Files
littlefs/scripts/crc32c.py
Christopher Haster 007ac97bec scripts: Adopted double-indent on multiline expressions
This matches the style used in C, which is good for consistency:

  a_really_long_function_name(
          double_indent_after_first_newline(
              single_indent_nested_newlines))

We were already doing this for multiline control-flow statements, simply
because I'm not sure how else you could indent this without making
things really confusing:

  if a_really_long_function_name(
          double_indent_after_first_newline(
              single_indent_nested_newlines)):
      do_the_thing()

This was the only real difference style-wise between the Python code and
C code, so now both should be following roughly the same style (80 cols,
double-indent multiline exprs, prefix multiline binary ops, etc).
2024-11-06 15:31:17 -06:00

82 lines
2.2 KiB
Python
Executable File

#!/usr/bin/env python3
import io
import os
import struct
import sys
def openio(path, mode='r', buffering=-1):
# allow '-' for stdin/stdout
if path == '-':
if 'r' in mode:
return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
else:
return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
else:
return open(path, mode, buffering)
def crc32c(data, crc=0):
crc ^= 0xffffffff
for b in data:
crc ^= b
for j in range(8):
crc = (crc >> 1) ^ ((crc & 1) * 0x82f63b78)
return 0xffffffff ^ crc
def main(paths, **args):
# interpret as sequence of hex bytes
if args.get('hex'):
print('%08x' % crc32c(bytes(int(path, 16) for path in paths)))
# interpret as strings
elif args.get('string'):
for path in paths:
print('%08x' % crc32c(path.encode('utf8')))
# default to interpreting as paths
else:
if not paths:
paths = [None]
for path in paths:
with openio(path or '-', 'rb') as f:
# calculate crc
crc = 0
while True:
block = f.read(io.DEFAULT_BUFFER_SIZE)
if not block:
break
crc = crc32c(block, crc)
# print what we found
if path is not None:
print('%08x %s' % (crc, path))
else:
print('%08x' % crc)
if __name__ == "__main__":
import argparse
import sys
parser = argparse.ArgumentParser(
description="Calculates crc32cs.",
allow_abbrev=False)
parser.add_argument(
'paths',
nargs='*',
help="Paths to read. Reads stdin by default.")
parser.add_argument(
'-x', '--hex',
action='store_true',
help="Interpret as a sequence of hex bytes.")
parser.add_argument(
'-s', '--string',
action='store_true',
help="Interpret as strings.")
sys.exit(main(**{k: v
for k, v in vars(parser.parse_intermixed_args()).items()
if v is not None}))