From 7a73162607544204032aa66cce755daf21edebda Mon Sep 17 00:00:00 2001
From: Matt Strapp <matt@mattstrapp.net>
Date: Tue, 24 May 2022 11:18:46 -0500
Subject: Graduate

Signed-off-by: Matt Strapp <matt@mattstrapp.net>
---
 csci4061/112320_breakout/sol-semaphore.c | 128 +++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 csci4061/112320_breakout/sol-semaphore.c

(limited to 'csci4061/112320_breakout/sol-semaphore.c')

diff --git a/csci4061/112320_breakout/sol-semaphore.c b/csci4061/112320_breakout/sol-semaphore.c
new file mode 100644
index 0000000..4af3a5b
--- /dev/null
+++ b/csci4061/112320_breakout/sol-semaphore.c
@@ -0,0 +1,128 @@
+#define NUM_ARGS 0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <string.h>
+#include <time.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include<sys/time.h>
+
+long semTotal = 0;
+
+struct buffer {
+
+	int vals[100];
+	int index;
+};
+
+struct semBuffer {
+
+	struct buffer* q;
+	sem_t* psem;
+	sem_t* csem;
+	pthread_mutex_t* mutex;
+};
+
+void insert(struct buffer* q, int val) {
+
+	q->vals[q->index] = val;
+	++q->index;
+}
+
+int delete(struct buffer* q) {
+
+	--q->index;
+	int val = q->vals[q->index];
+	return val;
+}
+
+// TODO: Insert code to use a semaphore.
+void* semProducer(void* arg) {
+
+	// Random delay. DO NOT REMOVE!
+	usleep(rand() % 1000);
+
+	struct semBuffer* sq = (struct semBuffer*) arg;
+	sem_wait(sq->psem);
+	pthread_mutex_lock(sq->mutex);
+
+	static int in = 0;
+	++in;
+	// Add an element to the queue.
+	insert(sq->q, in);
+
+	pthread_mutex_unlock(sq->mutex);
+	sem_post(sq->csem);
+
+}
+
+// TODO: Insert code to use a semaphore.
+void* semConsumer(void* arg) {
+
+	// Random delay. DO NOT REMOVE!
+	usleep(rand() % 1000);
+
+	struct semBuffer* sq = (struct semBuffer*) arg;
+
+	sem_wait(sq->csem);
+	pthread_mutex_lock(sq->mutex);
+
+	// Reove an element from the queue.
+	semTotal += delete(sq->q);
+
+	pthread_mutex_unlock(sq->mutex);
+	sem_post(sq->psem);
+}
+
+int main(int argc, char** argv) {
+
+	if (argc != NUM_ARGS + 1) {
+
+		printf("Wrong number of args, expected %d, given %d\n", NUM_ARGS, argc - 1);
+		exit(1);
+	}
+
+	// Seed the random generator.
+	srand(time(NULL));
+
+	// Create threads.
+	pthread_t semPool[100];
+
+	struct timeval start;
+	gettimeofday(&start, NULL);
+
+	// Create task queue.
+	struct semBuffer* sq = (struct semBuffer*) malloc(sizeof(struct semBuffer));
+
+	sq->q = (struct buffer*) malloc(sizeof(struct buffer));
+	sq->q->index=0;
+	sq->psem = (sem_t*) malloc(sizeof(sem_t));
+	sq->csem = (sem_t*) malloc(sizeof(sem_t));
+	sq->mutex = (pthread_mutex_t*) malloc(sizeof(pthread_mutex_t));
+
+	// TODO: Initilaize semaphores
+	sem_init(sq->psem, 0, 50);
+	sem_init(sq->csem, 0, 0);
+	
+	pthread_mutex_init(sq->mutex, NULL);
+
+	for (int i=0; i < 50; ++i) {
+
+		pthread_create(&semPool[i], NULL, semProducer, (void*) sq);
+		pthread_create(&semPool[50 + i], NULL, semConsumer, (void*) sq);
+	}
+
+	for (int i=0; i < 100; ++i) pthread_join(semPool[i], NULL);
+
+	struct timeval end;
+	gettimeofday(&end, NULL);
+	printf("Sem Test: \nTotal of buffer  = %ld\n", semTotal);
+	printf("Time (in us) to complete = %ld\n", ((end.tv_sec - start.tv_sec) * 1000000) + (end.tv_usec - start.tv_usec));
+}
-- 
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