This module is intended to have a similar interface as the python struct module, but working on bits instead of primitive data types (char, int, ...).
Documentation: https://bitstruct.readthedocs.org/en/latest
pip install bitstructSee the test suite: https://github.com/eerimoq/bitstruct/blob/master/tests/test_bitstruct.py
A basic example of packing/unpacking four integers:
>>> from bitstruct import *
>>> pack('u1u3u4s16', 1, 2, 3, -4)
b'\xa3\xff\xfc'
>>> unpack('u1u3u4s16', b'\xa3\xff\xfc')
(1, 2, 3, -4)
>>> calcsize('u1u3u4s16')
24The unpacked fields can be named by assigning them to variables or by wrapping the result in a named tuple:
>>> from bitstruct import *
>>> from collections import namedtuple
>>> MyName = namedtuple('myname', [ 'a', 'b', 'c', 'd' ])
>>> unpacked = unpack('u1u3u4s16', b'\xa3\xff\xfc')
>>> myname = MyName(*unpacked)
>>> myname
myname(a=1, b=2, c=3, d=-4)
>>> myname.c
3An example of packing/unpacking a unsinged integer, a signed integer, a float, a boolean, a byte string and a string:
>>> from bitstruct import *
>>> pack('u5s5f32b1r13t40', 1, -1, 3.75, True, b'\xff\xff', 'hello')
b'\x0f\xd0\x1c\x00\x00?\xffhello'
>>> unpack('u5s5f32b1r13t40', b'\x0f\xd0\x1c\x00\x00?\xffhello')
(1, -1, 3.75, True, b'\xff\xf8', 'hello')
>>> calcsize('u5s5f32b1r13t40')
96The same format and values as in the previous example, but using LSB (Least Significant Bit) first instead of the default MSB (Most Significant Bit) first:
>>> from bitstruct import *
>>> pack('<u5s5f32b1r13t40', 1, -1, 3.75, True, b'\xff\xff', 'hello')
b'\x87\xc0\x00\x03\x80\xbf\xff\xf666\xa6\x16'
>>> unpack('<u5s5f32b1r13t40', b'\x87\xc0\x00\x03\x80\xbf\xff\xf666\xa6\x16')
(1, -1, 3.75, True, b'\xff\xf8', 'hello')
>>> calcsize('<u5s5f32b1r13t40')
96An example of unpacking values from a hexstring and a binary file:
>>> from bitstruct import *
>>> from binascii import unhexlify
>>> unpack('s17s13r24', unhexlify('0123456789abcdef'))
(582, -3751, b'\xe2j\xf3')
>>> with open("test.bin", "rb") as fin:
... unpack('s17s13r24', fin.read(8))
...
...
(582, -3751, b'\xe2j\xf3')Change endianness of the data with byteswap(), and then unpack the values:
>>> from bitstruct import *
>>> packed = pack('u1u3u4s16', 1, 2, 3, 1)
>>> unpack('u1u3u4s16', byteswap('12', packed))
(1, 2, 3, 256)