Fix unescaped 8-bit characters in C code

fix_chars.py

#!/usr/bin/env python3
"""Fix unescaped 8-bit characters in C code."""
import os
import re
import sys
import tempfile

PRINTABLE = b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$'\
            b'%&\'()*+,-./:;<=>?@[\\]^_`{|}~ '


def escape_match(m):
    value = m.group(1)
    if value in PRINTABLE:
        return m.group(0)
    else:
        return b"'\\x%02x'" % ord(value)


def process(path):
    with open(path, 'rb') as f:
        data = f.read()
    fixed = re.sub(b"'(.)'", escape_match, data)
    with tempfile.NamedTemporaryFile(delete=False) as f:
        f.write(fixed)
        fixed_path = f.name
    os.replace(fixed_path, path)


def main():
    if len(sys.argv) == 1:
        print('Fix unescaped 8-bit characters in C code')
        print('USAGE: fix_chars.py <file1.c> <file2.c> ...')
    for arg in sys.argv[1:]:
        process(arg)


if __name__ == '__main__':
    main()