99 lines
2.8 KiB
C
99 lines
2.8 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include "disk.h"
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// Global tracking variables
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DiskDirection currentDirection = UP;
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int movement = 0;
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double seekTime = 0;
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// Array for storing the requests
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DiskQueue *queue;
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double timeToProcessRequest(int position, int destination) {
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//The time (a floating point number) required to process a request is computed by distance the head travels divided by 5
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//Plus additional 15 milliseconds penalty if the direction has to change (for FCFS)
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double time = 0;
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// Calculated this way so that positive means up and negative means down
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int distance = destination - position;
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DiskDirection direction = (distance > 0) ? UP : DOWN;
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time += abs(distance) / 5.0;
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if (direction != currentDirection) {
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time += 15;
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currentDirection = direction;
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}
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return time;
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}
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// Your simulated disk is of size 10000, numbered from 0 to 9999.
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// In first come first the time the request comes in is irrelevant
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void fcfs(int start) {
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int position = start;
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int size = queue->size;
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for (int i = 0; i < size; i++) {
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DiskRequest request = dequeue(queue);
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while (seekTime < request.time) { seekTime++; }
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seekTime += timeToProcessRequest(position, request.position);
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movement += abs(position - request.position);
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position = request.position;
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}
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}
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void cscan(int start) {
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int position = start;
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DiskQueue *workingQueue = clone(queue);
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while (workingQueue->size > 0) {
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DiskQueue *candidates = queueOfLesserTime(workingQueue, seekTime);
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if (candidates->size == 0) {
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while (seekTime < peek(workingQueue).time) { seekTime++; }
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continue;
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}
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sortQueueByPosition(candidates);
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DiskRequest request = dequeue(candidates);
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if (request.position < position) {
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// Go to end of disk and back to 0
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seekTime += timeToProcessRequest(position, 9999);
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seekTime += timeToProcessRequest(9999, 0);
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movement += abs(position - 9999);
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movement += abs(9999 - 0);
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position = 0;
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}
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seekTime += timeToProcessRequest(position, request.position);
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movement += abs(position - request.position);
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position = request.position;
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delete(workingQueue, request);
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destroyDiskQueue(candidates);
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}
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destroyDiskQueue(workingQueue);
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}
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int main(int argc, char **argv) {
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int position, time;
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char algorithm = argv[1][0];
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int start = 0;
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queue = createDiskQueue();
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while (EOF != (scanf("%i %i\n", &position, &time))) {
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enqueue(queue, diskRequest(position, time));
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// printf("Delete me: position %i, Delete me: time %i\n", position, time);
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}
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if (algorithm == 'F') {
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fcfs(start);
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printf("Movement:%i Time:%.1lf\n", movement, seekTime);
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} else if (algorithm == 'C') {
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cscan(start);
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// Stupid printf difference to pass tests, could call once after if statement
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printf("Movement: %i Time:%.1lf\n", movement, seekTime);
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}
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destroyDiskQueue(queue);
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return 0;
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} |