import std.buffer as buf
import std.encoding as enc
import std.fs as fs

let input_path: str = "example_firmware.bin"
let output_path: str = "example_firmware.patched.bin"

fs.write_bytes(input_path, b"\x00\xDE\xAD\xBE\xEF\x00")

let image: buffer = buf.load(input_path)
let offset: int = buf.find(image, b"\xDE\xAD\xBE\xEF")

if offset >= 0:
    buf.replace(image, offset, b"\x90\x90\x90\x90")
    buf.save(output_path, image)
    print("patched", offset)
else:
    print("pattern not found")

let patched: bytes = fs.read_bytes(output_path)
print(enc.hex_encode(patched))