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Diffstat (limited to 'nuttx/sched/clock_abstime2ticks.c')
-rw-r--r-- | nuttx/sched/clock_abstime2ticks.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/nuttx/sched/clock_abstime2ticks.c b/nuttx/sched/clock_abstime2ticks.c new file mode 100644 index 000000000..2d7f7f480 --- /dev/null +++ b/nuttx/sched/clock_abstime2ticks.c @@ -0,0 +1,126 @@ +/******************************************************************************** + * clock_abstime2ticks.c + * + * Copyright (C) 2007, 2008 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_internal.h" + +/******************************************************************************** + * Definitions + ********************************************************************************/ + +/******************************************************************************** + * Private Type Declarations + ********************************************************************************/ + +/******************************************************************************** + * Global Variables + ********************************************************************************/ + +/******************************************************************************** + * Private Variables + ********************************************************************************/ + +/******************************************************************************** + * Private Functions + ********************************************************************************/ + +/******************************************************************************** + * Public Functions + ********************************************************************************/ + +/******************************************************************************** + * Name: clock_abstime2ticks + * + * Description: + * Convert an absolute timespec delay to system timer ticks. + * + * Parameters: + * clockid - The timing source to use in the conversion + * reltime - Convert this absolue time to system clock ticks. + * ticks - Return the converted number of ticks here. + * + * Return 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 int *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) + { + return EINVAL; + } + + /* 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 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 microseconds.*/ + + return clock_time2ticks(&reltime, ticks); +} |