• A generic doubly linked list implementation


    redis-4.0.11srcadlist.h

    /* adlist.h - A generic doubly linked list implementation
     *
     * Copyright (c) 2006-2012, Salvatore Sanfilippo <antirez at gmail dot com>
     * All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions are met:
     *
     *   * Redistributions of source code must retain the above copyright notice,
     *     this list of conditions and the following disclaimer.
     *   * Redistributions in binary form must reproduce the above copyright
     *     notice, this list of conditions and the following disclaimer in the
     *     documentation and/or other materials provided with the distribution.
     *   * Neither the name of Redis nor the names of its contributors may be used
     *     to endorse or promote products derived from this software without
     *     specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
     * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    #ifndef __ADLIST_H__
    #define __ADLIST_H__
    
    /* Node, List, and Iterator are the only data structures used currently. */
    
    typedef struct listNode {
        struct listNode *prev;
        struct listNode *next;
        void *value;
    } listNode;
    
    typedef struct listIter {
        listNode *next;
        int direction;
    } listIter;
    
    typedef struct list {
        listNode *head;
        listNode *tail;
        void *(*dup)(void *ptr);
        void (*free)(void *ptr);
        int (*match)(void *ptr, void *key);
        unsigned long len;
    } list;
    
    /* Functions implemented as macros */
    #define listLength(l) ((l)->len)
    #define listFirst(l) ((l)->head)
    #define listLast(l) ((l)->tail)
    #define listPrevNode(n) ((n)->prev)
    #define listNextNode(n) ((n)->next)
    #define listNodeValue(n) ((n)->value)
    
    #define listSetDupMethod(l,m) ((l)->dup = (m))
    #define listSetFreeMethod(l,m) ((l)->free = (m))
    #define listSetMatchMethod(l,m) ((l)->match = (m))
    
    #define listGetDupMethod(l) ((l)->dup)
    #define listGetFree(l) ((l)->free)
    #define listGetMatchMethod(l) ((l)->match)
    
    /* Prototypes */
    list *listCreate(void);
    void listRelease(list *list);
    void listEmpty(list *list);
    list *listAddNodeHead(list *list, void *value);
    list *listAddNodeTail(list *list, void *value);
    list *listInsertNode(list *list, listNode *old_node, void *value, int after);
    void listDelNode(list *list, listNode *node);
    listIter *listGetIterator(list *list, int direction);
    listNode *listNext(listIter *iter);
    void listReleaseIterator(listIter *iter);
    list *listDup(list *orig);
    listNode *listSearchKey(list *list, void *key);
    listNode *listIndex(list *list, long index);
    void listRewind(list *list, listIter *li);
    void listRewindTail(list *list, listIter *li);
    void listRotate(list *list);
    void listJoin(list *l, list *o);
    
    /* Directions for iterators */
    #define AL_START_HEAD 0
    #define AL_START_TAIL 1
    
    #endif /* __ADLIST_H__ */

    redis-4.0.11srcadlist.c

    /* adlist.c - A generic doubly linked list implementation
     *
     * Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>
     * All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions are met:
     *
     *   * Redistributions of source code must retain the above copyright notice,
     *     this list of conditions and the following disclaimer.
     *   * Redistributions in binary form must reproduce the above copyright
     *     notice, this list of conditions and the following disclaimer in the
     *     documentation and/or other materials provided with the distribution.
     *   * Neither the name of Redis nor the names of its contributors may be used
     *     to endorse or promote products derived from this software without
     *     specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
     * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    
    #include <stdlib.h>
    #include "adlist.h"
    
    /* Create a new list. The created list can be freed with
     * AlFreeList(), but private value of every node need to be freed
     * by the user before to call AlFreeList().
     *
     * On error, NULL is returned. Otherwise the pointer to the new list. */
    list *listCreate(void)
    {
        struct list *list;
    
        if ((list = malloc(sizeof(*list))) == NULL)
            return NULL;
        list->head = list->tail = NULL;
        list->len = 0;
        list->dup = NULL;
        list->free = NULL;
        list->match = NULL;
        return list;
    }
    
    /* Remove all the elements from the list without destroying the list itself. */
    void listEmpty(list *list)
    {
        unsigned long len;
        listNode *current, *next;
    
        current = list->head;
        len = list->len;
        while(len--) {
            next = current->next;
            if (list->free) list->free(current->value);
            free(current);
            current = next;
        }
        list->head = list->tail = NULL;
        list->len = 0;
    }
    
    /* Free the whole list.
     *
     * This function can't fail. */
    void listRelease(list *list)
    {
        listEmpty(list);
        free(list);
    }
    
    /* Add a new node to the list, to head, containing the specified 'value'
     * pointer as value.
     *
     * On error, NULL is returned and no operation is performed (i.e. the
     * list remains unaltered).
     * On success the 'list' pointer you pass to the function is returned. */
    list *listAddNodeHead(list *list, void *value)
    {
        listNode *node;
    
        if ((node = malloc(sizeof(*node))) == NULL)
            return NULL;
        node->value = value;
        if (list->len == 0) {
            list->head = list->tail = node;
            node->prev = node->next = NULL;
        } else {
            node->prev = NULL;
            node->next = list->head;
            list->head->prev = node;
            list->head = node;
        }
        list->len++;
        return list;
    }
    
    /* Add a new node to the list, to tail, containing the specified 'value'
     * pointer as value.
     *
     * On error, NULL is returned and no operation is performed (i.e. the
     * list remains unaltered).
     * On success the 'list' pointer you pass to the function is returned. */
    list *listAddNodeTail(list *list, void *value)
    {
        listNode *node;
    
        if ((node = malloc(sizeof(*node))) == NULL)
            return NULL;
        node->value = value;
        if (list->len == 0) {
            list->head = list->tail = node;
            node->prev = node->next = NULL;
        } else {
            node->prev = list->tail;
            node->next = NULL;
            list->tail->next = node;
            list->tail = node;
        }
        list->len++;
        return list;
    }
    
    list *listInsertNode(list *list, listNode *old_node, void *value, int after) {
        listNode *node;
    
        if ((node = malloc(sizeof(*node))) == NULL)
            return NULL;
        node->value = value;
        if (after) {
            node->prev = old_node;
            node->next = old_node->next;
            if (list->tail == old_node) {
                list->tail = node;
            }
        } else {
            node->next = old_node;
            node->prev = old_node->prev;
            if (list->head == old_node) {
                list->head = node;
            }
        }
        if (node->prev != NULL) {
            node->prev->next = node;
        }
        if (node->next != NULL) {
            node->next->prev = node;
        }
        list->len++;
        return list;
    }
    
    /* Remove the specified node from the specified list.
     * It's up to the caller to free the private value of the node.
     *
     * This function can't fail. */
    void listDelNode(list *list, listNode *node)
    {
        if (node->prev)
            node->prev->next = node->next;
        else
            list->head = node->next;
        if (node->next)
            node->next->prev = node->prev;
        else
            list->tail = node->prev;
        if (list->free) list->free(node->value);
        free(node);
        list->len--;
    }
    
    /* Returns a list iterator 'iter'. After the initialization every
     * call to listNext() will return the next element of the list.
     *
     * This function can't fail. */
    listIter *listGetIterator(list *list, int direction)
    {
        listIter *iter;
    
        if ((iter = malloc(sizeof(*iter))) == NULL) return NULL;
        if (direction == AL_START_HEAD)
            iter->next = list->head;
        else
            iter->next = list->tail;
        iter->direction = direction;
        return iter;
    }
    
    /* Release the iterator memory */
    void listReleaseIterator(listIter *iter) {
        free(iter);
    }
    
    /* Create an iterator in the list private iterator structure */
    void listRewind(list *list, listIter *li) {
        li->next = list->head;
        li->direction = AL_START_HEAD;
    }
    
    void listRewindTail(list *list, listIter *li) {
        li->next = list->tail;
        li->direction = AL_START_TAIL;
    }
    
    /* Return the next element of an iterator.
     * It's valid to remove the currently returned element using
     * listDelNode(), but not to remove other elements.
     *
     * The function returns a pointer to the next element of the list,
     * or NULL if there are no more elements, so the classical usage patter
     * is:
     *
     * iter = listGetIterator(list,<direction>);
     * while ((node = listNext(iter)) != NULL) {
     *     doSomethingWith(listNodeValue(node));
     * }
     *
     * */
    listNode *listNext(listIter *iter)
    {
        listNode *current = iter->next;
    
        if (current != NULL) {
            if (iter->direction == AL_START_HEAD)
                iter->next = current->next;
            else
                iter->next = current->prev;
        }
        return current;
    }
    
    /* Duplicate the whole list. On out of memory NULL is returned.
     * On success a copy of the original list is returned.
     *
     * The 'Dup' method set with listSetDupMethod() function is used
     * to copy the node value. Otherwise the same pointer value of
     * the original node is used as value of the copied node.
     *
     * The original list both on success or error is never modified. */
    list *listDup(list *orig)
    {
        list *copy;
        listIter iter;
        listNode *node;
    
        if ((copy = listCreate()) == NULL)
            return NULL;
        copy->dup = orig->dup;
        copy->free = orig->free;
        copy->match = orig->match;
        listRewind(orig, &iter);
        while((node = listNext(&iter)) != NULL) {
            void *value;
    
            if (copy->dup) {
                value = copy->dup(node->value);
                if (value == NULL) {
                    listRelease(copy);
                    return NULL;
                }
            } else
                value = node->value;
            if (listAddNodeTail(copy, value) == NULL) {
                listRelease(copy);
                return NULL;
            }
        }
        return copy;
    }
    
    /* Search the list for a node matching a given key.
     * The match is performed using the 'match' method
     * set with listSetMatchMethod(). If no 'match' method
     * is set, the 'value' pointer of every node is directly
     * compared with the 'key' pointer.
     *
     * On success the first matching node pointer is returned
     * (search starts from head). If no matching node exists
     * NULL is returned. */
    listNode *listSearchKey(list *list, void *key)
    {
        listIter iter;
        listNode *node;
    
        listRewind(list, &iter);
        while((node = listNext(&iter)) != NULL) {
            if (list->match) {
                if (list->match(node->value, key)) {
                    return node;
                }
            } else {
                if (key == node->value) {
                    return node;
                }
            }
        }
        return NULL;
    }
    
    /* Return the element at the specified zero-based index
     * where 0 is the head, 1 is the element next to head
     * and so on. Negative integers are used in order to count
     * from the tail, -1 is the last element, -2 the penultimate
     * and so on. If the index is out of range NULL is returned. */
    listNode *listIndex(list *list, long index) {
        listNode *n;
    
        if (index < 0) {
            index = (-index)-1;
            n = list->tail;
            while(index-- && n) n = n->prev;
        } else {
            n = list->head;
            while(index-- && n) n = n->next;
        }
        return n;
    }
    
    /* Rotate the list removing the tail node and inserting it to the head. */
    void listRotate(list *list) {
        listNode *tail = list->tail;
    
        if (listLength(list) <= 1) return;
    
        /* Detach current tail */
        list->tail = tail->prev;
        list->tail->next = NULL;
        /* Move it as head */
        list->head->prev = tail;
        tail->prev = NULL;
        tail->next = list->head;
        list->head = tail;
    }
    
    /* Add all the elements of the list 'o' at the end of the
     * list 'l'. The list 'other' remains empty but otherwise valid. */
    void listJoin(list *l, list *o) {
        if (o->head)
            o->head->prev = l->tail;
    
        if (l->tail)
            l->tail->next = o->head;
        else
            l->head = o->head;
    
        if (o->tail) l->tail = o->tail;
        l->len += o->len;
    
        /* Setup other as an empty list. */
        o->head = o->tail = NULL;
        o->len = 0;
    }
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  • 原文地址:https://www.cnblogs.com/dong1/p/14040123.html
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