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@@ -0,0 +1,227 @@
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+#include"basical/type_checking.h"
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+#include<cstdlib>
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+#include<cstring>
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+#include<exception>
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+#include<random>
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+namespace nanxing_extend
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+{
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+ //错误处理机制
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+ class nextpoint_new:std::exception //skip_node分配空间失败的时候
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+ {
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+ const char* what() const noexcept
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+ {
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+ return "malloc next_node point fault";
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+ }
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+ };
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+
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+
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+ class newNode_error:std::exception //申请新的空间的时候
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+ {
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+ const char* what() const noexcept
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+ {
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+ return "malloc new node error";
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+ }
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+ };
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+ class random_error:std::exception //申请预设随机数空间的时候
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+ {
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+ const char* what() const noexcept
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+ {
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+ return "malloc random space error";
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+ }
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+ };
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+
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+
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+
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+ enum class Skip_result //跳表操作的结果
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+ {
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+ successufl,
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+ fault,
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+ full
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+ };
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+ template<typename V>
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+ union skiplistre
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+ {
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+ V value,
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+ Skip_result result
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+ };
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+
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+
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+ //注意这里的V只能是要么是能直接深拷贝的类型，要么是指向堆上数据的指针类型
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+ template<typename K,typename V>
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+ struct skip_node
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+ {
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+ static_assert(nanxing_extend::compare_admit<K>value);
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+ static_assert(nanxing_extend::compare_admit<V>value);
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+ skip_node<K,V>** next_node;
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+ V value;
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+ private:
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+ K key;
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+ int level;
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+
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+ public:
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+
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+ skip_node(){};
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+ skip_node(K _key,V _value,int _level):key(_key),value(_value),level(_level){};
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+ init_next(int level)
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+ {
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+ try
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+ {
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+ next_node=::new (skip_node<K,V>*)[level];
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+ }
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+ catch(std::bad_alloc){ //捕获内存分配错误
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+ throw nextpoint_new(); //重新抛出一个定制的更详细的类型用以明确错误的具体位置
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+ }
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+ std::memset(next_node,0,sizeof(skip_node<K,V>*)*level);
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+ }
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+ K get_key(){ return key; }
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+ };
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+
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+
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+ template<typename K,typename V>
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+ class skipList
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+ {
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+ static_assert(nanxing_extend::compare_admit<K>value);
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+ static_assert(nanxing_extend::compare_admit<V>value);
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+ private:
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+ using Node=skip_node<K,V>;
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+ using Nptr=Node**;
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+ //由于C++的便利性我们考虑使用带头节点的跳表（C++允许对数据不进行初始化(默认构造函数))
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+ Nptr head; //头节点
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+ int max_level; //最大高度
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+ int* random_level;
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+ int current_level; //跳表当前高度
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+ int current_size; //跳表当前尺寸
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+ //这里出于一个考虑，当跳表单纯作为小数据内存数据库，单表大小限制是没有意义的
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+ //但是像level_db这样作为KV数据库的缓存的时候，就需要限制大小进行落盘
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+
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+ #ifdef SKIP_MAX_SIZE
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+ int max_size; //跳表允许的最大尺寸
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+ #endif
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+ public:
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+ #ifndef SKIP_MAX_SIZE
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+ skipList(int _max_level):max_level(_max_level),random_level(nullptr)
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+ {
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+ try
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+ {
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+ Node* middle=::new skip_node;
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+ middle->init_next(max_level);
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+ head=::new (Node*)[max_level];
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+ for(auto& i in head)
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+ {
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+ i=middle;
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+ }
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+ }
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+ catch(std::bad_alloc)
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+ {
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+ throw newNode_error();
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+ }
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+ }
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+ #elif
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+ skipList(int _max_level,int _max_size):max_size(_max_size),max_level(_max_level),random_level(nullptr)
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+ {
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+ try
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+ {
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+ Node* middle=::new skip_node;
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+ middle->init_next(max_level);
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+ head=::new (Node*)[max_level];
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+ for(auto& i in head)
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+ {
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+ i=middle;
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+ }
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+ }
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+ catch(std::bad_alloc)
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+ {
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+ throw newNode_error();
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+ }
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+ }
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+ #endif
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+ [[nodiscard]] //这个返回值最好不要忽略否则很有可能会出现内存泄漏
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+ skiplistre<V> insert(K _key,V _value) //如果相同的时候我们考虑将value返回因为value很可能会是一个指针，需要手动清空内存
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+ {
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+ using ptr=Node*;
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+ int rand_level=0;
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+ ptr updata[max_level]={nullptr}; //用于更新的数组
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+ int level=current_level-1;
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+ ptr point=head[level];
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+ skiplistre<V> sk;
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+ ptr new_node;
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+
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+ for(int i=level;i>=0;i--)
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+ {
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+ for(;;)
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+ {
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+ if(point->next_node[level]==nullptr)
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+ {
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+ updata[level]=point;
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+ break;
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+ }
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+ else if(point->next_node[level]->key>=_key)
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+ {
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+ if(point->next_node[level]->key==_key)
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+ {
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+
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+ sk.value=std::move(point->next_node[level]->value); //这个值已经不需要了，直接移动
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+ point->next_node[level]->value=_value;
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+ return sk;
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+ }
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+ else
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+ {
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+ updata[level]=point;
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+ break;
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+ }
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+ else{
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+ point=point->head[level]; //更新point指针
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+ }
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+ }
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+ }
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+ [[likely]]
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+ if(random_level!=nullptr)
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+ {
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+ rand_level=random_level[current_size%1024];
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+ new_node=new skip_node(_key,_value,rand_level);
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+ }
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+ [[unlikely]]
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+ else
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+ {
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+ rand_level=std::rand(chrono::system_clock::now().time_since_epoch().count())%(1+max_level);
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+ new_node=new skip_node(_key,_value,rand_level);
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+ }
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+ ptr tmp=nullptr;
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+ for(int i=0;i<=level;i++)
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+ {
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+ tmp=updata[i]->next_node[i];
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+ updata[i]->next_node[i]=new_node;
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+ new_node->next_node[i]=tmp;
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+ }
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+ }
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+ sk.Skip_result=Skip_result::successufl;
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+ }
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+
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+ skiplistre<V> search(K _key)
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+ {
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+
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+ }
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+
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+
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+ void init_skip() //直接生成随机数表
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+ {
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+ try{
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+ random_level=new int[1024]; //刚好是一页的大小（4KB）
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+ }
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+ catch(std::bad_alloc)
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+ {
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+ throw random_error();
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+ }
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+ std::mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());
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+ for(auto& i :random_level)
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+ {
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+ i=(rnd()%max_level)+1;
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+ }
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+
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+ }
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+ };
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+
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+
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+}
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+
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+
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