#include <stdlib.h>

#include "list_int.h"

struct list_int {
    int value;
    struct list_int * prev;
    struct list_int * next;
};

struct list_int * list_int_new () {
    struct list_int * this = malloc(sizeof(struct list_int));
    if (this) {
	this->prev = this;
	this->next = this;
    }
    return this;
}

void list_int_delete (struct list_int * l) {
    struct list_int * i = l->next;
    while (i != l) {
	struct list_int * tmp = i;
	i = i->next;
	free(tmp);
    }
    free(l);
}

list_int_iterator list_int_append (struct list_int * l, int v) {
    return list_int_insert(l, v);
}

list_int_iterator list_int_insert (list_int_iterator i, int v) {
    struct list_int * new_l = malloc(sizeof(struct list_int));
    if (new_l) {
	new_l->value = v;
	new_l->next = i;
	new_l->prev = i->prev;
	new_l->prev->next = new_l;
	new_l->next->prev = new_l;
    }
    return new_l;
}

list_int_iterator list_int_begin (struct list_int * l) {
    return l->next;
}

list_int_iterator list_int_end (struct list_int * l) {
    return l;
}

int list_int_get (list_int_iterator i) {
    return i->value;
}

void list_int_put (list_int_iterator i, int v) {
    i->value = v;
}

list_int_iterator list_int_next (list_int_iterator i) {
    return i->next;
}

list_int_iterator list_int_prev (list_int_iterator i) {
    return i->prev;
}

list_int_iterator list_int_erase (struct list_int * l) {
    struct list_int * next = l->next;
    if (l != next) {
	next->prev = l->prev;
	next->prev->next = next;
	free(l);
    }
    return next;
}

void list_int_clear (struct list_int * l) {
    struct list_int * i = l->next;
    while (i != l) {
	struct list_int * tmp = i;
	i = i->next;
	free(tmp);
    }
    l->next = l;
    l->prev = l;
}

int list_int_empty (struct list_int * l) {
    return l->next == l;
}