| 1 | #!/usr/bin/python |
| 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:' % location, |
| 35 | print '%s<%s>%s' % (data[:location],target,data[location+len(target):]) |
| 36 | else: |
| 37 | print 'Not found' |
| 38 | |
| 39 | # convert integer to binary string |
| 40 | def binstring(number): |
| 41 | return bin(number)[2:] if number > 0 else '' |
| 42 | |
| 43 | # reverse string order |
| 44 | def stringreverse(data): |
| 45 | return data[::-1] |
| 46 | |
| 47 | # match forward, backward and inverted |
| 48 | def domatch(binary,number): |
| 49 | reversed= stringreverse(number) |
| 50 | inverted= invert(binary) |
| 51 | |
| 52 | print ' Forward: (%s)' % number, |
| 53 | search(binary,number) |
| 54 | print ' Reverse: (%s)' % reversed, |
| 55 | search(binary,reversed) |
| 56 | print ' Inverse: (%s)' % inverted |
| 57 | print ' Forward: (%s)' % number, |
| 58 | search(inverted,number) |
| 59 | print ' Reverse: (%s)' % reversed, |
| 60 | search(inverted,reversed) |
| 61 | |
| 62 | def main(): |
| 63 | if(len(sys.argv) < 3): |
| 64 | print |
| 65 | print '\t'+sys.argv[0] + ' - Search bitstream for a known number' |
| 66 | print |
| 67 | print 'Usage: ' + sys.argv[0] + ' <NUMBER> <BITSTREAM>' |
| 68 | print |
| 69 | print '\tNUMBER will be converted to it\'s BINARY equivalent for all valid' |
| 70 | print '\tinstances of BINARY, OCTAL, DECIMAL and HEX, and the bitstream' |
| 71 | print '\tand it\'s inverse will be searched for a pattern match. Note that' |
| 72 | print '\tNUMBER must be specified in BINARY to match leading zeros.' |
| 73 | print |
| 74 | print 'Example:' |
| 75 | print |
| 76 | print '\tfindbits.py 73 0110010101110011' |
| 77 | print |
| 78 | os._exit(True) |
| 79 | |
| 80 | bases= { |
| 81 | 2:'BINARY', |
| 82 | 8:'OCTAL', |
| 83 | 10:'DECIMAL', |
| 84 | 16:'HEX', |
| 85 | } |
| 86 | |
| 87 | for base, base_name in sorted(bases.iteritems()): |
| 88 | try: |
| 89 | number= int(sys.argv[1],base) |
| 90 | print |
| 91 | print 'Trying', base_name |
| 92 | # do BINARY as specified to preserve leading zeros |
| 93 | if base == 2: |
| 94 | domatch(sys.argv[1],sys.argv[2]) |
| 95 | else: |
| 96 | domatch(binstring(number),sys.argv[2]) |
| 97 | except: |
| 98 | continue |
| 99 | |
| 100 | if __name__ == '__main__': |
| 101 | main() |