read method

@override Future<Uint8List> read(int offset, int length)

Reads exactly length bytes starting at byte offset.

Throws UnexpectedEofException if the range extends past the end of the source and ArchiveClosedException if the source is closed.

Implementation

@override
Future<Uint8List> read(int offset, int length) {
  checkByteSourceRange(this, offset, length);
  return _synchronized(() async {
    if (_closed) {
      throw ArchiveClosedException('read($offset, $length) after close()');
    }
    await _file.setPosition(offset);
    final result = Uint8List(length);
    var filled = 0;
    while (filled < length) {
      final got = await _file.readInto(result, filled, length);
      if (got <= 0) {
        // The file shrank underneath us after open().
        throw UnexpectedEofException(
          'file ended at ${offset + filled} while reading '
          '$length byte(s) at offset $offset',
          offset: offset + filled,
        );
      }
      filled += got;
    }
    return result;
  });
}