Spaghetti stack in C

Question

Does anybody know where I can find an example of a Spaghetti stack written in C?

Answer 1

It should be something similar to that:

struct stack_item;

struct stack_item
{
    stack_item *parent;
    void *ptr_data;
};

stack_item *stack_pointer = null;

void push(stack_item *item)
{
    if (stack_pointer == null)
        item->parent = null;
    else
        item->parent = cur; 

stack_pointer = item;
}

/* like push but doesn't update cur stack item to the one pushed, just add a child */
void push_parallel(stack_item *item)
{
    if (stack_pointer == null)
    {
        stack_pointer = item;
        item->parent = null;
    }
    else
        item->parent = stack_pointer;
}

stack_item *pop()
{
    if (stack_pointer == null)
    {
        printf("error: stack is empty.\r\n");
        return null;
    }

    stack_item *current = stack_pointer;
    stack_pointer = current->parent;

    return current;
}

Mind that a spaghetti stack is useful when you want to keep references of things that you pop out of the stack, having many parallel linked list that end to a common root. So you have to keep references of item you pop out because you need to traverse them in a bottom-up way from the leaf to the root, and of course using a different leaf node will produce a different linked list that has elements in common with other lists that start from other leaves..