/*-
 * LstFindFrom.c --
 *	Find a node on a list from a given starting point. Used by Lst_Find.
 *
 * Copyright (c) 1988 by University of California Regents
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appears in all copies.  Neither the University of California nor
 * Adam de Boor makes any representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 */
#ifndef lint
static char *rcsid =
"$Id: lstFindFrom.c,v 1.6 88/11/17 20:52:37 adam Exp $ SPRITE (Berkeley)";
#endif lint

#include	"lstInt.h"

/*-
 *-----------------------------------------------------------------------
 * Lst_FindFrom --
 *	Search for a node starting and ending with the given one on the
 *	given list using the passed datum and comparison function to
 *	determine when it has been found.
 *
 * Results:
 *	The found node or NILLNODE
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
LstNode
Lst_FindFrom (l, ln, d, cProc)
    Lst		      	l;
    register LstNode    ln;
    register ClientData d;
    register int	(*cProc)();
{
    register ListNode	tln;
    Boolean		found = FALSE;
    
    if (!LstValid (l) || LstIsEmpty (l) || !LstNodeValid (ln, l)) {
	return (NILLNODE);
    }
    
    tln = (ListNode)ln;
    
    do {
	if ((*cProc) (tln->datum, d) == 0) {
	    found = TRUE;
	    break;
	} else {
	    tln = tln->nextPtr;
	}
    } while (tln != (ListNode)ln && tln != NilListNode);
    
    if (found) {
	return ((LstNode)tln);
    } else {
	return (NILLNODE);
    }
}