Minimal tool to compress/decompress mozlz4 format

mozlz4

#!/usr/bin/env python3

# MIT license (c) 2024 https://github.com/slowpeek
# Homepage: https://gist.github.com/slowpeek/06bfe5f00900f09ad015ddf6da1d0714

# Minimal tool to compress/decompress mozlz4 format

import sys
import lz4.block

def bye( s, exit_code=1):
    print(s)
    sys.exit(exit_code)

def main():
    usage = "Usage: mozlz4 [-d] <in >out"
    argc = len(sys.argv)

    if (argc > 2):
        bye(usage)

    fi = sys.stdin.buffer
    fo = sys.stdout.buffer
    magic = b"mozLz40\0"

    if (argc == 1):
        fo.write(magic)
        fo.write(lz4.block.compress(fi.read()))
    elif (sys.argv[1] == "-d"):
        if fi.read(8) != magic:
            bye("input does not look like mozlz4")

        fo.write(lz4.block.decompress(fi.read()))
    else:
        bye(usage)

if __name__ == "__main__":
    main()