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#! /usr/bin/env python
"""bro %s -- compression/decompression utility using the Brotli algorithm."""
from __future__ import print_function
import argparse
import sys
import os
import brotli
import platform
__version__ = '1.0'
# default values of encoder parameters
DEFAULT_PARAMS = {
'mode': brotli.MODE_TEXT,
'quality': 11,
'lgwin': 22,
'lgblock': 0,
'enable_dictionary': True,
'enable_transforms': False,
'greedy_block_split': False,
'enable_context_modeling': True
}
def get_binary_stdio(stream):
""" Return the specified standard input, output or errors stream as a
'raw' buffer object suitable for reading/writing binary data from/to it.
"""
assert stream in ['stdin', 'stdout', 'stderr'], "invalid stream name"
stdio = getattr(sys, stream)
if sys.version_info[0] < 3:
if sys.platform == 'win32':
# set I/O stream binary flag on python2.x (Windows)
runtime = platform.python_implementation()
if runtime == "PyPy":
# the msvcrt trick doesn't work in pypy, so I use fdopen
mode = "rb" if stream == "stdin" else "wb"
stdio = os.fdopen(stdio.fileno(), mode, 0)
else:
# this works with CPython -- untested on other implementations
import msvcrt
msvcrt.setmode(stdio.fileno(), os.O_BINARY)
return stdio
else:
# get 'buffer' attribute to read/write binary data on python3.x
if hasattr(stdio, 'buffer'):
return stdio.buffer
else:
orig_stdio = getattr(sys, "__%s__" % stream)
return orig_stdio.buffer
def main():
parser = argparse.ArgumentParser(
prog='bro.py',
description="Compression/decompression utility using the Brotli algorithm.")
parser.add_argument('--version', action='version', version='%(prog)s 1.0')
parser.add_argument('-i', '--input', metavar='FILE', type=str, dest='infile',
help='Input file', default=None)
parser.add_argument('-o', '--output', metavar='FILE', type=str, dest='outfile',
help='Output file', default=None)
parser.add_argument('-f', '--force', action='store_true',
help='Overwrite existing output file', default=False)
parser.add_argument('-d', '--decompress', action='store_true',
help='Decompress input file', default=False)
params = parser.add_argument_group('optional encoder parameters')
params.add_argument('-m', '--mode', metavar="MODE", type=int, choices=[0, 1],
help='The compression mode can be 0 (text) or 1 (font). '
'Defaults to text mode.')
params.add_argument('-q', '--quality', metavar="QUALITY", type=int,
choices=list(range(0, 12)),
help='Controls the compression-speed vs compression-density '
'tradeoff. The higher the quality, the slower the '
'compression. Range is 0 to 11. Defaults to 11.')
params.add_argument('--lgwin', metavar="LGWIN", type=int,
choices=list(range(16, 25)),
help='Base 2 logarithm of the sliding window size. Range is '
'16 to 24. Defaults to 22.')
params.add_argument('--lgblock', metavar="LGBLOCK", type=int,
choices=[0] + list(range(16, 25)),
help='Base 2 logarithm of the maximum input block size. '
'Range is 16 to 24. If set to 0, the value will be set based '
'on the quality. Defaults to 0.')
above9 = parser.add_argument_group(
'encoder parameters respected only if quality > 9.')
above9.add_argument('--no-dictionary', action='store_false',
dest='enable_dictionary',
help='Disable encoder dictionary.')
above9.add_argument('--transform', action='store_true',
dest='enable_transforms',
help='Enable encoder transforms.')
above9.add_argument('--greedy-block-split', action='store_true',
dest='greedy_block_split',
help='Enable a faster but less dense compression mode.')
above9.add_argument('--no-context-modeling', action='store_false',
dest='enable_context_modeling',
help='Disable context modeling.')
# set default values using global DEFAULT_PARAMS dictionary
parser.set_defaults(**DEFAULT_PARAMS)
options = parser.parse_args()
from pprint import pprint
pprint(options.__dict__)
if options.infile:
if not os.path.isfile(options.infile):
parser.error('file "%s" not found' % options.infile)
with open(options.infile, "rb") as infile:
data = infile.read()
else:
if sys.stdin.isatty():
# interactive console, just quit
parser.error('no input')
infile = get_binary_stdio('stdin')
data = infile.read()
if options.outfile:
if os.path.isfile(options.outfile) and not options.force:
parser.error('output file exists')
outfile = open(options.outfile, "wb")
else:
outfile = get_binary_stdio('stdout')
try:
if options.decompress:
data = brotli.decompress(data)
else:
data = brotli.compress(
data, mode=options.mode, quality=options.quality,
lgwin=options.lgwin, lgblock=options.lgblock,
enable_dictionary=options.enable_dictionary,
enable_transforms=options.enable_transforms,
greedy_block_split=options.greedy_block_split,
enable_context_modeling=options.enable_context_modeling)
except brotli.error as e:
parser.exit(1,'bro: error: %s: %s' % (e, options.infile or 'sys.stdin'))
outfile.write(data)
outfile.close()
if __name__ == '__main__':
main()
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