nuttx/sched/clock/clock_timespec_add.c

/****************************************************************************
 * sched/clock/clock_timespec_add.c
 *
 *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <time.h>

#include "clock/clock.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name:  clock_timespec_add
 *
 * Description:
 *   Add timespec ts1 to to2 and return the result in ts3
 *
 * Input Parameters:
 *   ts1 and ts2: The two timespecs to be added
 *   t23: The location to return the result (may be ts1 or ts2)
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void clock_timespec_add(FAR const struct timespec *ts1,
                        FAR const struct timespec *ts2,
                        FAR struct timespec *ts3)
{
  time_t sec = ts1->tv_sec + ts2->tv_sec;
  long nsec  = ts1->tv_nsec + ts2->tv_nsec;

  if (nsec >= NSEC_PER_SEC)
    {
      nsec -= NSEC_PER_SEC;
      sec++;
    }

  ts3->tv_sec  = sec;
  ts3->tv_nsec = nsec;
}