tool to find UIDs in bitstream

diff --git a/tools/findbits.py b/tools/findbits.py
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+++ b/tools/findbits.py
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+#!/usr/bin/python
+
+#  findbits.py - find Binary, Octal, Decimal or Hex number in bitstream
+# 
+#  Adam Laurie <adam@algroup.co.uk>
+#  http://rfidiot.org/
+# 
+#  This code is copyright (c) Adam Laurie, 2009, All rights reserved.
+#  For non-commercial use only, the following terms apply - for all other
+#  uses, please contact the author:
+#
+#    This code 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 code 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.
+#
+
+import sys
+import os
+import string
+
+# invert binary string
+def invert(data):
+       i=  0
+       out= ''
+       while(i < len(data)):
+               if data[i] == '0':
+                       out += '1'
+               else:
+                       out += '0'
+               i += 1
+       return out
+
+# do the actual search
+def search(data,target):
+       location= string.find(data,target)
+       if location >= 0:
+               print '*** Match at bit %d:' % location,
+               print '%s<%s>%s' % (data[:location],target,data[location+len(target):])
+       else:
+               print 'Not found'
+
+# convert integer to binary string
+def binstring(number):
+       out= ''
+       while number > 0:
+               out += chr(0x30 + (number & 0x01))
+               number= number >> 1
+       return stringreverse(out)
+
+# reverse string order
+def stringreverse(data):
+       out= ''
+       for x in range(len(data) -1,-1,-1):
+               out += data[x]
+       return out
+
+# match forward, backward and inverted
+def domatch(number,binary):
+       reversed= stringreverse(number)
+       inverted= invert(binary)
+
+       print '  Forward: (%s)' % number,
+       search(binary,number)
+       print '  Reverse: (%s)' % reversed,
+       search(binary,reversed)
+       print '  Inverse: (%s)' % inverted
+       print '    Forward: (%s)' % number,
+       search(inverted,number)
+       print '    Reverse: (%s)' % reversed,
+       search(inverted,reversed)
+
+if(len(sys.argv) < 3):
+       print
+       print '\t'+sys.argv[0] + ' - Search bitstream for a known number'
+       print
+       print 'Usage: ' + sys.argv[0] + ' <NUMBER> <BITSTREAM>'
+       print
+       print '\tNUMBER will be converted to it\'s BINARY equivalent for all valid'
+       print '\tinstances of BINARY, OCTAL, DECIMAL and HEX, and the bitstream'
+       print '\tand it\'s inverse will be searched for a pattern match. Note that'
+       print '\tNUMBER must be specified in BINARY to match leading zeros.'
+       print
+       print 'Example:'
+       print
+       print '\tfindbits.py 73 0110010101110011'
+       print
+       os._exit(True)
+
+bases= { 
+       2:'BINARY',
+       8:'OCTAL',
+       10:'DECIMAL',
+       16:'HEX',
+               }
+
+for base in 2,8,10,16:
+       try:
+               number= int(sys.argv[1],base)
+               print
+               print 'Trying', bases[base]
+               # do BINARY as specified to preserve leading zeros
+               if base == 2:
+                       domatch(sys.argv[1],sys.argv[2])
+               else:
+                       domatch(binstring(number),sys.argv[2])
+       except:
+               continue