ttcmap0.c

下载来的一个看图软件的源代码

    {
      FT_UInt  gindex;


      for ( ; count > 0; count-- )
      {
        gindex = TT_NEXT_USHORT( p );
        if ( gindex >= TT_VALID_GLYPH_COUNT( valid ) )
          FT_INVALID_GLYPH_ID;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap6_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*  table  = cmap->data;
    FT_UInt   result = 0;
    FT_Byte*  p      = table + 6;
    FT_UInt   start  = TT_NEXT_USHORT( p );
    FT_UInt   count  = TT_NEXT_USHORT( p );
    FT_UInt   idx    = (FT_UInt)( char_code - start );


    if ( idx < count )
    {
      p += 2 * idx;
      result = TT_PEEK_USHORT( p );
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap6_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_Byte*   table     = cmap->data;
    FT_UInt32  result    = 0;
    FT_UInt32  char_code = *pchar_code + 1;
    FT_UInt    gindex    = 0;

    FT_Byte*   p         = table + 6;
    FT_UInt    start     = TT_NEXT_USHORT( p );
    FT_UInt    count     = TT_NEXT_USHORT( p );
    FT_UInt    idx;


    if ( char_code >= 0x10000UL )
      goto Exit;

    if ( char_code < start )
      char_code = start;

    idx = (FT_UInt)( char_code - start );
    p  += 2 * idx;

    for ( ; idx < count; idx++ )
    {
      gindex = TT_NEXT_USHORT( p );
      if ( gindex != 0 )
      {
        result = char_code;
        break;
      }
      char_code++;
    }

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap6_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap6_char_index,
      (FT_CMap_CharNextFunc) tt_cmap6_char_next
    },
    6,
    (TT_CMap_ValidateFunc)   tt_cmap6_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_6 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 8                             *****/
  /*****                                                               *****/
  /***** It's hard to completely understand what the OpenType spec     *****/
  /***** says about this format, but here is my conclusion.            *****/
  /*****                                                               *****/
  /***** The purpose of this format is to easily map UTF-16 text to    *****/
  /***** glyph indices.  Basically, the `char_code' must be in one of  *****/
  /***** the following formats:                                        *****/
  /*****                                                               *****/
  /*****   - A 16-bit value that isn't part of the Unicode Surrogates  *****/
  /*****     Area (i.e. U+D800-U+DFFF).                                *****/
  /*****                                                               *****/
  /*****   - A 32-bit value, made of two surrogate values, i.e.. if    *****/
  /*****     `char_code = (char_hi << 16) | char_lo', then both        *****/
  /*****     `char_hi' and `char_lo' must be in the Surrogates Area.   *****/
  /*****      Area.                                                    *****/
  /*****                                                               *****/
  /***** The 'is32' table embedded in the charmap indicates whether a  *****/
  /***** given 16-bit value is in the surrogates area or not.          *****/
  /*****                                                               *****/
  /***** So, for any given `char_code', we can assert the following:   *****/
  /*****                                                               *****/
  /*****   If `char_hi == 0' then we must have `is32[char_lo] == 0'.   *****/
  /*****                                                               *****/
  /*****   If `char_hi != 0' then we must have both                    *****/
  /*****   `is32[char_hi] != 0' and `is32[char_lo] != 0'.              *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET         TYPE        DESCRIPTION                  */
  /*                                                                       */
  /*   format      0              USHORT      must be 8                    */
  /*   reseved     2              USHORT      reserved                     */
  /*   length      4              ULONG       length in bytes              */
  /*   language    8              ULONG       Mac language code            */
  /*   is32        12             BYTE[8192]  32-bitness bitmap            */
  /*   count       8204           ULONG       number of groups             */
  /*                                                                       */
  /* This header is followed by 'count' groups of the following format:    */
  /*                                                                       */
  /*   start       0              ULONG       first charcode               */
  /*   end         4              ULONG       last charcode                */
  /*   startId     8              ULONG       start glyph id for the group */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_8

  FT_CALLBACK_DEF( void )
  tt_cmap8_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*   p = table + 4;
    FT_Byte*   is32;
    FT_UInt32  length;
    FT_UInt32  num_groups;


    if ( table + 16 + 8192 > valid->limit )
      FT_INVALID_TOO_SHORT;

    length = TT_NEXT_ULONG( p );
    if ( table + length > valid->limit || length < 8208 )
      FT_INVALID_TOO_SHORT;

    is32       = table + 12;
    p          = is32  + 8192;          /* skip `is32' array */
    num_groups = TT_NEXT_ULONG( p );

    if ( p + num_groups * 12 > valid->limit )
      FT_INVALID_TOO_SHORT;

    /* check groups, they must be in increasing order */
    {
      FT_UInt32  n, start, end, start_id, count, last = 0;


      for ( n = 0; n < num_groups; n++ )
      {
        FT_UInt   hi, lo;


        start    = TT_NEXT_ULONG( p );
        end      = TT_NEXT_ULONG( p );
        start_id = TT_NEXT_ULONG( p );

        if ( start > end )
          FT_INVALID_DATA;

        if ( n > 0 && start <= last )
          FT_INVALID_DATA;

        if ( valid->level >= FT_VALIDATE_TIGHT )
        {
          if ( start_id + end - start >= TT_VALID_GLYPH_COUNT( valid ) )
            FT_INVALID_GLYPH_ID;

          count = (FT_UInt32)( end - start + 1 );

          if ( start & ~0xFFFFU )
          {
            /* start_hi != 0; check that is32[i] is 1 for each i in */
            /* the `hi' and `lo' of the range [start..end]          */
            for ( ; count > 0; count--, start++ )
            {
              hi = (FT_UInt)( start >> 16 );
              lo = (FT_UInt)( start & 0xFFFFU );

              if ( (is32[hi >> 3] & ( 0x80 >> ( hi & 7 ) ) ) == 0 )
                FT_INVALID_DATA;

              if ( (is32[lo >> 3] & ( 0x80 >> ( lo & 7 ) ) ) == 0 )
                FT_INVALID_DATA;
            }
          }
          else
          {
            /* start_hi == 0; check that is32[i] is 0 for each i in */
            /* the range [start..end]                               */

            /* end_hi cannot be != 0! */
            if ( end & ~0xFFFFU )
              FT_INVALID_DATA;

            for ( ; count > 0; count--, start++ )
            {
              lo = (FT_UInt)( start & 0xFFFFU );

              if ( (is32[lo >> 3] & ( 0x80 >> ( lo & 7 ) ) ) != 0 )
                FT_INVALID_DATA;
            }
          }
        }

        last = end;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap8_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*   table      = cmap->data;
    FT_UInt    result     = 0;
    FT_Byte*   p          = table + 8204;
    FT_UInt32  num_groups = TT_NEXT_ULONG( p );
    FT_UInt32  start, end, start_id;


    for ( ; num_groups > 0; num_groups-- )
    {
      start    = TT_NEXT_ULONG( p );
      end      = TT_NEXT_ULONG( p );
      start_id = TT_NEXT_ULONG( p );

      if ( char_code < start )
        break;

      if ( char_code <= end )
      {
        result = (FT_UInt)( start_id + char_code - start );
        break;
      }
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap8_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_UInt32  result     = 0;
    FT_UInt32  char_code  = *pchar_code + 1;
    FT_UInt    gindex     = 0;
    FT_Byte*   table      = cmap->data;
    FT_Byte*   p          = table + 8204;
    FT_UInt32  num_groups = TT_NEXT_ULONG( p );
    FT_UInt32  start, end, start_id;


    p = table + 8208;

    for ( ; num_groups > 0; num_groups-- )
    {
      start    = TT_NEXT_ULONG( p );
      end      = TT_NEXT_ULONG( p );
      start_id = TT_NEXT_ULONG( p );

      if ( char_code < start )
        char_code = start;

      if ( char_code <= end )
      {
        gindex = (FT_UInt)( char_code - start + start_id );
        if ( gindex != 0 )
        {
          result = char_code;
          goto Exit;
        }
      }
    }

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap8_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap8_char_index,
      (FT_CMap_CharNextFunc) tt_cmap8_char_next
    },
    8,
    (TT_CMap_ValidateFunc)   tt_cmap8_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_8 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 10                            *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME      OFFSET  TYPE               DESCRIPTION                    */
  /*                                                                       */
  /*   format     0      USHORT             must be 10                     */
  /*   reserved   2      USHORT             reserved                       */
  /*   length     4      ULONG              length in bytes                */
  /*   language   8      ULONG              Mac language code              */
  /*                                                                       */
  /*   start     12      ULONG              first char in range            */
  /*   count     16      ULONG              number of chars in range       */
  /*   glyphIds  20      USHORT[count]      glyph indices covered          */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_10

  FT_CALLBACK_DEF( void )
  tt_cmap10_validate( FT_Byte*      table,
                      FT_Validator  valid )
  {
    FT_Byte*  p = table + 4;
    FT_ULong  length, count;


    if ( table + 20 > valid->limit )
      FT_INVALID_TOO_SHORT;

    length = TT_NEXT_ULONG( p );
    p      = table + 16;
    count  = TT_NEXT_ULONG( p );

    if ( table + length > valid->limit || length < 20 + count * 2 )
      FT_INVALID_TOO_SHORT;