Lab6: add monitor code

lab6/demos/monitor.c

@@ -0,0 +1,95 @@
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct {
+    int* buffer;
+    int buffer_len;
+    int buffer_cap;
+    pthread_mutex_t mutex;
+    pthread_cond_t not_full;
+    pthread_cond_t not_empty;
+} monitor_t;
+
+volatile monitor_t monitor;
+
+monitor_t* init_monitor(int buffer_cap) {
+    monitor_t* monitor = malloc(sizeof(monitor_t));
+
+    monitor->buffer = calloc(buffer_cap, sizeof(int));
+    monitor->buffer_len = 0;
+    monitor->buffer_cap = buffer_cap;
+    pthread_mutex_init(&monitor->mutex, NULL);
+    pthread_cond_init(&monitor->not_full, NULL);
+    pthread_cond_init(&monitor->not_empty, NULL);
+
+    return monitor;
+}
+
+void destroy_monitor(monitor_t* monitor) {
+    pthread_mutex_destroy(&monitor->mutex);
+    pthread_cond_destroy(&monitor->not_full);
+    pthread_cond_destroy(&monitor->not_empty);
+
+    free(monitor->buffer);
+    free(monitor);
+}
+
+void produce(monitor_t* monitor, int item) {
+    pthread_mutex_lock(&monitor->mutex);
+    while (monitor->buffer_len == monitor->buffer_cap) {
+        pthread_cond_wait(&monitor->not_full, &monitor->mutex);
+    }
+    monitor->buffer[monitor->buffer_len] = item;
+    monitor->buffer_len += 1;
+    pthread_cond_signal(&monitor->not_empty);
+    pthread_mutex_unlock(&monitor->mutex);
+}
+
+int consume(monitor_t* monitor) {
+    pthread_mutex_lock(&monitor->mutex);
+    while (monitor->buffer_len == 0) {
+        pthread_cond_wait(&monitor->not_empty, &monitor->mutex);
+    }
+
+    monitor->buffer_len -= 1;
+    int item = monitor->buffer[monitor->buffer_len];
+    pthread_cond_signal(&monitor->not_full);
+    pthread_mutex_unlock(&monitor->mutex);
+
+    return item;
+}
+
+void* producer_func(void* arg) {
+    monitor_t* monitor = arg;
+
+    for (int i = 0; i < 20; i++) {
+        produce(monitor, i);
+        printf("Produced item %d\n", i);
+    }
+    pthread_exit(NULL);
+}
+
+void* consumer_func(void* arg) {
+    monitor_t* monitor = arg;
+    for (int i = 0; i < 20; i++) {
+        int item = consume(monitor);
+        printf("Consumed item %d\n", item);
+    }
+    pthread_exit(NULL);
+}
+
+int main(void) {
+    pthread_t thread_producer, thread_consumer;
+
+    fprintf(stderr, "Line: %d\n", __LINE__);
+    monitor_t* monitor = init_monitor(3);
+
+    pthread_create(&thread_producer, NULL, producer_func, (void*) monitor);
+    pthread_create(&thread_consumer, NULL, consumer_func, (void*) monitor);
+
+    pthread_join(thread_producer, NULL);
+    pthread_join(thread_consumer, NULL);
+
+    destroy_monitor(monitor);
+}