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- /****************************************************************************
- * sched/clock/clock_abstime2ticks.c
- *
- * Copyright (C) 2007, 2008, 2013-2014, 2016 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 <time.h>
- #include <errno.h>
- #include <debug.h>
- #include "clock/clock.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: clock_timespec_compare
- *
- * Description:
- * Return < 0 if time a is before time b
- * Return > 0 if time b is before time a
- * Return 0 if time a is the same as time b
- *
- ****************************************************************************/
- int clock_timespec_compare(FAR const struct timespec *a,
- FAR const struct timespec *b)
- {
- if (a->tv_sec < b->tv_sec)
- {
- return -1;
- }
- if (a->tv_sec > b->tv_sec)
- {
- return 1;
- }
- return a->tv_nsec - b->tv_nsec;
- }
- /****************************************************************************
- * Name: clock_abstime2ticks
- *
- * Description:
- * Convert an absolute timespec delay to system timer ticks.
- *
- * Input Parameters:
- * clockid - The timing source to use in the conversion
- * reltime - Convert this absolute time to system clock ticks.
- * ticks - Return the converted number of ticks here.
- *
- * Returned Value:
- * OK on success; A non-zero error number on failure
- *
- * Assumptions:
- * Interrupts should be disabled so that the time is not changing during
- * the calculation
- *
- ****************************************************************************/
- int clock_abstime2ticks(clockid_t clockid, FAR const struct timespec *abstime,
- FAR sclock_t *ticks)
- {
- struct timespec currtime;
- struct timespec reltime;
- int ret;
- /* Convert the timespec to clock ticks. NOTE: Here we use internal knowledge
- * that CLOCK_REALTIME is defined to be zero!
- */
- ret = clock_gettime(clockid, &currtime);
- if (ret != OK)
- {
- return EINVAL;
- }
- if (clock_timespec_compare(abstime, &currtime) < 0)
- {
- /* Every caller of clock_abstime2ticks check 'ticks < 0' to see if
- * absolute time is in the past. So lets just return negative tick
- * here.
- */
- *ticks = -1;
- return OK;
- }
- /* The relative time to wait is the absolute time minus the current time. */
- reltime.tv_nsec = (abstime->tv_nsec - currtime.tv_nsec);
- reltime.tv_sec = (abstime->tv_sec - currtime.tv_sec);
- /* Check if we were supposed to borrow from the seconds. */
- if (reltime.tv_nsec < 0)
- {
- reltime.tv_nsec += NSEC_PER_SEC;
- reltime.tv_sec -= 1;
- }
- /* Convert this relative time into clock ticks. */
- return clock_time2ticks(&reltime, ticks);
- }
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