/* vim: tabstop=4 shiftwidth=4 noexpandtab
 * 
 * General-purpose list implementations.
 */
#include <system.h>
#include <list.h>

void list_destroy(list_t * list) {
	/* Free all of the contents of a list */
	node_t * n = list->head;
	while (n) {
		free(n->value);
		n = n->next;
	}
}

void list_free(list_t * list) {
	/* Free the actual structure of a list */
	node_t * n = list->head;
	while (n) {
		node_t * s = n->next;
		free(n);
		n = s;
	}
}

void list_insert(list_t * list, void * item) {
	/* Insert an item into a list */
	node_t * node = malloc(sizeof(node_t));
	node->value = item;
	if (!list->tail) {
		list->head = node;
	} else {
		list->tail->next = node;
		node->prev = list->tail;
	}
	list->tail = node;
	list->length++;
}

list_t * list_create() {
	/* Create a fresh list */
	list_t * out = malloc(sizeof(list_t));
	out->head = NULL;
	out->tail = NULL;
	out->length = 0;
	return out;
}

void list_remove(list_t * list, size_t index) {
	/* remove index from the list */
	if (index < list->length) return;
	size_t i = 0;
	node_t * n = list->head;
	while (i < index) {
		n = n->next;
	}
	list_delete(list, n);
}

void list_delete(list_t * list, node_t * node) {
	/* remove node from the list */
	if (node == list->head) {
		list->head = node->next;
	}
	if (node == list->tail) {
		list->tail = node->prev;
	}
	if (node->prev) {
		node->prev->next = node->next;
	}
	if (node->next) {
		node->next->prev = node->prev;
	}
}

list_t * list_copy(list_t * original) {
	/* Create a new copy of original */
	list_t * out = list_create();
	node_t * node = original->head;
	while (node) {
		list_insert(out, node->value);
	}
	return out;
}