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/* |
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* Copyright (c) 2002-2003 Erik Fears |
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* Copyright (c) 2014-2021 ircd-hybrid development team |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 |
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* USA |
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*/ |
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|
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/*! \file list.c |
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* \brief Maintains doubly-linked lists. |
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* \version $Id$ |
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*/ |
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|
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#include <stdlib.h> |
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#include <assert.h> |
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|
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#include "memory.h" |
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#include "list.h" |
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|
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|
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node_t * |
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node_create(void) |
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{ |
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node_t *node = xcalloc(sizeof *node); |
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return node; |
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} |
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|
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void |
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node_free(node_t *node) |
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{ |
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xfree(node); |
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} |
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|
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node_t * |
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list_add(void *data, node_t *node, list_t *list) |
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{ |
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node->data = data; |
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node->prev = NULL; |
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node->next = list->head; |
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|
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/* Assumption: If list->tail != NULL, list->head != NULL */ |
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if (list->head) |
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list->head->prev = node; |
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else if (list->tail == NULL) |
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list->tail = node; |
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|
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list->head = node; |
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list->elements++; |
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|
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return node; |
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} |
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|
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node_t * |
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list_remove(node_t *node, list_t *list) |
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{ |
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/* Assumption: If node->next == NULL, then list->tail == node |
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* and: If node->prev == NULL, then list->head == node |
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*/ |
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if (node->next) |
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node->next->prev = node->prev; |
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else |
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{ |
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assert(list->tail == node); |
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list->tail = node->prev; |
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} |
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|
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if (node->prev) |
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node->prev->next = node->next; |
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else |
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{ |
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assert(list->head == node); |
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list->head = node->next; |
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} |
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|
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/* Set this to NULL does matter */ |
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node->next = NULL; |
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node->prev = NULL; |
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list->elements--; |
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|
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return node; |
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} |
