| #!/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) |