hexdump.py

#!/usr/bin/env python
#
# $Id$
#
# implemented a couple of useful functions for displaying binary data.
#

def tobin(i):
	"""Convert an int to a binary
	
	This function converts an int into a string representing the int
	in binary.
	
	e.g.  tobin(170) would produce 10101010
	
	the string is left padded with 0's to the nearest 32, 16, or 8 bit boundry.
	
	e.g.:
	
	  170                          10101010
	  342                  0000000101010110
	65537  00000000000000010000000000000001
	"""
	s = ""
	max = 8
	if i > 255:
		max = 16
	if i > 65535:
		max = 32
	if i > 2**32:
		max = 64
	
	bins = range(max)
	bins = map(lambda a: 2 ** a, bins)
	bins.reverse()
	
	for b in bins:
		if b & i == b:
			s+= "1"
		else:
			s+= "0"
	return s

def hexdump(str, prepend = '', start = 0):
	"""Hexdump's things
	
	The prepend arg is prepended to every string thats printed out, 
	useful if you want to indent stuff, it defaults to ''.
	"""
	x = y = count = 0
	indent = 16
	out = ''

	print "%s" % (' ' * (len(prepend) + 6)),
	for i in range(start % indent, indent):
#	for i in range(0, indent):
		print "%02x" % (i),
	if start != 0:
		for i in range(0, start % indent):
			print "%02x" % (i),
	print
		
	out = ''

	while (count < len(str)):
		out = "%s%04x : " % (prepend, start + count)
		
		x = 0
		while x < indent:
			if (x + count + 1 ) > len(str):
				break
			out = out + "%02x " % (ord(str[x + count]))
			if (x + count + 1) >= len(str):
				x += 1
				y = 0
				for y in range(indent - x):
					out = out + '   '
				break

			x += 1
		
		out = out + ": "
		
		x = 0
		while x < indent:
			if (x + count + 1) > len(str):
				break
			if ord(str[x + count]) >= 32 and ord(str[x + count]) <= 126:
				out = out + str[x + count]
			elif ord(str[x + count]) == 0:
				out = out + ' '
			else:
				out = out + '.'
			
			if (x + count + 1) >= len(str):
				x += 1
				y = 0
				while y < (indent - x):
					out += ' '
					y += 1
			
			x += 1
			
		print out
		count += indent
			
	print

# given a hex string like '035344534c30384780e2b9f64d00f501'
# turn it back into binary
# binascii.a2b_hex might be a better choice
def unhex(s):
	o = ''
	for (a, b) in zip(s[0::2], s[1::2]):
		o = o + chr(int(a+b, 16))
	return o

if __name__ == "__main__":
	s = "lksdhfkahsdflakhjsdflahfalsdfakhfdw98345\000\001\006\077$%$^%$%"
	hexdump(s, "%% ")
	hexdump(s, '', 90)
	for i in [1, 0x24, 0x23, 255, 192, 7, 42, 128, 42 + 128, 342, 65537, 0xfffffffff7b0b000]:
		print "%20d %65s" % (i, tobin(i))
	s = '035344534c30384780e2b9f64d00f501'
	print s
	hexdump(unhex(s))