ttcmap.c

下载来的一个看图软件的源代码

      n = cmap10->numChars;

      if ( FT_NEW_ARRAY( cmap10->glyphs, n ) ||
           FT_FRAME_ENTER( n * 2L )          )
        goto Fail;

      for ( j = 0; j < n; j++ )
        cmap10->glyphs[j] = FT_GET_USHORT();

      FT_FRAME_EXIT();
      cmap->get_index     = code_to_index10;
      cmap->get_next_char = code_to_next10;
      break;

    default:   /* corrupt character mapping table */
      return SFNT_Err_Invalid_CharMap_Format;

    }

    return SFNT_Err_Ok;

  Fail:
    tt_face_free_charmap( face, cmap );
    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_free_charmap                                               */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Destroys a character mapping table.                                */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face :: A handle to the parent face object.                        */
  /*                                                                       */
  /*    cmap :: A handle to a cmap object.                                 */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_free_charmap( TT_Face       face,
                        TT_CMapTable  cmap )
  {
    FT_Memory  memory;


    if ( !cmap )
      return SFNT_Err_Ok;

    memory = face->root.driver->root.memory;

    switch ( cmap->format )
    {
    case 0:
      FT_FREE( cmap->c.cmap0.glyphIdArray );
      break;

    case 2:
      FT_FREE( cmap->c.cmap2.subHeaderKeys );
      FT_FREE( cmap->c.cmap2.subHeaders );
      FT_FREE( cmap->c.cmap2.glyphIdArray );
      break;

    case 4:
      FT_FREE( cmap->c.cmap4.segments );
      FT_FREE( cmap->c.cmap4.glyphIdArray );
      cmap->c.cmap4.segCountX2 = 0;
      break;

    case 6:
      FT_FREE( cmap->c.cmap6.glyphIdArray );
      cmap->c.cmap6.entryCount = 0;
      break;

    case 8:
    case 12:
      FT_FREE( cmap->c.cmap8_12.groups );
      cmap->c.cmap8_12.nGroups = 0;
      break;

    case 10:
      FT_FREE( cmap->c.cmap10.glyphs );
      cmap->c.cmap10.numChars = 0;
      break;

    default:
      /* invalid table format, do nothing */
      ;
    }

    cmap->loaded = FALSE;
    return SFNT_Err_Ok;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    code_to_index0                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Converts the character code into a glyph index.  Uses format 0.    */
  /*    `charCode' must be in the range 0x00-0xFF (otherwise 0 is          */
  /*    returned).                                                         */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charCode :: The wanted character code.                             */
  /*                                                                       */
  /*    cmap0    :: A pointer to a cmap table in format 0.                 */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Glyph index into the glyphs array.  0 if the glyph does not exist. */
  /*                                                                       */
  FT_CALLBACK_DEF( FT_UInt )
  code_to_index0( TT_CMapTable  cmap,
                  FT_ULong      charCode )
  {
    TT_CMap0  cmap0 = &cmap->c.cmap0;


    return ( charCode <= 0xFF ? cmap0->glyphIdArray[charCode] : 0 );
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    code_to_next0                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Finds the next encoded character after the given one.  Uses        */
  /*    format 0. `charCode' must be in the range 0x00-0xFF (otherwise 0   */
  /*    is returned).                                                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charCode :: The wanted character code.                             */
  /*                                                                       */
  /*    cmap0    :: A pointer to a cmap table in format 0.                 */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Next char code.  0 if no higher one is encoded.                    */
  /*                                                                       */
  FT_CALLBACK_DEF( FT_ULong )
  code_to_next0( TT_CMapTable  cmap,
                 FT_ULong      charCode )
  {
    TT_CMap0  cmap0 = &cmap->c.cmap0;


    while ( ++charCode <= 0xFF )
      if ( cmap0->glyphIdArray[charCode] )
        return ( charCode );
    return ( 0 );
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    code_to_index2                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Converts the character code into a glyph index.  Uses format 2.    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charCode :: The wanted character code.                             */
  /*                                                                       */
  /*    cmap2    :: A pointer to a cmap table in format 2.                 */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Glyph index into the glyphs array.  0 if the glyph does not exist. */
  /*                                                                       */
  FT_CALLBACK_DEF( FT_UInt )
  code_to_index2( TT_CMapTable  cmap,
                  FT_ULong      charCode )
  {
    FT_UInt            result, index1, offset;
    FT_UInt            char_lo;
    FT_ULong           char_hi;
    TT_CMap2SubHeader  sh2;
    TT_CMap2           cmap2;


    cmap2   = &cmap->c.cmap2;
    result  = 0;
    char_lo = (FT_UInt)( charCode & 0xFF );
    char_hi = charCode >> 8;

    if ( char_hi == 0 )
    {
      /* an 8-bit character code -- we use the subHeader 0 in this case */
      /* to test whether the character code is in the charmap           */
      index1 = cmap2->subHeaderKeys[char_lo];
      if ( index1 != 0 )
        return 0;
    }
    else
    {
      /* a 16-bit character code */
      index1 = cmap2->subHeaderKeys[char_hi & 0xFF];
      if ( index1 == 0 )
        return 0;
    }

    sh2      = cmap2->subHeaders + index1;
    char_lo -= sh2->firstCode;

    if ( char_lo < (FT_UInt)sh2->entryCount )
    {
      offset = sh2->idRangeOffset / 2 + char_lo;
      if ( offset < (FT_UInt)cmap2->numGlyphId )
      {
        result = cmap2->glyphIdArray[offset];
        if ( result )
          result = ( result + sh2->idDelta ) & 0xFFFFU;
      }
    }

    return result;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    code_to_next2                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Find the next encoded character.  Uses format 2.                   */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charCode :: The wanted character code.                             */
  /*                                                                       */
  /*    cmap2    :: A pointer to a cmap table in format 2.                 */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Next encoded character.  0 if none exists.                         */
  /*                                                                       */
  FT_CALLBACK_DEF( FT_ULong )
  code_to_next2( TT_CMapTable  cmap,
                 FT_ULong      charCode )
  {
    FT_UInt            index1, offset;
    FT_UInt            char_lo;
    FT_ULong           char_hi;
    TT_CMap2SubHeader  sh2;
    TT_CMap2           cmap2;


    cmap2 = &cmap->c.cmap2;
    charCode++;

    /*
     * This is relatively simplistic -- look for a subHeader containing
     * glyphs and then walk to the first glyph in that subHeader.
     */
    while ( charCode < 0x10000L )
    {
      char_lo = (FT_UInt)( charCode & 0xFF );
      char_hi = charCode >> 8;

      if ( char_hi == 0 )
      {
        /* an 8-bit character code -- we use the subHeader 0 in this case */
        /* to test whether the character code is in the charmap           */
        index1 = cmap2->subHeaderKeys[char_lo];
        if ( index1 != 0 )
        {
          charCode++;
          continue;
        }
      }
      else
      {
        /* a 16-bit character code */
        index1 = cmap2->subHeaderKeys[char_hi & 0xFF];
        if ( index1 == 0 )
        {
          charCode = ( char_hi + 1 ) << 8;
          continue;
        }
      }

      sh2      = cmap2->subHeaders + index1;
      char_lo -= sh2->firstCode;

      if ( char_lo > (FT_UInt)sh2->entryCount )
      {
        charCode = ( char_hi + 1 ) << 8;
        continue;
      }

      offset = sh2->idRangeOffset / 2 + char_lo;
      if ( offset >= (FT_UInt)cmap2->numGlyphId ||
           cmap2->glyphIdArray[offset] == 0     )
      {
        charCode++;
        continue;
      }

      return charCode;
    }
    return 0;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    code_to_index4                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Converts the character code into a glyph index.  Uses format 4.    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charCode :: The wanted character code.                             */
  /*                                                                       */
  /*    cmap4    :: A pointer to a cmap table in format 4.                 */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Glyph index into the glyphs array.  0 if the glyph does not exist. */
  /*                                                                       */
  FT_CALLBACK_DEF( FT_UInt )
  code_to_index4( TT_CMapTable  cmap,
                  FT_ULong      charCode )
  {
    FT_UInt             result, index1, segCount;
    TT_CMap4            cmap4;
    TT_CMap4SegmentRec  *seg4, *limit;


    cmap4    = &cmap->c.cmap4;
    result   = 0;
    segCount = cmap4->segCountX2 / 2;
    limit    = cmap4->segments + segCount;

    /* first, check against the last used segment */

    seg4 = cmap4->last_segment;

    /* the following is equivalent to performing two tests, as in         */
    /*                                                                    */
    /*  if ( charCode >= seg4->startCount && charCode <= seg4->endCount ) */
    /*                                                                    */
    /* This is a bit strange, but it is faster, and the idea behind the   */
    /* cache is to significantly speed up charcode to glyph index         */
    /* conversion.                                                        */

    if ( (FT_ULong)( charCode       - seg4->startCount ) <
         (FT_ULong)( seg4->endCount - seg4->startCount ) )
      goto Found1;

    for ( seg4 = cmap4->segments; seg4 < limit; seg4++ )
    {
      /* the ranges are sorted in increasing order.  If we are out of */
      /* the range here, the char code isn't in the charmap, so exit. */

      if ( charCode > (FT_UInt)seg4->endCount )
        continue;

      if ( charCode >= (FT_UInt)seg4->startCount )
        goto Found;
    }
    return 0;

  Found:
    cmap4->last_segment = seg4;