C++ TT_Face::goto_table方法代码示例

  tt_face_load_loca( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error  error;
    FT_ULong  table_len;


    /* we need the size of the `glyf' table for malformed `loca' tables */
    error = face->goto_table( face, TTAG_glyf, stream, &face->glyf_len );
    if ( error )
      goto Exit;

    FT_TRACE2(( "Locations " ));
    error = face->goto_table( face, TTAG_loca, stream, &table_len );
    if ( error )
    {
      error = TT_Err_Locations_Missing;
      goto Exit;
    }

    if ( face->header.Index_To_Loc_Format != 0 )
    {
      if ( table_len >= 0x40000L )
      {
        FT_TRACE2(( "table too large!\n" ));
        error = TT_Err_Invalid_Table;
        goto Exit;
      }
      face->num_locations = (FT_UInt)( table_len >> 2 );
    }
    else
    {
      if ( table_len >= 0x20000L )

  tt_face_load_loca( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error  error;
    FT_ULong  table_len;
    FT_Int    shift;


    /* we need the size of the `glyf' table for malformed `loca' tables */
    error = face->goto_table( face, TTAG_glyf, stream, &face->glyf_len );

    /* it is possible that a font doesn't have a glyf table at all */
    /* or its size is zero                                         */
    if ( FT_ERR_EQ( error, Table_Missing ) )
    {
      face->glyf_len    = 0;
      face->glyf_offset = 0;
    }
    else if ( error )
      goto Exit;
    else
    {
#ifdef FT_CONFIG_OPTION_INCREMENTAL
      if ( face->root.internal->incremental_interface )
        face->glyf_offset = 0;
      else
#endif
        face->glyf_offset = FT_STREAM_POS();
    }

    FT_TRACE2(( "Locations " ));
    error = face->goto_table( face, TTAG_loca, stream, &table_len );
    if ( error )
    {
      error = FT_THROW( Locations_Missing );
      goto Exit;
    }

    if ( face->header.Index_To_Loc_Format != 0 )
    {
      shift = 2;

      if ( table_len >= 0x40000L )
      {
        FT_TRACE2(( "table too large\n" ));
        table_len = 0x3FFFFL;
      }
      face->num_locations = table_len >> shift;
    }

  static FT_Error
  load_post_names( TT_Face  face )
  {
    FT_Stream  stream;
    FT_Error   error;
    FT_Fixed   format;


    /* get a stream for the face's resource */
    stream = face->root.stream;

    /* seek to the beginning of the PS names table */
    error = face->goto_table( face, TTAG_post, stream, 0 );
    if ( error )
      goto Exit;

    format = face->postscript.FormatType;

    /* go to beginning of subtable */
    if ( FT_STREAM_SKIP( 32 ) )
      goto Exit;

    /* now read postscript table */
    if ( format == 0x00020000L )
      error = load_format_20( face, stream );
    else if ( format == 0x00028000L )
      error = load_format_25( face, stream );
    else
      error = SFNT_Err_Invalid_File_Format;

    face->postscript_names.loaded = 1;

  Exit:
    return error;
  }

  tt_face_load_hmtx( TT_Face    face,
                     FT_Stream  stream,
                     FT_Bool    vertical )
  {
    FT_Error   error;
    FT_ULong   tag, table_size;
    FT_ULong*  ptable_offset;
    FT_ULong*  ptable_size;


    if ( vertical )
    {
      tag           = TTAG_vmtx;
      ptable_offset = &face->vert_metrics_offset;
      ptable_size   = &face->vert_metrics_size;
    }
    else
    {
      tag           = TTAG_hmtx;
      ptable_offset = &face->horz_metrics_offset;
      ptable_size   = &face->horz_metrics_size;
    }

    error = face->goto_table( face, tag, stream, &table_size );
    if ( error )
      goto Fail;

    *ptable_size   = table_size;
    *ptable_offset = FT_STREAM_POS();

  Fail:
    return error;
  }

  tt_face_load_gasp( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    FT_UInt        j,num_ranges;
    TT_GaspRange   gaspranges;


    /* the gasp table is optional */
    error = face->goto_table( face, TTAG_gasp, stream, 0 );
    if ( error )
      goto Exit;

    if ( FT_FRAME_ENTER( 4L ) )
      goto Exit;

    face->gasp.version   = FT_GET_USHORT();
    face->gasp.numRanges = FT_GET_USHORT();

    FT_FRAME_EXIT();

    /* only support versions 0 and 1 of the table */
    if ( face->gasp.version >= 2 )
    {
      face->gasp.numRanges = 0;
      error = SFNT_Err_Invalid_Table;
      goto Exit;
    }

    num_ranges = face->gasp.numRanges;
    FT_TRACE3(( "numRanges: %u\n", num_ranges ));

    if ( FT_QNEW_ARRAY( gaspranges, num_ranges ) ||
         FT_FRAME_ENTER( num_ranges * 4L )      )
      goto Exit;

    face->gasp.gaspRanges = gaspranges;

    for ( j = 0; j < num_ranges; j++ )
    {
      gaspranges[j].maxPPEM  = FT_GET_USHORT();
      gaspranges[j].gaspFlag = FT_GET_USHORT();

      FT_TRACE3(( "gaspRange %d: rangeMaxPPEM %5d, rangeGaspBehavior 0x%x\n",
                  j,
                  gaspranges[j].maxPPEM,
                  gaspranges[j].gaspFlag ));
    }

    FT_FRAME_EXIT();

  Exit:
    return error;
  }

  tt_face_load_loca( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error  error;
    FT_ULong  table_len;
    FT_Int    shift;


    /* we need the size of the `glyf' table for malformed `loca' tables */
    error = face->goto_table( face, TTAG_glyf, stream, &face->glyf_len );

    /* it is possible that a font doesn't have a glyf table at all */
    /* or its size is zero                                         */
    if ( FT_ERR_EQ( error, Table_Missing ) )
      face->glyf_len = 0;
    else if ( error )
      goto Exit;

    FT_TRACE2(( "Locations " ));
    error = face->goto_table( face, TTAG_loca, stream, &table_len );
    if ( error )
    {
      error = FT_THROW( Locations_Missing );
      goto Exit;
    }

    if ( face->header.Index_To_Loc_Format != 0 )
    {
      shift = 2;

      if ( table_len >= 0x40000L )
      {
        FT_TRACE2(( "table too large\n" ));
        error = FT_THROW( Invalid_Table );
        goto Exit;
      }
      face->num_locations = table_len >> shift;
    }

  tt_face_load_hmtx( TT_Face    face,
                     FT_Stream  stream,
                     FT_Bool    vertical )
  {
    FT_Error   error;
    FT_ULong   table_size;
    FT_Byte**  ptable;
    FT_ULong*  ptable_size;
    
    
    if ( vertical )
    {
      error = face->goto_table( face, TTAG_vmtx, stream, &table_size );
      if ( error )
        goto Fail;

      ptable      = &face->vert_metrics;
      ptable_size = &face->vert_metrics_size;
    }
    else
    {
      error = face->goto_table( face, TTAG_hmtx, stream, &table_size );
      if ( error )
        goto Fail;

      ptable      = &face->horz_metrics;
      ptable_size = &face->horz_metrics_size;
    }
    
    if ( FT_FRAME_EXTRACT( table_size, *ptable ) )
      goto Fail;
      
    *ptable_size = table_size;

  Fail:
    return error;
  }

  FT_LOCAL_DEF
  FT_Error  TT_Load_Locations( TT_Face    face,
                               FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;
    FT_Short   LongOffsets;
    FT_ULong   table_len;


    FT_TRACE2(( "Locations " ));
    LongOffsets = face->header.Index_To_Loc_Format;

    error = face->goto_table( face, TTAG_loca, stream, &table_len );
    if ( error )
    {
      error = TT_Err_Locations_Missing;
      goto Exit;
    }

    if ( LongOffsets != 0 )
    {
      face->num_locations = (FT_UShort)( table_len >> 2 );

      FT_TRACE2(( "(32bit offsets): %12d ", face->num_locations ));

      if ( ALLOC_ARRAY( face->glyph_locations,
                        face->num_locations,
                        FT_Long ) )
        goto Exit;

      if ( ACCESS_Frame( face->num_locations * 4L ) )
        goto Exit;

      {
        FT_Long*  loc   = face->glyph_locations;
        FT_Long*  limit = loc + face->num_locations;


        for ( ; loc < limit; loc++ )
          *loc = GET_Long();
      }

      FORGET_Frame();
    }

  static
  FT_Error  Load_Post_Names( TT_Face  face )
  {
    FT_Stream  stream;
    FT_Error   error;
    FT_Fixed   format;


    /* get a stream for the face's resource */
    stream = face->root.stream;

    /* seek to the beginning of the PS names table */
    error = face->goto_table( face, TTAG_post, stream, 0 );
    if ( error )
      goto Exit;

    format = face->postscript.FormatType;

    /* go to beginning of subtable */
    if ( FILE_Skip( 32 ) )
      goto Exit;

    /* now read postscript table */
    switch ( format )
    {
    case 0x00020000L:
      error = Load_Format_20( face, stream );
      break;

    case 0x00028000L:
      error = Load_Format_25( face, stream );
      break;

    default:
      error = TT_Err_Invalid_File_Format;
    }

    face->postscript_names.loaded = 1;

  Exit:
    return error;
  }

static FT_ULong
tt_get_sfnt_checksum( TT_Face    face,
                      FT_UShort  i )
{
#if 0 /* if we believe the written value, use following part. */
    if ( face->dir_tables[i].CheckSum )
        return face->dir_tables[i].CheckSum;
#endif

    if ( !face->goto_table )
        return 0;

    if ( face->goto_table( face,
                           face->dir_tables[i].Tag,
                           face->root.stream,
                           NULL ) )
        return 0;

    return (FT_ULong)tt_synth_sfnt_checksum( face->root.stream,
            face->dir_tables[i].Length );
}

  sfnt_load_face( FT_Stream      stream,
                  TT_Face        face,
                  FT_Int         face_index,
                  FT_Int         num_params,
                  FT_Parameter*  params )
  {
    FT_Error      error;
#ifdef TT_CONFIG_OPTION_POSTSCRIPT_NAMES
    FT_Error      psnames_error;
#endif
    FT_Bool       has_outline;
    FT_Bool       is_apple_sbit;
    FT_Bool       is_apple_sbix;
    FT_Bool       ignore_preferred_family    = FALSE;
    FT_Bool       ignore_preferred_subfamily = FALSE;

    SFNT_Service  sfnt = (SFNT_Service)face->sfnt;

    FT_UNUSED( face_index );


    /* Check parameters */

    {
      FT_Int  i;


      for ( i = 0; i < num_params; i++ )
      {
        if ( params[i].tag == FT_PARAM_TAG_IGNORE_PREFERRED_FAMILY )
          ignore_preferred_family = TRUE;
        else if ( params[i].tag == FT_PARAM_TAG_IGNORE_PREFERRED_SUBFAMILY )
          ignore_preferred_subfamily = TRUE;
      }
    }

    /* Load tables */

    /* We now support two SFNT-based bitmapped font formats.  They */
    /* are recognized easily as they do not include a `glyf'       */
    /* table.                                                      */
    /*                                                             */
    /* The first format comes from Apple, and uses a table named   */
    /* `bhed' instead of `head' to store the font header (using    */
    /* the same format).  It also doesn't include horizontal and   */
    /* vertical metrics tables (i.e. `hhea' and `vhea' tables are  */
    /* missing).                                                   */
    /*                                                             */
    /* The other format comes from Microsoft, and is used with     */
    /* WinCE/PocketPC.  It looks like a standard TTF, except that  */
    /* it doesn't contain outlines.                                */
    /*                                                             */

    FT_TRACE2(( "sfnt_load_face: %08p\n\n", face ));

    /* do we have outlines in there? */
#ifdef FT_CONFIG_OPTION_INCREMENTAL
    has_outline = FT_BOOL( face->root.internal->incremental_interface != 0 ||
                           tt_face_lookup_table( face, TTAG_glyf )    != 0 ||
                           tt_face_lookup_table( face, TTAG_CFF )     != 0 );
#else
    has_outline = FT_BOOL( tt_face_lookup_table( face, TTAG_glyf ) != 0 ||
                           tt_face_lookup_table( face, TTAG_CFF )  != 0 );
#endif

    is_apple_sbit = 0;
    is_apple_sbix = !face->goto_table( face, TTAG_sbix, stream, 0 );

    /* Apple 'sbix' color bitmaps are rendered scaled and then the 'glyf'
     * outline rendered on top.  We don't support that yet, so just ignore
     * the 'glyf' outline and advertise it as a bitmap-only font. */
    if ( is_apple_sbix )
      has_outline = FALSE;

    /* if this font doesn't contain outlines, we try to load */
    /* a `bhed' table                                        */
    if ( !has_outline && sfnt->load_bhed )
    {
      LOAD_( bhed );
      is_apple_sbit = FT_BOOL( !error );
    }

    /* load the font header (`head' table) if this isn't an Apple */
    /* sbit font file                                             */
    if ( !is_apple_sbit || is_apple_sbix )
    {
      LOAD_( head );
      if ( error )
        goto Exit;
    }

    if ( face->header.Units_Per_EM == 0 )
    {
      error = FT_THROW( Invalid_Table );

      goto Exit;
    }

    /* the following tables are often not present in embedded TrueType */
    /* fonts within PDF documents, so don't check for them.            */
//.........这里部分代码省略.........

  tt_face_load_kern( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_ULong   table_size;
    FT_Byte*   p;
    FT_Byte*   p_limit;
    FT_UInt    nn, num_tables;
    FT_UInt32  avail = 0, ordered = 0;


    /* the kern table is optional; exit silently if it is missing */
    error = face->goto_table( face, TTAG_kern, stream, &table_size );
    if ( error )
      goto Exit;

    if ( table_size < 4 )  /* the case of a malformed table */
    {
      FT_ERROR(( "tt_face_load_kern:"
                 " kerning table is too small - ignored\n" ));
      error = FT_THROW( Table_Missing );
      goto Exit;
    }

    if ( FT_FRAME_EXTRACT( table_size, face->kern_table ) )
    {
      FT_ERROR(( "tt_face_load_kern:"
                 " could not extract kerning table\n" ));
      goto Exit;
    }

    face->kern_table_size = table_size;

    p       = face->kern_table;
    p_limit = p + table_size;

    p         += 2; /* skip version */
    num_tables = FT_NEXT_USHORT( p );

    if ( num_tables > 32 ) /* we only support up to 32 sub-tables */
      num_tables = 32;

    for ( nn = 0; nn < num_tables; nn++ )
    {
      FT_UInt    num_pairs, length, coverage;
      FT_Byte*   p_next;
      FT_UInt32  mask = (FT_UInt32)1UL << nn;


      if ( p + 6 > p_limit )
        break;

      p_next = p;

      p += 2; /* skip version */
      length   = FT_NEXT_USHORT( p );
      coverage = FT_NEXT_USHORT( p );

      if ( length <= 6 )
        break;

      p_next += length;

      if ( p_next > p_limit )  /* handle broken table */
        p_next = p_limit;

      /* only use horizontal kerning tables */
      if ( ( coverage & ~8 ) != 0x0001 ||
           p + 8 > p_limit             )
        goto NextTable;

      num_pairs = FT_NEXT_USHORT( p );
      p        += 6;

      if ( ( p_next - p ) < 6 * (int)num_pairs ) /* handle broken count */
        num_pairs = (FT_UInt)( ( p_next - p ) / 6 );

      avail |= mask;

      /*
       *  Now check whether the pairs in this table are ordered.
       *  We then can use binary search.
       */
      if ( num_pairs > 0 )
      {
        FT_ULong  count;
        FT_ULong  old_pair;


        old_pair = FT_NEXT_ULONG( p );
        p       += 2;

        for ( count = num_pairs - 1; count > 0; count-- )
        {
          FT_UInt32  cur_pair;


          cur_pair = FT_NEXT_ULONG( p );
          if ( cur_pair <= old_pair )
            break;
//.........这里部分代码省略.........

  tt_face_load_colr( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = face->root.memory;

    FT_Byte*  table = NULL;
    FT_Byte*  p     = NULL;

    Colr*  colr = NULL;

    FT_ULong  base_glyph_offset, layer_offset;
    FT_ULong  table_size;


    /* `COLR' always needs `CPAL' */
    if ( !face->cpal )
      return FT_THROW( Invalid_File_Format );

    error = face->goto_table( face, TTAG_COLR, stream, &table_size );
    if ( error )
      goto NoColr;

    if ( table_size < COLR_HEADER_SIZE )
      goto InvalidTable;

    if ( FT_FRAME_EXTRACT( table_size, table ) )
      goto NoColr;

    p = table;

    if ( FT_NEW( colr ) )
      goto NoColr;

    colr->version = FT_NEXT_USHORT( p );
    if ( colr->version != 0 )
      goto InvalidTable;

    colr->num_base_glyphs = FT_NEXT_USHORT( p );
    base_glyph_offset     = FT_NEXT_ULONG( p );

    if ( base_glyph_offset >= table_size )
      goto InvalidTable;
    if ( colr->num_base_glyphs * BASE_GLYPH_SIZE >
           table_size - base_glyph_offset )
      goto InvalidTable;

    layer_offset     = FT_NEXT_ULONG( p );
    colr->num_layers = FT_NEXT_USHORT( p );

    if ( layer_offset >= table_size )
      goto InvalidTable;
    if ( colr->num_layers * LAYER_SIZE > table_size - layer_offset )
      goto InvalidTable;

    colr->base_glyphs = (FT_Byte*)( table + base_glyph_offset );
    colr->layers      = (FT_Byte*)( table + layer_offset      );
    colr->table       = table;
    colr->table_size  = table_size;

    face->colr = colr;

    return FT_Err_Ok;

  InvalidTable:
    error = FT_THROW( Invalid_Table );

  NoColr:
    FT_FRAME_RELEASE( table );
    FT_FREE( colr );

    return error;
  }