/*
 *
 *  oFono - Open Source Telephony
 *
 *  Copyright (C) 2008-2009  Intel Corporation. All rights reserved.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <glib.h>

#include "simutil.h"

/* Parse ASN.1 Basic Encoding Rules TLVs per ISO/IEC 7816 */
const guint8 *ber_tlv_find_by_tag(const guint8 *pdu, guint8 in_tag,
					int in_len, int *out_len)
{
	guint8 tag;
	int len;
	const guint8 *end = pdu + in_len;

	do {
		while (pdu < end && (*pdu == 0x00 || *pdu == 0xff))
			pdu ++;
		if (pdu == end)
			break;

		tag = *pdu ++;
		if (!(0x1f & ~tag))
			while (pdu < end && (*pdu ++ & 0x80));
		if (pdu == end)
			break;

		for (len = 0; pdu + 1 < end && (*pdu & 0x80);
				len = (len | (*pdu ++ & 0x7f)) << 7);
		if (*pdu & 0x80)
			break;
		len |= *pdu ++;

		if (tag == in_tag && pdu + len <= end) {
			if (out_len)
				*out_len = len;
			return pdu;
		}

		pdu += len;
	} while (pdu < end);

	return NULL;
}