Copies a title into any blank titles in a DS ROM

title-copier.py

#!/usr/bin/env python3

# Requirements:
# pip3 install libscrc

"""
title copier © 2022 Pk11

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the “Software”), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

import argparse
import struct

from libscrc import modbus

parser = argparse.ArgumentParser(description="Copies a title into any blank titles in a DS ROM")
parser.add_argument("input", metavar="in.nds", type=str, help="input ROM")
parser.add_argument("output", metavar="out.nds", type=str, help="output ROM")
parser.add_argument("-l", "--language", metavar="1", default=1, type=int, help="language (0-7)")
# 0=Japanese, 1=English, 2=French, 3=German, 4=Italian, 5=Spanish, 6=Chinese, 7=Korean

args = parser.parse_args()

languages = ("Japanese", "English", "French", "German", "Italian", "Spanish", "Chinese", "Korean")

if args.input == args.output:
	print("Please use a different output path")
	exit()

with open(args.output, "wb+") as out:
	print("Copying file...")
	with open(args.input, "rb") as rom:
		out.write(rom.read())

	# Get banner
	out.seek(0x68)
	bannerAddr = struct.unpack("<I", out.read(4))[0]
	out.seek(bannerAddr)
	bannerVer = struct.unpack("<H", out.read(2))[0]
	print("Banner version: 0x%04X" % bannerVer)

	# Check that language is supported
	if(args.language < 0 or args.language > 5 + ((bannerVer & 3) - 1)):
		print("Error: Invalid language")
		exit()

	# Copy title to any blank ones
	out.seek(bannerAddr)
	bannerData = out.read(0x23C0 if (bannerVer & 0x100) else (0x840 + ((bannerVer & 3) - 1) * 0x100))
	title = bannerData[0x240 + (args.language * 0x100):0x340 + (args.language * 0x100)]
	for i in range(6 + ((bannerVer & 3) - 1)):
		if bannerData[0x240 + (i * 0x100)] in (0x00, 0x0A):
			print("Copying %s title to %s..." % (languages[args.language], languages[i]))
			out.seek(bannerAddr + 0x240 + (i * 0x100))
			out.write(title)

	# Update CRCs
	out.seek(bannerAddr)
	bannerData = out.read(0x23C0 if (bannerVer & 0x100) else (0x840 + ((bannerVer & 3) - 1) * 0x100))
	print("Updating CRCs...")
	out.seek(bannerAddr + 2)

	# Base banner
	crc = modbus(bannerData[0x20:0x840])
	print("0x%04X" % crc)
	out.write(struct.pack("<H", crc))

	# Chinese
	if((bannerVer & 3) >= 2):
		crc = modbus(bannerData[0x20:0x940])
		print("0x%04X" % crc)
		out.write(struct.pack("<H", crc))

	# Korean
	if((bannerVer & 3) >= 3):
		crc = modbus(bannerData[0x20:0xA40])
		print("0x%04X" % crc)
		out.write(struct.pack("<H", crc))

	# DSi
	if(bannerVer & 0x100):
		crc = modbus(bannerData[0x1240:])
		print("0x%04X" % crc)
		out.write(struct.pack("<H", crc))