xn297_decod.cpp

#include <QtCore/QCoreApplication>
#include <stdio.h>
#include <stdint.h>
#include "qfile.h"

// xn297 scramble table
static const uint8_t xn297_scramble[] = {
    0xe3, 0xb1, 0x4b, 0xea, 0x85, 0xbc, 0xe5, 0x66,
    0x0d, 0xae, 0x8c, 0x88, 0x12, 0x69, 0xee, 0x1f,
    0xc7, 0x62, 0x97, 0xd5, 0x0b, 0x79, 0xca, 0xcc,
    0x1b, 0x5d, 0x19, 0x10, 0x24, 0xd3, 0xdc, 0x3f,
    0x8e, 0xc5, 0x2f};

uint8_t bit_reverse(uint8_t b_in)
{
    uint8_t b_out = 0;
    for (uint8_t i = 0; i < 8; ++i) {
        b_out = (b_out << 1) | (b_in & 1);
        b_in >>= 1;
    }
    return b_out;
}

int main(int argc, char *argv[])
{
	if(argc<2 || !(QFile::exists(argv[1]))) {
		printf("no input file\npress return to exit");
		getchar();
		return 1;
	}
	
	QFile in_file(argv[1]);
	in_file.open(QIODevice::ReadOnly);
	uint8_t byte, bit_count, byte_count;
	bool in_packet = false;

	uint8_t address_length = 5;
	uint8_t packet_size = 19;

	for(;;)
	while(!in_file.atEnd()) {
		char bit;
		in_file.read(&bit, 1);
		if((bit & 0x02) && !in_packet ) { // found correlate access code bit (1st bit of address)
			byte = 0;
			bit_count = 0;
			byte_count = 0;
			in_packet = true;
			//     adress    |                     data
			// CC CC CC CC CC AA D7 23 63 27 FF FF FF FF D0 07 D0 07 E8 03 E8 03 11 00
		}
        
		if(in_packet) {
			if(bit & 0x01) {
				byte |= 1 << (7-bit_count);
			}
			bit_count++;
			if(bit_count > 7) {
				if(byte_count < address_length)
					byte = byte ^ xn297_scramble[byte_count];
				else
					byte = bit_reverse(byte) ^ bit_reverse(xn297_scramble[byte_count]);
				if(byte_count == address_length)
                    			printf("| ");
                		printf("%02x ", byte);
				bit_count = 0;
				byte = 0;
				byte_count++;
				if(byte_count == address_length + packet_size) {
					in_packet = false;
					printf("\n");
				}
			}
		}
	}
	in_file.close();
	printf("press return to exit");
	getchar();
	return 0;
}