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gxvopbd.c

/***************************************************************************/
/*                                                                         */
/*  gxvopbd.c                                                              */
/*                                                                         */
/*    TrueTypeGX/AAT opbd table validation (body).                         */
/*                                                                         */
/*  Copyright 2004, 2005 by suzuki toshiya, Masatake YAMATO, Red Hat K.K., */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  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.                                        */
/*                                                                         */
/***************************************************************************/

/***************************************************************************/
/*                                                                         */
/* gxvalid is derived from both gxlayout module and otvalid module.        */
/* Development of gxlayout is supported by the Information-technology      */
/* Promotion Agency(IPA), Japan.                                           */
/*                                                                         */
/***************************************************************************/


#include "gxvalid.h"
#include "gxvcommn.h"


  /*************************************************************************/
  /*                                                                       */
  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  /* messages during execution.                                            */
  /*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_gxvopbd


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                      Data and Types                           *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  typedef struct  GXV_opbd_DataRec_
  {
    FT_UShort  format;
    FT_UShort  valueOffset_min;

  } GXV_opbd_DataRec, *GXV_opbd_Data;


#define GXV_OPBD_DATA( FIELD )  GXV_TABLE_DATA( opbd, FIELD )


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                      UTILITY FUNCTIONS                        *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  static void
  gxv_opbd_LookupValue_validate( FT_UShort            glyph,
                                 GXV_LookupValueDesc  value,
                                 GXV_Validator        valid )
  {
    /* offset in LookupTable is measured from the head of opbd table */
    FT_Bytes   p     = valid->root->base + value.u;
    FT_Bytes   limit = valid->root->limit;
    FT_Short   delta_value;
    int        i;


    if ( value.u < GXV_OPBD_DATA( valueOffset_min ) )
      GXV_OPBD_DATA( valueOffset_min ) = value.u;

    for ( i = 0; i < 4; i++ )
    {
      GXV_LIMIT_CHECK( 2 );
      delta_value = FT_NEXT_SHORT( p );

      if ( GXV_OPBD_DATA( format ) )    /* format 1, value is ctrl pt. */
      {
        if ( delta_value == -1 )
          continue;

        gxv_ctlPoint_validate( glyph, delta_value, valid );
      }
      else                              /* format 0, value is distance */
        continue;
    }
  }


  /*
    opbd ---------------------+
                              |
    +===============+         |
    | lookup header |         |
    +===============+         |
    | BinSrchHeader |         |
    +===============+         |
    | lastGlyph[0]  |         |
    +---------------+         |
    | firstGlyph[0] |         |  head of opbd sfnt table
    +---------------+         |             +
    | offset[0]     |    ->   |          offset            [byte]
    +===============+         |             +
    | lastGlyph[1]  |         | (glyphID - firstGlyph) * 4 * sizeof(FT_Short) [byte]
    +---------------+         |
    | firstGlyph[1] |         |
    +---------------+         |
    | offset[1]     |         |
    +===============+         |
                              |
     ....                     |
                              |
    48bit value array         |
    +===============+         |
    |     value     | <-------+
    |               |
    |               |
    |               |
    +---------------+
    .... */

  static GXV_LookupValueDesc
  gxv_opbd_LookupFmt4_transit( FT_UShort            relative_gindex,
                               GXV_LookupValueDesc  base_value,
                               FT_Bytes             lookuptbl_limit,
                               GXV_Validator        valid )
  {
    GXV_LookupValueDesc  value;

    FT_UNUSED( lookuptbl_limit );
    FT_UNUSED( valid );

    /* XXX: check range? */
    value.u = (FT_UShort)( base_value.u +
                           relative_gindex * 4 * sizeof ( FT_Short ) );

    return value;
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                         opbd TABLE                            *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  FT_LOCAL_DEF( void )
  gxv_opbd_validate( FT_Bytes      table,
                     FT_Face       face,
                     FT_Validator  ftvalid )
  {
    GXV_ValidatorRec  validrec;
    GXV_Validator     valid = &validrec;
    GXV_opbd_DataRec  opbdrec;
    GXV_opbd_Data     opbd  = &opbdrec;
    FT_Bytes          p     = table;
    FT_Bytes          limit = 0;

    FT_ULong  version;


    valid->root       = ftvalid;
    valid->table_data = opbd;
    valid->face       = face;

    FT_TRACE3(( "validating `opbd' table\n" ));
    GXV_INIT;
    GXV_OPBD_DATA( valueOffset_min ) = 0xFFFFU;


    GXV_LIMIT_CHECK( 4 + 2 );
    version                 = FT_NEXT_ULONG( p );
    GXV_OPBD_DATA( format ) = FT_NEXT_USHORT( p );


    /* only 0x00010000 is defined (1996) */
    GXV_TRACE(( "(version=0x%08x)\n", version ));
    if ( 0x00010000UL != version )
      FT_INVALID_FORMAT;

    /* only values 0 and 1 are defined (1996) */
    GXV_TRACE(( "(format=0x%04x)\n", GXV_OPBD_DATA( format ) ));
    if ( 0x0001 < GXV_OPBD_DATA( format ) )
      FT_INVALID_FORMAT;

    valid->lookupval_sign   = GXV_LOOKUPVALUE_UNSIGNED;
    valid->lookupval_func   = gxv_opbd_LookupValue_validate;
    valid->lookupfmt4_trans = gxv_opbd_LookupFmt4_transit;

    gxv_LookupTable_validate( p, limit, valid );
    p += valid->subtable_length;

    if ( p > table + GXV_OPBD_DATA( valueOffset_min ) )
    {
      GXV_TRACE((
        "found overlap between LookupTable and opbd_value array\n" ));
      FT_INVALID_OFFSET;
    }

    FT_TRACE4(( "\n" ));
  }


/* END */

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