sllLib.c

/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
* National Laboratory.
* Copyright (c) 2002 Deutches Elektronen-Synchrotron in der Helmholtz-
* Gemelnschaft (DESY).
* Copyright (c) 2002 Berliner Speicherring-Gesellschaft fuer Synchrotron-
* Strahlung mbH (BESSY).
* Copyright (c) 2002 Southeastern Universities Research Association, as
* Operator of Thomas Jefferson National Accelerator Facility.
* Copyright (c) 2002 The Regents of the University of California, as
* Operator of Los Alamos National Laboratory.
* This file is distributed subject to a Software License Agreement found
* in the file LICENSE that is included with this distribution. 
\*************************************************************************/
/* sllLib.c */

/************************DESCRIPTION***********************************
  *PUBLIC* functions for single link list operations.
**********************************************************************/

#include <stdio.h>
#include "sllLib.h"

/*********************************************************
	add a node at the end of the list
**********************************************************/
int sllAdd(SLIST *list,SNODE *new)
{
	if (list->count > 0) {
		list->last->next = new;

	}
	else
		list->first = new;
	new->next = NULL;
	list->last = new;
	list->count++;
	return(0);
}

/*********************************************************
	find the N th node of the list
**********************************************************/
SNODE *sllNth(SLIST *list,int n)
{
	SNODE *pt;
	int i,count;

	count = list->count;
	if (n >= count) return(list->last);
	if ( n <= 0) return(list->first);
	pt = list->first;
	for (i=1;i<n;i++)
		pt = pt->next;
	return(pt);
}

/*********************************************************
	insert a node after prev node of the list
**********************************************************/
void sllInsert(SLIST *list,SNODE *prev,SNODE *new)
{
	if (prev == NULL) {
		new->next = list->first;
		list->first = new;
	}
	else if (prev == list->last) {
		prev->next = new;
		list->last = new;
		new->next = NULL;
	}
	else {
		new->next = prev->next;
		prev->next = new;
	}
	list->count++;
	return;

}

/*********************************************************
	insert a new node before next node of the list
**********************************************************/
int sllPrecede(SLIST *list,SNODE *next,SNODE *new)
{
	SNODE *prev,*last,*now;

	if (next == NULL) {
		if (list->count == 0){
			list->first = new;
			list->last = new;
		}
		else {
			last = list->last;
			last->next = new;
			list->last = new;
		}
	}
	else {
		prev = NULL;
		now = list->first;

		while (now ) {
			if (now == next) break;
			prev = now;
			now = now->next;
		}
		if (now) {
			new->next = now;
			if (prev == NULL)
				list->first = new;
			else prev->next = new;
		}
		else return(-1);
	}
	list->count++;
	return(0);
}

/*********************************************************
	remove the node from the list
**********************************************************/
void sllRemove(SLIST *list,SNODE *node)
{
	SNODE *prev,*now,*last;
	prev = NULL;
	now = list->first;
	last = list->last;

	while (now ) {
		if (now == node) break;
		else {
			prev = now;
			now = now->next;
		}
	}
	if (now) {
		if (prev == NULL){
			list->first = now->next;
			prev = node;
		}
		else prev->next = now->next;
		if (node == last) list->last = prev;
		list->count--;
	}
}

/*********************************************************
	find the node from the list
**********************************************************/
int sllFind(SLIST *plist,SNODE *pnode)
{
	int i;
	SNODE *pt;
	pt = plist->first;
	for (i=1;i<=plist->count;i++) {
		if (pt == pnode) {
			return(i);
		}
		pt = sllNext(pt);
	}
	return(-1);
}