evtimer.h
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/*
* Copyright (C) 2016-17 Kaspar Schleiser <kaspar@schleiser.de>
* 2017 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup sys_evtimer Millisecond interval event timers
* @ingroup sys
* @brief Provides timers for events up to @$2^{32}@$ milliseconds in the
* future
*
* @note Experimental and likely to replaced with unified timer API
*
* RIOT's main timer subsystem is @ref sys_xtimer "xtimer", but for many
* applications @ref sys_xtimer "xtimer's" 64-bit absolute time values are
* wasteful or clumsy to use.
*
* Compared to @ref sys_xtimer "xtimer", evtimer offers:
*
* - only relative 32-bit millisecond timer values
* Events can be scheduled with a relative offset of up to ~49.7 days in the
* future.
* **For time-critical stuff, use @ref sys_xtimer "xtimer"!**
* - more flexible, "intrusive" timer type @ref evtimer_event_t only contains
* the necessary fields, which can be extended as needed, and handlers define
* actions taken on timer triggers. Check out @ref evtimer_msg_event_t as
* example.
* - uses @ref sys_xtimer "xtimer" as backend
*
* @{
*
* @file
* @brief evtimer API definitions
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
* @author Martine Lenders <m.lenders@fu-berlin.de>
*/
#ifndef EVTIMER_H
#define EVTIMER_H
#include <stdint.h>
#include "xtimer.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Generic event
*/
typedef struct evtimer_event {
struct evtimer_event *next; /**< the next event in the queue */
uint32_t offset; /**< offset in milliseconds from previous event */
} evtimer_event_t;
/**
* @brief Event timer callback type
*/
typedef void(*evtimer_callback_t)(evtimer_event_t* event);
/**
* @brief Event timer
*/
typedef struct {
xtimer_t timer; /**< Timer */
evtimer_callback_t callback; /**< Handler function for this evtimer's
event type */
evtimer_event_t *events; /**< Event queue */
} evtimer_t;
/**
* @brief Initializes an event timer
*
* @param[in] evtimer An event timer
* @param[in] handler An event handler function
*/
void evtimer_init(evtimer_t *evtimer, evtimer_callback_t handler);
/**
* @brief Adds event to an event timer
*
* @param[in] evtimer An event timer
* @param[in] event An event
*/
void evtimer_add(evtimer_t *evtimer, evtimer_event_t *event);
/**
* @brief Removes an event from an event timer
*
* @param[in] evtimer An event timer
* @param[in] event An event
*/
void evtimer_del(evtimer_t *evtimer, evtimer_event_t *event);
/**
* @brief Print overview of current state of an event timer
*
* @param[in] evtimer An event timer
*/
void evtimer_print(const evtimer_t *evtimer);
#ifdef __cplusplus
}
#endif
#endif /* EVTIMER_H */
/** @} */