cpython/Demo/zlib/zlibdemo.py

#!/usr/bin/env python

import zlib, sys
if len(sys.argv)>1: filename=sys.argv[1]
else: filename='zlibdemo.py'
print 'Reading', filename
f=open(filename, 'r')		# Get the data to compress
s=f.read()
f.close()

# First, we'll compress the string in one step
comptext=zlib.compress(s, 1)
decomp=zlib.decompress(comptext)

print '1-step compression: (level 1)'
print '    Original:', len(s), 'Compressed:', len(comptext),
print 'Uncompressed:', len(decomp)

# Now, let's compress the string in stages; set chunk to work in smaller steps

chunk=256
compressor=zlib.compressobj(9)
decompressor=zlib.decompressobj()
comptext=decomp=''
for i in range(0, len(s), chunk):
    comptext=comptext+compressor.compress(s[i:i+chunk])
comptext=comptext+compressor.flush()	# Don't forget to call flush()!!

for i in range(0, len(comptext), chunk):
    decomp=decomp+decompressor.decompress(comptext[i:i+chunk])
decomp=decomp+decompressor.flush()

print 'Progressive compression (level 9):'
print '    Original:', len(s), 'Compressed:', len(comptext),
print 'Uncompressed:', len(decomp)