#!/usr/bin/env python

"""
	wipefreespace.py
	
	This program is a simple, one-pass disk overwrite utility.  
	It overwrites all the unused space on the disk volume you 
	specify in 'filepath' with the bit pattern you specify in 
	'pattern1', 'pattern2', 'pattern3', and 'pattern4'.   It 
	overwrites the disk's free space; it does nothing for the 
	disk space used by virtual memory.
	
	To wipe the free space for other than the volume of the 
	current directory, change "filepath" below.  You may also 
	change the bit patterns written by altering the four 
	pattern variables.  
	
	It would be a simple exercise to mod for multiple passes 
	with different or randomly varying bit patterns.
	
	The time required depends on the amount of free space to 
	be wiped and drive speed.  On my PowerBook... 15MB/sec.  
	YMMV. 
	
	NB: This program in NO WAY conforms to any of the MIL-SPECs 
	for wiping drives.
	
	Larry Bugbee
	August 2003
	
"""

import os, struct, time
						# '.' = current directory
filepath = '.'			# '/'  '/mnt/hdb2/'  'D:/'			<---<<
pattern1 = 0xf3			# 0x00 0xc3  0x3c  0xff  etc.		<---<<
pattern2 = 0x81			# 0x00 0xc3  0x3c  0xff  etc.		<---<<
pattern3 = 0x82			# 0x00 0xc3  0x3c  0xff  etc.		<---<<
pattern4 = 0x03			# 0x00 0xc3  0x3c  0xff  etc.		<---<<

t0 = time.time()
filename = filepath+'___wiped___'

# the *4 /4 is to get around word alignment issues (64 bit? *8 /8)
chunksize = 1024*128	# assures easy divisibility by 4 (or 8?)
data = struct.pack('4B', pattern1, pattern2, pattern3, pattern4)
data *= (chunksize/4)

mb = 0					# megabytes written
try:
	f = open(filename, 'wb')
	try:
		while 1:			# repeat until disk full exception
			f.write(data)
			mb += 1
	except:
		f.close()
	
	mb *= float(chunksize)/(1024*1024)
	t1 = time.time()
	t = t1-t0
	print '  elapsed time of %5.2f seconds for %5.1f MB' % (t, mb)
	print '  rate: %5.1f MB per sec' % (mb/t)
	
	# comment out the next line only if you want to see the file and
	# are willing to delete it manually
	os.remove(filename)

except Exception, e:
	print e