/*
* Copyright (c) 2019-2021 David Timber <mieabby@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "llist.h"
#include "util_rt.h"


void prne_init_llist (prne_llist_t *llist) {
	llist->head = NULL;
	llist->tail = NULL;
	llist->size = 0;
}

void prne_free_llist (prne_llist_t *llist) {
	prne_llist_clear(llist);
}

void prne_llist_clear (prne_llist_t *llist) {
	struct prne_llist_entry *cur = llist->head, *next;

	while (cur != NULL) {
		next = cur->next;
		prne_free(cur);
		cur = next;
	}

	llist->head = llist->tail = NULL;
	llist->size = 0;
}

prne_llist_entry_t *prne_llist_insert (
	prne_llist_t *llist,
	prne_llist_entry_t *entry,
	const prne_llist_element_t element)
{
	prne_llist_entry_t *ny;

	if (entry == NULL) {
		return prne_llist_append(llist, element);
	}

	ny = (prne_llist_entry_t*)prne_malloc(sizeof(prne_llist_entry_t), 1);
	if (ny == NULL) {
		return NULL;
	}
	ny->prev = entry;
	ny->next = entry->next;
	ny->element = element;
	if (entry->next != NULL) {
		entry->next->prev = ny;
	}
	else {
		llist->tail = ny;
	}
	entry->next = ny;

	llist->size += 1;
	return ny;
}

prne_llist_entry_t *prne_llist_append (
	prne_llist_t *llist,
	const prne_llist_element_t element)
{
	prne_llist_entry_t *ny = (prne_llist_entry_t*)prne_malloc(
		sizeof(prne_llist_entry_t),
		1);

	if (ny == NULL) {
		return NULL;
	}
	ny->next = NULL;
	ny->element = element;

	if (llist->tail == NULL) {
		llist->head = llist->tail = ny;
		ny->prev = NULL;
	}
	else {
		llist->tail->next = ny;
		ny->prev = llist->tail;
		llist->tail = ny;
	}

	llist->size += 1;
	return ny;
}

prne_llist_entry_t *prne_llist_erase (
	prne_llist_t *llist,
	prne_llist_entry_t *entry)
{
	prne_llist_entry_t *ret;

	if (entry == NULL) {
		return NULL;
	}

	if (entry == llist->head && entry == llist->tail) {
		llist->head = llist->tail = NULL;
		ret = NULL;
	}
	else if (entry == llist->head) {
		ret = llist->head = llist->head->next;
		llist->head->prev = NULL;
	}
	else if (entry == llist->tail) {
		ret = llist->tail = llist->tail->prev;
		llist->tail->next = NULL;
	}
	else {
		ret = entry->prev->next = entry->next;
		entry->next->prev = entry->prev;
	}

	prne_free(entry);
	llist->size -= 1;
	return ret;
}