update method

@override BLAKE2b update(List<int> data, { int? length, })

Updates the BLAKE2b hash with the given data, optionally specifying the data length.

This method updates the hash state with the provided data. If a specific data length is provided, only that amount of data will be processed. If the hash was previously finished, an exception will be thrown.

Parameters:

• data: The data to be hashed.
• length (optional): The length of data to process. If not specified, the entire data will be processed.

Returns:

• The modified BLAKE2b instance with updated hash state.

Implementation

@override
BLAKE2b update(List<int> data, {int? length}) {
  if (_finished) {
    throw const ArgumentException(
        "blake2b: can't update because hash was finished.");
  }

  int left = _blockSize - _bufferLength;
  int dataPos = 0;

  int dataLength = length ?? data.length;

  if (dataLength == 0) {
    return this;
  }

  // Finish buffer.
  if (dataLength > left) {
    for (int i = 0; i < left; i++) {
      _buffer[_bufferLength + i] = data[dataPos + i] & mask8;
    }
    _processBlock(_blockSize);
    dataPos += left;
    dataLength -= left;
    _bufferLength = 0;
  }

  // Process data blocks.
  while (dataLength > _blockSize) {
    for (int i = 0; i < _blockSize; i++) {
      _buffer[i] = data[dataPos + i] & mask8;
    }
    _processBlock(_blockSize);
    dataPos += _blockSize;
    dataLength -= _blockSize;
    _bufferLength = 0;
  }

  // Copy leftovers to buffer.
  for (int i = 0; i < dataLength; i++) {
    _buffer[_bufferLength + i] = data[dataPos + i] & mask8;
  }
  _bufferLength += dataLength;

  return this;
}