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#!/usr/bin/env python3
# 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), end=' ')
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), end=' ')
print('Uncompressed:', len(decomp))
if __name__ == '__main__':
main()
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