#!/usr/bin/python3
#
"""Pack the compressed files created by test_lzx_huffman.c (with
LZXHUFF_DEBUG_FILES) into the format used by the decompression fuzzer.

That is, the first 3 bytes are the length of the decompressed file,
and the rest of the file is the compressed data.

USAGE: make-fuzz-examples DIR

where DIR is probably '/tmp'.
"""
import os
import sys


if '--help' in sys.argv or '-h' in sys.argv or len(sys.argv) != 2:
    print(__doc__)
    exit(len(sys.argv) != 2)


def main():
    files = set(os.listdir(sys.argv[1]))

    for fn in files:
        if fn.endswith('-compressed'):
            fn2 = fn.replace('-compressed', '-decompressed')
            if fn2 not in files:
                print(f"skipping {fn}, no {fn2}")
                continue
            cfn = '/tmp/' + fn
            dfn = '/tmp/' + fn2
            wfn = '/tmp/' + fn.replace('-compressed', '.fuzz')

            size = os.stat(dfn).st_size
            sbytes = bytes([(size & 0xff), (size >> 8) & 0xff, (size >> 16) & 0xff])

            with open(cfn, 'rb') as f:
                s = f.read()

            with open(wfn, 'wb') as f:
                s = f.write(sbytes + s)


main()