1 //QuickAccess.h
2
3 #pragma once
4
5 #include <map>
6
7 struct QANode
8 {
9 QANode(int _key, int _value)
10 : key(_key)
11 , value(_value)
12 , next(nullptr)
13 , prev(nullptr)
14 {}
15 QANode* next;
16 QANode* prev;
17 int key;
18 int value;
19 };
20
21 class QuickAccess
22 {
23 public:
24 QuickAccess();
25
26 QuickAccess(int size);
27
28 ~QuickAccess();
29
30 int Access(int id);
31
32 double GetHitRate();
33
34 void PrintItems();
35
36 private:
37 void MoveToHead(QANode* hitNode);
38
39 void InsertNode(QANode* newNode);
40
41 int Search(int id);
42
43 private:
44 int m_nCapacity;
45 int m_nSize = 0;
46 std::map<int, void*> m_map;
47 QANode* m_pRoot;
48
49 int m_nAccessCount = 0;
50 int m_nHitCount = 0;
51 };
1 //QuickAccess.cpp
2
3 #include "QuickAccess.h"
4 #include <cstdlib>
5 #include <ctime>
6
7 QuickAccess::QuickAccess()
8 : m_nCapacity(10)
9 {
10 QuickAccess(m_nCapacity);
11 }
12
13 QuickAccess::QuickAccess(int nCapacity)
14 : m_nCapacity(nCapacity)
15 {
16 srand(time(0));
17 m_pRoot = new QANode(0, 0);
18 m_pRoot->prev = m_pRoot;
19 m_pRoot->next = m_pRoot;
20 }
21
22 QuickAccess::~QuickAccess()
23 {
24 QANode* currentNode = m_pRoot->next;
25 QANode* deleteNode = currentNode;
26 while (currentNode != m_pRoot) {
27 currentNode = currentNode->next;
28 delete deleteNode;
29 deleteNode = currentNode;
30 }
31 delete m_pRoot;
32 m_pRoot = nullptr;
33 }
34
35 int QuickAccess::Access(int key)
36 {
37 m_nAccessCount++;
38 auto it = m_map.find(key);
39 if (it == m_map.end()) {//未命中
40 int value = Search(key);
41 InsertNode(new QANode(key, value));
42 }
43 else {//命中
44 m_nHitCount++;
45 MoveToHead((QANode*)m_map[key]);
46 }
47 return ((QANode*)m_map[key])->value;
48 }
49
50 //1,2,3,4,5
51 void QuickAccess::MoveToHead(QANode* hitNode)
52 {
53 hitNode->prev->next = hitNode->next;
54 hitNode->next->prev = hitNode->prev;
55
56 hitNode->next = m_pRoot->next;
57 m_pRoot->next->prev = hitNode;
58
59 hitNode->prev = m_pRoot;
60 m_pRoot->next = hitNode;
61 }
62
63 void QuickAccess::InsertNode(QANode* newNode)
64 {
65 //insert new item to head
66 newNode->next = m_pRoot->next;
67 m_pRoot->next->prev = newNode;
68 m_pRoot->next = newNode;
69 newNode->prev = m_pRoot;
70 m_map[newNode->key] = newNode;
71 if (m_nSize == m_nCapacity) {//full
72 //delete last item
73 QANode* lastSecondItem = m_pRoot->prev->prev;
74 m_map.erase(lastSecondItem->next->key);
75 delete lastSecondItem->next;
76 lastSecondItem->next = m_pRoot;
77 m_pRoot->prev = lastSecondItem;
78 }
79 else {
80 m_nSize++;
81 }
82 }
83
84 int QuickAccess::Search(int id)
85 {
86 int reverse = 0;
87 while (id) {
88 reverse = (reverse * 10) + (id % 10);
89 id /= 10;
90 }
91 return reverse;
92 }
93
94 double QuickAccess::GetHitRate()
95 {
96 return (m_nHitCount * 1.0) / m_nAccessCount;
97 }
98
99 void QuickAccess::PrintItems()
100 {
101 QANode* currentNode = m_pRoot->next;
102 int alignCnt = 1;
103 printf("\n******************************PrintItems*************************************\n");
104 while (currentNode != m_pRoot) {
105 printf("%d[%d] ", currentNode->key, currentNode->value);
106 if (alignCnt % 10 == 0) {
107 printf("\n");
108 alignCnt = 0;
109 }
110 alignCnt++;
111 currentNode = currentNode->next;
112 }
113 printf("\n");
114 }
// ConsoleApplication1.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//
#include <iostream>
#include <random>
#include "QuickAccess.h"
void QuickAccessTest();
int main()
{
QuickAccessTest();
return 0;
}
void QuickAccessTest()
{
srand(time(0));
int cacheSize = 0;
int searchRange = 0;
while (1) {
printf("input cache size and search range: ");
if (scanf_s("%d,%d", &cacheSize, &searchRange) != 2) {
return;
}
QuickAccess qa(cacheSize);
for (int i = 0; i < 100000; i++) {
int randValue = rand() % searchRange;
qa.Access(randValue);
}
qa.PrintItems();
printf("\nhitRate = %lf\n", qa.GetHitRate());
}
printf("\n\n");
}
