HBLink/hamming.py
2016-09-15 07:52:45 -05:00

115 lines
5.1 KiB
Python
Executable File

#!/usr/bin/env python
#
# This work is licensed under the Creative Attribution-NonCommercial-ShareAlike
# 3.0 Unported License.To view a copy of this license, visit
# http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to
# Creative Commons, 444 Castro Street, Suite 900, Mountain View,
# California, 94041, USA.
from __future__ import print_function
from bitstring import BitArray
# Does anybody read this stuff? There's a PEP somewhere that says I should do this.
__author__ = 'Cortney T. Buffington, N0MJS'
__copyright__ = 'Copyright (c) 2016 Cortney T. Buffington, N0MJS and the K0USY Group'
__credits__ = 'Jonathan Naylor, G4KLX'
__license__ = 'Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported'
__maintainer__ = 'Cort Buffington, N0MJS'
__email__ = 'n0mjs@me.com'
def enc_hamming_15113(_data):
csum = BitArray(4)
csum[0] = _data[0] ^ _data[1] ^ _data[2] ^ _data[3] ^ _data[5] ^ _data[7] ^ _data[8]
csum[1] = _data[1] ^ _data[2] ^ _data[3] ^ _data[4] ^ _data[6] ^ _data[8] ^ _data[9]
csum[2] = _data[2] ^ _data[3] ^ _data[4] ^ _data[5] ^ _data[7] ^ _data[9] ^ _data[10]
csum[3] = _data[0] ^ _data[1] ^ _data[2] ^ _data[4] ^ _data[6] ^ _data[7] ^ _data[10]
return csum
def dec_hamming_15113(_data):
chk0 = _data[0] ^ _data[1] ^ _data[2] ^ _data[3] ^ _data[5] ^ _data[7] ^ _data[8]
chk1 = _data[1] ^ _data[2] ^ _data[3] ^ _data[4] ^ _data[6] ^ _data[8] ^ _data[9]
chk2 = _data[2] ^ _data[3] ^ _data[4] ^ _data[5] ^ _data[7] ^ _data[9] ^ _data[10]
chk3 = _data[0] ^ _data[1] ^ _data[2] ^ _data[4] ^ _data[6] ^ _data[7] ^ _data[10]
n = 0
error = False
n |= 0x01 if chk0 != _data[11] else 0x00
n |= 0x02 if chk1 != _data[12] else 0x00
n |= 0x04 if chk2 != _data[13] else 0x00
n |= 0x08 if chk3 != _data[14] else 0x00
if n == 0x01: _data[11] = not _data[11]; return (_data, True)
if n == 0x02: _data[12] = not _data[12]; return (_data, True)
if n == 0x04: _data[13] = not _data[13]; return (_data, True)
if n == 0x08: _data[14] = not _data[14]; return (_data, True)
if n == 0x0f: _data[0] = not _data[0]; return (_data, True)
if n == 0x07: _data[1] = not _data[1]; return (_data, True)
if n == 0x0b: _data[2] = not _data[2]; return (_data, True)
if n == 0x03: _data[3] = not _data[3]; return (_data, True)
if n == 0x0d: _data[4] = not _data[4]; return (_data, True)
if n == 0x05: _data[5] = not _data[5]; return (_data, True)
if n == 0x09: _data[6] = not _data[6]; return (_data, True)
if n == 0x0e: _data[7] = not _data[7]; return (_data, True)
if n == 0x06: _data[8] = not _data[8]; return (_data, True)
if n == 0x0a: _data[9] = not _data[9]; return (_data, True)
if n == 0x0c: _data[10] = not _data[10]; return (_data, True)
return (_data, False)
def enc_hamming_1393(_data):
csum = BitArray(4)
csum[0] = _data[0] ^ _data[1] ^ _data[3] ^ _data[5] ^ _data[6]
csum[1] = _data[0] ^ _data[1] ^ _data[2] ^ _data[4] ^ _data[6] ^ _data[7]
csum[2] = _data[0] ^ _data[1] ^ _data[2] ^ _data[3] ^ _data[5] ^ _data[7] ^ _data[8]
csum[3] = _data[0] ^ _data[2] ^ _data[4] ^ _data[5] ^ _data[8]
return csum
def dec_hamming_1393(_data):
chk0 = _data[0] ^ _data[1] ^ _data[3] ^ _data[5] ^ _data[6]
chk1 = _data[0] ^ _data[1] ^ _data[2] ^ _data[4] ^ _data[6] ^ _data[7]
chk2 = _data[0] ^ _data[1] ^ _data[2] ^ _data[3] ^ _data[5] ^ _data[7] ^ _data[8]
chk3 = _data[0] ^ _data[2] ^ _data[4] ^ _data[5] ^ _data[8]
n = 0
error = False
n |= 0x01 if chk0 != _data[9] else 0x00
n |= 0x02 if chk1 != _data[10] else 0x00
n |= 0x04 if chk2 != _data[11] else 0x00
n |= 0x08 if chk3 != _data[12] else 0x00
if n == 0x01: _data[9] = not _data[9]; return (_data, True)
if n == 0x02: _data[10] = not _data[10]; return (_data, True)
if n == 0x04: _data[11] = not _data[11]; return (_data, True)
if n == 0x08: _data[12] = not _data[12]; return (_data, True)
if n == 0x0f: _data[0] = not _data[0]; return (_data, True)
if n == 0x07: _data[1] = not _data[1]; return (_data, True)
if n == 0x0b: _data[2] = not _data[2]; return (_data, True)
if n == 0x03: _data[3] = not _data[3]; return (_data, True)
if n == 0x0d: _data[4] = not _data[4]; return (_data, True)
if n == 0x05: _data[5] = not _data[5]; return (_data, True)
if n == 0x09: _data[6] = not _data[6]; return (_data, True)
if n == 0x0e: _data[7] = not _data[7]; return (_data, True)
if n == 0x06: _data[8] = not _data[8]; return (_data, True)
return (_data, False)
if __name__ == '__main__':
# Validation Example
data = BitArray('0x1cd1bb1910f3051031011061cc1aa3800e204002100100147')
print(data[0:11].bin, data[11:15].bin)
print(dec_hamming_15113(data[0:15])[0][0:11].bin, dec_hamming_15113(data[0:15])[0][11:15].bin)
print(enc_hamming_15113(data[0:11]).bin)
print()
print(data[0:9].bin, data[9:13].bin)
print(dec_hamming_1393(data[0:13])[0][0:9].bin, dec_hamming_1393(data[0:13])[0][9:13].bin)
print(enc_hamming_1393(data[0:9]).bin)