Better implemenation?

Assignment8/code/main.c

@@ -9,7 +9,6 @@ typedef struct DiskRequest {
 
 typedef struct DiskQueue {
 	DiskRequest *requests;
-	int index;
 	int size;
 } DiskQueue;
 
@@ -24,7 +23,6 @@ DiskQueue *createDiskQueue() {
 		printf("Error allocating memory for queue requests\n");
 		exit(EXIT_FAILURE);
 	}
-	queue->index = 0;
 	queue->size = 0;
 	return queue;
 }
@@ -38,21 +36,65 @@ DiskRequest diskRequest(int position, int time) {
 
 void enqueue(DiskQueue *queue, DiskRequest request) {
 	queue->requests = realloc(queue->requests, sizeof(DiskRequest) * (queue->size + 1));
+	if (queue->requests == NULL) {
+		printf("Error reallocating memory for queue requests\n");
+		exit(EXIT_FAILURE);
+	}
 	queue->requests[queue->size] = request;
 	queue->size++;
 }
 
-DiskRequest dequeue(DiskQueue *queue) {
-	DiskRequest request = queue->requests[queue->index];
-	queue->index++;
+
+
+DiskRequest delete(DiskQueue *queue, DiskRequest request) {
+	// Find the index of the request
+	int index = -1;
+	for (int i = 0; i < queue->size; i++) {
+		if (queue->requests[i].position == request.position && queue->requests[i].time == request.time) {
+			index = i;
+			break;
+		}
+	}
+	if (index == -1) {
+		printf("Error: Request not found in queue\n");
+		exit(EXIT_FAILURE);
+	}
+	// Shift all the elements after the index down one
+	for (int i = index; i < queue->size - 1; i++) {
+		queue->requests[i] = queue->requests[i + 1];
+	}
+	// Resize the queue
+	queue->requests = realloc(queue->requests, sizeof(DiskRequest) * (queue->size - 1));
+	if (queue->requests == NULL) {
+		printf("Error reallocating memory for queue requests\n");
+		exit(EXIT_FAILURE);
+	}
+	queue->size--;
 	return request;
 }
 
-// Allocates a new queue with the requests that have the same time
-DiskQueue *queueOfSameTime(DiskQueue *queue, int time) {
+
+
+DiskQueue* clone(DiskQueue *queue) {
+	DiskQueue *clone = createDiskQueue();
+	for (int i = 0; i < queue->size; i++) {
+		enqueue(clone, queue->requests[i]);
+	}
+	return clone;
+}
+
+DiskRequest peek(DiskQueue *queue) {
+	return queue->requests[0];
+}
+
+DiskRequest dequeue(DiskQueue *queue) {
+	return delete(queue, peek(queue));
+}
+
+DiskQueue *queueOfLesserTime(DiskQueue *queue, double time) {
 	DiskQueue *sameTimeQueue = createDiskQueue();
-	for (int i = queue->index; i < queue->size - queue->index; i++) {
-		if (queue->requests[i].time == time) {
+	for (int i = 0; i < queue->size; i++) {
+		if (queue->requests[i].time <= time) {
 			enqueue(sameTimeQueue, queue->requests[i]);
 		}
 	}
@@ -111,7 +153,9 @@ double timeToProcessRequest(int position, int destination) {
 // In first come first the time the request comes in is irrelevant
 void fcfs(int start) {
 	int position = start;
-	for (int i = 0; i < queue->size; i++) {
+	int size = queue->size;
+
+	for (int i = 0; i < size; i++) {
 		DiskRequest request = dequeue(queue);
 		while (seekTime < request.time) { seekTime++; }
 		seekTime += timeToProcessRequest(position, request.position);
@@ -121,31 +165,35 @@ void fcfs(int start) {
 }
 
 void cscan(int start) {
-	int currentTime = 0;
 	int position = start;
-	for (int i = 0; i < queue->size; i++) {
-		DiskRequest request = dequeue(queue);
-		while (currentTime < request.time) { currentTime++; }
 
-		DiskQueue *sameTimeQueue = sortQueueByPosition(queueOfSameTime(queue, request.time));
-		for (; i < sameTimeQueue->size; i++) {
-			DiskRequest request = dequeue(sameTimeQueue);
+	DiskQueue *workingQueue = clone(queue);
 
-			// Need to return to 0 because we have reached the end of the disk on the current pass
-			if (request.position < position) {
-				seekTime += timeToProcessRequest(position, 9999);
-				movement += abs(position - 9999);
-				position = 9999;
-				seekTime += timeToProcessRequest(position, 0);
-				movement += abs(position - 0);
-				position = 0;
-			}
-			seekTime += timeToProcessRequest(position, request.position);
-			movement += abs(position - request.position);
-			position = request.position;
+	while (workingQueue->size > 0) {
+		DiskQueue *candidates = queueOfLesserTime(workingQueue, seekTime);
+
+		if (candidates->size == 0) {
+			while (seekTime < peek(workingQueue).time) { seekTime++; }
+			continue;
 		}
-		//destroyDiskQueue(sameTimeQueue);
+		sortQueueByPosition(candidates);
+		DiskRequest request = dequeue(candidates);
+
+		if (request.position < position) {
+			// Go to end of disk and back to 0
+			seekTime += timeToProcessRequest(position, 9999);
+			seekTime += timeToProcessRequest(9999, 0);
+			movement += abs(position - 9999);
+			movement += abs(9999 - 0);
+			position = 0;
+		}
+		seekTime += timeToProcessRequest(position, request.position);
+		movement += abs(position - request.position);
+		position = request.position;
+		delete(workingQueue, request);
+		destroyDiskQueue(candidates);
 	}
+	destroyDiskQueue(workingQueue);
 }