ttload.c

下载来的一个看图软件的源代码

  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_names( TT_Face    face,
                      FT_Stream  stream )
  {
    FT_Error      error;
    FT_Memory     memory = stream->memory;
    FT_ULong      table_pos, table_len;
    FT_ULong      storage_start, storage_limit;
    FT_UInt       count;
    TT_NameTable  table;

    static const FT_Frame_Field  name_table_fields[] =
    {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  TT_NameTableRec

      FT_FRAME_START( 6 ),
        FT_FRAME_USHORT( format ),
        FT_FRAME_USHORT( numNameRecords ),
        FT_FRAME_USHORT( storageOffset ),
      FT_FRAME_END
    };

    static const FT_Frame_Field  name_record_fields[] =
    {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  TT_NameEntryRec

      /* no FT_FRAME_START */
        FT_FRAME_USHORT( platformID ),
        FT_FRAME_USHORT( encodingID ),
        FT_FRAME_USHORT( languageID ),
        FT_FRAME_USHORT( nameID ),
        FT_FRAME_USHORT( stringLength ),
        FT_FRAME_USHORT( stringOffset ),
      FT_FRAME_END
    };


    table         = &face->name_table;
    table->stream = stream;

    FT_TRACE2(( "Names " ));

    error = face->goto_table( face, TTAG_name, stream, &table_len );
    if ( error )
    {
      /* The name table is required so indicate failure. */
      FT_TRACE2(( "is missing!\n" ));
      error = SFNT_Err_Name_Table_Missing;
      goto Exit;
    }

    table_pos = FT_STREAM_POS();


    if ( FT_STREAM_READ_FIELDS( name_table_fields, table ) )
      goto Exit;

    /* Some popular Asian fonts have an invalid `storageOffset' value   */
    /* (it should be at least "6 + 12*num_names").  However, the string */
    /* offsets, computed as "storageOffset + entry->stringOffset", are  */
    /* valid pointers within the name table...                          */
    /*                                                                  */
    /* We thus can't check `storageOffset' right now.                   */
    /*                                                                  */
    storage_start = table_pos + 6 + 12*table->numNameRecords;
    storage_limit = table_pos + table_len;

    if ( storage_start > storage_limit )
    {
      FT_ERROR(( "tt_face_load_names: invalid `name' table\n" ));
      error = SFNT_Err_Name_Table_Missing;
      goto Exit;
    }

    /* Allocate the array of name records. */
    count                 = table->numNameRecords;
    table->numNameRecords = 0;

    if ( FT_NEW_ARRAY( table->names, count ) ||
         FT_FRAME_ENTER( count * 12 )        )
      goto Exit;

    /* Load the name records and determine how much storage is needed */
    /* to hold the strings themselves.                                */
    {
      TT_NameEntryRec*  entry = table->names;


      for ( ; count > 0; count-- )
      {
        if ( FT_STREAM_READ_FIELDS( name_record_fields, entry ) )
          continue;

        /* check that the name is not empty */
        if ( entry->stringLength == 0 )
          continue;

        /* check that the name string is within the table */
        entry->stringOffset += table_pos + table->storageOffset;
        if ( entry->stringOffset                       < storage_start ||
             entry->stringOffset + entry->stringLength > storage_limit )
        {
          /* invalid entry - ignore it */
          entry->stringOffset = 0;
          entry->stringLength = 0;
          continue;
        }

        entry++;
      }

      table->numNameRecords = (FT_UInt)( entry - table->names );
    }

    FT_FRAME_EXIT();

    FT_TRACE2(( "loaded\n" ));

    /* everything went well, update face->num_names */
    face->num_names = (FT_UShort) table->numNameRecords;

  Exit:
    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_free_names                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Frees the name records.                                            */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face :: A handle to the target face object.                        */
  /*                                                                       */
  FT_LOCAL_DEF( void )
  tt_face_free_names( TT_Face  face )
  {
    FT_Memory     memory = face->root.driver->root.memory;
    TT_NameTable  table  = &face->name_table;
    TT_NameEntry  entry  = table->names;
    FT_UInt       count  = table->numNameRecords;


    for ( ; count > 0; count--, entry++ )
    {
      FT_FREE( entry->string );
      entry->stringLength = 0;
    }

    /* free strings table */
    FT_FREE( table->names );

    table->numNameRecords = 0;
    table->format         = 0;
    table->storageOffset  = 0;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_cmap                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads the cmap directory in a face object.  The cmaps itselves are */
  /*    loaded on demand in the `ttcmap.c' module.                         */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */

  FT_LOCAL_DEF( FT_Error )
  tt_face_load_cmap( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error  error;


    error = face->goto_table( face, TTAG_cmap, stream, &face->cmap_size );
    if ( error )
    {
      FT_TRACE2(( "No `cmap' table in font !\n" ));
      error = SFNT_Err_CMap_Table_Missing;
      goto Exit;
    }

    if ( !FT_FRAME_EXTRACT( face->cmap_size, face->cmap_table ) )
      FT_TRACE2(( "`cmap' table loaded\n" ));
    else
    {
      FT_ERROR(( "`cmap' table is too short!\n" ));
      face->cmap_size = 0;
    }

  Exit:
    return error;
  }



  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_os2                                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads the OS2 table.                                               */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_os2( TT_Face    face,
                    FT_Stream  stream )
  {
    FT_Error  error;
    TT_OS2*   os2;

    const FT_Frame_Field  os2_fields[] =
    {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  TT_OS2

      FT_FRAME_START( 78 ),
        FT_FRAME_USHORT( version ),
        FT_FRAME_SHORT ( xAvgCharWidth ),
        FT_FRAME_USHORT( usWeightClass ),
        FT_FRAME_USHORT( usWidthClass ),
        FT_FRAME_SHORT ( fsType ),
        FT_FRAME_SHORT ( ySubscriptXSize ),
        FT_FRAME_SHORT ( ySubscriptYSize ),
        FT_FRAME_SHORT ( ySubscriptXOffset ),
        FT_FRAME_SHORT ( ySubscriptYOffset ),
        FT_FRAME_SHORT ( ySuperscriptXSize ),
        FT_FRAME_SHORT ( ySuperscriptYSize ),
        FT_FRAME_SHORT ( ySuperscriptXOffset ),
        FT_FRAME_SHORT ( ySuperscriptYOffset ),
        FT_FRAME_SHORT ( yStrikeoutSize ),
        FT_FRAME_SHORT ( yStrikeoutPosition ),
        FT_FRAME_SHORT ( sFamilyClass ),
        FT_FRAME_BYTE  ( panose[0] ),
        FT_FRAME_BYTE  ( panose[1] ),
        FT_FRAME_BYTE  ( panose[2] ),
        FT_FRAME_BYTE  ( panose[3] ),
        FT_FRAME_BYTE  ( panose[4] ),
        FT_FRAME_BYTE  ( panose[5] ),
        FT_FRAME_BYTE  ( panose[6] ),
        FT_FRAME_BYTE  ( panose[7] ),
        FT_FRAME_BYTE  ( panose[8] ),
        FT_FRAME_BYTE  ( panose[9] ),
        FT_FRAME_ULONG ( ulUnicodeRange1 ),
        FT_FRAME_ULONG ( ulUnicodeRange2 ),
        FT_FRAME_ULONG ( ulUnicodeRange3 ),
        FT_FRAME_ULONG ( ulUnicodeRange4 ),
        FT_FRAME_BYTE  ( achVendID[0] ),
        FT_FRAME_BYTE  ( achVendID[1] ),
        FT_FRAME_BYTE  ( achVendID[2] ),
        FT_FRAME_BYTE  ( achVendID[3] ),

        FT_FRAME_USHORT( fsSelection ),
        FT_FRAME_USHORT( usFirstCharIndex ),
        FT_FRAME_USHORT( usLastCharIndex ),
        FT_FRAME_SHORT ( sTypoAscender ),
        FT_FRAME_SHORT ( sTypoDescender ),
        FT_FRAME_SHORT ( sTypoLineGap ),
        FT_FRAME_USHORT( usWinAscent ),
        FT_FRAME_USHORT( usWinDescent ),
      FT_FRAME_END
    };

    const FT_Frame_Field  os2_fields_extra[] =
    {
      FT_FRAME_START( 8 ),
        FT_FRAME_ULONG( ulCodePageRange1 ),
        FT_FRAME_ULONG( ulCodePageRange2 ),
      FT_FRAME_END
    };

    const FT_Frame_Field  os2_fields_extra2[] =
    {
      FT_FRAME_START( 10 ),
        FT_FRAME_SHORT ( sxHeight ),
        FT_FRAME_SHORT ( sCapHeight ),
        FT_FRAME_USHORT( usDefaultChar ),
        FT_FRAME_USHORT( usBreakChar ),
        FT_FRAME_USHORT( usMaxContext ),
      FT_FRAME_END
    };


    FT_TRACE2(( "OS/2 Table " ));

    /* We now support old Mac fonts where the OS/2 table doesn't  */
    /* exist.  Simply put, we set the `version' field to 0xFFFF   */
    /* and test this value each time we need to access the table. */
    error = face->goto_table( face, TTAG_OS2, stream, 0 );
    if ( error )
    {
      FT_TRACE2(( "is missing!\n" ));
      face->os2.version = 0xFFFFU;
      error = SFNT_Err_Ok;
      goto Exit;
    }

    os2 = &face->os2;

    if ( FT_STREAM_READ_FIELDS( os2_fields, os2 ) )
      goto Exit;

    os2->ulCodePageRange1 = 0;
    os2->ulCodePageRange2 = 0;
    os2->sxHeight         = 0;
    os2->sCapHeight       = 0;
    os2->usDefaultChar    = 0;
    os2->usBreakChar      = 0;
    os2->usMaxContext     = 0;

    if ( os2->version >= 0x0001 )
    {
      /* only version 1 tables */
      if ( FT_STREAM_READ_FIELDS( os2_fields_extra, os2 ) )
        goto Exit;

      if ( os2->version >= 0x0002 )
      {
        /* only version 2 tables */
        if ( FT_STREAM_READ_FIELDS( os2_fields_extra2, os2 ) )
          goto Exit;
      }
    }