kots_linkedlist.c

#include <stdlib.h>
#include "kots_linkedlist.h"

list_t *List_Create(void (*freeItem)(listitem_t *))
{
	list_t *list = malloc(sizeof(list_t));
	list->first = NULL;
	list->last = NULL;
	list->length = 0;
	list->freeItem = freeItem;
	return list;
}

void List_Delete(list_t *list)
{
	if (list)
	{
		List_Clear(list);
		free(list);
	}
}

void List_AddItem(list_t *list, void *data)
{
	if (!list->first)
	{
		list->first = malloc(sizeof(listitem_t));
		list->last = list->first;
		list->first->data = data;
		list->first->prev = NULL;
		list->first->next = NULL;
	}
	else
	{
		list->last->next = malloc(sizeof(listitem_t));
		list->last->next->prev = list->last;
		list->last = list->last->next;
		list->last->data = data;
		list->last->next = NULL;
	}

	++list->length;
}

listitem_t *List_GetItem(list_t *list, int index)
{
	listitem_t *item;

	if (index == 0)
		return list->first;
	else if (index == list->length - 1)
		return list->last;
	else if (index < 0 || index >= list->length)
		return NULL;
	else
	{
		item = list->first;
		while (index != 0 && item)
		{
			item = item->next;
			--index;
		}

		return item;
	}
}

//Used internally to remove an item without freeing it (dangerous)
void List_RemoveItemInternal(list_t *list, listitem_t *item)
{
	if (item->prev)
		item->prev->next = item->next;

	if (item->next)
		item->next->prev = item->prev;

	if (list->first == item)
		list->first = item->next;

	if (list->last == item)
		list->last = item->prev;

	--list->length;
}

void List_RemoveItem(list_t *list, listitem_t *item)
{
	List_RemoveItemInternal(list, item);
	list->freeItem(item);
}

listitem_t *List_Dequeue(list_t *list)
{
	return List_DequeueItem(list, list->first);
}

listitem_t *List_DequeueItem(list_t *list, listitem_t *item)
{
	if (item)
	{
		List_RemoveItemInternal(list, item);
		item->next = NULL;
		item->prev = NULL;
	}

	return item;
}

listitem_t *List_Pop(list_t *list)
{
	listitem_t *item = list->last;

	if (item)
	{
		List_RemoveItemInternal(list, item);
		item->next = NULL;
		item->prev = NULL;
	}

	return item;
}

void List_RemoveAt(list_t *list, int index)
{
	listitem_t *item = List_GetItem(list, index);

	if (item)
		List_RemoveItem(list, item);
}

void List_Clear(list_t *list)
{
	listitem_t *item = list->first;
	listitem_t *next = item;

	while (item)
	{
		next = item->next;
		list->freeItem(item);
		item = next;
	}

	list->first = NULL;
	list->last = NULL;
	list->length = 0;
}

int List_GetLength(list_t *list)
{
	return list->length;
}

void List_FreeItemDefault(listitem_t *item)
{
	free(item->data);
	free(item);
}

void List_FreeItemOnly(listitem_t *item)
{
	free(item);
}