/** Sort an array in ascending order using Merge Sort.
 * @param array The data to sort.
 * @param size The number of elements in the array.
 */
void MergeSort(int *array, int size) {
   int start, stop, middle;
   int x, y, z, i;
   int *lp, *tp, *temp;

   lp = malloc(size * sizeof(int));
   tp = array;
   for(i = 2; i < size << 1; i <<= 1) {
      for(start = 0; start < size; start += i) {
         stop = start + i - 1;
         middle = (stop + start) >> 1;
         if(stop >= size) stop = size - 1;
         if(middle >= size) middle = start;
         x = z = start; y = middle + 1;
         while(x <= middle && y <= stop) {
            if(tp[x] > tp[y]) lp[z++] = tp[y++];
            else lp[z++] = tp[x++];
         }
         while(x <= middle) lp[z++] = tp[x++];
         while(y <= stop) lp[z++] = tp[y++];
      }
      temp = tp; tp = lp; lp = temp;
   }
   if(tp != array) {
      for(x = 0; x < size; x++) {
         array[x] = tp[x];
      }
      free(tp);
   } else {
      free(lp);
   }
}