115 lines
2.9 KiB
C
115 lines
2.9 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include "disk.h"
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DiskQueue *createDiskQueue() {
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DiskQueue *queue = malloc(sizeof(DiskQueue));
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if (queue == NULL) {
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printf("Error allocating memory for queue\n");
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exit(EXIT_FAILURE);
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}
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queue->head = NULL;
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queue->size = 0;
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return queue;
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}
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void enqueue(DiskQueue *queue, int time, int position) {
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DiskRequest *request = malloc(sizeof(DiskRequest));
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if (request == NULL) {
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printf("Error allocating memory for request\n");
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exit(EXIT_FAILURE);
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}
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request->time = time;
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request->position = position;
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request->next = NULL;
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if (queue->head == NULL) {
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queue->head = request;
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} else {
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DiskRequest *current = queue->head;
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while (current->next != NULL) {
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current = current->next;
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}
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current->next = request;
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}
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queue->size++;
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}
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void delete(DiskQueue *queue, DiskRequest request) {
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DiskRequest *current = queue->head;
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DiskRequest *previous = NULL;
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while (current != NULL) {
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if (current->position == request.position && current->time == request.time) {
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if (previous == NULL) {
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queue->head = current->next;
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} else {
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previous->next = current->next;
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}
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queue->size--;
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free(current);
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return;
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}
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previous = current;
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current = current->next;
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}
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printf("Error: Request not found\n");
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exit(EXIT_FAILURE);
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}
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DiskRequest peek(DiskQueue *queue) {
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return *queue->head;
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}
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DiskRequest *dequeue(DiskQueue *queue) {
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DiskRequest *head = queue->head;
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queue->head = head->next;
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queue->size--;
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return head;
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}
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void destroyDiskQueue(DiskQueue *queue) {
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DiskRequest *current = queue->head;
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DiskRequest *next = NULL;
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while (current != NULL) {
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next = current->next;
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free(current);
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current = next;
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}
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free(queue);
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}
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DiskRequest* findClosest(DiskQueue *queue, int position, double time) {
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DiskRequest *current = queue->head;
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DiskRequest *next = NULL;
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DiskRequest *first = NULL;
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while (current != NULL) {
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if (current->time <= time) { // Filter out requests that haven't come in yet
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if (first == NULL) {
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first = current;
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} else {
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if (current->position < first->position) {
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first = current;
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}
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}
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int currentDistance = current->position - position; // Distance from the current to the current position, negative means down (bad)
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if (currentDistance > 0) { // If the current is up
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if (next == NULL) { // If there is no next yet, set it to the current
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next = current;
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} else {
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int nextDistance = next->position - position; // Distance from the next to the current position, negative means down (bad)
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if (currentDistance < nextDistance) { // If the current is closer than the next
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next = current;
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}
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}
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}
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}
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current = current->next;
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}
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// If we didn't find a request that is above the current position, return the first as a fallback
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if (next == NULL) {
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return first;
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}
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return next;
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}
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