coap-timer.h

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/*
 * Copyright (c) 2016, SICS, Swedish ICT AB.
 * 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
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 */
 
/**
 * \file
 *         CoAP timer API.
 * \author
 *         Niclas Finne <nfi@sics.se>
 *         Joakim Eriksson <joakime@sics.se>
 */
 
/**
 * \addtogroup coap
 * @{
 *
 * \defgroup coap-timer CoAP timer API
 * @{
 *
 * The CoAP timer API defines a common interface for CoAP timer and time functionality.
 */
 
#ifndef COAP_TIMER_H_
#define COAP_TIMER_H_
 
#include "contiki.h"
#include <stdint.h>
 
typedef struct coap_timer coap_timer_t;
struct coap_timer {
  coap_timer_t *next;
  void (* callback)(coap_timer_t *);
  void *user_data;
  uint64_t expiration_time;
};
 
typedef struct {
  void     (* init)(void);
  uint64_t (* uptime)(void);
  void     (* update)(void);
} coap_timer_driver_t;
 
#ifndef COAP_TIMER_DRIVER
#ifdef COAP_TIMER_CONF_DRIVER
#define COAP_TIMER_DRIVER COAP_TIMER_CONF_DRIVER
#else /* COAP_TIMER_CONF_DRIVER */
#define COAP_TIMER_DRIVER coap_timer_default_driver
#endif /* COAP_TIMER_CONF_DRIVER */
#endif /* COAP_TIMER_DRIVER */
 
extern const coap_timer_driver_t COAP_TIMER_DRIVER;
 
/**
 * \brief       Get the time since boot in milliseconds.
 * \return      The number of milliseconds since boot.
 */
static inline uint64_t
coap_timer_uptime(void)
{
  return COAP_TIMER_DRIVER.uptime();
}
 
/**
 * \brief       Get the time since boot in seconds.
 * \return      The number of seconds since boot.
 */
static inline uint32_t
coap_timer_seconds(void)
{
  return (uint32_t)(COAP_TIMER_DRIVER.uptime() / 1000);
}
 
/**
 * \brief       Set a callback function to be called when a CoAP timer expires.
 *
 * \param timer A pointer to a CoAP timer.
 * \param callback A callback function.
 */
static inline void
coap_timer_set_callback(coap_timer_t *timer, void (* callback)(coap_timer_t *))
{
  timer->callback = callback;
}
 
/**
 * \brief       Get user data that has been attached to a CoAP timer.
 *
 * \param timer A pointer to a CoAP timer.
 * \return      An opaque pointer to user data or NULL if no user data is
 *              attached to the timer.
 */
static inline void *
coap_timer_get_user_data(coap_timer_t *timer)
{
  return timer->user_data;
}
 
/**
 * \brief       Attach user data to a CoAP timer.
 *
 * \param timer A pointer to a CoAP timer.
 * \param data  An opaque pointer to user data.
 */
static inline void
coap_timer_set_user_data(coap_timer_t *timer, void *data)
{
  timer->user_data = data;
}
 
/**
 * \brief       Check if a CoAP timer has expired.
 *
 * \param timer A pointer to a CoAP timer.
 * \return      Non-zero if the timer has expired, zero otherwise.
 */
static inline int
coap_timer_expired(const coap_timer_t *timer)
{
  return timer->expiration_time <= coap_timer_uptime();
}
 
/**
 * \brief       Stop a pending CoAP timer.
 *
 *              After this function has been called, the timer will be expired
 *              and will not call the callback function.
 *
 * \param timer A pointer to a CoAP timer.
 */
void coap_timer_stop(coap_timer_t *timer);
 
/**
 * \brief       Set a CoAP timer to expire after the specified time.
 *
 * \param timer A pointer to a CoAP timer.
 * \param time  The time until the timer expires.
 */
void coap_timer_set(coap_timer_t *timer, uint64_t time);
 
/**
 * \brief       Reset a CoAP timer to expire a specified time after the
 *              last expiration time.
 *
 *              This function sets the CoAP timer to expire the specified time
 *              after the previous expiration time. If the new expiration time
 *              has already passed, the timer will expire as soon as possible.
 *
 *              If the timer has not yet expired when this function is called,
 *              the time until the timer expires will be extended by the
 *              specified time.
 *
 * \param timer A pointer to a CoAP timer.
 * \param time  The time after previous expiration the timer expires.
 */
void coap_timer_reset(coap_timer_t *timer, uint64_t time);
 
/**
 * Get the time until next CoAP timer expires or 0 if there already exists
 * expired timers that have not yet been processed. This function is normally
 * never called by application code.
 *
 * Returns the time to next CoAP timer expires or 0 if unprocessed expired
 * timers exists. Returns a time in the future if there are no timers pending.
 */
uint64_t coap_timer_time_to_next_expiration(void);
 
/**
 * This function must be called periodically by the CoAP timer driver to
 * process any expired CoAP timers. This function is normally never called by
 * application code.
 *
 * Returns non-zero if it needs to run again to process more timers.
 */
int coap_timer_run(void);
 
/**
 * This function initializes the CoAP timer library. It is automatically
 * called at first use of a CoAP timer. This function is normally never called
 * by application code.
 */
void coap_timer_init(void);
 
#endif /* COAP_TIMER_H_ */
/** @} */
/** @} */