mirror of https://github.com/python/cpython
37 lines
1.0 KiB
Python
37 lines
1.0 KiB
Python
|
#!/usr/local/bin/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)
|
||
|
|
|