writeAt method

@override Future<void> writeAt(int position, List<int> bytes)

Implementation

@override
Future<void> writeAt(int position, List<int> bytes) async {
  int offset = 0;
  while (offset < bytes.length) {
    final int absolute = position + offset;
    final int index = absolute ~/ chunkSize;
    final int within = absolute % chunkSize;
    final _PendingChunk chunk = _pending.putIfAbsent(index, () => _PendingChunk(chunkSize));
    if (within != chunk.filled) throw StateError("Vault chunk $index must be written sequentially.");
    final int take = min(chunkSize - within, bytes.length - offset);
    chunk.bytes.setRange(within, within + take, bytes, offset);
    chunk.filled += take;
    offset += take;
    final int? known = _knownLength;
    final bool isLast = known != null && (index + 1) * chunkSize >= known;
    if (chunk.filled == chunkSize || (isLast && index * chunkSize + chunk.filled == known)) {
      await _seal(index, chunk.filled, last: isLast);
    }
  }
}