/*
 * Copyright (c) 1993-1995 Argonaut Technologies Limited. All rights reserved.
 *
 * $Id: brlists.c 1.4 1995/02/22 21:41:24 sam Exp $
 * $Locker:  $
 *
 * Doubly linked list support - has a full and simple version
 */

#include "fw.h"

static char rscid[] = "$Id: brlists.c 1.4 1995/02/22 21:41:24 sam Exp $";

/**
 ** Full features list handling
 **/

/*
 * Initialse a list structure to be empty list
 */
void BR_PUBLIC_ENTRY BrNewList(struct br_list *list)
{
	list->head = (struct br_node *)&(list->_null);
	list->tail = (struct br_node *)&(list->head);
	list->_null = NULL;
}

/*
 * Add node at head of list
 */
void BR_PUBLIC_ENTRY BrAddHead(struct br_list *list, struct br_node *node)
{
	node->prev = (struct br_node *)&(list->head);
	node->next = list->head;
	node->next->prev = node;
	list->head = node;
}

/*
 * Add node at tail of list
 */
void BR_PUBLIC_ENTRY BrAddTail(struct br_list *list, struct br_node *node)
{
	node->next = (struct br_node *)&(list->_null);
	node->prev = list->tail;
	node->prev->next = node;
	list->tail = node;
}

/*
 * Take node of head of list and return pointer to it
 */
struct br_node * BR_PUBLIC_ENTRY BrRemHead(struct br_list *list)
{
	struct br_node *n = list->head;

	/*
	 * Trap case of empty list
	 */
	if(n == (struct br_node *)&(list->_null))
		return NULL;

	list->head = n->next;

	return n;
}

/*
 * Take node of tail of list and return pointer to it
 */
struct br_node * BR_PUBLIC_ENTRY BrRemTail(struct br_list *list)
{
	struct br_node *n = list->tail;

	/*
	 * Trap case of empty list
	 */
	if(n == (struct br_node *)&(list->head))
		return NULL;

	list->tail = n->prev;

	return n;
}

/*
 * Add a node to list following the node 'here'
 */
void BR_PUBLIC_ENTRY BrInsert(struct br_list *list, struct br_node *here, struct br_node *node)
{
	node->next=here->next;
	node->prev=here;

	here->next->prev = node;
	here->next = node;
}

/*
 * Remove a node from the containing list
 */
struct br_node * BR_PUBLIC_ENTRY BrRemove(struct br_node *node)
{
	node->next->prev = node->prev;
	node->prev->next = node->next;

	return node;
}

/**
 ** Simple list handling
 **/

void BR_PUBLIC_ENTRY BrSimpleNewList(struct br_simple_list *list)
{
	list->head = NULL;
}

void BR_PUBLIC_ENTRY BrSimpleAddHead(struct br_simple_list *list, struct br_simple_node *node)
{
	node->next = list->head;
	node->prev = &list->head;

	if(node->next)
		node->next->prev = & node->next;

	list->head = node;
}

struct br_simple_node * BR_PUBLIC_ENTRY BrSimpleRemHead(struct br_simple_list *list)
{
	struct br_simple_node *node = list->head ;

	if(node)
		BrSimpleRemove(node);

	return node;
}

void BR_PUBLIC_ENTRY BrSimpleInsert(struct br_simple_list *list, struct br_simple_node *here, struct br_simple_node *node)
{
	node->next = here->next;
	node->prev = &here->next;

	if(node->next)
		node->next->prev = & node->next;

	here->next = node;
}

struct br_simple_node * BR_PUBLIC_ENTRY BrSimpleRemove(struct br_simple_node *node)
{
	*(node->prev) = node->next;

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

	node->prev = NULL;
	node->next = NULL;

	return node;
}