#!/usr/bin/env python

## smsdecode.py, v0.1
## Copyright (C) 2004 Gary Benson <gary@inauspicious.org>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.

"""Decode *.sm[io] files as produced by the Siemens S55."""

def decode(msg):
    start = {0: 0x2C, 3: 0x27}[ord(msg[7])]
    p, l, s, d, out = start + 1, ord(msg[start]), 0, 0, []
    while len(out) < l:
        c = ord(msg[p])
        p += 1
        out.append(((c & (0x7F >> s)) << s) | d)
        d = (c & (0x7F80 >> s)) >> (7 - s)
        s += 1
        if s == 7:
            out.append(d)
            s = d = 0
    return "".join(map(chr, out))

if __name__ == "__main__":
    import sys
    for path in sys.argv[1:]:
        print path + ":", decode(open(path, "r").read())