112 lines
3.4 KiB
C
112 lines
3.4 KiB
C
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/* dlist.c - doubly linked list routines */
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/*
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* Copyright (c) 2013-2014 Wind River Systems, Inc.
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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 are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND 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 COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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DESCRIPTION
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This module implements various routines for manipulating linked lists.
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The lists are expected to be initialized such that both the head and tail
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pointers point to the list itself. Initializing the lists in such a fashion
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simplifies the adding and removing of nodes to/from the list.
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\NOMANUAL
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*/
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/* includes */
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#include <stddef.h>
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#include <misc/dlist.h>
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/*******************************************************************************
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*
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* dlistAdd - add node to tail of list
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*
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* This routine adds a node to the tail of the specified list. It is assumed
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* that the node is not part of any linked list before this routine is called.
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*
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* RETURNS: N/A
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*/
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void dlistAdd(
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dlist_t *pList, /* pointer to list to which to append node */
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dnode_t *pNode /* pointer to node to append */
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)
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{
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pNode->next = pList;
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pNode->prev = pList->tail;
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pList->tail->next = pNode;
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pList->tail = pNode;
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}
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/*******************************************************************************
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*
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* dlistRemove - remove a node from the list
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*
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* This routine removes a node from the list on which it resides. An explicit
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* pointer to the list is not required due to the way the node and list are
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* structured and initialized.
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*
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* RETURNS: N/A
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*/
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void dlistRemove(dnode_t *pNode /* pointer to node to remove */
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)
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{
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pNode->prev->next = pNode->next;
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pNode->next->prev = pNode->prev;
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}
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/*******************************************************************************
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*
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* dlistGet - get the node from the head of the list
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*
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* This routine removes the node from the head of the list and then returns
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* a pointer to it.
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*
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* RETURNS: pointer to node
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*/
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dnode_t *dlistGet(
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dlist_t *pList /* pointer to list from which to get the item */
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)
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{
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dnode_t *pNode = pList->head;
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if (pNode == pList) {
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return NULL;
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}
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dlistRemove(pNode); /* remove from <pList> */
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return pNode;
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}
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