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counter.c
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counter.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include "counter.h"
struct Counter {
unsigned long n;
unsigned long min;
unsigned long max;
pthread_mutex_t lock;
};
counter_t * counter_create()
{
counter_t *counter;
counter = malloc(sizeof(counter_t));
memset(counter, 0, sizeof(*counter));
counter->min = COUNTER_MIN;
counter->max = COUNTER_MAX;
counter->n = counter->min;
pthread_mutex_init(&counter->lock, NULL);
return counter;
}
void counter_destroy(counter_t *counter)
{
pthread_mutex_destroy(&counter->lock);
free(counter);
}
unsigned long counter_next(counter_t *counter)
{
unsigned long next;
pthread_mutex_lock(&counter->lock);
if( counter->n >= counter->max )
counter->n = counter->min;
next = counter->n++;
pthread_mutex_unlock(&counter->lock);
return next;
}
void counter_reset(counter_t *counter)
{
counter_ctl(counter, COUNTER_CTL_MIN, counter->min);
}
void counter_ctl(counter_t *counter, int opt, unsigned long value)
{
pthread_mutex_lock(&counter->lock);
switch( opt ) {
case COUNTER_CTL_MIN:
counter->min = value;
break;
case COUNTER_CTL_MAX:
counter->max = value;
break;
case COUNTER_CTL_CURRENT:
counter->n = value;
break;
}
pthread_mutex_unlock(&counter->lock);
}