initialize method

@visibleForTesting void initialize({ required Uint8List h0, })

Initializes the first two blocks of every lane.

Implementation

@visibleForTesting
void initialize({
  required Uint8List h0,
}) {
  if (h0.length != 64) {
    throw ArgumentError();
  }

  // Our implementation uses the third block for temporarily storing input for
  // the hash function.
  final thirdBlock = getBlock(lane: 0, slice: 0, index: 3);
  final input = Uint8List.view(
    thirdBlock.buffer,
    thirdBlock.offsetInBytes,
    _blake2bSize + 8,
  );
  input.setAll(0, h0);

  final inputByteData = ByteData.view(
    input.buffer,
    input.offsetInBytes,
    input.lengthInBytes,
  );

  // For each lane
  for (var lane = 0; lane < parallelism; lane++) {
    // Set lane index
    inputByteData.setUint32(
      64 + 4,
      lane,
      Endian.little,
    );

    // Block 0 of the lane
    {
      // Set block index
      inputByteData.setUint32(
        64,
        0,
        Endian.little,
      );

      // BLAKE2B
      final block = getBlock(lane: lane, slice: 0, index: 0);
      variableLengthHash(
        output: block.buffer.asUint8List(
          block.offsetInBytes,
          block.lengthInBytes,
        ),
        input: input,
      );
    }

    // Block 1 of the lane
    {
      // Set: block index
      inputByteData.setUint32(
        64,
        1,
        Endian.little,
      );

      // BLAKE2B
      final block = getBlock(lane: lane, slice: 0, index: 1);
      variableLengthHash(
        output: block.buffer.asUint8List(
          block.offsetInBytes,
          block.lengthInBytes,
        ),
        input: input,
      );
    }
  }

  // Erase the temporary buffer
  input.fillRange(0, input.length, 0);
}