gzip_compresslevel.py

#1/usr/bin/env python

# this is from The Python
# Standard Library by example
# ISBN13: 9780321767349

import gzip
import os
import hashlib


def get_hash(data):
    return hashlib.md5(data).hexdigest()

data = open('lorem.txt', 'r').read() * 1024
cksum = get_hash(data)

print 'Level    Size        Checksum'
print '------   -------  ---------------------'
print 'data     %10d %s' % (len(data), cksum)

for i in xrange(1, 10):
    filename = 'compress-level-%s.gz' % i
    with gzip.open(filename, 'wb', compresslevel=i) as output:
        output.write(data)
    size = os.stat(filename).st_size
    cksum = get_hash(open(filename, 'rb').read())
    print '%5d %10d %s' % (i, size, cksum)