forked from Imagelibrary/littlefs
87 lines
2.2 KiB
Python
Executable File
87 lines
2.2 KiB
Python
Executable File
#!/usr/bin/env python3
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import io
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import os
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import struct
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import sys
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import functools as ft
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import operator as op
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def openio(path, mode='r', buffering=-1):
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# allow '-' for stdin/stdout
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if path == '-':
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if 'r' in mode:
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return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
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else:
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return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
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else:
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return open(path, mode, buffering)
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def popc(x):
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return bin(x).count('1')
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def parity(x):
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return popc(x) & 1
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def main(paths, **args):
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# interpret as sequence of hex bytes
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if args.get('hex'):
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print('%01x' % parity(ft.reduce(
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op.xor,
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bytes(int(path, 16) for path in paths),
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0)))
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# interpret as strings
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elif args.get('string'):
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for path in paths:
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print('%01x' % parity(ft.reduce(
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op.xor,
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path.encode('utf8'),
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0)))
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# default to interpreting as paths
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else:
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if not paths:
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paths = [None]
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for path in paths:
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with openio(path or '-', 'rb') as f:
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# calculate parity
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xor = 0
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while True:
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block = f.read(io.DEFAULT_BUFFER_SIZE)
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if not block:
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break
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xor = ft.reduce(op.xor, block, xor)
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# print what we found
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if path is not None:
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print('%01x %s' % (parity(xor), path))
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else:
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print('%01x' % parity(xor))
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if __name__ == "__main__":
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import argparse
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import sys
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parser = argparse.ArgumentParser(
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description="Calculates parity.",
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allow_abbrev=False)
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parser.add_argument(
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'paths',
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nargs='*',
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help="Paths to read. Reads stdin by default.")
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parser.add_argument(
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'-x', '--hex',
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action='store_true',
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help="Interpret as a sequence of hex bytes.")
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parser.add_argument(
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'-s', '--string',
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action='store_true',
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help="Interpret as strings.")
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sys.exit(main(**{k: v
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for k, v in vars(parser.parse_intermixed_args()).items()
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if v is not None}))
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