tools/findbits.py

   1 #!/usr/bin/env python3
   2
   3 #  findbits.py - find Binary, Octal, Decimal or Hex number in bitstream
   4 #
   5 #  Adam Laurie <adam@algroup.co.uk>
   6 #  http://rfidiot.org/
   7 #
   8 #  This code is copyright (c) Adam Laurie, 2009, All rights reserved.
   9 #  For non-commercial use only, the following terms apply - for all other
  10 #  uses, please contact the author:
  11 #
  12 #    This code is free software; you can redistribute it and/or modify
  13 #    it under the terms of the GNU General Public License as published by
  14 #    the Free Software Foundation; either version 2 of the License, or
  15 #    (at your option) any later version.
  16 #
  17 #    This code is distributed in the hope that it will be useful,
  18 #    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 #    GNU General Public License for more details.
  21 #
  22
  23 import sys
  24 import os
  25
  26 # invert binary string
  27 def invert(data):
  28     return ''.join('0' if c == '1' else '1' for c in data)
  29
  30 # do the actual search
  31 def search(target,data):
  32     location = data.find(target)
  33     if location >= 0:
  34         print('*** Match at bit {:d}: {}<{}>{}'.format(location, data[:location],target,data[location+len(target):]))
  35     else:
  36         print('Not found')
  37
  38 # convert integer to binary string
  39 def binstring(number):
  40     return bin(number)[2:] if number > 0 else ''
  41
  42 # reverse string order
  43 def stringreverse(data):
  44     return data[::-1]
  45
  46 # match forward, backward and inverted
  47 def domatch(binary,number):
  48     reversed= stringreverse(number)
  49     inverted= invert(binary)
  50
  51     print('  Forward: (%s) ' % number, end = '')
  52     search(binary,number)
  53     print('  Reverse: (%s) ' % reversed, end = '')
  54     search(binary,reversed)
  55     print('  Inverse: (%s) ' % inverted)
  56     print('    Forward: (%s) ' % number, end = '')
  57     search(inverted,number)
  58     print('    Reverse: (%s) ' % reversed, end = '')
  59     search(inverted,reversed)
  60
  61 def main():
  62     if(len(sys.argv) < 3):
  63         print("""
  64 \t{0} - Search bitstream for a known number
  65
  66 Usage: {0} <NUMBER> <BITSTREAM>
  67
  68 \tNUMBER will be converted to its BINARY equivalent for all valid
  69 \tinstances of BINARY, OCTAL, DECIMAL and HEX, and the bitstream
  70 \tand its inverse will be searched for a pattern match. Note that
  71 \tNUMBER must be specified in BINARY to match leading zeros.
  72
  73 Example:
  74
  75 \t{0} 73 0110010101110011
  76 """.format(sys.argv[0]))
  77         os._exit(True)
  78
  79     bases=    {
  80         2:'BINARY',
  81         8:'OCTAL',
  82         10:'DECIMAL',
  83         16:'HEX',
  84             }
  85
  86     for base, base_name in sorted(bases.items()):
  87         try:
  88             number= int(sys.argv[1],base)
  89             print('\nTrying ' + base_name)
  90             # do BINARY as specified to preserve leading zeros
  91             if base == 2:
  92                 domatch(sys.argv[1],sys.argv[2])
  93             else:
  94                 domatch(binstring(number),sys.argv[2])
  95         except:
  96             continue
  97
  98 if __name__ == '__main__':
  99     main()