/* Allocate resources in request for process i, only if it
results in a safe state and return 1, else return 0 */
int resource_request(int i, int *request)
{
pthread_mutex_lock(&state_mutex);
if(islarger(request, s->need[i], n)) {
printf("¡¡¡ERROR!!!\n");
printf("Process %i's request is greather than its need.\n", i);
killProcesses();
}
subArr(s->available, request, n);
addArr(s->allocation[i], request, n);
subArr(s->need[i], request, n);
if (safe_state(s)) {
pthread_mutex_unlock(&state_mutex);
return 1;
} else {
addArr(s->available, request, n);
subArr(s->allocation[i], request, n);
addArr(s->need[i], request, n);
pthread_mutex_unlock(&state_mutex);
return 0;
}
}
/* Release the resources in request for process i */
void resource_release(int i, int *request)
{
pthread_mutex_lock(&state_mutex);
if(islarger(request, s->allocation[i], n)) {
printf("¡¡¡ERROR!!!\n");
printf("Process %i tries to release more resources than it has allocated.\n", i);
killProcesses();
}
addArr(s->available, request, n);
subArr(s->allocation[i], request, n);
addArr(s->need[i], request, n);
pthread_mutex_unlock(&state_mutex);
}
/*Checks if a given state is safe.*/
int safe_state(State *s) {
int count = m, i, isSafe;
int *finish = (int *)malloc(n * sizeof(int));
int *work = (int *)malloc(m * sizeof(int));
for (i = 0; i < m; i++) {
finish[i] = 0;
work[i] = s->available[i];
}
while (count != 0) {
isSafe = 0;
for (i = 0; i < m; i++) {
if (!finish[i]) {
if (islarger(work, s->need[i], n)) {
finish[i] = 1;
count--;
isSafe = 1;
addArr(work, s->allocation[i],n);
break;
}
}
}
if (!isSafe) {
printf("The requested state is unsafe.\n");
return 0;
}
}
printf("The requested state is safe.\n");
return 1;
}
int *algorithm_1(int *arr, int *outputArr, int size, int value) {
int i, k, *tempArr1, *tempArr2, *tempArr3;
k = value;
if (k == 1) {
outputArr[0]++;
return outputArr;
}
else if ((i = isCoin(arr, size, k))) {
outputArr[i]++;
return outputArr;
}
else {
//loop through every integer from 1 to "value"
for (i = 1; i < k; i++) {
//create and initilize three temprorary arrays of size "size" to all 0's
tempArr1 = createArr(size);
tempArr2 = createArr(size);
tempArr3 = createArr(size);
initArr(tempArr1, size);
initArr(tempArr2, size);
initArr(tempArr3, size);
//recursively call algorithm_1 on array from 1 -> i and i + 1 -> "value"
tempArr1 = algorithm_1(arr, tempArr1, size, i);
tempArr2 = algorithm_1(arr, tempArr2, size, k - i);
//add the sum of all elements at each index of tempArr1 and temArr2 together, assign to tempArr3
addArr(tempArr1, tempArr2, tempArr3, size);
//if this new sum of elements array (tempArr3) is less than the running min (outputArr) or the current output array is not a solution, then replace outputArr with tempArr3
if ((sumArray(tempArr3, size) < sumArray(outputArr, size)) || !coinCheck(outputArr, arr, size, k)) {
copyArr(tempArr3, outputArr, size);
}
free(tempArr1);
free(tempArr2);
free(tempArr3);
}
}
return outputArr;
}
