#!/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()