kiss_encode.py

#!/usr/bin/python3

"""
Mostly written by GPT-4 using prompt:
'Write python script to HDLC escape a packet'

"""
def hdlc_escape(packet):
    FLAG_BYTE = 0x7E
    ESCAPE_BYTE = 0x7D
    XOR_BYTE = 0x20

    escaped_packet = bytearray()
    for byte in packet:
        if byte == FLAG_BYTE or byte == ESCAPE_BYTE:
            escaped_packet.append(ESCAPE_BYTE)
            escaped_packet.append(byte ^ XOR_BYTE)
        else:
            escaped_packet.append(byte)

    return escaped_packet

if False:
    # Example usage
    original_packet = bytearray([0x7E, 0x11, 0x7D, 0x7E, 0x22, 0x33])
    escaped_packet = hdlc_escape(original_packet)

    print("Original Packet:", original_packet)
    print("Escaped Packet: ", escaped_packet)

open("/dev/stdout", "wb").write(bytes(
    bytearray([0xC0, 0])
    + hdlc_escape(open("/dev/stdin", 'rb').read())
    + bytearray([0xC0])))