Convert Sega Saturn save files between MiSTer and Mednafen format

ss-sav-conv.py

#!/usr/bin/env python3

import argparse
import os
import struct
import sys

def read_chunks(f, length):
    while True:
        data = f.read(length)
        if not data: break
        yield data

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument(dest="in_file", metavar="IN_FILE", help="input file")
    parser.add_argument(dest="out_file", metavar="OUT_FILE", help="output file")
    try:
        args = parser.parse_args()
        in_size = os.path.getsize(args.in_file)

        if in_size == 0x10000:
            print("converting Saturn_MiSTer save to Mednafen format...", args.in_file, "->", args.out_file)
            out = bytes()
            with open(args.in_file, "rb") as in_fh:
                for _, word in enumerate(read_chunks(in_fh, 2)):
                    out += struct.pack("<B", word[1])
            with open(args.out_file, "wb") as out_fh:
                out_fh.write(out)

        elif in_size == 0X8000:
            print("converting Mednafen save to Saturn_MiSTer format...", args.in_file, "->", args.out_file)
            out = bytes()
            with open(args.in_file, "rb") as in_fh:
                for _, byte in enumerate(read_chunks(in_fh, 1)):
                    out += struct.pack(">H", byte[0])
            with open(args.out_file, "wb") as out_fh:
                out_fh.write(out)

        else:
            raise IOError("unrecognized save format in file '{}'".format(args.in_file))

        return 0

    # except Exception as err:
    except IOError as err:
        print("error - {}".format(err))
        sys.exit(1)

if __name__ == "__main__":
    sys.exit(main())