update method

void update(Uint8List message, int offset, int len)

Implementation

void update(Uint8List message, int offset, int len) {
  if (0 == len) {
    return;
  }

  int remainingLength = 0;

  if (0 != _bufferPos) {
    // commenced, incomplete buffer

    // complete the buffer:
    remainingLength = Const.blockLengthBytes - _bufferPos;
    if (remainingLength < len) {
      // full buffer + at least 1 byte
      _buffer = _arrayCopy(message, offset, _buffer, _bufferPos, remainingLength);
      _t0 += Const.blockLengthBytes;
      if (_t0 == 0) {
        // if message > 2^64
        _t1++;
      }
      _compress(_buffer, 0);
      _bufferPos = 0;
      _buffer.fillRange(0, _buffer.length, 0);
    } else {
      _buffer = _arrayCopy(message, offset, _buffer, _bufferPos, len);
      _bufferPos += len;
      return;
    }
  }

  // process blocks except last block (also if last block is full)
  int messagePos;
  final int blockWiseLastPos = offset + len - Const.blockLengthBytes;

  // block wise 128 bytes
  for (messagePos = offset + remainingLength; messagePos < blockWiseLastPos; messagePos += Const.blockLengthBytes) {
    // without buffer:
    _t0 += Const.blockLengthBytes;

    if (_t0 == 0) {
      _t1++;
    }

    _compress(message, messagePos);
  }

  // fill the buffer with left bytes, this might be a full block
  _buffer = _arrayCopy(message, messagePos, _buffer, 0, offset + len - messagePos);

  _bufferPos += (offset + len) - messagePos;
}