/*
* Copyright 2021 Jeisson Hidalgo-Cespedes - Universidad de Costa Rica
* Creates a secondary thread that greets in the standard output
*/
#include <assert.h>
#include <inttypes.h>
#include <pthread.h>
#include <semaphore.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
typedef struct queue_node {
size_t product_number;
struct queue_node* next;
} queue_node_t;
/**
* Thread-safe queue
*/
typedef struct queue {
queue_node_t* head;
queue_node_t* tail;
pthread_mutex_t mutex;
} queue_t;
int queue_init(queue_t* queue);
int queue_destroy(queue_t* queue);
bool queue_is_empty(queue_t* queue);
int queue_append(queue_t* queue, size_t data);
/**
* @remarks Queue must be not empty, otherwise it will crash
*/
size_t queue_dequeue(queue_t* queue);
int queue_free(queue_t* queue);
typedef struct shared_data {
size_t product_count;
size_t next_product_index;
pthread_mutex_t next_product_mutex;
queue_t queue;
size_t producer_count;
size_t consumer_count;
useconds_t min_producer_delay;
useconds_t max_producer_delay;
useconds_t min_consumer_delay;
useconds_t max_consumer_delay;
sem_t can_consume;
pthread_mutex_t stdout_mutex;
} shared_thread_data_t;
typedef struct private_thread_data {
size_t thread_number; // rank
shared_thread_data_t* shared_data;
} private_thread_data_t;
int analyze_arguments(int argc, char* argv[]
, shared_thread_data_t* shared_data);
int simulate_producer_consumer(shared_thread_data_t* shared_data);
int create_threads(shared_thread_data_t* shared_data);
void* produce(void* data);
void* consume(void* data);
/**
* @param min must be less than @a max
* @param max must be greater than @a min
*/
void random_delay(useconds_t min, useconds_t max);
int main(int argc, char* argv[]) {
int error = 0;
struct timespec time;
clock_gettime(/*clk_id*/CLOCK_MONOTONIC, &time);
srand(time.tv_nsec);
shared_thread_data_t* shared_data = (shared_thread_data_t*)
calloc(1, sizeof(shared_thread_data_t));
error = analyze_arguments(argc, argv, shared_data);
if (error == EXIT_SUCCESS) {
error = simulate_producer_consumer(shared_data);
}
return error;
}
int analyze_arguments(int argc, char* argv[]
, shared_thread_data_t* shared_data) {
int error = 0;
if (argc == 8) {
if (sscanf(argv[1], "%zu", &shared_data->product_count) != 1
|| shared_data->product_count == 0) {
fprintf(stderr, "error: invalid product count\n");
error = 2;
} else if (sscanf(argv[2], "%zu", &shared_data->producer_count) != 1
|| shared_data->producer_count == 0) {
fprintf(stderr, "error: invalid producer count\n");
error = 3;
} else if (sscanf(argv[3], "%zu", &shared_data->consumer_count) != 1
|| shared_data->consumer_count == 0) {
fprintf(stderr, "error: invalid consumer count\n");
error = 4;
} else if (sscanf(argv[4], "%u"
, &shared_data->min_producer_delay) != 1) {
fprintf(stderr, "error: invalid min producer delay\n");
error = 5;
} else if (sscanf(argv[5], "%u"
, &shared_data->max_producer_delay) != 1) {
fprintf(stderr, "error: invalid max producer delay\n");
error = 6;
} else if (sscanf(argv[6], "%u"
, &shared_data->min_consumer_delay) != 1) {
fprintf(stderr, "error: invalid min consumer delay\n");
error = 7;
} else if (sscanf(argv[7], "%u"
, &shared_data->max_consumer_delay) != 1) {
fprintf(stderr, "error: invalid max consumer delay\n");
error = 8;
}
} else {
fprintf(stderr, "usage: producer_consumer product_count producers consumers"
" min_producer_delay max_producer_delay"
" min_consumer_delay max_consumer_delay\n");
error = 1;
}
return error;
}
int simulate_producer_consumer(shared_thread_data_t* shared_data) {
assert(shared_data);
int error = 0;
if (shared_data) {
error += queue_init(&shared_data->queue);
error += sem_init(&shared_data->can_consume, /*pshared*/0, 0);
error += pthread_mutex_init(&shared_data->stdout_mutex, /*attr*/NULL);
error += pthread_mutex_init(&shared_data->next_product_mutex
, /*attr*/NULL);
if (error == 0) {
struct timespec start_time, finish_time;
clock_gettime(/*clk_id*/CLOCK_MONOTONIC, &start_time);
error = create_threads(shared_data);
clock_gettime(/*clk_id*/CLOCK_MONOTONIC, &finish_time);
double elapsed_time = finish_time.tv_sec - start_time.tv_sec +
(finish_time.tv_nsec - start_time.tv_nsec) * 1e-9;
printf("execution time: %.9lfs\n", elapsed_time);
pthread_mutex_destroy(&shared_data->next_product_mutex);
pthread_mutex_destroy(&shared_data->stdout_mutex);
} else {
fprintf(stderr, "error: could not init mutex\n");
error = 11;
}
queue_free(&shared_data->queue);
queue_destroy(&shared_data->queue);
free(shared_data);
} else {
fprintf(stderr, "error: could not allocated shared memory\n");
error = 12;
}
return error;
}
int create_threads(shared_thread_data_t* shared_data) {
assert(shared_data);
int error = 0;
const size_t thread_count = shared_data->producer_count
+ shared_data->consumer_count;
pthread_t* threads = (pthread_t*) malloc(thread_count * sizeof(pthread_t));
private_thread_data_t* private_data = (private_thread_data_t*)
calloc(thread_count, sizeof(private_thread_data_t));
if (threads && private_data) {
for (size_t index = 0; index < shared_data->producer_count; ++index) {
private_data[index].thread_number = index;
private_data[index].shared_data = shared_data;
error = pthread_create(&threads[index], NULL, produce
, &private_data[index]);
if (error) {
fprintf(stderr, "error: could not create thread %zu\n", index);
error = 21;
break;
}
}
for (size_t index = 0; index < shared_data->consumer_count; ++index) {
const size_t array_index = shared_data->producer_count + index;
private_data[array_index].thread_number = index;
private_data[array_index].shared_data = shared_data;
error = pthread_create(&threads[array_index], NULL, consume
, &private_data[array_index]);
if (error) {
fprintf(stderr, "error: could not create thread %zu\n", array_index);
error = 21;
break;
}
}
for (size_t index = 0; index < thread_count; ++index) {
pthread_join(threads[index], NULL);
}
free(private_data);
free(threads);
} else {
fprintf(stderr, "error: could not allocate memory for %zu threads\n"
, thread_count);
error = 22;
}
return error;
}
void* produce(void* data) {
assert(data);
private_thread_data_t* private_data = (private_thread_data_t*)data;
shared_thread_data_t *shared_data = private_data->shared_data;
while (true) {
pthread_mutex_lock(&shared_data->next_product_mutex);
size_t product_index = shared_data->next_product_index++;
pthread_mutex_unlock(&shared_data->next_product_mutex);
if (product_index >= shared_data->product_count) {
break;
}
random_delay(shared_data->min_producer_delay
, shared_data->max_producer_delay);
queue_append(&shared_data->queue, product_index);
sem_post(&shared_data->can_consume);
pthread_mutex_lock(&shared_data->stdout_mutex);
printf("%zu produced %zu\n", private_data->thread_number
, product_index + 1);
pthread_mutex_unlock(&shared_data->stdout_mutex);
}
return NULL;
}
void* consume(void* data) {
assert(data);
private_thread_data_t* private_data = (private_thread_data_t*)data;
shared_thread_data_t *shared_data = private_data->shared_data;
while (true) {
pthread_mutex_lock(&shared_data->next_product_mutex);
size_t product_index = shared_data->next_product_index;
pthread_mutex_unlock(&shared_data->next_product_mutex);
sem_wait(&shared_data->can_consume);
product_index = queue_dequeue(&shared_data->queue);
pthread_mutex_lock(&shared_data->stdout_mutex);
printf("\t\t%zu consuming %zu\n", private_data->thread_number
, product_index + 1);
pthread_mutex_unlock(&shared_data->stdout_mutex);
random_delay(shared_data->min_consumer_delay
, shared_data->max_consumer_delay);
if (product_index >= shared_data->product_count
+ shared_data->producer_count) {
break;
}
// pthread_mutex_lock(&shared_data->stdout_mutex);
// printf("\t\t%zu consumed %zu\n", private_data->thread_number
// , product_index + 1);
// pthread_mutex_unlock(&shared_data->stdout_mutex);
}
return NULL;
}
void random_delay(useconds_t min, useconds_t max) {
assert(min <= max);
useconds_t milliseconds = min;
if (max > min) {
milliseconds += rand() % (max - min);
}
usleep(milliseconds * 1000);
}
// ------------ queue.c
bool queue_is_empty_private(const queue_t* queue);
int queue_init(queue_t* queue) {
assert(queue);
return pthread_mutex_init(&queue->mutex, /*attr*/NULL);
}
int queue_destroy(queue_t* queue) {
assert(queue);
return pthread_mutex_destroy(&queue->mutex);
}
bool queue_is_empty_private(const queue_t* queue) {
assert(queue);
return queue->head == NULL;
}
int queue_append(queue_t* queue, size_t data) {
assert(queue);
int error = 0;
queue_node_t* new_node = (queue_node_t*)calloc(1, sizeof(queue_node_t));
if (new_node) {
new_node->product_number = data;
pthread_mutex_lock(&queue->mutex);
if (queue_is_empty_private(queue)) {
queue->head = queue->tail = new_node;
} else {
queue->tail = queue->tail->next = new_node;
}
pthread_mutex_unlock(&queue->mutex);
} else {
fprintf(stderr, "error: could not allocate memory for a queue node\n");
error = 41;
}
return error;
}
bool queue_is_empty(queue_t* queue) {
assert(queue);
pthread_mutex_lock(&queue->mutex);
bool result = queue->head == NULL;
pthread_mutex_unlock(&queue->mutex);
return result;
}
int queue_free(queue_t* queue) {
assert(queue);
return 0;
}
size_t queue_dequeue(queue_t* queue) {
assert(queue);
pthread_mutex_lock(&queue->mutex);
assert(queue_is_empty_private(queue) == false);
queue_node_t* first = queue->head;
size_t data = first->product_number;
queue->head = first->next;
free(first);
if (queue->head == NULL) {
queue->tail = NULL;
}
pthread_mutex_unlock(&queue->mutex);
return data;
}