ttcmap0.c

下载来的一个看图软件的源代码

  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap4_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*  table  = cmap->data;
    FT_UInt   result = 0;


    if ( char_code < 0x10000UL )
    {
      FT_UInt   idx, num_segs2;
      FT_Int    delta;
      FT_UInt   code = (FT_UInt)char_code;
      FT_Byte*  p;


      p         = table + 6;
      num_segs2 = TT_PEEK_USHORT( p ) & -2;  /* be paranoid! */

#if 1
      /* Some fonts have more than 170 segments in their charmaps! */
      /* We changed this function to use a more efficient binary   */
      /* search for improving performance                          */
      {
        FT_UInt  min = 0;
        FT_UInt  max = num_segs2 >> 1;
        FT_UInt  mid, start, end, offset;


        while ( min < max )
        {
          mid   = ( min + max ) >> 1;
          p     = table + 14 + mid * 2;
          end   = TT_NEXT_USHORT( p );
          p    += num_segs2;
          start = TT_PEEK_USHORT( p);

          if ( code < start )
            max = mid;
          else if ( code > end )
            min = mid + 1;
          else
          {
            /* we found the segment */
            idx = code;

            p += num_segs2;
            delta = TT_PEEK_SHORT( p );

            p += num_segs2;
            offset = TT_PEEK_USHORT( p );

            if ( offset == 0xFFFFU )
              goto Exit;

            if ( offset != 0 )
            {
              p  += offset + 2 * ( idx - start );
              idx = TT_PEEK_USHORT( p );
            }

            if ( idx != 0 )
              result = (FT_UInt)( idx + delta ) & 0xFFFFU;

            goto Exit;
          }
        }
      }

#else /* 0 - old code */

      {
        FT_UInt   n;
        FT_Byte*  q;


        p = table + 14;               /* ends table   */
        q = table + 16 + num_segs2;   /* starts table */


        for ( n = 0; n < num_segs2; n += 2 )
        {
          FT_UInt  end   = TT_NEXT_USHORT( p );
          FT_UInt  start = TT_NEXT_USHORT( q );
          FT_UInt  offset;


          if ( code < start )
            break;

          if ( code <= end )
          {
            idx = code;

            p = q + num_segs2 - 2;
            delta = TT_PEEK_SHORT( p );
            p += num_segs2;
            offset = TT_PEEK_USHORT( p );

            if ( offset == 0xFFFFU )
              goto Exit;

            if ( offset != 0 )
            {
              p  += offset + 2 * ( idx - start );
              idx = TT_PEEK_USHORT( p );
            }

            if ( idx != 0 )
              result = (FT_UInt)( idx + delta ) & 0xFFFFU;
          }
        }
      }

#endif /* 0 */

    }

  Exit:
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap4_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_Byte*   table     = cmap->data;
    FT_UInt32  result    = 0;
    FT_UInt    gindex    = 0;
    FT_UInt32  char_code = *pchar_code;
    FT_Byte*   p;
    FT_UInt    code, num_segs2;


    if ( char_code >= 0xFFFFUL )
      goto Exit;

    code      = (FT_UInt)char_code + 1;
    p         = table + 6;
    num_segs2 = TT_PEEK_USHORT(p) & -2;  /* ensure even-ness */

#if 1

    for (;;)
    {
      /* Some fonts have more than 170 segments in their charmaps! */
      /* We changed this function to use a more efficient binary   */
      /* search                                                    */
      FT_UInt  offset;
      FT_Int   delta;
      FT_UInt  min = 0;
      FT_UInt  max = num_segs2 >> 1;
      FT_UInt  mid, start, end;
      FT_UInt  hi;


      /* we begin by finding the segment which end is
         closer to our code point */
      hi = max + 1;
      while ( min < max )
      {
        mid = ( min + max ) >> 1;
        p   = table + 14 + mid * 2;
        end = TT_PEEK_USHORT( p );

        if ( end < code )
          min = mid + 1;
        else
        {
          hi  = mid;
          max = mid;
        }
      }

      if ( hi > max )
      {
        /* the point is behind the last segment;
           we will exit right now */
        goto Exit;
      }

      p   = table + 14 + hi * 2;
      end = TT_PEEK_USHORT( p );

      p    += 2 + num_segs2;
      start = TT_PEEK_USHORT( p );

      if ( code < start )
        code = start;

      p    += num_segs2;
      delta = TT_PEEK_USHORT( p );

      p     += num_segs2;
      offset = TT_PEEK_USHORT( p );

      if ( offset != 0 && offset != 0xFFFFU )
      {
        /* parse the glyph ids array for non-zero index */
        p += offset + ( code - start ) * 2;
        while ( code <= end )
        {
          gindex = TT_NEXT_USHORT( p );
          if ( gindex != 0 )
          {
            gindex = (FT_UInt)( gindex + delta ) & 0xFFFFU;
            if ( gindex != 0 )
            {
              result = code;
              goto Exit;
            }
          }
          code++;
        }
      }
      else if ( offset == 0xFFFFU )
      {
        /* an offset of 0xFFFF means an empty glyph in certain fonts! */
        code = end + 1;
      }
      else  /* offset == 0 */
      {
        gindex = (FT_UInt)( code + delta ) & 0xFFFFU;
        if ( gindex != 0 )
        {
          result = code;
          goto Exit;
        }
        code++;
      }
    }

#else   /* old code -- kept for reference */

    for ( ;; )
    {
      FT_UInt   offset, n;
      FT_Int    delta;
      FT_Byte*  q;


      p = table + 14;              /* ends table  */
      q = table + 16 + num_segs2;  /* starts table */

      for ( n = 0; n < num_segs2; n += 2 )
      {
        FT_UInt  end   = TT_NEXT_USHORT( p );
        FT_UInt  start = TT_NEXT_USHORT( q );


        if ( code < start )
          code = start;

        if ( code <= end )
        {
          p = q + num_segs2 - 2;
          delta = TT_PEEK_SHORT( p );
          p += num_segs2;
          offset = TT_PEEK_USHORT( p );

          if ( offset != 0 && offset != 0xFFFFU )
          {
            /* parse the glyph ids array for non-0 index */
            p += offset + ( code - start ) * 2;
            while ( code <= end )
            {
              gindex = TT_NEXT_USHORT( p );
              if ( gindex != 0 )
              {
                gindex = (FT_UInt)( gindex + delta ) & 0xFFFFU;
                if ( gindex != 0 )
                  break;
              }
              code++;
            }
          }
          else if ( offset == 0xFFFFU )
          {
            /* an offset of 0xFFFF means an empty glyph in certain fonts! */
            code = end;
            break;
          }
          else
            gindex = (FT_UInt)( code + delta ) & 0xFFFFU;

          if ( gindex == 0 )
            break;

          result = code;
          goto Exit;
        }
      }
      /* loop to next trial charcode */
      if ( code >= 0xFFFFU )
        break;

      code++;
    }

#endif /* !1 */

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap4_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap4_char_index,
      (FT_CMap_CharNextFunc) tt_cmap4_char_next
    },
    4,
    (TT_CMap_ValidateFunc)   tt_cmap4_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_4 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 6                             *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET          TYPE             DESCRIPTION            */
  /*                                                                       */
  /*   format       0              USHORT           must be 4              */
  /*   length       2              USHORT           table length in bytes  */
  /*   language     4              USHORT           Mac language code      */
  /*                                                                       */
  /*   first        6              USHORT           first segment code     */
  /*   count        8              USHORT           segment size in chars  */
  /*   glyphIds     10             USHORT[count]    glyph ids              */
  /*                                                                       */
  /* A very simplified segment mapping.                                    */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_6

  FT_CALLBACK_DEF( void )
  tt_cmap6_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*  p;
    FT_UInt   length, count;


    if ( table + 10 > valid->limit )
      FT_INVALID_TOO_SHORT;

    p      = table + 2;
    length = TT_NEXT_USHORT( p );

    p      = table + 8;             /* skip language and start index */
    count  = TT_NEXT_USHORT( p );

    if ( table + length > valid->limit || length < 10 + count * 2 )
      FT_INVALID_TOO_SHORT;

    /* check glyph indices */
    if ( valid->level >= FT_VALIDATE_TIGHT )