/*
 * This module handles the lowest level of serial packet Rx
 */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "../include/pktmux.h"
#include "../include/limits.h"

extern int target_fd;

u_char rxpkt[MAX_PKT_FROM_TARGET];
size_t rxpkt_len;

static int in_pkt, dle_state, toobig;

static void
process_inbyte(inb)
{
	char errbuf[128];

	if (!in_pkt) {
		if (inb != STX || dle_state) {
			rxpkt_len++;
			dle_state = (inb == DLE);
			return;
		}
		if (rxpkt_len) {
			sprintf(errbuf,
				"Warning: Rx %u byte%s outside of a packet",
				(unsigned)rxpkt_len, rxpkt_len != 1 ? "s" : "");
			output_line(errbuf);
			rxpkt_len = 0;
		}
		in_pkt = 1;
		toobig = 0;
		return;
	}
	if (dle_state) {
		dle_state = 0;
		if (inb != STX && inb != DLE) {
			sprintf(errbuf,
				"Rx framing error: %02X after DLE", inb);
			output_line(errbuf);
			in_pkt = 0;
			rxpkt_len = 0;
			return;
		}
		goto data;
	}
	if (inb == DLE) {
		dle_state = 1;
		return;
	} else if (inb == STX) {
		if (!rxpkt_len)
			return;
		in_pkt = 0;
		handle_rx_packet();
		rxpkt_len = 0;
		return;
	}
data:	if (rxpkt_len >= MAX_PKT_FROM_TARGET) {
		if (!toobig) {
			output_line("Error: Rx packet too big!");
			toobig = 1;
		}
		return;
	}
	rxpkt[rxpkt_len++] = inb;
}

void
process_serial_rx()
{
	u_char rdbuf[512];
	int cc, i;

	cc = read(target_fd, rdbuf, sizeof rdbuf);
	if (cc <= 0) {
		perror("Error/EOF reading from target");
		exit(1);
	}
	for (i = 0; i < cc; i++)
		process_inbyte(rdbuf[i]);
}