REDIS data structure storage linked list design details (Redis design and implementation notes)

Redis has a flexible extension and gets a double-ended list with a table header complexity of O (1), which is divided into list and listNode2 components.

List

1typedefstructList {//Linked list2ListNode *head;//Linked list Header3ListNode *tail;//Chain Footer4     void* (*dup) (void*PTR);//copy function Pointers5     void(* Free)(void*PTR);//releasing the memory function pointer6     int(*match) (void*ptr,void*key);//Compare function Pointers7UnsignedLongLen//Linked list length8} list;

ListNode:

1 struct ListNode {  2     struct listnode *prev;   precursor pointer   3     struct listnode *next;   successor Pointer   4     void// node value   5 } ListNode;  

The following are the implementation principles of a doubly linked list:

The meaning of the list structure exists:
1. The time complexity for getting the first and the trailing elements is O (1), and you can choose to traverse the linked list elements backwards or forwards
2. Get the number of elements time complexity is 0 (1), the number of elements can be quickly removed without traversing

REDIS data structure storage linked list design details (Redis design and implementation notes)