| /* |
| * Copyright (c) 2004, 2008, Swedish Institute of Computer Science. |
| * All rights reserved. |
| * |
| * 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 of the Institute 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 INSTITUTE 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 INSTITUTE 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. |
| * |
| * This file is part of the Contiki operating system. |
| * |
| * Author: Adam Dunkels <adam@sics.se>, Nicolas Tsiftes <nvt@sics.se> |
| * |
| */ |
| |
| /** |
| * \file |
| * Timer of seconds library implementation. |
| * \author |
| * Adam Dunkels <adam@sics.se>, Nicolas Tsiftes <nvt@sics.se> |
| */ |
| |
| /** |
| * \addtogroup stimer |
| * @{ |
| */ |
| |
| #include "contiki-conf.h" |
| #include "sys/clock.h" |
| #include "sys/stimer.h" |
| |
| #define SCLOCK_GEQ(a, b) ((unsigned long)((a) - (b)) < \ |
| ((unsigned long)(~((unsigned long)0)) >> 1)) |
| |
| /*---------------------------------------------------------------------------*/ |
| /** |
| * Set a timer. |
| * |
| * This function is used to set a timer for a time sometime in the |
| * future. The function stimer_expired() will evaluate to true after |
| * the timer has expired. |
| * |
| * \param t A pointer to the timer |
| * \param interval The interval before the timer expires. |
| * |
| */ |
| void |
| stimer_set(struct stimer *t, unsigned long interval) |
| { |
| t->interval = interval; |
| t->start = clock_seconds(); |
| } |
| /*---------------------------------------------------------------------------*/ |
| /** |
| * Reset the timer with the same interval. |
| * |
| * This function resets the timer with the same interval that was |
| * given to the stimer_set() function. The start point of the interval |
| * is the exact time that the timer last expired. Therefore, this |
| * function will cause the timer to be stable over time, unlike the |
| * stimer_restart() function. |
| * |
| * \param t A pointer to the timer. |
| * |
| * \sa stimer_restart() |
| */ |
| void |
| stimer_reset(struct stimer *t) |
| { |
| t->start += t->interval; |
| } |
| /*---------------------------------------------------------------------------*/ |
| /** |
| * Restart the timer from the current point in time |
| * |
| * This function restarts a timer with the same interval that was |
| * given to the stimer_set() function. The timer will start at the |
| * current time. |
| * |
| * \note A periodic timer will drift if this function is used to reset |
| * it. For preioric timers, use the stimer_reset() function instead. |
| * |
| * \param t A pointer to the timer. |
| * |
| * \sa stimer_reset() |
| */ |
| void |
| stimer_restart(struct stimer *t) |
| { |
| t->start = clock_seconds(); |
| } |
| /*---------------------------------------------------------------------------*/ |
| /** |
| * Check if a timer has expired. |
| * |
| * This function tests if a timer has expired and returns true or |
| * false depending on its status. |
| * |
| * \param t A pointer to the timer |
| * |
| * \return Non-zero if the timer has expired, zero otherwise. |
| * |
| */ |
| int |
| stimer_expired(struct stimer *t) |
| { |
| return SCLOCK_GEQ(clock_seconds(), t->start + t->interval); |
| } |
| /*---------------------------------------------------------------------------*/ |
| /** |
| * The time until the timer expires |
| * |
| * This function returns the time until the timer expires. |
| * |
| * \param t A pointer to the timer |
| * |
| * \return The time until the timer expires |
| * |
| */ |
| unsigned long |
| stimer_remaining(struct stimer *t) |
| { |
| return t->start + t->interval - clock_seconds(); |
| } |
| /*---------------------------------------------------------------------------*/ |
| /** |
| * The time elapsed since the timer started |
| * |
| * This function returns the time elapsed. |
| * |
| * \param t A pointer to the timer |
| * |
| * \return The time elapsed since the last start of the timer |
| * |
| */ |
| unsigned long |
| stimer_elapsed(struct stimer *t) |
| { |
| return clock_seconds() - t->start; |
| } |
| |
| /*---------------------------------------------------------------------------*/ |
| |
| /** @} */ |