/**

 * @file sysoff.h

 * @brief Implements the system offset estimation method.

 * @note Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>

 *

 * 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

 * (at your option) 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.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include <stdint.h>

enum {

	SYSOFF_COMPILE_TIME_MISSING = -2,

	SYSOFF_RUN_TIME_MISSING = -1,

	SYSOFF_PRECISE,

	SYSOFF_EXTENDED,

	SYSOFF_BASIC,

	SYSOFF_LAST,

};

/**

 * Check to see if a PTP_SYS_OFFSET ioctl is supported.

 * @param fd  An open file descriptor to a PHC device.

 * @return  One of the SYSOFF_ enumeration values.

 */

int sysoff_probe(int fd, int n_samples);

/**

 * Measure the offset between a PHC and the system time.

 * @param fd         An open file descriptor to a PHC device.

 * @param method     A non-negative SYSOFF_ value returned by sysoff_probe().

 * @param n_samples  The number of consecutive readings to make.

 * @param result     The estimated offset in nanoseconds.

 * @param ts         The system time corresponding to the 'result'.

 * @param delay      The delay in reading of the clock in nanoseconds.

 * @return  One of the SYSOFF_ enumeration values.

 */

int sysoff_measure(int fd, int method, int n_samples,

		   int64_t *result, uint64_t *ts, int64_t *delay);