV_PROP_HEADER_SIZE
  51
  52   typedef struct  GXV_prop_DataRec_
  53   {
  54     FT_Fixed  version;
  55
  56   } GXV_prop_DataRec, *GXV_prop_Data;
  57
  58 #define GXV_PROP_DATA( field )  GXV_TABLE_DATA( prop, field )
  59
  60 #define GXV_PROP_FLOATER                      0x8000U
  61 #define GXV_PROP_USE_COMPLEMENTARY_BRACKET    0x1000U
  62 #define GXV_PROP_COMPLEMENTARY_BRACKET_OFFSET 0x0F00U
  63 #define GXV_PROP_ATTACHING_TO_RIGHT           0x0080U
  64 #define GXV_PROP_RESERVED                     0x0060U
  65 #define GXV_PROP_DIRECTIONALITY_CLASS         0x001FU
  66
  67
  68   /*************************************************************************/
  69   /*************************************************************************/
  70   /*****                                                               *****/
  71   /*****                      UTILITY FUNCTIONS                        *****/
  72   /*****                                                               *****/
  73   /*************************************************************************/
  74   /*************************************************************************/
  75
  76   static void
  77   gxv_prop_zero_advance_validate( FT_UShort      gid,
  78                                   GXV_Validator  valid )
  79   {
  80     FT_Face       face;
  81     FT_Error      error;
  82     FT_GlyphSlot  glyph;
  83
  84
  85     GXV_NAME_ENTER( "zero advance" );
  86
  87     face = valid->face;
  88
  89     error = FT_Load_Glyph( face,
  90                            gid,
  91                            FT_LOAD_IGNORE_TRANSFORM );
  92     if ( error )
  93       FT_INVALID_GLYPH_ID;
  94
  95     glyph = face->glyph;
  96
  97     if ( glyph->advance.x != (FT_Pos)0 ||
  98          glyph->advance.y != (FT_Pos)0 )
  99       FT_INVALID_DATA;
 100
 101     GXV_EXIT;
 102   }
 103
 104
 105   /* Pass 0 as GLYPH to check the default property */
 106   static void
 107   gxv_prop_property_validate( FT_UShort      property,
 108                               FT_UShort      glyph,
 109                               GXV_Validator  valid )
 110   {
 111     if ( glyph != 0 && ( property & GXV_PROP_FLOATER ) )
 112       gxv_prop_zero_advance_validate( glyph, valid );
 113
 114     if ( property & GXV_PROP_USE_COMPLEMENTARY_BRACKET )
 115     {
 116       FT_UShort  offset;
 117       char       complement;
 118
 119
 120       offset = (FT_UShort)( property & GXV_PROP_COMPLEMENTARY_BRACKET_OFFSET );
 121       if ( offset == 0 )
 122         FT_INVALID_DATA;
 123
 124       complement = (char)( offset >> 8 );
 125       if ( complement & 0x08 )
 126       {
 127         /* Top bit is set: negative */
 128
 129         /* Calculate the absolute offset */
 130         complement = (char)( ( complement & 0x07 ) + 1 );
 131
 132         /* The gid for complement must be greater than 0 */
 133         if ( glyph <= complement )
 134           FT_INVALID_DATA;
 135       }
 136       else
 137       {
 138         /* The gid for complement must be the face. */
 139         gxv_glyphid_validate( (FT_UShort)( glyph + complement ), valid );
 140       }
 141     }
 142     else
 143     {
 144       if ( property & GXV_PROP_COMPLEMENTARY_BRACKET_OFFSET )
 145         GXV_TRACE(( "glyph %d cannot have complementary bracketing\n",
 146                     glyph ));
 147     }
 148
 149     /* this is introduced in version 2.0 */
 150     if ( property & GXV_PROP_ATTACHING_TO_RIGHT )
 151     {
 152       if ( GXV_PROP_DATA( version ) == 0x00010000UL )
 153         FT_INVALID_DATA;
 154     }
 155
 156     if ( property & GXV_PROP_RESERVED )
 157       FT_INVALID_DATA;
 158
 159     if ( ( property & GXV_PROP_DIRECTIONALITY_CLASS ) > 11 )
 160     {
 161       /* TODO: Too restricted. Use the validation level. */
 162       if ( GXV_PROP_DATA( version ) == 0x00010000UL ||
 163            GXV_PROP_DATA( version ) == 0x00020000UL )
 164         FT_INVALID_DATA;
 165     }
 166   }
 167
 168
 169   static void
 170   gxv_prop_LookupValue_validate( FT_UShort            glyph,
 171                                  GXV_LookupValueCPtr  value_p,
 172                                  GXV_Validator        valid )
 173   {
 174     gxv_prop_property_validate( value_p->u, glyph, valid );
 175   }
 176
 177
 178   /*
 179     +===============+ --------+
 180     | lookup header |         |
 181     +===============+         |
 182     | BinSrchHeader |         |
 183     +===============+         |
 184     | lastGlyph[0]  |         |
 185     +---------------+         |
 186     | firstGlyph[0] |         |    head of lookup table
 187     +---------------+         |             +
 188     | offset[0]     |    ->   |          offset            [byte]
 189     +===============+         |             +
 190     | lastGlyph[1]  |         | (glyphID - firstGlyph) * 2 [byte]
 191     +---------------+         |
 192     | firstGlyph[1] |         |
 193     +---------------+         |
 194     | offset[1]     |         |
 195     +===============+         |
 196                               |
 197      ...                      |
 198                               |
 199     16bit value array         |
 200     +===============+         |
 201     |     value     | <-------+
 202     ...
 203   */
 204
 205   static GXV_LookupValueDesc
 206   gxv_prop_LookupFmt4_transit( FT_UShort            relative_gindex,
 207                                GXV_LookupValueCPtr  base_value_p,
 208                                FT_Bytes             lookuptbl_limit,
 209                                GXV_Validator        valid )
 210   {
 211     FT_Bytes             p;
 212     FT_Bytes             limit;
 213     FT_UShort            offset;
 214     GXV_LookupValueDesc  value;
 215
 216     /* XXX: check range? */
 217     offset = (FT_UShort)( base_value_p->u +
 218                           relative_gindex * sizeof( FT_UShort ) );
 219     p      = valid->lookuptbl_head + offset;
 220     limit  = lookuptbl_limit;
 221
 222     GXV_LIMIT_CHECK ( 2 );
 223     value.u = FT_NEXT_USHORT( p );
 224
 225     return value;
 226   }
 227
 228
 229   /*************************************************************************/
 230   /*************************************************************************/
 231   /*****                                                               *****/
 232   /*****                         prop TABLE                            *****/
 233   /*****                                                               *****/
 234   /*************************************************************************/
 235   /*************************************************************************/
 236
 237   FT_LOCAL_DEF( void )
 238   gxv_prop_validate( FT_Bytes      table,
 239                      FT_Face       face,
 240                      FT_Validator  ftvalid )
 241   {
 242     FT_Bytes          p     = table;
 243     FT_Bytes          limit = 0;
 244     GXV_ValidatorRec  validrec;
 245     GXV_Validator     valid = &validrec;
 246
 247     GXV_prop_DataRec  proprec;
 248     GXV_prop_Data     prop = &proprec;
 249
 250     FT_Fixed          version;
 251     FT_UShort         format;
 252     FT_UShort         defaultProp;
 253
 254
 255     valid->root       = ftvalid;
 256     valid->table_data = prop;
 257     valid->face       = face;
 258
 259     FT_TRACE3(( "validating `prop' table\n" ));
 260     GXV_INIT;
 261
 262     GXV_LIMIT_CHECK( 4 + 2 + 2 );
 263     version     = FT_NEXT_ULONG( p );
 264     format      = FT_NEXT_USHORT( p );
 265     defaultProp = FT_NEXT_USHORT( p );
 266
 267     /* only versions 1.0, 2.0, 3.0 are defined (1996) */
 268     if ( version != 0x00010000UL &&
 269          version != 0x00020000UL &&
 270          version != 0x00030000UL )
 271       FT_INVALID_FORMAT;
 272
 273
 274     /* only formats 0x0000, 0x0001 are defined (1996) */
 275     if ( format > 1 )
 276       FT_INVALID_FORMAT;
 277
 278     gxv_prop_property_validate( defaultProp, 0, valid );
 279
 280     if ( format == 0 )
 281     {
 282       FT_TRACE3(( "(format 0, no per-glyph properties, "
 283                   "remaining %d bytes are skipped)", limit - p ));
 284       goto Exit;
 285     }
 286
 287     /* format == 1 */
 288     GXV_PROP_DATA( version ) = version;
 289
 290     valid->lookupval_sign   = GXV_LOOKUPVALUE_UNSIGNED;
 291     valid->lookupval_func   = gxv_prop_LookupValue_validate;
 292     valid->lookupfmt4_trans = gxv_prop_LookupFmt4_transit;
 293
 294     gxv_LookupTable_validate( p, limit, valid );
 295
 296   Exit:
 297     FT_TRACE4(( "\n" ));
 298   }
 299
 300
 301 /* END */