kc3-lang/freetype/src/sfnt/ttsbit0.c

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• Hash : 858abbed
  Author :
  Date : 2009-06-26T06:15:41
  

  For warning messages, replace FT_ERROR with FT_TRACE0. FT_ERROR is now used only if a function produces a non-zero `error' value. Formatting, improving and harmonizing debug strings.

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• src/sfnt/ttsbit0.c

• /***************************************************************************/
  /*                                                                         */
  /*  ttsbit0.c                                                              */
  /*                                                                         */
  /*    TrueType and OpenType embedded bitmap support (body).                */
  /*    This is a heap-optimized version.                                    */
  /*                                                                         */
  /*  Copyright 2005, 2006, 2007, 2008, 2009 by                              */
  /*  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.                                        */
  /*                                                                         */
  /***************************************************************************/
  
  
  /* This file is included by ttsbit.c */
  
  
  #include <ft2build.h>
  #include FT_INTERNAL_DEBUG_H
  #include FT_INTERNAL_STREAM_H
  #include FT_TRUETYPE_TAGS_H
  #include "ttsbit.h"
  
  #include "sferrors.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_ttsbit
  
  
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_eblc( TT_Face    face,
                       FT_Stream  stream )
    {
      FT_Error  error = SFNT_Err_Ok;
      FT_Fixed  version;
      FT_ULong  num_strikes, table_size;
      FT_Byte*  p;
      FT_Byte*  p_limit;
      FT_UInt   count;
  
  
      face->sbit_num_strikes = 0;
  
      /* this table is optional */
      error = face->goto_table( face, TTAG_EBLC, stream, &table_size );
      if ( error )
        error = face->goto_table( face, TTAG_bloc, stream, &table_size );
      if ( error )
        goto Exit;
  
      if ( table_size < 8 )
      {
        FT_ERROR(( "tt_face_load_sbit_strikes: table too short\n" ));
        error = SFNT_Err_Invalid_File_Format;
        goto Exit;
      }
  
      if ( FT_FRAME_EXTRACT( table_size, face->sbit_table ) )
        goto Exit;
  
      face->sbit_table_size = table_size;
  
      p       = face->sbit_table;
      p_limit = p + table_size;
  
      version     = FT_NEXT_ULONG( p );
      num_strikes = FT_NEXT_ULONG( p );
  
      if ( version != 0x00020000UL || num_strikes >= 0x10000UL )
      {
        FT_ERROR(( "tt_face_load_sbit_strikes: invalid table version\n" ));
        error = SFNT_Err_Invalid_File_Format;
        goto Fail;
      }
  
      /*
       *  Count the number of strikes available in the table.  We are a bit
       *  paranoid there and don't trust the data.
       */
      count = (FT_UInt)num_strikes;
      if ( 8 + 48UL * count > table_size )
        count = (FT_UInt)( ( p_limit - p ) / 48 );
  
      face->sbit_num_strikes = count;
  
      FT_TRACE3(( "sbit_num_strikes: %u\n", count ));
    Exit:
      return error;
  
    Fail:
      FT_FRAME_RELEASE( face->sbit_table );
      face->sbit_table_size = 0;
      goto Exit;
    }
  
  
    FT_LOCAL_DEF( void )
    tt_face_free_eblc( TT_Face  face )
    {
      FT_Stream  stream = face->root.stream;
  
  
      FT_FRAME_RELEASE( face->sbit_table );
      face->sbit_table_size  = 0;
      face->sbit_num_strikes = 0;
    }
  
  
    FT_LOCAL_DEF( FT_Error )
    tt_face_set_sbit_strike( TT_Face          face,
                             FT_Size_Request  req,
                             FT_ULong*        astrike_index )
    {
      return FT_Match_Size( (FT_Face)face, req, 0, astrike_index );
    }
  
  
    FT_LOCAL_DEF( FT_Error )
    tt_face_load_strike_metrics( TT_Face           face,
                                 FT_ULong          strike_index,
                                 FT_Size_Metrics*  metrics )
    {
      FT_Byte*  strike;
  
  
      if ( strike_index >= (FT_ULong)face->sbit_num_strikes )
        return SFNT_Err_Invalid_Argument;
  
      strike = face->sbit_table + 8 + strike_index * 48;
  
      metrics->x_ppem = (FT_UShort)strike[44];
      metrics->y_ppem = (FT_UShort)strike[45];
  
      metrics->ascender  = (FT_Char)strike[16] << 6;  /* hori.ascender  */
      metrics->descender = (FT_Char)strike[17] << 6;  /* hori.descender */
      metrics->height    = metrics->ascender - metrics->descender;
  
      /* XXX: Is this correct? */
      metrics->max_advance = ( (FT_Char)strike[22] + /* min_origin_SB  */
                                        strike[18] + /* max_width      */
                               (FT_Char)strike[23]   /* min_advance_SB */
                                                   ) << 6;
  
      return SFNT_Err_Ok;
    }
  
  
    typedef struct  TT_SBitDecoderRec_
    {
      TT_Face          face;
      FT_Stream        stream;
      FT_Bitmap*       bitmap;
      TT_SBit_Metrics  metrics;
      FT_Bool          metrics_loaded;
      FT_Bool          bitmap_allocated;
      FT_Byte          bit_depth;
  
      FT_ULong         ebdt_start;
      FT_ULong         ebdt_size;
  
      FT_ULong         strike_index_array;
      FT_ULong         strike_index_count;
      FT_Byte*         eblc_base;
      FT_Byte*         eblc_limit;
  
    } TT_SBitDecoderRec, *TT_SBitDecoder;
  
  
    static FT_Error
    tt_sbit_decoder_init( TT_SBitDecoder       decoder,
                          TT_Face              face,
                          FT_ULong             strike_index,
                          TT_SBit_MetricsRec*  metrics )
    {
      FT_Error   error;
      FT_Stream  stream = face->root.stream;
      FT_ULong   ebdt_size;
  
  
      error = face->goto_table( face, TTAG_EBDT, stream, &ebdt_size );
      if ( error )
        error = face->goto_table( face, TTAG_bdat, stream, &ebdt_size );
      if ( error )
        goto Exit;
  
      decoder->face    = face;
      decoder->stream  = stream;
      decoder->bitmap  = &face->root.glyph->bitmap;
      decoder->metrics = metrics;
  
      decoder->metrics_loaded   = 0;
      decoder->bitmap_allocated = 0;
  
      decoder->ebdt_start = FT_STREAM_POS();
      decoder->ebdt_size  = ebdt_size;
  
      decoder->eblc_base  = face->sbit_table;
      decoder->eblc_limit = face->sbit_table + face->sbit_table_size;
  
      /* now find the strike corresponding to the index */
      {
        FT_Byte*  p;
  
  
        if ( 8 + 48 * strike_index + 3 * 4 + 34 + 1 > face->sbit_table_size )
        {
          error = SFNT_Err_Invalid_File_Format;
          goto Exit;
        }
  
        p = decoder->eblc_base + 8 + 48 * strike_index;
  
        decoder->strike_index_array = FT_NEXT_ULONG( p );
        p                          += 4;
        decoder->strike_index_count = FT_NEXT_ULONG( p );
        p                          += 34;
        decoder->bit_depth          = *p;
  
        if ( decoder->strike_index_array > face->sbit_table_size             ||
             decoder->strike_index_array + 8 * decoder->strike_index_count >
               face->sbit_table_size                                         )
          error = SFNT_Err_Invalid_File_Format;
      }
  
    Exit:
      return error;
    }
  
  
    static void
    tt_sbit_decoder_done( TT_SBitDecoder  decoder )
    {
      FT_UNUSED( decoder );
    }
  
  
    static FT_Error
    tt_sbit_decoder_alloc_bitmap( TT_SBitDecoder  decoder )
    {
      FT_Error    error = SFNT_Err_Ok;
      FT_UInt     width, height;
      FT_Bitmap*  map = decoder->bitmap;
      FT_Long     size;
  
  
      if ( !decoder->metrics_loaded )
      {
        error = SFNT_Err_Invalid_Argument;
        goto Exit;
      }
  
      width  = decoder->metrics->width;
      height = decoder->metrics->height;
  
      map->width = (int)width;
      map->rows  = (int)height;
  
      switch ( decoder->bit_depth )
      {
      case 1:
        map->pixel_mode = FT_PIXEL_MODE_MONO;
        map->pitch      = ( map->width + 7 ) >> 3;
        break;
  
      case 2:
        map->pixel_mode = FT_PIXEL_MODE_GRAY2;
        map->pitch      = ( map->width + 3 ) >> 2;
        break;
  
      case 4:
        map->pixel_mode = FT_PIXEL_MODE_GRAY4;
        map->pitch      = ( map->width + 1 ) >> 1;
        break;
  
      case 8:
        map->pixel_mode = FT_PIXEL_MODE_GRAY;
        map->pitch      = map->width;
        break;
  
      default:
        error = SFNT_Err_Invalid_File_Format;
        goto Exit;
      }
  
      size = map->rows * map->pitch;
  
      /* check that there is no empty image */
      if ( size == 0 )
        goto Exit;     /* exit successfully! */
  
      error = ft_glyphslot_alloc_bitmap( decoder->face->root.glyph, size );
      if ( error )
        goto Exit;
  
      decoder->bitmap_allocated = 1;
  
    Exit:
      return error;
    }
  
  
    static FT_Error
    tt_sbit_decoder_load_metrics( TT_SBitDecoder  decoder,
                                  FT_Byte*       *pp,
                                  FT_Byte*        limit,
                                  FT_Bool         big )
    {
      FT_Byte*         p       = *pp;
      TT_SBit_Metrics  metrics = decoder->metrics;
  
  
      if ( p + 5 > limit )
        goto Fail;
  
      metrics->height       = p[0];
      metrics->width        = p[1];
      metrics->horiBearingX = (FT_Char)p[2];
      metrics->horiBearingY = (FT_Char)p[3];
      metrics->horiAdvance  = p[4];
  
      p += 5;
      if ( big )
      {
        if ( p + 3 > limit )
          goto Fail;
  
        metrics->vertBearingX = (FT_Char)p[0];
        metrics->vertBearingY = (FT_Char)p[1];
        metrics->vertAdvance  = p[2];
  
        p += 3;
      }
  
      decoder->metrics_loaded = 1;
      *pp = p;
      return SFNT_Err_Ok;
  
    Fail:
      return SFNT_Err_Invalid_Argument;
    }
  
  
    /* forward declaration */
    static FT_Error
    tt_sbit_decoder_load_image( TT_SBitDecoder  decoder,
                                FT_UInt         glyph_index,
                                FT_Int          x_pos,
                                FT_Int          y_pos );
  
    typedef FT_Error  (*TT_SBitDecoder_LoadFunc)( TT_SBitDecoder  decoder,
                                                  FT_Byte*        p,
                                                  FT_Byte*        plimit,
                                                  FT_Int          x_pos,
                                                  FT_Int          y_pos );
  
  
    static FT_Error
    tt_sbit_decoder_load_byte_aligned( TT_SBitDecoder  decoder,
                                       FT_Byte*        p,
                                       FT_Byte*        limit,
                                       FT_Int          x_pos,
                                       FT_Int          y_pos )
    {
      FT_Error    error = SFNT_Err_Ok;
      FT_Byte*    line;
      FT_Int      bit_height, bit_width, pitch, width, height, h;
      FT_Bitmap*  bitmap;
  
  
      if ( !decoder->bitmap_allocated )
      {
        error = tt_sbit_decoder_alloc_bitmap( decoder );
        if ( error )
          goto Exit;
      }
  
      /* check that we can write the glyph into the bitmap */
      bitmap     = decoder->bitmap;
      bit_width  = bitmap->width;
      bit_height = bitmap->rows;
      pitch      = bitmap->pitch;
      line       = bitmap->buffer;
  
      width  = decoder->metrics->width;
      height = decoder->metrics->height;
  
      if ( x_pos < 0 || x_pos + width > bit_width   ||
           y_pos < 0 || y_pos + height > bit_height )
      {
        error = SFNT_Err_Invalid_File_Format;
        goto Exit;
      }
  
      if ( p + ( ( width + 7 ) >> 3 ) * height > limit )
      {
        error = SFNT_Err_Invalid_File_Format;
        goto Exit;
      }
  
      /* now do the blit */
      line  += y_pos * pitch + ( x_pos >> 3 );
      x_pos &= 7;
  
      if ( x_pos == 0 )  /* the easy one */
      {
        for ( h = height; h > 0; h--, line += pitch )
        {
          FT_Byte*  write = line;
          FT_Int    w;
  
  
          for ( w = width; w >= 8; w -= 8 )
          {
            write[0] = (FT_Byte)( write[0] | *p++ );
            write   += 1;
          }
  
          if ( w > 0 )
            write[0] = (FT_Byte)( write[0] | ( *p++ & ( 0xFF00U >> w ) ) );
        }
      }
      else  /* x_pos > 0 */
      {
        for ( h = height; h > 0; h--, line += pitch )
        {
          FT_Byte*  write = line;
          FT_Int    w;
          FT_UInt   wval = 0;
  
  
          for ( w = width; w >= 8; w -= 8 )
          {
            wval      = (FT_UInt)( wval | *p++ );
            write[0]  = (FT_Byte)( write[0] | ( wval >> x_pos ) );
            write    += 1;
            wval    <<= 8;
          }
  
          if ( w > 0 )
            wval = (FT_UInt)( wval | ( *p++ & ( 0xFF00U >> w ) ) );
  
          /* all bits read and there are `x_pos + w' bits to be written */
  
          write[0] = (FT_Byte)( write[0] | ( wval >> x_pos ) );
  
          if ( x_pos + w > 8 )
          {
            write++;
            wval   <<= 8;
            write[0] = (FT_Byte)( write[0] | ( wval >> x_pos ) );
          }
        }
      }
  
    Exit:
      return error;
    }
  
  
    /*
     * Load a bit-aligned bitmap (with pointer `p') into a line-aligned bitmap
     * (with pointer `write').  In the example below, the width is 3 pixel,
     * and `x_pos' is 1 pixel.
     *
     *       p                               p+1
     *     |                               |                               |
     *     | 7   6   5   4   3   2   1   0 | 7   6   5   4   3   2   1   0 |...
     *     |                               |                               |
     *       +-------+   +-------+   +-------+ ...
     *           .           .           .
     *           .           .           .
     *           v           .           .
     *       +-------+       .           .
     * |                               | .
     * | 7   6   5   4   3   2   1   0 | .
     * |                               | .
     *   write               .           .
     *                       .           .
     *                       v           .
     *                   +-------+       .
     *             |                               |
     *             | 7   6   5   4   3   2   1   0 |
     *             |                               |
     *               write+1             .
     *                                   .
     *                                   v
     *                               +-------+
     *                         |                               |
     *                         | 7   6   5   4   3   2   1   0 |
     *                         |                               |
     *                           write+2
     *
     */
  
    static FT_Error
    tt_sbit_decoder_load_bit_aligned( TT_SBitDecoder  decoder,
                                      FT_Byte*        p,
                                      FT_Byte*        limit,
                                      FT_Int          x_pos,
                                      FT_Int          y_pos )
    {
      FT_Error    error = SFNT_Err_Ok;
      FT_Byte*    line;
      FT_Int      bit_height, bit_width, pitch, width, height, h, nbits;
      FT_Bitmap*  bitmap;
      FT_UShort   rval;
  
  
      if ( !decoder->bitmap_allocated )
      {
        error = tt_sbit_decoder_alloc_bitmap( decoder );
        if ( error )
          goto Exit;
      }
  
      /* check that we can write the glyph into the bitmap */
      bitmap     = decoder->bitmap;
      bit_width  = bitmap->width;
      bit_height = bitmap->rows;
      pitch      = bitmap->pitch;
      line       = bitmap->buffer;
  
      width  = decoder->metrics->width;
      height = decoder->metrics->height;
  
      if ( x_pos < 0 || x_pos + width  > bit_width  ||
           y_pos < 0 || y_pos + height > bit_height )
      {
        error = SFNT_Err_Invalid_File_Format;
        goto Exit;
      }
  
      if ( p + ( ( width * height + 7 ) >> 3 ) > limit )
      {
        error = SFNT_Err_Invalid_File_Format;
        goto Exit;
      }
  
      /* now do the blit */
  
      /* adjust `line' to point to the first byte of the bitmap */
      line  += y_pos * pitch + ( x_pos >> 3 );
      x_pos &= 7;
  
      /* the higher byte of `rval' is used as a buffer */
      rval  = 0;
      nbits = 0;
  
      for ( h = height; h > 0; h--, line += pitch )
      {
        FT_Byte*  write = line;
        FT_Int    w     = width;
  
  
        /* handle initial byte (in target bitmap) specially if necessary */
        if ( x_pos )
        {
          w = ( width < 8 - x_pos ) ? width : 8 - x_pos;
  
          if ( h == height )
          {
            rval  = *p++;
            nbits = x_pos;
          }
          else if ( nbits < w )
          {
            if ( p < limit )
              rval |= *p++;
            nbits += 8 - w;
          }
          else
          {
            rval  >>= 8;
            nbits  -= w;
          }
  
          *write++ |= ( ( rval >> nbits ) & 0xFF ) &
                      ( ~( 0xFF << w ) << ( 8 - w - x_pos ) );
          rval    <<= 8;
  
          w = width - w;
        }
  
        /* handle medial bytes */
        for ( ; w >= 8; w -= 8 )
        {
          rval     |= *p++;
          *write++ |= ( rval >> nbits ) & 0xFF;
  
          rval <<= 8;
        }
  
        /* handle final byte if necessary */
        if ( w > 0 )
        {
          if ( nbits < w )
          {
            if ( p < limit )
              rval |= *p++;
            *write |= ( ( rval >> nbits ) & 0xFF ) & ( 0xFF00U >> w );
            nbits  += 8 - w;
  
            rval <<= 8;
          }
          else
          {
            *write |= ( ( rval >> nbits ) & 0xFF ) & ( 0xFF00U >> w );
            nbits  -= w;
          }
        }
      }
  
    Exit:
      return error;
    }
  
  
    static FT_Error
    tt_sbit_decoder_load_compound( TT_SBitDecoder  decoder,
                                   FT_Byte*        p,
                                   FT_Byte*        limit,
                                   FT_Int          x_pos,
                                   FT_Int          y_pos )
    {
      FT_Error  error = SFNT_Err_Ok;
      FT_UInt   num_components, nn;
  
      FT_Char  horiBearingX = decoder->metrics->horiBearingX;
      FT_Char  horiBearingY = decoder->metrics->horiBearingY;
      FT_Byte  horiAdvance  = decoder->metrics->horiAdvance;
      FT_Char  vertBearingX = decoder->metrics->vertBearingX;
      FT_Char  vertBearingY = decoder->metrics->vertBearingY;
      FT_Byte  vertAdvance  = decoder->metrics->vertAdvance;
  
  
      if ( p + 2 > limit )
        goto Fail;
  
      num_components = FT_NEXT_USHORT( p );
      if ( p + 4 * num_components > limit )
        goto Fail;
  
      if ( !decoder->bitmap_allocated )
      {
        error = tt_sbit_decoder_alloc_bitmap( decoder );
        if ( error )
          goto Exit;
      }
  
      for ( nn = 0; nn < num_components; nn++ )
      {
        FT_UInt  gindex = FT_NEXT_USHORT( p );
        FT_Byte  dx     = FT_NEXT_BYTE( p );
        FT_Byte  dy     = FT_NEXT_BYTE( p );
  
  
        /* NB: a recursive call */
        error = tt_sbit_decoder_load_image( decoder, gindex,
                                            x_pos + dx, y_pos + dy );
        if ( error )
          break;
      }
  
      decoder->metrics->horiBearingX = horiBearingX;
      decoder->metrics->horiBearingY = horiBearingY;
      decoder->metrics->horiAdvance  = horiAdvance;
      decoder->metrics->vertBearingX = vertBearingX;
      decoder->metrics->vertBearingY = vertBearingY;
      decoder->metrics->vertAdvance  = vertAdvance;
      decoder->metrics->width        = (FT_UInt)decoder->bitmap->width;
      decoder->metrics->height       = (FT_UInt)decoder->bitmap->rows;
  
    Exit:
      return error;
  
    Fail:
      error = SFNT_Err_Invalid_File_Format;
      goto Exit;
    }
  
  
    static FT_Error
    tt_sbit_decoder_load_bitmap( TT_SBitDecoder  decoder,
                                 FT_UInt         glyph_format,
                                 FT_ULong        glyph_start,
                                 FT_ULong        glyph_size,
                                 FT_Int          x_pos,
                                 FT_Int          y_pos )
    {
      FT_Error   error;
      FT_Stream  stream = decoder->stream;
      FT_Byte*   p;
      FT_Byte*   p_limit;
      FT_Byte*   data;
  
  
      /* seek into the EBDT table now */
      if ( glyph_start + glyph_size > decoder->ebdt_size )
      {
        error = SFNT_Err_Invalid_Argument;
        goto Exit;
      }
  
      if ( FT_STREAM_SEEK( decoder->ebdt_start + glyph_start ) ||
           FT_FRAME_EXTRACT( glyph_size, data )                )
        goto Exit;
  
      p       = data;
      p_limit = p + glyph_size;
  
      /* read the data, depending on the glyph format */
      switch ( glyph_format )
      {
      case 1:
      case 2:
      case 8:
        error = tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 0 );
        break;
  
      case 6:
      case 7:
      case 9:
        error = tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 1 );
        break;
  
      default:
        error = SFNT_Err_Ok;
      }
  
      if ( error )
        goto Fail;
  
      {
        TT_SBitDecoder_LoadFunc  loader;
  
  
        switch ( glyph_format )
        {
        case 1:
        case 6:
          loader = tt_sbit_decoder_load_byte_aligned;
          break;
  
        case 2:
        case 5:
        case 7:
          loader = tt_sbit_decoder_load_bit_aligned;
          break;
  
        case 8:
          if ( p + 1 > p_limit )
            goto Fail;
  
          p += 1;  /* skip padding */
          /* fall-through */
  
        case 9:
          loader = tt_sbit_decoder_load_compound;
          break;
  
        default:
          goto Fail;
        }
  
        error = loader( decoder, p, p_limit, x_pos, y_pos );
      }
  
    Fail:
      FT_FRAME_RELEASE( data );
  
    Exit:
      return error;
    }
  
  
    static FT_Error
    tt_sbit_decoder_load_image( TT_SBitDecoder  decoder,
                                FT_UInt         glyph_index,
                                FT_Int          x_pos,
                                FT_Int          y_pos )
    {
      /*
       *  First, we find the correct strike range that applies to this
       *  glyph index.
       */
  
      FT_Byte*  p          = decoder->eblc_base + decoder->strike_index_array;
      FT_Byte*  p_limit    = decoder->eblc_limit;
      FT_ULong  num_ranges = decoder->strike_index_count;
      FT_UInt   start, end, index_format, image_format;
      FT_ULong  image_start = 0, image_end = 0, image_offset;
  
  
      for ( ; num_ranges > 0; num_ranges-- )
      {
        start = FT_NEXT_USHORT( p );
        end   = FT_NEXT_USHORT( p );
  
        if ( glyph_index >= start && glyph_index <= end )
          goto FoundRange;
  
        p += 4;  /* ignore index offset */
      }
      goto NoBitmap;
  
    FoundRange:
      image_offset = FT_NEXT_ULONG( p );
  
      /* overflow check */
      if ( decoder->eblc_base + decoder->strike_index_array + image_offset <
             decoder->eblc_base )
        goto Failure;
  
      p = decoder->eblc_base + decoder->strike_index_array + image_offset;
      if ( p + 8 > p_limit )
        goto NoBitmap;
  
      /* now find the glyph's location and extend within the ebdt table */
      index_format = FT_NEXT_USHORT( p );
      image_format = FT_NEXT_USHORT( p );
      image_offset = FT_NEXT_ULONG ( p );
  
      switch ( index_format )
      {
      case 1: /* 4-byte offsets relative to `image_offset' */
        {
          p += 4 * ( glyph_index - start );
          if ( p + 8 > p_limit )
            goto NoBitmap;
  
          image_start = FT_NEXT_ULONG( p );
          image_end   = FT_NEXT_ULONG( p );
  
          if ( image_start == image_end )  /* missing glyph */
            goto NoBitmap;
        }
        break;
  
      case 2: /* big metrics, constant image size */
        {
          FT_ULong  image_size;
  
  
          if ( p + 12 > p_limit )
            goto NoBitmap;
  
          image_size = FT_NEXT_ULONG( p );
  
          if ( tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 1 ) )
            goto NoBitmap;
  
          image_start = image_size * ( glyph_index - start );
          image_end   = image_start + image_size;
        }
        break;
  
      case 3: /* 2-byte offsets relative to 'image_offset' */
        {
          p += 2 * ( glyph_index - start );
          if ( p + 4 > p_limit )
            goto NoBitmap;
  
          image_start = FT_NEXT_USHORT( p );
          image_end   = FT_NEXT_USHORT( p );
  
          if ( image_start == image_end )  /* missing glyph */
            goto NoBitmap;
        }
        break;
  
      case 4: /* sparse glyph array with (glyph,offset) pairs */
        {
          FT_ULong  mm, num_glyphs;
  
  
          if ( p + 4 > p_limit )
            goto NoBitmap;
  
          num_glyphs = FT_NEXT_ULONG( p );
  
          /* overflow check */
          if ( p + ( num_glyphs + 1 ) * 4 < p )
            goto Failure;
  
          if ( p + ( num_glyphs + 1 ) * 4 > p_limit )
            goto NoBitmap;
  
          for ( mm = 0; mm < num_glyphs; mm++ )
          {
            FT_UInt  gindex = FT_NEXT_USHORT( p );
  
  
            if ( gindex == glyph_index )
            {
              image_start = FT_NEXT_USHORT( p );
              p          += 2;
              image_end   = FT_PEEK_USHORT( p );
              break;
            }
            p += 2;
          }
  
          if ( mm >= num_glyphs )
            goto NoBitmap;
        }
        break;
  
      case 5: /* constant metrics with sparse glyph codes */
        {
          FT_ULong  image_size, mm, num_glyphs;
  
  
          if ( p + 16 > p_limit )
            goto NoBitmap;
  
          image_size = FT_NEXT_ULONG( p );
  
          if ( tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 1 ) )
            goto NoBitmap;
  
          num_glyphs = FT_NEXT_ULONG( p );
  
          /* overflow check */
          if ( p + 2 * num_glyphs < p )
            goto Failure;
  
          if ( p + 2 * num_glyphs > p_limit )
            goto NoBitmap;
  
          for ( mm = 0; mm < num_glyphs; mm++ )
          {
            FT_UInt  gindex = FT_NEXT_USHORT( p );
  
  
            if ( gindex == glyph_index )
              break;
          }
  
          if ( mm >= num_glyphs )
            goto NoBitmap;
  
          image_start = image_size * mm;
          image_end   = image_start + image_size;
        }
        break;
  
      default:
        goto NoBitmap;
      }
  
      if ( image_start > image_end )
        goto NoBitmap;
  
      image_end  -= image_start;
      image_start = image_offset + image_start;
  
      return tt_sbit_decoder_load_bitmap( decoder,
                                          image_format,
                                          image_start,
                                          image_end,
                                          x_pos,
                                          y_pos );
  
    Failure:
      return SFNT_Err_Invalid_Table;
  
    NoBitmap:
      return SFNT_Err_Invalid_Argument;
    }
  
  
    FT_LOCAL( FT_Error )
    tt_face_load_sbit_image( TT_Face              face,
                             FT_ULong             strike_index,
                             FT_UInt              glyph_index,
                             FT_UInt              load_flags,
                             FT_Stream            stream,
                             FT_Bitmap           *map,
                             TT_SBit_MetricsRec  *metrics )
    {
      TT_SBitDecoderRec  decoder[1];
      FT_Error           error;
  
      FT_UNUSED( load_flags );
      FT_UNUSED( stream );
      FT_UNUSED( map );
  
  
      error = tt_sbit_decoder_init( decoder, face, strike_index, metrics );
      if ( !error )
      {
        error = tt_sbit_decoder_load_image( decoder, glyph_index, 0, 0 );
        tt_sbit_decoder_done( decoder );
      }
  
      return error;
    }
  
  /* EOF */
  

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