/**

 * @file clockcheck.h

 * @brief Implements clock sanity checking.

 * @note Copyright (C) 2013 Miroslav Lichvar <mlichvar@redhat.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.

 */

#ifndef HAVE_CLOCKCHECK_H

#define HAVE_CLOCKCHECK_H

#include <stdint.h>

/** Opaque type */

struct clockcheck;

/**

 * Create a new instance of a clock sanity check.

 * @param freq_limit The maximum allowed frequency offset between uncorrected

 *                   clock and the system monotonic clock in ppb.

 * @return A pointer to a new clock check on success, NULL otherwise.

 */

struct clockcheck *clockcheck_create(int freq_limit);

/**

 * Perform the sanity check on a time stamp.

 * @param cc Pointer to a clock check obtained via @ref clockcheck_create().

 * @param ts Time stamp made by the clock in nanoseconds.

 * @return Zero if ts passed the check, non-zero otherwise.

 */

int clockcheck_sample(struct clockcheck *cc, uint64_t ts);

/**

 * Inform clock check about changes in current frequency of the clock.

 * @param cc   Pointer to a clock check obtained via @ref clockcheck_create().

 * @param freq Frequency correction applied to the clock in ppb.

 */

void clockcheck_set_freq(struct clockcheck *cc, int freq);

/**

 * Inform clock check that the clock was stepped.

 * @param cc   Pointer to a clock check obtained via @ref clockcheck_create().

 * @param step Step correction applied to the clock in nanoseconds.

 */

void clockcheck_step(struct clockcheck *cc, int64_t step);

/**

 * Destroy a clock check.

 * @param cc Pointer to a clock check obtained via @ref clockcheck_create().

 */

void clockcheck_destroy(struct clockcheck *cc);

#endif