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48 lines
1.5 KiB
Python
Executable file
48 lines
1.5 KiB
Python
Executable file
#!/usr/bin/env python
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# Takes an optional filename, defaulting to this file itself.
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# Reads the file and compresses the content using level 1 and level 9
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# compression, printing a summary of the results.
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import zlib, sys
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def main():
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if len(sys.argv) > 1:
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filename = sys.argv[1]
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else:
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filename = sys.argv[0]
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print('Reading', filename)
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f = open(filename, 'rb') # Get the data to compress
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s = f.read()
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f.close()
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# First, we'll compress the string in one step
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comptext = zlib.compress(s, 1)
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decomp = zlib.decompress(comptext)
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print('1-step compression: (level 1)')
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print(' Original:', len(s), 'Compressed:', len(comptext), end=' ')
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print('Uncompressed:', len(decomp))
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# Now, let's compress the string in stages; set chunk to work in smaller steps
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chunk = 256
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compressor = zlib.compressobj(9)
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decompressor = zlib.decompressobj()
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comptext = decomp = ''
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for i in range(0, len(s), chunk):
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comptext = comptext+compressor.compress(s[i:i+chunk])
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# Don't forget to call flush()!!
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comptext = comptext + compressor.flush()
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for i in range(0, len(comptext), chunk):
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decomp = decomp + decompressor.decompress(comptext[i:i+chunk])
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decomp=decomp+decompressor.flush()
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print('Progressive compression (level 9):')
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print(' Original:', len(s), 'Compressed:', len(comptext), end=' ')
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print('Uncompressed:', len(decomp))
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if __name__ == '__main__':
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main()
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