c语言实现通用数据结构（五）：通用映射（HashMap）

这是在通用链表的基础上实现的映射，关于链表的实现参见：http://blog.csdn.net/swwlqw/article/details/22498833。

注意映射中只存储了key和value的指针，没有储存实际的数据。

对于新的key类型来说，需要自定义HashCode函数和equal函数。

在HashSet的实现中给出了几个常见的hashCode函数和equal函数。参见：http://blog.csdn.net/swwlqw/article/details/22664129。

头文件：myHashMap.h

#ifndef MYHASHMAP_H_INCLUDED
#define MYHASHMAP_H_INCLUDED
#include "myList.h"

#define DEFAULT_INITIAL_CAPACITY 16
#define DEFAULT_LOAD_FACTOR 0.75f

typedef struct entry
{
    void * key;
    void * value;
} Entry;

typedef struct myHashMap
{
    int size;   //大小
    int initialCapacity; //初始容量
    float loadFactor;   //加载因子
    int (*hashCode)(void *key);
    int (*equal)(void *key1,void *key2);
    MyList ** entryList;
} MyHashMap;

typedef struct myHashMapEntryIterator
{
    int index;       //第几个链表
    MyHashMap *map;
    MyNode *current;
    int count;        //第几个数据
} MyHashMapEntryIterator;

//创建HashMap
MyHashMap *createMyHashMap(int (*hashCode)(void *key),int (*equal)(void *key1,void *key2));

//使用全部参数创建HashMap
MyHashMap *createMyHashMapForAll(int initialCapacity,float loadFactor,int (*hashCode)(void *key),int (*equal)(void *key1,void *key2));

//释放HashMap
void freeMyHashMap(MyHashMap * map);

//是否包含某个key
int myHashMapContainsKey(MyHashMap *const map,void * const key);

//增加一条映射
void myHashMapPutData(MyHashMap *const map,void * const key,void * const value);

//通过key得到数据，如果没有数据则返回null
void* myHashMapGetDataByKey(MyHashMap * const map,void *const key);

//数据的容量
int myHashMapGetSize(const MyHashMap * const map);

//创建Entry迭代器
MyHashMapEntryIterator* createMyHashMapEntryIterator( MyHashMap *const map);

//释放Entry迭代器
void freeMyHashMapEntryIterator(MyHashMapEntryIterator* iterator);

//Entry迭代器是否有下一个
int myHashMapEntryIteratorHasNext(MyHashMapEntryIterator* iterator);

//遍历下一个Entry元素
Entry* myHashMapEntryIteratorNext(MyHashMapEntryIterator* iterator);

//删除一条数据，返回是否删除成功
int myHashMapRemoveDataByKey(MyHashMap *const map,void * const key);

//遍历
void myHashMapOutput(MyHashMap *map, void(*pt)(Entry*));

#endif // MYHASHMAP_H_INCLUDED

源文件: myHashMap.c

#include "myHashMap.h"
#include <stdlib.h>

//某条Entry链表上是否包含某个key值。
Entry* listContainsEntry(MyList * list, void * key,
		int(*equal)(void *key1, void *key2)) {
	MyListIterator* it = createMyListIterator(list);
	while (myListIteratorHasNext(it)) {
		Entry * entry = (Entry *) (myListIteratorNext(it));
		if (entry->key == key || (equal != NULL && (*equal)(entry->key, key))) {
			return entry;
		}
	}
	freeMyListIterator(it);
	return NULL;
}

void rebuildMyHashMap(MyHashMap * map) {
	int newSize = map->initialCapacity * 2;
	MyList **newentryList = (MyList **) malloc(sizeof(MyList*) * newSize);
	for (int i = 0; i < newSize; i++) {
		newentryList[i] = createMyList();
	}
	MyHashMapEntryIterator* it = createMyHashMapEntryIterator(map);
	while (myHashMapEntryIteratorHasNext(it)) {
		Entry * entry = myHashMapEntryIteratorNext(it);
		int hasCode = (*(map->hashCode))(entry->key);
		hasCode %= newSize;
		if (hasCode < 0)
			hasCode += newSize;
		myListInsertDataAtLast(newentryList[hasCode], entry);
	}
	freeMyHashMapEntryIterator(it);
	for (int i = 0; i < map->initialCapacity; i++) {
		freeMyList(map->entryList[i]);
	}
	free(map->entryList);
	map->entryList = newentryList;
	map->initialCapacity = newSize;
}

//创建HashMap
MyHashMap *createMyHashMap(int(*hashCode)(void *key),
		int(*equal)(void *key1, void *key2)) {
	MyHashMap *re = (MyHashMap *) malloc(sizeof(MyHashMap));
	re->size = 0;
	re->loadFactor = DEFAULT_LOAD_FACTOR;
	re->initialCapacity = DEFAULT_INITIAL_CAPACITY;
	re->entryList = (MyList **) malloc(sizeof(MyList*) * re->initialCapacity);
	re->hashCode = hashCode;
	re->equal = equal;
	for (int i = 0; i < re->initialCapacity; i++) {
		re->entryList[i] = createMyList();
	}
	return re;
}

//使用全部参数创建HashMap
MyHashMap *createMyHashMapForAll(int initialCapacity, float loadFactor,
		int(*hashCode)(void *key), int(*equal)(void *key1, void *key2)) {
	MyHashMap *re = createMyHashMap(hashCode, equal);
	re->initialCapacity = initialCapacity;
	re->loadFactor = loadFactor;
	return re;
}

//是否包含某个key
int myHashMapContainsKey(MyHashMap * const map, void * const key) {
	int hasCode = (*(map->hashCode))(key);
	hasCode %= map->initialCapacity;
	if (hasCode < 0)
		hasCode += map->initialCapacity;
	Entry * re = listContainsEntry(map->entryList[hasCode], key, map->equal);
	return re != NULL;
}

//增加一条映射
void myHashMapPutData(MyHashMap * const map, void * const key,
		void * const value) {
	int hasCode = (*(map->hashCode))(key);
	hasCode %= map->initialCapacity;
	if (hasCode < 0)
		hasCode += map->initialCapacity;
	Entry * re = listContainsEntry(map->entryList[hasCode], key, map->equal);
	if (re == NULL) {
		Entry * entry = (Entry*) malloc(sizeof(Entry));
		entry->key = key;
		entry->value = value;
		myListInsertDataAtLast(map->entryList[hasCode], entry);
		(map->size)++;
		if (map->size > map->initialCapacity * map->loadFactor) {
			rebuildMyHashMap(map);
		}
	} else {
		re->value = value;
	}
}

//通过key得到数据，如果没有数据则返回null
void* myHashMapGetDataByKey(MyHashMap * const map, void * const key) {
	int hasCode = (*(map->hashCode))(key);
	hasCode %= map->initialCapacity;
	if (hasCode < 0)
		hasCode += map->initialCapacity;
	Entry * re = listContainsEntry(map->entryList[hasCode], key, map->equal);
	if (re == NULL) {
		return NULL;
	}
	return re->value;
}

//数据的容量
int myHashMapGetSize(const MyHashMap * const map) {
	return map->size;
}

//创建Entry迭代器
MyHashMapEntryIterator* createMyHashMapEntryIterator(MyHashMap * const map) {
	MyHashMapEntryIterator* re = (MyHashMapEntryIterator*) malloc(
			sizeof(MyHashMapEntryIterator));
	re->count = 0;
	re->index = 0;
	re->map = map;
	re->current = map->entryList[0]->first;
	return re;
}

//释放Entry迭代器
void freeMyHashMapEntryIterator(MyHashMapEntryIterator* iterator) {
	free(iterator);
}

//Entry迭代器是否有下一个
int myHashMapEntryIteratorHasNext(MyHashMapEntryIterator* iterator) {
	return iterator->count < iterator->map->size;
}

//遍历下一个Entry元素
Entry* myHashMapEntryIteratorNext(MyHashMapEntryIterator* iterator) {
	(iterator->count)++;
	while (!(iterator->current)) {
		(iterator->index)++;
		iterator->current = iterator->map->entryList[iterator->index]->first;
	}
	Entry * re = (Entry *) iterator->current->data;
	iterator->current = iterator->current->next;
	return re;
}

//删除一条数据，返回是否删除成功
int myHashMapRemoveDataByKey(MyHashMap * const map, void * const key) {
	int hasCode = (*(map->hashCode))(key);
	hasCode %= map->initialCapacity;
	if (hasCode < 0)
		hasCode += map->initialCapacity;
	MyListIterator* it = createMyListIterator(map->entryList[hasCode]);
	int re = 0;
	while (myListIteratorHasNext(it)) {
		Entry * entry = (Entry *) (myListIteratorNext(it));
		if ((*(map->equal))(entry->key, key)) {
			myListRemoveDataAt(map->entryList[hasCode], it->count - 1);
			re = 1;
			(map->size)--;
			break;
		}
	}
	freeMyListIterator(it);
	return re;
}

void myFree(Entry * p){
    free(p);
}

//释放HashMap
void freeMyHashMap(MyHashMap * map) {
	myHashMapOutput(map, myFree);
	for (int i = 0; i < map->initialCapacity; i++) {
		freeMyList(map->entryList[i]);
	}
	free(map->entryList);
	free(map);
}

//遍历
void myHashMapOutput(MyHashMap *map, void(*pt)(Entry*)) {
	MyHashMapEntryIterator* iterator = createMyHashMapEntryIterator(map);
	while (myHashMapEntryIteratorHasNext(iterator)) {
		pt(myHashMapEntryIteratorNext(iterator));
	}
	freeMyHashMapEntryIterator(iterator);
}

测试文件

/*************************
*** File main.c
*** test for MyHashMap
**************************/
#include <stdio.h>
#include <stdlib.h>
#include "myEqual.h"
#include "myHashCode.h"
#include "myHashMap.h"

#define S 10

char* strs[S]=
{
    "abc",
    "qq",
    "hello",
    "abc",
    "lmy",
    "ab",
    "qq",
    "lqw",
    "sww",
    "lqw"
};


int main()
{

    int*  data = malloc(sizeof(int)* S);
    for (int i=0; i<S; i++)
    {
        data[i]=i;
    }

    //创建映射需要指定两个函数，hashCode函数和equal函数。
    MyHashMap * map = createMyHashMap(myHashCodeString, myEqualString);

    //插入数据
    for (int i=0; i<S; i++)
    {
        myHashMapPutData(map, strs[i], &data[i]);
    }

    //输出大小
    printf("size=%d\n",myHashMapGetSize(map));

    //测试删除
    myHashMapRemoveDataByKey(map,"qq");
    myHashMapRemoveDataByKey(map,"ab");
    myHashMapRemoveDataByKey(map,"qwert");

    //输出大小
    printf("after remove size=%d\n",myHashMapGetSize(map));

    //遍历
    MyHashMapEntryIterator * it = createMyHashMapEntryIterator(map);
    while(myHashMapEntryIteratorHasNext(it))
    {
        Entry * pp= myHashMapEntryIteratorNext(it);
        char * key = pp-> key;
        int * value = pp->value;
        printf("%s(%d)\n", key, *value);
    }
    //释放遍历器
    freeMyHashMapEntryIterator(it);

    //释放映射
    freeMyHashMap(map);

    //释放数据
    free(data);
    return 0;
}

c语言实现通用数据结构（五）：通用映射（HashMap）

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