#!/usr/bin/env python

import os
import mmap
import md5

fn = 'bigfile'
f=open(fn, 'wb')
f.write('hi')
f.seek(2**30)
f.write('foo')
f.seek(2**31)
f.write('bar')
f.seek(2**32)
f.write('baz')
f.close()

size = os.path.getsize(fn)

f = open(fn, 'rb')
m = mmap.mmap(f.fileno(), size, access=mmap.ACCESS_READ)
print 'python mmap md5:', md5.md5(m).hexdigest()
os.system('md5sum -b %s' % fn)