110 lines
2.4 KiB
C
110 lines
2.4 KiB
C
#include <assert.h>
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#include <pthread.h>
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#include <semaphore.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "common.h"
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#include "common_threads.h"
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int max;
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int loops;
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int *buffer;
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int use_ptr = 0;
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int fill_ptr = 0;
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int num_full = 0;
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pthread_cond_t empty = PTHREAD_COND_INITIALIZER;
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pthread_cond_t fill = PTHREAD_COND_INITIALIZER;
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pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
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int consumers = 1;
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int verbose = 1;
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void do_fill(int value) {
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buffer[fill_ptr] = value;
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fill_ptr = (fill_ptr + 1) % max;
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num_full++;
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}
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int do_get() {
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int tmp = buffer[use_ptr];
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use_ptr = (use_ptr + 1) % max;
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num_full--;
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return tmp;
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}
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void *producer(void *arg) {
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int i;
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for (i = 0; i < loops; i++) {
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Mutex_lock(&m); // p1
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while (num_full == max) // p2
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Cond_wait(&empty, &m); // p3
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do_fill(i); // p4
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Cond_signal(&fill); // p5
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Mutex_unlock(&m); // p6
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}
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// end case: put an end-of-production marker (-1)
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// into shared buffer, one per consumer
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for (i = 0; i < consumers; i++) {
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Mutex_lock(&m);
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while (num_full == max)
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Cond_wait(&empty, &m);
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do_fill(-1);
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Cond_signal(&fill);
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Mutex_unlock(&m);
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}
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return NULL;
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}
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void *consumer(void *arg) {
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int tmp = 0;
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// consumer: keep pulling data out of shared buffer
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// until you receive a -1 (end-of-production marker)
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while (tmp != -1) {
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Mutex_lock(&m); // c1
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while (num_full == 0) // c2
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Cond_wait(&fill, &m); // c3
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tmp = do_get(); // c4
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Cond_signal(&empty); // c5
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Mutex_unlock(&m); // c6
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}
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return NULL;
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}
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int
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main(int argc, char *argv[])
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{
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if (argc != 4) {
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fprintf(stderr, "usage: %s <buffersize> <loops> <consumers>\n", argv[0]);
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exit(1);
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}
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max = atoi(argv[1]);
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loops = atoi(argv[2]);
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consumers = atoi(argv[3]);
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buffer = (int *) malloc(max * sizeof(int));
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assert(buffer != NULL);
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int i;
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for (i = 0; i < max; i++) {
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buffer[i] = 0;
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}
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pthread_t pid, cid[consumers];
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Pthread_create(&pid, NULL, producer, NULL);
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for (i = 0; i < consumers; i++) {
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Pthread_create(&cid[i], NULL, consumer, (void *) (long long int) i);
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}
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Pthread_join(pid, NULL);
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for (i = 0; i < consumers; i++) {
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Pthread_join(cid[i], NULL);
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}
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return 0;
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}
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