#!/usr/bin/env python3

# Prepend a length and CRC32 checksum to a binary file so that it can be sent
# to the DOOMSoC UART bootloader. Both values are unsigned 32-bit
# little-endian. CRC32 is calculated with standard parameters (input and
# output reflected, seed all-ones, final XOR all-ones).

import argparse
import binascii
import struct

parser = argparse.ArgumentParser()
parser.add_argument("ifile")
parser.add_argument("ofile")
args = parser.parse_args()

data = open(args.ifile, "rb").read()

with open(args.ofile, "wb") as ofile:
	ofile.write(struct.pack("<L", len(data)))
	ofile.write(struct.pack("<L", binascii.crc32(data)))
	ofile.write(data)