forked from Imagelibrary/littlefs
62cc4dbb14
Moved local import hack behind if __name__ == "__main__" These scripts aren't really intended to be used as python libraries. Still, it's useful to import them for debugging and to get access to their juicy internals.
86 lines
2.3 KiB
Python
Executable File
86 lines
2.3 KiB
Python
Executable File
#!/usr/bin/env python3
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# prevent local imports
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if __name__ == "__main__":
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__import__('sys').path.pop(0)
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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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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 crc32c(data, crc=0):
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crc ^= 0xffffffff
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for b in data:
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crc ^= b
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for j in range(8):
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crc = (crc >> 1) ^ ((crc & 1) * 0x82f63b78)
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return 0xffffffff ^ crc
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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('%08x' % crc32c(bytes(int(path, 16) for path in paths)))
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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('%08x' % crc32c(path.encode('utf8')))
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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 crc
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crc = 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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crc = crc32c(block, crc)
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# print what we found
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if path is not None:
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print('%08x %s' % (crc, path))
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else:
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print('%08x' % crc)
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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 crc32cs.",
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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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