1 /* $OpenBSD: lstRequeue.c,v 1.1 2008/01/12 13:05:57 espie Exp $ */ 2 /* 3 * Copyright (c) 2008 Marc Espie. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS 15 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD 18 * PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 #include "lstInt.h" 27 #include <stdlib.h> 28 29 30 /* Lst_Requeue(l, ln): takes node ln from the list and requeue it at front. 31 */ 32 void 33 Lst_Requeue(Lst l, LstNode ln) 34 { 35 36 /* already at front */ 37 if (l->firstPtr == ln) 38 return; 39 /* unlink element */ 40 if (ln->nextPtr != NULL) 41 ln->nextPtr->prevPtr = ln->prevPtr; 42 if (ln->prevPtr != NULL) 43 ln->prevPtr->nextPtr = ln->nextPtr; 44 45 if (l->lastPtr == ln) 46 l->lastPtr = ln->prevPtr; 47 48 /* relink at front */ 49 ln->nextPtr = l->firstPtr; 50 ln->prevPtr = NULL; 51 l->firstPtr->prevPtr = ln; 52 l->firstPtr = ln; 53 } 54 55