/*
 * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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

static const char *TAG = "base16";

void base16_encode(uint8_t *raw, size_t len, char *encoded) {
	uint8_t *raw_bytes = raw;
	char *encoded_bytes = encoded;
	size_t remaining = len;

	for (; remaining--; encoded_bytes += 2)
		snprintf(encoded_bytes, 3, "%02X", *(raw_bytes++));

}

int base16_decode(const char *encoded, uint8_t *raw) {
	const char *encoded_bytes = encoded;
	uint8_t *raw_bytes = raw;
	char buf[3];
	char *endp;
	size_t len;

	while (encoded_bytes[0]) {
		if (!encoded_bytes[1]) {
			ESP_LOGE(TAG, "Base16-encoded string \"%s\" has invalid length\n",
					encoded);
			return -22;
		}
		memcpy(buf, encoded_bytes, 2);
		buf[2] = '\0';
		*(raw_bytes++) = strtoul(buf, &endp, 16);
		if (*endp != '\0') {
			ESP_LOGE(TAG,"Base16-encoded string \"%s\" has invalid byte \"%s\"\n",
					encoded, buf);
			return -22;
		}
		encoded_bytes += 2;
	}
	len = (raw_bytes - raw);
	return (len);
}