nuttx/sched/clock/clock_timespec_subtract.c
Juha Niskanen a762c06ed9 Fix typos and some incorrect comments
Author: Alan Carvalho de Assis <acassis@gmail.com>

    Run nxstyle against .c and .h files and fix it

Author: Juha Niskanen <juha.niskanen@haltian.com>

    Fix typos and some incorrect comments
2020-01-20 09:32:36 -03:00

101 lines
3.4 KiB
C

/****************************************************************************
* 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)
* ts3: 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;
}