#!/usr/bin/env python

# Takes an optional filename, defaulting to this file itself.

# Reads the file and compresses the content using level 1 and level 9

# compression, printing a summary of the results.

import zlib, sys

def main():

    if len(sys.argv) > 1:

        filename = sys.argv[1]

    else:

        filename = sys.argv[0]

    print 'Reading', filename

    f = open(filename, 'rb')           # 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])

    # Don't forget to call flush()!!

    comptext = comptext + compressor.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)

if __name__ == '__main__':

    main()