Function bpmnode_create

dependency/densecrf/examples/lodepng.cpp:698–728

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)