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- /****************************************************************************
- * sched/clock/clock_timespec_subtract.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
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <stdint.h>
- #include <time.h>
- #include "clock/clock.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: clock_timespec_subtract
- *
- * Description:
- * Subtract timespec ts2 from to1 and return the result in ts3.
- * Zero is returned if the time difference is negative.
- *
- * Input Parameters:
- * ts1 and ts2: The two timespecs to be subtracted (ts1 - ts2)
- * t23: The location to return the result (may be ts1 or ts2)
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
- void clock_timespec_subtract(FAR const struct timespec *ts1,
- FAR const struct timespec *ts2,
- FAR struct timespec *ts3)
- {
- time_t sec;
- long nsec;
- if (ts1->tv_sec < ts2->tv_sec)
- {
- sec = 0;
- nsec = 0;
- }
- else if (ts1->tv_sec == ts2->tv_sec && ts1->tv_nsec <= ts2->tv_nsec)
- {
- sec = 0;
- nsec = 0;
- }
- else
- {
- sec = ts1->tv_sec - ts2->tv_sec;
- if (ts1->tv_nsec < ts2->tv_nsec)
- {
- nsec = (ts1->tv_nsec + NSEC_PER_SEC) - ts2->tv_nsec;
- sec--;
- }
- else
- {
- nsec = ts1->tv_nsec - ts2->tv_nsec;
- }
- }
- ts3->tv_sec = sec;
- ts3->tv_nsec = nsec;
- }
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