Function encode_long

Lib/pickle.py:372–400

r"""Encode a long to a two's complement little-endian binary string. Note that 0 is a special case, returning an empty string, to save a byte in the LONG1 pickling context. >>> encode_long(0) b'' >>> encode_long(255) b'\xff\x00' >>> encode_long(32767) b'\xff\x7f'

(x)

        f"Can't pickle {obj!r}: it's not the same object as {module_name}.{name}")

def encode_long(x):
    r"""Encode a long to a two's complement little-endian binary string.
    Note that 0 is a special case, returning an empty string, to save a
    byte in the LONG1 pickling context.

    >>> encode_long(0)
    b''
    >>> encode_long(255)
    b'\xff\x00'
    >>> encode_long(32767)
    b'\xff\x7f'
    >>> encode_long(-256)
    b'\x00\xff'
    >>> encode_long(-32768)
    b'\x00\x80'
    >>> encode_long(-128)
    b'\x80'
    >>> encode_long(127)
    b'\x7f'
    >>>
    """
    if x == 0:
        return b''
    nbytes = (x.bit_length() >> 3) + 1
    result = x.to_bytes(nbytes, byteorder='little', signed=True)
    if x < 0 and nbytes > 1:
        if result[-1] == 0xff and (result[-2] & 0x80) != 0:
            result = result[:-1]
    return result

def decode_long(data):
    r"""Decode a long from a two&#x27;s complement little-endian binary string.