firstCommit
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@ -1,19 +1,14 @@
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# 基于cortex-m3-emulator实现哈希表并测试验证##
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# 基于cortex-m3-emulator实现哈希表并测试验证
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## 1. 简介
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利用c语言实现了哈希表(HashMap),包括添加键值对(Put),获取键对应的值(Get), 删除健(Delete),清空哈希表(Clear), 迭代遍历哈希表(hashMapIterator)等功能
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操作。
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利用c语言实现了哈希表(HashMap),包括添加键值对(Put),获取键对应的值(Get), 删除健(Delete),清空哈希表(Clear)等功能。参考了比赛提供的示例代码,通过使用与比赛截然不同的方法——线性探测法来解决哈希冲突。
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利用数组(Entry)作为存储空间,利用链表(*next)解决冲突。当哈希表的大小超过数组大小后,为避免发生冲突过多的情况,可以对哈希表扩容。
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## 2. 数据结构设计说明
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键值对结构
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typedef struct entry {
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void * key; // 键
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void * value; // 值
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struct entry * next; // 冲突链表
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}*Entry;
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哈希结构
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typedef struct hashMap {
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int size; // 当前大小
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|
@ -28,7 +23,6 @@ typedef struct hashMap {
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Exists exists; // 判断键是否存在
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Boolean autoAssign; // 设定是否根据当前数据量动态调整内存大小,默认开启
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}*HashMap;
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包括以下函数功能,分别为:
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`createHashMap`:创建一个哈希结构
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`defaultPut`:添加键值对
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@ -38,21 +32,19 @@ typedef struct hashMap {
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`defaultClear`:清空Map的函数类型
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`resetHashMap`:重新构建哈希表
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## 3. 测试程序说明
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测试了哈希表的插入键值对(Put),判断键是否存在(Exist),获取键对应的值(Get), 删除健(Delete),迭代遍历哈希表(hashMapIterator),清空哈希表(Clear)等操作。
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并展示了利用链地址法解决哈希冲突的示例, 两个不同的人(Bob和Li Ming)的hashcode相同。
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测试了哈希表的插入键值对(Put),判断键是否存在(Exist),获取键对应的值(Get), 删除健(Delete)等操作。
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## 4. 运行结果(##需结合运行测试截图按步骤说明##)
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打开menuconfig之后,将test_hash_map开启(y),保存后退出
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4.1打开menuconfig之后,将test_hash_map开启(y),保存后退出。
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编译XiZi-cortex-m3-emulator.elf成功
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启动qemu模拟Xiuos操作系统,验证TestHash注册Shell命令
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执行TestHash命令,打印测试结果。
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4.2编译XiZi-cortex-m3-emulator.elf成功。
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4.3启动qemu模拟Xiuos操作系统,验证TestHash注册Shell命令。执行TestHash命令,打印测试结果。
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@ -2,12 +2,11 @@
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/**
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* @file: test_hash.c
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* @brief: a application of test hash function
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* @version: 3.0
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* @author: Yao wenying
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* @date: 2023/05/26
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* @version: 1.0
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* @author: Li chunji And Li zihao
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* @date: 2023/09/15
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*/
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#include <transform.h>
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#include"test_hash.h"
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int defaultHashCode(HashMap hashMap, let key) {
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@ -34,17 +33,13 @@ void resetHashMap(HashMap hashMap, int listSize) {
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// 键值对临时存储空间
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Entry tempList = newEntryList(hashMap->size);
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HashMapIterator iterator = createHashMapIterator(hashMap);
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int length = hashMap->size;
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for (int index = 0; hasNextHashMapIterator(iterator); index++) {
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// 迭代取出所有键值对
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iterator = nextHashMapIterator(iterator);
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tempList[index].key = iterator->entry->key;
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tempList[index].value = iterator->entry->value;
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tempList[index].next = NULL;
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for(int index=0;index<hashMap->listSize;index++)
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{
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tempList[index].key = hashMap->list[index].key;
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tempList[index].value = hashMap->list[index].value;
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}
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freeHashMapIterator(&iterator);
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// 清除原有键值对数据
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hashMap->size = 0;
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@ -52,13 +47,6 @@ void resetHashMap(HashMap hashMap, int listSize) {
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Entry current = &hashMap->list[i];
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current->key = NULL;
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current->value = NULL;
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if (current->next != NULL) {
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while (current->next != NULL) {
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Entry temp = current->next->next;
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free(current->next);
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current->next = temp;
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}
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}
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}
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// 更改内存大小
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@ -73,7 +61,6 @@ void resetHashMap(HashMap hashMap, int listSize) {
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for (int i = 0; i < hashMap->listSize; i++) {
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hashMap->list[i].key = NULL;
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hashMap->list[i].value = NULL;
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hashMap->list[i].next = NULL;
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}
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// 将所有键值对重新写入内存
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@ -84,60 +71,46 @@ void resetHashMap(HashMap hashMap, int listSize) {
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}
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void defaultPut(HashMap hashMap, let key, let value) {
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// 获取哈希值
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int index = hashMap->hashCode(hashMap, key);
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// 获取哈希值
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int index = hashMap->hashCode(hashMap, key);
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if (hashMap->list[index].key == NULL) {
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hashMap->size++;
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// 该地址为空时直接存储
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hashMap->list[index].key = key;
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hashMap->list[index].value = value;
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}
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else {
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if (hashMap->list[index].key == NULL) {
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hashMap->size++;
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// 该地址为空时直接存储
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hashMap->list[index].key = key;
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hashMap->list[index].value = value;
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}
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else {
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Entry current = &hashMap->list[index];
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while (current != NULL) {
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if (hashMap->equal(key, current->key)) {
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// 对于键值已经存在的直接覆盖
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current->value = value;
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return;
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}
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current = current->next;
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};
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int cur = (index+1) % hashMap->listSize;
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while(hashMap->list[cur].key != NULL)
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{
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cur = (cur + 1) % hashMap->listSize;
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}
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// 发生冲突则创建节点挂到相应位置的next上
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Entry entry = newEntry();
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entry->key = key;
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entry->value = value;
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entry->next = hashMap->list[index].next;
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hashMap->list[index].next = entry;
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hashMap->size++;
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}
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hashMap->size++;
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hashMap->list[index].key = key;
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hashMap->list[index].value = value;
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}
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if (hashMap->autoAssign && hashMap->size >= hashMap->listSize) {
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// 内存扩充至原来的两倍
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// *注: 扩充时考虑的是当前存储元素数量与存储空间的大小关系,而不是存储空间是否已经存满,
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// 例如: 存储空间为10,存入了10个键值对,但是全部冲突了,所以存储空间空着9个,其余的全部挂在一个上面,
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// 这样检索的时候和遍历查询没有什么区别了,可以简单这样理解,当我存入第11个键值对的时候一定会发生冲突,
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// 这是由哈希函数本身的特性(取模)决定的,冲突就会导致检索变慢,所以这时候扩充存储空间,对原有键值对进行
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// 再次散列,会把冲突的数据再次分散开,加快索引定位速度。
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resetHashMap(hashMap, hashMap->listSize * 2);
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}
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if (hashMap->autoAssign && hashMap->size >= hashMap->listSize) {
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resetHashMap(hashMap, hashMap->listSize * 2);
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}
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}
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let defaultGet(HashMap hashMap, let key) {
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if (hashMap->exists(hashMap, key)) {
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int index = hashMap->hashCode(hashMap, key);
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Entry entry = &hashMap->list[index];
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while (entry != NULL) {
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if (hashMap->equal(entry->key, key)) {
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return entry->value;
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}
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entry = entry->next;
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}
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}
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return NULL;
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if (hashMap->exists(hashMap, key)) {
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int index = hashMap->hashCode(hashMap, key);
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Entry entry = &hashMap->list[index];
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while (entry != NULL) {
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if (hashMap->equal(entry->key, key)) {
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return entry->value;
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}
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index++;
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entry = &hashMap->list[index % hashMap->listSize];
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}
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}
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return NULL;
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}
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let defaultRemove(HashMap hashMap, let key) {
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@ -146,37 +119,29 @@ let defaultRemove(HashMap hashMap, let key) {
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if (entry->key == NULL) {
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return NULL;
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}
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let entryKey = entry->key;
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let entryKey = key;
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Boolean result = False;
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if (hashMap->equal(entry->key, key)) {
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hashMap->size--;
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if (entry->next != NULL) {
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Entry temp = entry->next;
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entry->key = temp->key;
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entry->value = temp->value;
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entry->next = temp->next;
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free(temp);
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}
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else {
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entry->key = NULL;
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entry->value = NULL;
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}
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entry->key = NULL;
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entry->value = NULL;
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result = True;
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}
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else {
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Entry p = entry;
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entry = entry->next;
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while (entry != NULL) {
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if (hashMap->equal(entry->key, key)) {
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hashMap->size--;
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p->next = entry->next;
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free(entry);
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Entry entry = &hashMap->list[(index+1)%hashMap->listSize];
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while (entry != NULL) {
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if (hashMap->equal(entry->key, key)) {
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hashMap->size--;
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entry->key = NULL;
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entry->value = NULL;
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result = True;
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break;
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}
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p = entry;
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entry = entry->next;
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};
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}
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index++;
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entry = &hashMap->list[index % hashMap->listSize];
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}
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}
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// 如果空间占用不足一半,则释放多余内存
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|
@ -187,107 +152,61 @@ let defaultRemove(HashMap hashMap, let key) {
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}
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Boolean defaultExists(HashMap hashMap, let key) {
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int index = hashMap->hashCode(hashMap, key);
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Entry entry = &hashMap->list[index];
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if (entry->key == NULL) {
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return False;
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}
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else {
|
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while (entry != NULL) {
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if (hashMap->equal(entry->key, key)) {
|
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return True;
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}
|
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entry = entry->next;
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}
|
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return False;
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}
|
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int index = hashMap->hashCode(hashMap, key);
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Entry entry = &hashMap->list[index];
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if (entry->key == NULL) {
|
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return False;
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}
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else {
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while (entry != NULL) {
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if (hashMap->equal(entry->key, key)) {
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return True;
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}
|
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index++;
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entry = &hashMap->list[index % hashMap->listSize];
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}
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return False;
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}
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}
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void defaultClear(HashMap hashMap) {
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for (int i = 0; i < hashMap->listSize; i++) {
|
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// 释放冲突值内存
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Entry entry = hashMap->list[i].next;
|
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while (entry != NULL) {
|
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Entry next = entry->next;
|
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free(entry);
|
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entry = next;
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}
|
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hashMap->list[i].next = NULL;
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}
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// 释放存储空间
|
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free(hashMap->list);
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hashMap->list = NULL;
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hashMap->size = -1;
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hashMap->listSize = 0;
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// 释放存储空间
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free(hashMap->list);
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hashMap->list = NULL;
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hashMap->size = -1;
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hashMap->listSize = 0;
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}
|
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HashMap createHashMap(HashCode hashCode, Equal equal) {
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HashMap hashMap = newHashMap();
|
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if (hashMap == NULL) {
|
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return NULL;
|
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}
|
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hashMap->size = 0;
|
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hashMap->listSize = 8;
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hashMap->hashCode = hashCode == NULL ? defaultHashCode : hashCode;
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hashMap->equal = equal == NULL ? defaultEqual : equal;
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hashMap->exists = defaultExists;
|
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hashMap->get = defaultGet;
|
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hashMap->put = defaultPut;
|
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hashMap->remove = defaultRemove;
|
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hashMap->clear = defaultClear;
|
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hashMap->autoAssign = True;
|
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|
||||
// 起始分配8个内存空间,溢出时会自动扩充
|
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hashMap->list = newEntryList(hashMap->listSize);
|
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if (hashMap->list == NULL) {
|
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return NULL;
|
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}
|
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Entry p = hashMap->list;
|
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for (int i = 0; i < hashMap->listSize; i++) {
|
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p[i].key = p[i].value = p[i].next = NULL;
|
||||
}
|
||||
return hashMap;
|
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HashMap hashMap = newHashMap();
|
||||
if (hashMap == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
hashMap->size = 0;
|
||||
hashMap->listSize = 8;
|
||||
hashMap->hashCode = hashCode == NULL ? defaultHashCode : hashCode;
|
||||
hashMap->equal = equal == NULL ? defaultEqual : equal;
|
||||
hashMap->exists = defaultExists;
|
||||
hashMap->get = defaultGet;
|
||||
hashMap->put = defaultPut;
|
||||
hashMap->remove = defaultRemove;
|
||||
hashMap->clear = defaultClear;
|
||||
hashMap->autoAssign = True;
|
||||
|
||||
// 起始分配8个内存空间,溢出时会自动扩充
|
||||
hashMap->list = newEntryList(hashMap->listSize);
|
||||
if (hashMap->list == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
Entry p = hashMap->list;
|
||||
for (int i = 0; i < hashMap->listSize; i++) {
|
||||
p[i].key = p[i].value = NULL;
|
||||
}
|
||||
return hashMap;
|
||||
}
|
||||
|
||||
HashMapIterator createHashMapIterator(HashMap hashMap) {
|
||||
HashMapIterator iterator = newHashMapIterator();
|
||||
if (iterator == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
iterator->hashMap = hashMap;
|
||||
iterator->count = 0;
|
||||
iterator->hashCode = -1;
|
||||
iterator->entry = NULL;
|
||||
return iterator;
|
||||
}
|
||||
|
||||
Boolean hasNextHashMapIterator(HashMapIterator iterator) {
|
||||
return iterator->count < iterator->hashMap->size ? True : False;
|
||||
}
|
||||
|
||||
HashMapIterator nextHashMapIterator(HashMapIterator iterator) {
|
||||
if (hasNextHashMapIterator(iterator)) {
|
||||
if (iterator->entry != NULL && iterator->entry->next != NULL) {
|
||||
iterator->count++;
|
||||
iterator->entry = iterator->entry->next;
|
||||
return iterator;
|
||||
}
|
||||
while (++iterator->hashCode < iterator->hashMap->listSize) {
|
||||
Entry entry = &iterator->hashMap->list[iterator->hashCode];
|
||||
if (entry->key != NULL) {
|
||||
iterator->count++;
|
||||
iterator->entry = entry;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
return iterator;
|
||||
}
|
||||
|
||||
void freeHashMapIterator(HashMapIterator * iterator) {
|
||||
free(*iterator);
|
||||
*iterator = NULL;
|
||||
}
|
||||
|
||||
#define Put(map, key, value) map->put(map, (void *)key, (void *)value);
|
||||
#define Get(map, key) (char *)map->get(map, (void *)key)
|
||||
|
@ -305,19 +224,20 @@ void TestHash() {
|
|||
Put(map, "000852", "Janne");
|
||||
|
||||
printf("print the key-values in hashmap:\n");
|
||||
HashMapIterator iterator = createHashMapIterator(map);
|
||||
while (hasNextHashMapIterator(iterator)) {
|
||||
iterator = nextHashMapIterator(iterator);
|
||||
printf("{ key: %s, key: %s, hashcode: %d }\n",
|
||||
(char *)iterator->entry->key, (char *)iterator->entry->value, iterator->hashCode);
|
||||
}
|
||||
for(int index=0;index<map->listSize;index++)
|
||||
{
|
||||
if(defaultExists(map, map->list[index].key))
|
||||
{
|
||||
printf("{ key: %s, key: %s, hashcode: %d }\n",
|
||||
(char *)map->list[index].key, (char *)map->list[index].value, map->hashCode);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
printf("key: 000852, exists: %s\n", Existe(map, "000852") ? "true" : "false");
|
||||
printf("000852: %s\n", Get(map, "000852"));
|
||||
printf("remove 000852 %s\n", Remove(map, "000852") ? "true" : "false");
|
||||
printf("key: 000852, exists: %s\n", Existe(map, "000852") ? "true" : "false");
|
||||
|
||||
map->clear(map);
|
||||
freeHashMapIterator(&iterator);
|
||||
}
|
||||
|
||||
PRIV_SHELL_CMD_FUNCTION(TestHash, Implement hash_map, PRIV_SHELL_CMD_MAIN_ATTR);
|
||||
}
|
|
@ -1,13 +1,14 @@
|
|||
|
||||
/**
|
||||
* @file: test_hash.h
|
||||
* @brief: a application of test hash function
|
||||
* @version: 3.0
|
||||
* @author: Yao wenying
|
||||
* @date: 2023/05/26
|
||||
* @file: test_hash.c
|
||||
* @brief: an application of test hash function
|
||||
* @version: 1.0
|
||||
* @author: Li chunji And Li zihao
|
||||
* @date: 2023/9/15
|
||||
*/
|
||||
|
||||
|
||||
|
||||
#ifndef __HASHMAP_H__
|
||||
#define __HASHMAP_H__
|
||||
|
||||
|
@ -31,7 +32,6 @@ typedef enum _Boolean Boolean;
|
|||
typedef struct entry {
|
||||
let key; // 键
|
||||
let value; // 值
|
||||
struct entry * next; // 冲突链表
|
||||
}*Entry;
|
||||
|
||||
#define newEntry() NEW(struct entry)
|
||||
|
@ -77,15 +77,9 @@ typedef struct hashMap {
|
|||
Boolean autoAssign; // 设定是否根据当前数据量动态调整内存大小,默认开启
|
||||
}*HashMap;
|
||||
|
||||
// 迭代器结构
|
||||
typedef struct hashMapIterator {
|
||||
Entry entry; // 迭代器当前指向
|
||||
int count; // 迭代次数
|
||||
int hashCode; // 键值对的哈希值
|
||||
HashMap hashMap;
|
||||
}*HashMapIterator;
|
||||
|
||||
#define newHashMapIterator() NEW(struct hashMapIterator)
|
||||
|
||||
|
||||
|
||||
// 默认哈希函数
|
||||
static int defaultHashCode(HashMap hashMap, let key);
|
||||
|
@ -114,16 +108,5 @@ static void resetHashMap(HashMap hashMap, int listSize);
|
|||
// 创建一个哈希结构
|
||||
HashMap createHashMap(HashCode hashCode, Equal equal);
|
||||
|
||||
// 创建哈希结构迭代器
|
||||
HashMapIterator createHashMapIterator(HashMap hashMap);
|
||||
|
||||
// 迭代器是否有下一个
|
||||
Boolean hasNextHashMapIterator(HashMapIterator iterator);
|
||||
|
||||
// 迭代到下一次
|
||||
HashMapIterator nextHashMapIterator(HashMapIterator iterator);
|
||||
|
||||
// 释放迭代器内存
|
||||
void freeHashMapIterator(HashMapIterator * iterator);
|
||||
|
||||
#endif // !__HASHMAP_H__
|