mytimer.c

/* =====================================================================
   Copyright © 2016, Avnet (R)

   www.avnet.com 
 
   Licensed under the Apache License, Version 2.0 (the "License"); 
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, 
   software distributed under the License is distributed on an 
   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, 
   either express or implied. See the License for the specific 
   language governing permissions and limitations under the License.

    @file          mytimer.c
    @version       1.0
    @date          Sept 2017

======================================================================== */

/*mytimer.c*/
 
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <sys/timerfd.h>
#include <pthread.h>
#include <poll.h>
#include <stdio.h>
 
#include "mytimer.h"
 
#define MAX_TIMER_COUNT 1000
 
static void * _timer_thread(void * data);
static pthread_t g_thread_id;
static struct timer_node *g_head = NULL;
static int IoTtimers_running = 0;
 
int active_IoTtimer(void)
{
    return (IoTtimers_running>0);
}

int start_IoTtimers()
{
    IoTtimers_running++;
    if (IoTtimers_running>1)
        return IoTtimers_running;

    if(pthread_create(&g_thread_id, NULL, _timer_thread, NULL)) 
        return 0;
 
    return (IoTtimers_running = 1);
}
 
void stop_IoTtimers()
{
    IoTtimers_running--;

    if (!IoTtimers_running) {
        while(g_head) 
          delete_IoTtimer((size_t)g_head);
 
        pthread_cancel(g_thread_id);
        pthread_join(g_thread_id, NULL);
        }
}
 
size_t create_IoTtimer(unsigned int interval, time_handler handler, t_timer type, void * user_data)
{
    struct timer_node * new_node = NULL;
    struct itimerspec new_value;
 
    new_node = (struct timer_node *)malloc(sizeof(struct timer_node));
 
    if(new_node == NULL) return 0;
 
    new_node->callback  = handler;
    new_node->user_data = user_data;
    new_node->interval  = interval;
    new_node->type      = type;
 
    new_node->fd = timerfd_create(CLOCK_REALTIME, 0);
 
    if (new_node->fd == -1)
    {
        free(new_node);
        return 0;
    }
 
    new_value.it_value.tv_sec  = interval;
    new_value.it_value.tv_nsec = 0;
 
    if (type == TIMER_PERIODIC)
    {
        new_value.it_interval.tv_sec = interval;
    }
    else
    {
        new_value.it_interval.tv_sec = 0;
    }
    
    new_value.it_interval.tv_nsec = 0;
 
    timerfd_settime(new_node->fd, 0, &new_value, NULL);
 
    /*Inserting the timer node into the list*/
    new_node->next = g_head;
    g_head = new_node;
 
    return (size_t)new_node;
}
 
void delete_IoTtimer(size_t timer_id)
{
    struct timer_node * tmp = NULL;
    struct timer_node * node = (struct timer_node *)timer_id;
 
    if (node == NULL) return;
 
    close(node->fd);
 
    if(node == g_head)
    {
        g_head = g_head->next;
    }
 
    tmp = g_head;
 
    while(tmp && tmp->next != node) tmp = tmp->next;
 
    if(tmp && tmp->next)
    {
        tmp->next = tmp->next->next;
    }
 
    if(node) free(node);
}
 
void change_IoTtimer(size_t timer_id, int newperiod)
{
    struct timer_node * node = (struct timer_node *)timer_id;
 
    if (node == NULL) return;
 
    node->interval  = newperiod;
}
 
struct timer_node * _get_timer_from_fd(int fd)
{
    struct timer_node * tmp = g_head;
 
    while(tmp)
    {
        if(tmp->fd == fd) return tmp;
 
        tmp = tmp->next;
    }
    return NULL;
}
 
void * _timer_thread(void * data)
{
    struct pollfd ufds[MAX_TIMER_COUNT] = {{0}};
    int iMaxCount = 0;
    struct timer_node * tmp = NULL;
    int read_fds = 0, i, s;
    uint64_t exp;
 
    while(1)
    {
        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
        pthread_testcancel();
        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
 
        iMaxCount = 0;
        tmp = g_head;
 
        memset(ufds, 0, sizeof(struct pollfd)*MAX_TIMER_COUNT);
        while(tmp)
        {
            ufds[iMaxCount].fd = tmp->fd;
            ufds[iMaxCount].events = POLLIN;
            iMaxCount++;
 
            tmp = tmp->next;
        }
        read_fds = poll(ufds, iMaxCount, 100);
 
        if (read_fds <= 0) continue;
 
        for (i = 0; i < iMaxCount; i++)
        {
            if (ufds[i].revents & POLLIN)
            {
                s = read(ufds[i].fd, &exp, sizeof(uint64_t));
 
                if (s != sizeof(uint64_t)) continue;
 
                tmp = _get_timer_from_fd(ufds[i].fd);
 
                if(tmp && tmp->callback) tmp->callback((size_t)tmp, tmp->user_data);
            }
        }
    }
 
    return NULL;
}

size_t create_ms_IoTtimer(unsigned int interval, time_handler handler, t_timer type, void * user_data)
{
    struct timer_node * new_node = NULL;
    struct itimerspec new_value;
    unsigned long intval = interval*1000000;  //convert ms to nsec
 
    new_node = (struct timer_node *)malloc(sizeof(struct timer_node));
 
    if(new_node == NULL) return 0;

 
    new_node->callback  = handler;
    new_node->user_data = user_data;
    new_node->interval  = intval;;
    new_node->type      = type;
 
    new_node->fd = timerfd_create(CLOCK_REALTIME, 0);
 
    if (new_node->fd == -1)
    {
        free(new_node);
        return 0;
    }

    new_value.it_value.tv_sec  = 0;
    new_value.it_value.tv_nsec = intval;;
 
    if (type == TIMER_PERIODIC)
    {
        new_value.it_interval.tv_nsec = intval;;
    }
    else
    {
        new_value.it_interval.tv_nsec = 0;
    }
    
    new_value.it_interval.tv_sec = 0;
 


    timerfd_settime(new_node->fd, 0, &new_value, NULL);
 
    /*Inserting the timer node into the list*/
    new_node->next = g_head;
    g_head = new_node;
 
    return (size_t)new_node;
}