/*
 * CS5600 University of Utah
 * Charles McGarvey
 * mcgarvey@eng.utah.edu
 */

#ifndef _LIST_H_
#define _LIST_H_

#include "common.h"


/*
 * A linked-list with a stack-like interface.
 * The value of each node can be any pointer.
 */
struct list
{
    void*           val;
    struct list*    link;
    void            (*dtor)(void*);
};
typedef struct list list_t;


/*
 * Add a value to the list.  It will become the first item.
 * This is a O(1) operation.
 */
INLINE_MAYBE
void list_push2(list_t** l, void* value, void (*destructor)(void*))
{
    list_t* n = (list_t*)mem_alloc(sizeof(list_t));
    n->val = value;
    n->link = *l;
    n->dtor = destructor;
    *l = n;
}

/*
 * Add a value to the list with no destructor set.
 */
INLINE_MAYBE
void list_push(list_t** l, void* value)
{
    list_push2(l, value, NULL);
}


/*
 * Create a new list with a single value.
 */
INLINE_MAYBE
list_t* list_new2(void* value, void (*destructor)(void*))
{
    list_t* l = NULL;
    list_push2(&l, value, destructor);
    return l;
}

/*
 * Create a new list with a single value without a destructor set.
 */
INLINE_MAYBE
list_t* list_new(void* value)
{
    list_t* l = NULL;
    list_push2(&l, value, 0);
    return l;
}


/*
 * Remove a value from the front of the list.  If the node has dtor set, it
 * will be used to destroy the value.
 * This is a O(1) operation.
 */
INLINE_MAYBE
void list_pop(list_t** l)
{
    list_t* n = (*l)->link;

    if ((*l)->dtor) {
        (*l)->dtor((*l)->val);
    }
    mem_free(*l);

    *l = n;
}

/*
 * Destroy the list, freeing up all of its memory.
 * This is a O(n) operation.
 */
INLINE_MAYBE
void list_destroy(list_t** l)
{
    while (*l) {
        list_pop(l);
    }
}


/*
 * Reverse the order of the items in the list.
 * This is a O(n) operation.
 */
void list_reverse(list_t** l);


#endif // _LIST_H_