Function bpmnode_create

mujoco/src/simulate/lodepng.cpp:865–891

creates a new chain node with the given parameters, from the memory in the lists */

/*creates a new chain node with the given parameters, from the memory in the lists */
static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) {
  unsigned i;
  BPMNode* result;

  /*memory full, so garbage collect*/
  if(lists->nextfree >= lists->numfree) {
    /*mark only those that are in use*/
    for(i = 0; i != lists->memsize; ++i) lists->memory[i].in_use = 0;
    for(i = 0; i != lists->listsize; ++i) {
      BPMNode* node;
      for(node = lists->chains0[i]; node != 0; node = node->tail) node->in_use = 1;
      for(node = lists->chains1[i]; node != 0; node = node->tail) node->in_use = 1;
    }
    /*collect those that are free*/
    lists->numfree = 0;
    for(i = 0; i != lists->memsize; ++i) {
      if(!lists->memory[i].in_use) lists->freelist[lists->numfree++] = &lists->memory[i];
    }
    lists->nextfree = 0;
  }

  result = lists->freelist[lists->nextfree++];
  result->weight = weight;
  result->index = index;
  result->tail = tail;
  return result;
}

/*sort the leaves with stable mergesort*/
static void bpmnode_sort(BPMNode* leaves, size_t num) {