kmtimer.cpp

/*
* Linux multithreaded timer
* =========================
* Author: DJ0ABR
*
*   (c) DJ0ABR
*   www.dj0abr.de

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>
*
* Repeatable Timer for various needs
* ==================================
*
*/

#include "kmtimer.h"

typedef struct _TIMERDEF_ {
	int to_ms;								// timeout value in ms
	timer_t timerid;
	void(*timer_func_handler_pntr)(void);	// this user supplied function is called on timeout
    	struct itimerspec in, out;
} TIMERDEF;

#define MAXTIMERS 20 //maximum number of timers, may be increase if needed
TIMERDEF timers[MAXTIMERS];
int timernum = 0;

// callback function. The timer number is in val.sival_int
void timercallback(union sigval val)
{
	int tnum = val.sival_int;
	timers[tnum].timer_func_handler_pntr();
}

int start_timer(int mSec, void(*timer_func_handler)(void))
{
	timers[timernum].timer_func_handler_pntr = timer_func_handler;
	timers[timernum].to_ms = mSec;

	pthread_attr_t attr;
    	pthread_attr_init( &attr );

    	struct sched_param parm;
    	parm.sched_priority = 255;
    	pthread_attr_setschedparam(&attr, &parm);

	struct sigevent sig;
    	sig.sigev_notify = SIGEV_THREAD;
    	sig.sigev_notify_function = timercallback;
    	sig.sigev_value.sival_int = timernum;
    	sig.sigev_notify_attributes = &attr;
    
    	if (timer_create(CLOCK_REALTIME, &sig, &(timers[timernum].timerid)) == 0)
    	{
        	timers[timernum].in.it_value.tv_sec = mSec / 1000;
        	timers[timernum].in.it_value.tv_nsec = (mSec % 1000) * 1000000;
        	timers[timernum].in.it_interval.tv_sec = mSec / 1000;
        	timers[timernum].in.it_interval.tv_nsec = (mSec % 1000) * 1000000;

        	if(timer_settime(timers[timernum].timerid, 0, &timers[timernum].in, &timers[timernum].out) == -1)
		{
            		printf("timer_settime() failed, error: %d\n", errno);
			return -1;
		}
    	}
	else
	{
		printf("timer_create() failed, error: %d\n", errno);
		return -1;
	}

	int r = timernum;
	timernum++;

	return r;
}


void stop_timer(int timer)
{
	timer_delete(timers[timer].timerid);
}