04 关于 adlist

Posted 2021-05-24 蓝风9

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前言

关于 redis 的数据结构 adlist

相关介绍主要围绕着如下测试用例, 来看看 adlist 的存储, 以及相关的 api

本文的 adlist 相关代码拷贝自 redis-6.2.0

代码来自于 https://redis.io/

adlist 这个数据结构映射到 jdk 这边类似于 java.util.LinkedList

很多操作也是链表的基础操作, 呵呵相当于又温习了一遍

测试用例

//
// Created by Jerry.X.He on 2021/2/25.
//

#include<iostream>
#include "../libs/sds.h"
#include "../libs/adlist.h"

using namespace std;

int main(int argc, char **argv) {

    sds head = sdsnew("head");
    sds tail = sdsnew("tail");

    // listCreate
    list *list = listCreate();

    // listAddNodeHead/Tail
    listAddNodeHead(list, head);
    listAddNodeTail(list, tail);

    // listIndex
    listNode *secondEle = listIndex(list, 1);

    // listSearchKey
    listNode *searchedEle = listSearchKey(list, tail);

    // listGetIterator/listNext/listReleaseIterator
    // to head
    listIter *toTailIte = listGetIterator(list, AL_START_HEAD);
    listNode *toTailNode = NULL;
    while ((toTailNode = listNext(toTailIte)) != NULL) {
        cout << (sds) (toTailNode->value) << endl;
    }
    cout << "--------" << endl;

    // to tail
    listIter *toHeadIte = listGetIterator(list, AL_START_TAIL);
    listNode *toHeadNode = NULL;
    while ((toHeadNode = listNext(toHeadIte)) != NULL) {
        cout << (sds) (toHeadNode->value) << endl;
    }
    listReleaseIterator(toHeadIte);
    cout << "--------" << endl;

    // listRewind/listRewindTail
    listRewind(list, toTailIte);
    toTailNode = NULL;
    while ((toTailNode = listNext(toTailIte)) != NULL) {
        cout << (sds) (toTailNode->value) << endl;
    }
    cout << "--------" << endl;

    // listRotate
    listRotateTailToHead(list);
    listRewind(list, toTailIte);
    toTailNode = NULL;
    while ((toTailNode = listNext(toTailIte)) != NULL) {
        cout << (sds) (toTailNode->value) << endl;
    }
    cout << "--------" << endl;

    // listDelNode
    listDelNode(list, secondEle);

    int x = 0;

}

数据结构

普通的双向链表

listCreate

创建了一个 list 的对象, 并初始化

我们来 inspect 一下 list

所有的字段都是 NULL/0, 因此全部都是 0x00

(lldb) x 0x7fa05f402be0 -c 0x30
0x7fa05f402be0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0x7fa05f402bf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0x7fa05f402c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................