Returns the current checksum value.

  Returns the current checksum value.
Returns: the current checksum value

Resets the checksum to its initial value.

  Updates the current checksum with the specified array of bytes.

  Updates the current checksum with the specified array of bytes.
Parameters:
- b - the byte array to update the checksum with
- off - the start offset of the data
- len - the number of bytes to use for the update

  Updates the current checksum with the specified byte.

  Updates the current checksum with the specified byte.
Parameters:
- b - the byte to update the checksum with