heap_pop()

static heap_item heap_pop ( heap *  h )

static

{
     heap_item ret;
     int i, n, child;

     if (!(h->n)) {
          fprintf(stderr, "attempted to pop an empty heap\n");
          exit(EXIT_FAILURE);
     }

     ret = h->items[0];
     h->items[i = 0] = h->items[n = --(h->n)];
     while ((child = i * 2 + 1) < n) {
          int largest;
          heap_item swap;

          if (KEY(h->items[child]) <= KEY(h->items[i]))
               largest = i;
          else
               largest = child;
          if (++child < n && KEY(h->items[largest]) < KEY(h->items[child]))
               largest = child;
          if (largest == i)
               break;
          swap = h->items[i];
          h->items[i] = h->items[largest];
          h->items[i = largest] = swap;
     }

     {
          unsigned i, fdim = h->fdim;
          for (i = 0; i < fdim; ++i) {
               h->ee[i].val -= ret.ee[i].val;
               h->ee[i].err -= ret.ee[i].err;
          }
     }
     return ret;
}