thirdparty/freetype-2.3.12/src/gxvalid/gxvopbd.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  gxvopbd.c                                                              */
   4 /*                                                                         */
   5 /*    TrueTypeGX/AAT opbd 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_gxvopbd
  39
  40
  41   /*************************************************************************/
  42   /*************************************************************************/
  43   /*****                                                               *****/
  44   /*****                      Data and Types                           *****/
  45   /*****                                                               *****/
  46   /*************************************************************************/
  47   /*************************************************************************/
  48
  49   typedef struct  GXV_opbd_DataRec_
  50   {
  51     FT_UShort  format;
  52     FT_UShort  valueOffset_min;
  53
  54   } GXV_opbd_DataRec, *GXV_opbd_Data;
  55
  56
  57 #define GXV_OPBD_DATA( FIELD )  GXV_TABLE_DATA( opbd, FIELD )
  58
  59
  60   /*************************************************************************/
  61   /*************************************************************************/
  62   /*****                                                               *****/
  63   /*****                      UTILITY FUNCTIONS                        *****/
  64   /*****                                                               *****/
  65   /*************************************************************************/
  66   /*************************************************************************/
  67
  68   static void
  69   gxv_opbd_LookupValue_validate( FT_UShort            glyph,
  70                                  GXV_LookupValueCPtr  value_p,
  71                                  GXV_Validator        valid )
  72   {
  73     /* offset in LookupTable is measured from the head of opbd table */
  74     FT_Bytes   p     = valid->root->base + value_p->u;
  75     FT_Bytes   limit = valid->root->limit;
  76     FT_Short   delta_value;
  77     int        i;
  78
  79
  80     if ( value_p->u < GXV_OPBD_DATA( valueOffset_min ) )
  81       GXV_OPBD_DATA( valueOffset_min ) = value_p->u;
  82
  83     for ( i = 0; i < 4; i++ )
  84     {
  85       GXV_LIMIT_CHECK( 2 );
  86       delta_value = FT_NEXT_SHORT( p );
  87
  88       if ( GXV_OPBD_DATA( format ) )    /* format 1, value is ctrl pt. */
  89       {
  90         if ( delta_value == -1 )
  91           continue;
  92
  93         gxv_ctlPoint_validate( glyph, delta_value, valid );
  94       }
  95       else                              /* format 0, value is distance */
  96         continue;
  97     }
  98   }
  99
 100
 101   /*
 102     opbd ---------------------+
 103                               |
 104     +===============+         |
 105     | lookup header |         |
 106     +===============+         |
 107     | BinSrchHeader |         |
 108     +===============+         |
 109     | lastGlyph[0]  |         |
 110     +---------------+         |
 111     | firstGlyph[0] |         |  head of opbd sfnt table
 112     +---------------+         |             +
 113     | offset[0]     |    ->   |          offset            [byte]
 114     +===============+         |             +
 115     | lastGlyph[1]  |         | (glyphID - firstGlyph) * 4 * sizeof(FT_Short) [byte]
 116     +---------------+         |
 117     | firstGlyph[1] |         |
 118     +---------------+         |
 119     | offset[1]     |         |
 120     +===============+         |
 121                               |
 122      ....                     |
 123                               |
 124     48bit value array         |
 125     +===============+         |
 126     |     value     | <-------+
 127     |               |
 128     |               |
 129     |               |
 130     +---------------+
 131     .... */
 132
 133   static GXV_LookupValueDesc
 134   gxv_opbd_LookupFmt4_transit( FT_UShort            relative_gindex,
 135                                GXV_LookupValueCPtr  base_value_p,
 136                                FT_Bytes             lookuptbl_limit,
 137                                GXV_Validator        valid )
 138   {
 139     GXV_LookupValueDesc  value;
 140
 141     FT_UNUSED( lookuptbl_limit );
 142     FT_UNUSED( valid );
 143
 144     /* XXX: check range? */
 145     value.u = (FT_UShort)( base_value_p->u +
 146                            relative_gindex * 4 * sizeof ( FT_Short ) );
 147
 148     return value;
 149   }
 150
 151
 152   /*************************************************************************/
 153   /*************************************************************************/
 154   /*****                                                               *****/
 155   /*****                         opbd TABLE                            *****/
 156   /*****                                                               *****/
 157   /*************************************************************************/
 158   /*************************************************************************/
 159
 160   FT_LOCAL_DEF( void )
 161   gxv_opbd_validate( FT_Bytes      table,
 162                      FT_Face       face,
 163                      FT_Validator  ftvalid )
 164   {
 165     GXV_ValidatorRec  validrec;
 166     GXV_Validator     valid = &validrec;
 167     GXV_opbd_DataRec  opbdrec;
 168     GXV_opbd_Data     opbd  = &opbdrec;
 169     FT_Bytes          p     = table;
 170     FT_Bytes          limit = 0;
 171
 172     FT_ULong  version;
 173
 174
 175     valid->root       = ftvalid;
 176     valid->table_data = opbd;
 177     valid->face       = face;
 178
 179     FT_TRACE3(( "validating `opbd' table\n" ));
 180     GXV_INIT;
 181     GXV_OPBD_DATA( valueOffset_min ) = 0xFFFFU;
 182
 183
 184     GXV_LIMIT_CHECK( 4 + 2 );
 185     version                 = FT_NEXT_ULONG( p );
 186     GXV_OPBD_DATA( format ) = FT_NEXT_USHORT( p );
 187
 188
 189     /* only 0x00010000 is defined (1996) */
 190     GXV_TRACE(( "(version=0x%08x)\n", version ));
 191     if ( 0x00010000UL != version )
 192       FT_INVALID_FORMAT;
 193
 194     /* only values 0 and 1 are defined (1996) */
 195     GXV_TRACE(( "(format=0x%04x)\n", GXV_OPBD_DATA( format ) ));
 196     if ( 0x0001 < GXV_OPBD_DATA( format ) )
 197       FT_INVALID_FORMAT;
 198
 199     valid->lookupval_sign   = GXV_LOOKUPVALUE_UNSIGNED;
 200     valid->lookupval_func   = gxv_opbd_LookupValue_validate;
 201     valid->lookupfmt4_trans = gxv_opbd_LookupFmt4_transit;
 202
 203     gxv_LookupTable_validate( p, limit, valid );
 204     p += valid->subtable_length;
 205
 206     if ( p > table + GXV_OPBD_DATA( valueOffset_min ) )
 207     {
 208       GXV_TRACE((
 209         "found overlap between LookupTable and opbd_value array\n" ));
 210       FT_INVALID_OFFSET;
 211     }
 212
 213     FT_TRACE4(( "\n" ));
 214   }
 215
 216
 217 /* END */