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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 | import string | |
26 | ||
27 | # invert binary string | |
28 | def invert(data): | |
29 | i= 0 | |
30 | out= '' | |
31 | while(i < len(data)): | |
32 | if data[i] == '0': | |
33 | out += '1' | |
34 | else: | |
35 | out += '0' | |
36 | i += 1 | |
37 | return out | |
38 | ||
39 | # do the actual search | |
40 | def search(data,target): | |
41 | location= string.find(data,target) | |
42 | if location >= 0: | |
43 | print '*** Match at bit %d:' % location, | |
44 | print '%s<%s>%s' % (data[:location],target,data[location+len(target):]) | |
45 | else: | |
46 | print 'Not found' | |
47 | ||
48 | # convert integer to binary string | |
49 | def binstring(number): | |
50 | out= '' | |
51 | while number > 0: | |
52 | out += chr(0x30 + (number & 0x01)) | |
53 | number= number >> 1 | |
54 | return stringreverse(out) | |
55 | ||
56 | # reverse string order | |
57 | def stringreverse(data): | |
58 | out= '' | |
59 | for x in range(len(data) -1,-1,-1): | |
60 | out += data[x] | |
61 | return out | |
62 | ||
63 | # match forward, backward and inverted | |
64 | def domatch(number,binary): | |
65 | reversed= stringreverse(number) | |
66 | inverted= invert(binary) | |
67 | ||
68 | print ' Forward: (%s)' % number, | |
69 | search(binary,number) | |
70 | print ' Reverse: (%s)' % reversed, | |
71 | search(binary,reversed) | |
72 | print ' Inverse: (%s)' % inverted | |
73 | print ' Forward: (%s)' % number, | |
74 | search(inverted,number) | |
75 | print ' Reverse: (%s)' % reversed, | |
76 | search(inverted,reversed) | |
77 | ||
78 | if(len(sys.argv) < 3): | |
79 | ||
80 | print '\t'+sys.argv[0] + ' - Search bitstream for a known number' | |
81 | ||
82 | print 'Usage: ' + sys.argv[0] + ' <NUMBER> <BITSTREAM>' | |
83 | ||
84 | print '\tNUMBER will be converted to it\'s BINARY equivalent for all valid' | |
85 | print '\tinstances of BINARY, OCTAL, DECIMAL and HEX, and the bitstream' | |
86 | print '\tand it\'s inverse will be searched for a pattern match. Note that' | |
87 | print '\tNUMBER must be specified in BINARY to match leading zeros.' | |
88 | ||
89 | print 'Example:' | |
90 | ||
91 | print '\tfindbits.py 73 0110010101110011' | |
92 | ||
93 | os._exit(True) | |
94 | ||
95 | bases= { | |
96 | 2:'BINARY', | |
97 | 8:'OCTAL', | |
98 | 10:'DECIMAL', | |
99 | 16:'HEX', | |
100 | } | |
101 | ||
102 | for base in 2,8,10,16: | |
103 | try: | |
104 | number= int(sys.argv[1],base) | |
105 | ||
106 | print 'Trying', bases[base] | |
107 | # do BINARY as specified to preserve leading zeros | |
108 | if base == 2: | |
109 | domatch(sys.argv[1],sys.argv[2]) | |
110 | else: | |
111 | domatch(binstring(number),sys.argv[2]) | |
112 | except: | |
113 | continue |