codecs_incremental_bz2.py

#1/usr/bin/env python

# this is from The Python
# Standard Library by example
# ISBN13: 9780321767349

import codecs
import sys

from codecs_to_hex import to_hex

text = 'abcdefghijklmnopqrstuvwxyz\n'
repetitions = 50

print 'Text length :', len(text)
print 'Repetitions :', repetitions
print 'Expected len:', len(text) * repetitions

# Encode the text several times to build up a large amount of data
encoder = codecs.getincrementalencoder('bz2')()
encoded = []

print
print 'Encoding:',
for i in range(repetitions):
    en_c = encoder.encode(text, final=(i == repetitions - 1))
    if en_c:
        print '\nEncoded : {} bytes'.format(len(en_c))
        encoded.append(en_c)
    else:
        sys.stdout.write('.')

bytes = ''.join(encoded)
print
print 'Total encoded length:', len(bytes)
print

# Decode the byte string one byte at a time
decoder = codecs.getincrementaldecoder('bz2')()
decoded = []

print 'Decoding:',
for i, b in enumerate(bytes):
    final = (i + 1) == len(text)
    c = decoder.decode(b, final)
    if c:
        print '\nDecoded : {} characters'.format(len(c))
        print 'Decoding:',
        decoded.append(c)
    else:
        sys.stdout.write('.')

print

restored = u''.join(decoded)

print
print 'Total uncompressed length:', len(restored)