/*
 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
 *
 * This file is part of nios2sim-ng.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "nios2sim-ng.h"
#include "image.h"

#define SREC_CRC_COUNT		1

#define SREC_LINE_LENGTH	515
static char data_buf[SREC_LINE_LENGTH];

/**
 * @return  length of the line
 */
static ssize_t srec_read_line(FILE *fp, char *buf, size_t count)
{
	char c;
	ssize_t len = 0;

	while (count > 0 && !feof(fp)) {
		if (ferror(fp)) {
			err("ferror\n");
			goto err_out;
		}

		/* Read byte by byte */
		if (fread(&c, 1, 1, fp) == 1) {
			if (c == '\n' || c == '\r')
				break;	/* end of line */

			buf[len++] = c;
			count--;
		} else {
			if (feof(fp) && !ferror(fp))
				break;
			else
				goto err_out;
		}
	}

	return len;
err_out:
	return -1;
}

static int srec_load_S3(char *buf, size_t data_count,
		off_t offset, uint8_t *mem_base, size_t mem_size)
{
	size_t i;
	uint32_t *base = (uint32_t *) mem_base;

	for (i = 0; i < data_count; i += 4) {
		uint32_t tmp;

		if (sscanf(buf + i * 2, "%8x", &tmp) != 1) {
			err("sscanf() failed on S3 record\n");
			return -1;
		}
		/* SREC is Big Endian, NiosII is Little Endian */
		tmp = bswap_32(tmp);

		if (offset + i >= mem_size) {
			err("Image file too large for allocated memory of %zu bytes\n", mem_size);
			return -1;
		}

		/* Store in memory */
		base[offset / 4 + i] = tmp;
	}

	return 0;
}

static int srec_handle_line(char *buf, size_t len, uint8_t *mem_base, size_t mem_size)
{
	unsigned int data_count = 0;
	unsigned int start_addr;

	/* Minimum valid record size */
	if (len < 2) {
		err("Invalid line in SREC file\n");
		return -1;
	}

	if (buf[0] != 'S') {
		err("Invalid line in SREC file\n");
		return -1;
	}

	switch (buf[1]) {
	case '0':
		/* Ignore */
		break;
	case '1':
		dbg("handling S1\n");
		break;
	case '2':
		dbg("handling S2\n");
		break;
	case '3':
		if (sscanf(buf, "S3%2x%8x", &data_count, &start_addr) != 2) {
			err("Invalid S3 record\n");
			return -1;
		}

		if (srec_load_S3(buf + 12, data_count - 4, start_addr, mem_base, mem_size) != 0)
			return -1;
		break;
	case '4':
		dbg("handling S4\n");
		break;
	case '5':
		dbg("handling S5\n");
		break;
	case '6':
		dbg("handling S6\n");
		break;
	case '7':
		dbg("handling S7\n");
		break;
	case '8':
		dbg("handling S8\n");
		break;
	case '9':
		dbg("handling S9\n");
		break;
	default:
		err("Invalid SREC type: %c\n", buf[1]);
		return -1;
	}

	return 0;
}

int srec_load(FILE *fp, const char *name __unused, uint8_t *mem_base, size_t mem_size)
{
	ssize_t len;
	int ret = 0;

	while (1) {
		memset(data_buf, 0x00, SREC_LINE_LENGTH);
		len = srec_read_line(fp, data_buf, SREC_LINE_LENGTH);
		if (len < 0) {
			ret = -1;
			break;
		} else if (len == 0) {
			ret = 0;
			break;
		} else {
			ret = srec_handle_line(data_buf, len, mem_base, mem_size);
			if (ret < 0)
				break;
		}
	}

	return ret;
}