import mmap
import sys
import struct

def main(in_file, out_file):
    with open(in_file, "r+b") as f:
        map = mmap.mmap(f.fileno(), 0)
        data = map.readline()
        # Assuming first char is \x00 and
        # data is in blocks of 3.
        pos = 1
        # Output to CSV
        with open(out_file, "w") as o:
            while (pos + 3) < (len(data) - 1):
                row = struct.unpack('BBB', data[pos:pos+3])
                # o.write("{0}, {1}, {2}\n".format(*row))
                o.write(", ".join(row))
                pos += 4
        map.close()


if __name__ == "__main__":
    if sys.argv[1] == "-h":
        print("Parameters:")
        print("1: Input file")
        print("2: Output file")
    else:
        main(sys.argv[1], sys.argv[2])