pykerl.py 文件源码

def absorb(self, trits, offset=0, length=None):
    # type: (MutableSequence[int], int, Optional[int]) -> None
    """
    Absorb trits into the sponge from a buffer.

    :param trits:
      Buffer that contains the trits to absorb.

    :param offset:
      Starting offset in ``trits``.

    :param length:
      Number of trits to absorb.  Defaults to ``len(trits)``.
    """
    # Pad input if necessary, so that it can be divided evenly into
    # hashes.
    # Note that this operation creates a COPY of ``trits``; the
    # incoming buffer is not modified!
    pad = ((len(trits) % TRIT_HASH_LENGTH) or TRIT_HASH_LENGTH)
    trits += [0] * (TRIT_HASH_LENGTH - pad)

    if length is None:
      length = len(trits)

    if length < 1:
      raise with_context(
        exc = ValueError('Invalid length passed to ``absorb``.'),

        context = {
          'trits': trits,
          'offset': offset,
          'length': length,
        },
      )

    while offset < length:
      stop = min(offset + TRIT_HASH_LENGTH, length)

      # If we're copying over a full chunk, zero last trit
      if stop - offset == TRIT_HASH_LENGTH:
        trits[stop - 1] = 0

      signed_nums = conv.convertToBytes(trits[offset:stop])

      # Convert signed bytes into their equivalent unsigned representation
      # In order to use Python's built-in bytes type
      unsigned_bytes = bytearray(conv.convert_sign(b) for b in signed_nums)

      self.k.update(unsigned_bytes)

      offset += TRIT_HASH_LENGTH