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/* $OpenBSD: lstDeQueue.c,v 1.19 2010/07/19 19:46:44 espie Exp $ */ |
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/* $NetBSD: lstDeQueue.c,v 1.5 1996/11/06 17:59:36 christos Exp $ */ |
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/* |
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* Copyright (c) 1988, 1989, 1990, 1993 |
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* The Regents of the University of California. All rights reserved. |
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* |
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* This code is derived from software contributed to Berkeley by |
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* Adam de Boor. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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/*- |
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* LstDeQueue.c -- |
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* Remove the node and return its datum from the head of the list |
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*/ |
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#include "lstInt.h" |
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#include <stdlib.h> |
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/*- |
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*----------------------------------------------------------------------- |
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* Lst_DeQueue -- |
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* Remove and return the datum at the head of the given list. |
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* |
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* Results: |
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* The datum in the node at the head or NULL if the list is empty. |
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* |
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* Side Effects: |
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* The head node is removed from the list. |
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*----------------------------------------------------------------------- |
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*/ |
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void * |
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Lst_DeQueue(Lst l) |
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{ |
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void *rd; |
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LstNode tln; |
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tln = l->firstPtr; |
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✓✓ |
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if (tln == NULL) |
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return NULL; |
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rd = tln->datum; |
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l->firstPtr = tln->nextPtr; |
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if (l->firstPtr) |
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l->firstPtr->prevPtr = NULL; |
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else |
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l->lastPtr = NULL; |
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free(tln); |
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return rd; |
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} |
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