/*
 * Copyright (c) International Business Machines Corp., 2014
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 *   File: list_iter.c
 * Author: Shaun Wetzstein <shaun@us.ibm.com>
 *  Descr: List iterator
 *   Note:
 *   Date: 10/22/10
 */

#include <unistd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <malloc.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <limits.h>

#include "libclib.h"
#include "list_iter.h"

/* ======================================================================= */

static inline list_node_t *__list_iter_bwd(list_iter_t * self)
{
	assert(self != NULL);

	assert(self->list != NULL);
	assert(self->node != NULL);

	if (self->node == &self->list->node)
		self->node = NULL;
	else
		self->node = list_node_prev(self->node);

	return self->node;
}

static inline list_node_t *__list_iter_fwd(list_iter_t * self)
{
	assert(self != NULL);
	assert(self->list != NULL);
	assert(self->node != NULL);

	if (self->node == &self->list->node)
		self->node = NULL;
	else
		self->node = list_node_next(self->node);

	return self->node;
}

void list_iter_init(list_iter_t * self, list_t * list, uint32_t flags)
{
	assert(self != NULL);
	assert(list != NULL);

	self->flags = flags;
	self->list = list;

	if (self->flags & LI_FLAG_BWD)
		self->node = list_tail(self->list);
	else
		self->node = list_head(self->list);
}

void list_iter_clear(list_iter_t * self)
{
	assert(self != NULL);

	if (self->flags & LI_FLAG_BWD)
		self->node = list_tail(self->list);
	else
		self->node = list_head(self->list);
}

list_node_t *list_iter_elem(list_iter_t * self)
{
	assert(self != NULL);
	return self->node;
}

list_node_t *list_iter_inc1(list_iter_t * self)
{
	return list_iter_inc2(self, 1);
}

list_node_t *list_iter_inc2(list_iter_t * self, size_t count)
{
	assert(self != NULL);

	for (size_t i = 0; i < count && self->node != NULL; i++) {
		if (self->flags & LI_FLAG_BWD)
			__list_iter_bwd(self);
		else
			__list_iter_fwd(self);
	}

	return self->node;
}

list_node_t *list_iter_dec1(list_iter_t * self)
{
	return list_iter_dec2(self, 1);
}

list_node_t *list_iter_dec2(list_iter_t * self, size_t count)
{
	assert(self != NULL);

	for (size_t i = 0; i < count && self->node != NULL; i++) {
		if (self->flags & LI_FLAG_BWD)
			__list_iter_fwd(self);
		else
			__list_iter_bwd(self);
	}

	return self->node;
}

/* ======================================================================= */