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