/* mp5test.c; test program for MP5 */
/*  exercises mymalloc() and myfree() on a heap of size HEAPSIZE (see below)
 *  detects heap corruption fairly well, aborts test if corruption detected
 *  gives statistics about heap use if tests passed successfully
 */

#include <stdio.h>
#include <stdlib.h>
#include "myheap.h"

#define MAXBLOCKS 1024
#define MAXSIZE   1024
#define TRIALS    (MAXBLOCKS * 16)
#define HEAPSIZE  ((MAXBLOCKS / 2) * (MAXSIZE / 3))

void * block[MAXBLOCKS];

main(){
	/* count number of each kind of aciton taken */
	int allocations = 0;
	int allocationfailures = 0;
	int deallocations = 0;

	/* some statistics to keep */
	int demand = 0;
	int maxdemand = 0;
	int allocd = 0;
	int maxallocd = 0;

	int i;
	/* initialize */
	for (i = 0; i < MAXBLOCKS; i++) block[i] = NULL;
	heapinit(HEAPSIZE);   /* this was missing */

	/* test */
	for (i = 0; i < TRIALS; i++) {
		int j = random() % MAXBLOCKS;
		int * p = block[j];

		/* do one allocation or deallocation allocated blocks */
		if (p == NULL) { /* allocate a block */
			int s = random() % ((random() % MAXSIZE) + 1);
			int k = 0;
			if (s < sizeof(int)) s = sizeof(int);

			p = mymalloc(s);
			block[j] = p;
			
			if (p != NULL) {
				/* keep statistics */
				allocations++;
				demand = demand + s;
				if (demand > maxdemand) maxdemand = demand;
				allocd++;
				if (allocd > maxallocd) maxallocd = allocd;

				/* initialize block */
				while (s > 0) {
					p[k] = s;
					s = s - sizeof(int);
					k = k + 1;
				}
			} else {
				/* keep statistics */
				allocationfailures++;
			}
		} else { /* deallocate block p */
			int k = 0;
			int s = p[0];

			/* keep statistics */
			demand = demand - s;
			allocd--;

			/* check that the block is unchanged as initialized */
			while (s > 0) {
				if (p[k] != s) {
					fprintf(stderr,
						"deallocate detected heap"
						" corruption at trial number"
						" %d; deallocations: %d\n",
						i, deallocations
					);
					exit( EXIT_FAILURE );
				}
				s = s - sizeof(int);
				k = k + 1;
			}

			myfree( p );
			deallocations++;
			block[j] = NULL;
		}
	}

	/* report on successful test */
	fprintf(stderr,
		"Test program conducted %d trials:\n"
		" %d allocations, %d failed allocations,"
		" and %d deallocations.\n",
		TRIALS, allocations, allocationfailures, deallocations
	);
	fprintf(stderr,
		"at maximum %d bytes out of a heap of size %d were allocated;\n"
		" at termination, %d bytes were allocated.\n",
		maxdemand, HEAPSIZE, demand
	);
	fprintf(stderr,
		"at maximum, %d blocks were allocated out of %d possible;\n"
		" at termination, %d blocks were allocated.\n",
		maxallocd, MAXBLOCKS, allocd
	);
}