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/********************************************************************************
* sched/clock_time2ticks.c
*
* Copyright (C) 2007, 2009 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_internal.h"
/********************************************************************************
* Definitions
********************************************************************************/
/********************************************************************************
* Private Type Declarations
********************************************************************************/
/********************************************************************************
* Global Variables
********************************************************************************/
/********************************************************************************
* Private Variables
********************************************************************************/
/********************************************************************************
* Private Functions
********************************************************************************/
/********************************************************************************
* Public Functions
********************************************************************************/
/********************************************************************************
* Name: clock_time2ticks
*
* Description:
* Convert a timespec delay to system timer ticks. This function is suitable
* for calculating relative time delays and does not depend on the other
* clock_* logic.
*
* Parameters:
* reltime - Convert this relative time to system clock ticks.
* ticks - Return the converted number of ticks here.
*
* Return Value:
* Always returns OK
*
* Assumptions:
*
********************************************************************************/
int clock_time2ticks(FAR const struct timespec *reltime, FAR int *ticks)
{
#ifdef CONFIG_HAVE_LONG_LONG
int64_t relnsec;
/* Convert the relative time into nanoseconds. The range of the int64_t is
* sufficiently large that there is no real need for range checking.
*/
relnsec = (int64_t)reltime->tv_sec * NSEC_PER_SEC +
(int64_t)reltime->tv_nsec;
/* Convert nanoseconds to clock ticks, rounding up to the smallest integer
* that is greater than or equal to the exact number of tick.
*/
*ticks = (int)((relnsec + NSEC_PER_TICK - 1) / NSEC_PER_TICK);
return OK;
#else
int32_t relusec;
/* This function uses an int32_t to only the relative time in microseconds.
* that means that the maximum supported relative time is 2,147,487.647
* seconds
*/
#if 0 // overkill
DEBUGASSERT(reltime->tv_sec < 2147487 ||
reltime->tv_sec == 2147487 &&
reltime->tv_nsec <= 647 * NSEC_PER_MSEC);
#endif
/* Convert the relative time into microseconds, rounding up to the smallest
* value that is greater than or equal to the exact number of microseconds.
*/
relusec = reltime->tv_sec * USEC_PER_SEC +
(reltime->tv_nsec + NSEC_PER_USEC - 1) / NSEC_PER_USEC;
/* Convert microseconds to clock ticks, rounding up to the smallest integer
* that is greater than or equal to the exact number of tick.
*/
*ticks = (int)((relusec + USEC_PER_TICK - 1) / USEC_PER_TICK);
return OK;
#endif
}
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