129 lines
3.9 KiB
C
129 lines
3.9 KiB
C
/****************************************************************************
|
|
* sched/clock/clock_abstime2ticks.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* 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);
|
|
}
|