跟线性数组和链表不同,HashTable是快速查找的数据结构。本文中的HashTable使用链表处理数组。
该HashTable可以指定table的长度,提供了遍历的方法。包括table的长度的选择也比较讲究。
cp_int32 nPrime[MAX_HASH_PRIME_ARRAY_NUM] = { 17, 37, 79, 163, 331, 673, 1361 };
就是说table的长度来取自上面这个数组。比如用户设定了200,那么table的长度就是331,找到第一次比输入值大的数值。可以注意到上面的都是素数。
下面是具体的代码贴出来,共大家参考。
代码中有个接口是查到多个key使用到了动态数组dyArray,参考上一篇点击打开链接
// // cpPlatform.h // dataStruct // // Created by hherima on 14-7-29. // Copyright (c) 2014年 . All rights reserved. // #ifndef dataStruct_cpPlatform_h #define dataStruct_cpPlatform_h enum { CP_FALSE = 0, CP_TRUE = !CP_FALSE }; #define F_MALLOC_TYPE(s) (s*)f_malloc(sizeof(s)) #define FREEFUN free #define MIN_PRE_ALLOCATE_SIZE 10 //The initial size of the dynamic array. #define MEMSETFUN memset #define REALLOCFUN realloc #define MALLOCFUN malloc #define MEMCMPFUN memcmp #define MEMCPYFUN memcpy typedef unsigned char cp_bool; typedef signed int cp_int32; typedef char cp_int8; typedef unsigned int cp_uint32; #endif
上面是数据类型的定义,为了跨平台使用
下面是hashtable的数据结构头文件
// // hashStruct.h // dataStruct // // Created by hherima on 14-7-29. // Copyright (c) 2014年 . All rights reserved. // #ifndef dataStruct_hashStruct_h #define dataStruct_hashStruct_h #include <stdlib.h> #include "cpPlatform.h" #include "dyArray.h" struct Node { cp_int8* m_pKey; //the hash key. cp_int32 m_nKeyLength; // the length of the hash key in bytes. void* m_pVal;//hash_node value struct Node* m_pNext; };//hash table,use link list to process conflict struct HashTable { cp_int32 m_nLength; //hash table's length. cp_int32 m_nEleNum; //hash table's element count. struct Node **m_ppHead;//the hash table's array to record all key's value. }; cp_int32 GetHashFileNum(cp_int8* pKey, cp_int32 nKeyLength); struct Node* HashFindOne(cp_int8* pKey,cp_int32 nKeyLength,struct HashTable *pTable);//search cp_int32 HashFindMultkeyredund(cp_int8* pKey,cp_int32 nKeyLength,struct HashTable *pTable,struct DynamicArray *pdestArray); void HashInsertOne(cp_int8* pKey,cp_int32 nKeyLength,void* pVal,struct HashTable *pTable);//insert void HashInsertOneKeyredund(char* pKey,cp_int32 nKeyLength,void* pVal,struct HashTable *pTable); void HashDelOne(struct HashTable * pTable,void (*pFreeFunc) (void *),cp_int8 *pKey,cp_int32 nKeyLength); struct HashTable * HashTableCreate(cp_int32 nKeyNum); struct Node* HashGetFirst(struct HashTable *pTable); struct Node* HashGetNext(struct HashTable *pTable,cp_int8* pKey,cp_int32 nKeyLength); cp_int32 HashGetLength(struct HashTable *pTable); void HashTableVisit(struct HashTable * pTable,void (*pVisitFunc) (void *,void *),void *pAgent); void HashTableReset(struct HashTable * pTable,void (*pFreeFunc) (void *)); void HashTableDestroy(struct HashTable * pTable,void (*pFreeFunc) (void *)); cp_int32 HashGetValue(cp_int8* pKey,cp_int32 nKeyLength,cp_int32 nTableLength); #endif
源文件
// // hashStruct.c // dataStruct // // Created by hherima on 14-7-29. // Copyright (c) 2014年 . All rights reserved. // #include "hashStruct.h" #define MAX_HASH_PRIME_ARRAY_NUM 7 /************************************************************************************************** function name: HashGetValue description: the hash arithmetic to get the position of the certain key. parameter: pKey: the exclusive symbol which is related to a data block in hash table. nKeyLength: the key string's length. nTableLength: the hash table's length. return value: the position of the certain key. ***************************************************************************************************/ cp_int32 HashGetValue(cp_int8* pKey,cp_int32 nKeyLength,cp_int32 nTableLength) { cp_uint32 h = 0; cp_uint32 g = 0; if(!pKey || nKeyLength<1 || nTableLength<1) //if the input parameter is invalid, return. { return -1; } while(nKeyLength--) // get each charactor and use it to compute hash value. { h = (h<<4) + *pKey++; g = h & 0xF0000000L; if(g) { h ^= g>>24; } h &= ~g; } return h % nTableLength; } /************************************************************************************************** function name: HashFindOne description: search the position's node of the certain key. parameter: pKey: the exclusive symbol which is related to a data block in hash table. nKeyLength: the key string's length. pTable: the hash table. return value: the node pointer or null. ***************************************************************************************************/ struct Node* HashFindOne(cp_int8* pKey,cp_int32 nKeyLength,struct HashTable *pTable)//search { cp_int32 nPos = 0; struct Node* pCur = NULL; //if the input parameter is invalid, return. if(!pTable || !pKey || nKeyLength<1) { return NULL; } nPos = HashGetValue(pKey,nKeyLength,pTable->m_nLength); if(nPos>=0) pCur = pTable->m_ppHead[nPos]; //cur = table->head[hash_get_value(key,key_length,table->length)]; while(pCur) // if has link list, visit all the list to find the right one. { if(pCur->m_nKeyLength == nKeyLength && MEMCMPFUN(pCur->m_pKey,pKey,nKeyLength) == 0) { return pCur; } pCur = pCur->m_pNext; } return NULL; } /************************************************************************************************** function name: HashFindMultkeyredund description: search the node of the certain key, there will be several one. parameter: pKey: the exclusive symbol which is related to several data block in hash table. nKeyLength: the key string's length. pTable: the hash table. pdestArray: the dynamic array which is used to save results and need be initilalized. return value: the node pointer or null. ***************************************************************************************************/ cp_int32 HashFindMultkeyredund(cp_int8* pKey,cp_int32 nKeyLength,struct HashTable *pTable,struct DynamicArray *pDestArray) //search ,the key is redundant. { int nResNum = 0; struct Node* pCur = NULL; //if the input parameter is invalid, return. if(!pTable || !pKey || nKeyLength<1 || !pDestArray) { return -1; } pCur = pTable->m_ppHead[HashGetValue(pKey,nKeyLength,pTable->m_nLength)]; while(pCur) //if has link list, visit all the list and find the right one. { if(pCur->m_nKeyLength == nKeyLength && MEMCMPFUN(pCur->m_pKey,pKey,nKeyLength) == 0) { DyArrayAppend(pDestArray, pCur->m_pVal); // put the right one to array. nResNum++; //return cur; } pCur = pCur->m_pNext; } return nResNum; } /************************************************************************************************** function name: hashExpand description: expand the array when it's too small.THIS FUNCTION CAN'T BE USED BECAUSE HASH VALUE IS CHANGED WHEN TABLE LENGTH CHANGED. parameter: pTable: the hash table. nNeed: the needed new size. return value: if succeed,return the true, else, return false. ***************************************************************************************************/ cp_bool HashExpand(struct HashTable * pTable, cp_int32 nNeed) { cp_int32 i; struct Node ** pData = NULL; cp_int32 nAllocSize = 0; cp_int32 nPrime[MAX_HASH_PRIME_ARRAY_NUM] = { 17, //0 37, //1 79, //2 163, //3 331, //4 673, //5 1361 //6 };//The prime table used to be the length of hash table to decrease conflict. //if the input parameter is invalid, return. if(!pTable || nNeed<1) { return CP_FALSE; } //if need, expand to one and half times of original size. if(((pTable->m_nEleNum + nNeed) + ((pTable->m_nEleNum + nNeed)>>1) ) > pTable->m_nLength) { nAllocSize = pTable->m_nLength + (pTable->m_nLength>>1); for(i=0; i<MAX_HASH_PRIME_ARRAY_NUM; i++) //find the nearest one of prime array. { if(nPrime[i] > nAllocSize) { nAllocSize = nPrime[i]; break; } } pData = (struct Node **)REALLOCFUN(pTable->m_ppHead, sizeof(struct Node *) * nAllocSize); if(pData != NULL) { // clear the expanded space. MEMSETFUN(pData+pTable->m_nLength,0,(nAllocSize-pTable->m_nLength)*sizeof(struct Node *)); pTable->m_ppHead = pData; pTable->m_nLength = nAllocSize; } } return ((pTable->m_nEleNum + nNeed) + ((pTable->m_nEleNum + nNeed)>>1) <= pTable->m_nLength) ? CP_TRUE : CP_FALSE; } /************************************************************************************************** function name: HashInsertOne description: insert the node of the certain key. parameter: pKey: the exclusive symbol which is related to a data block in hash table. nKeyLength: the key string's length. pVal: the node pointer of the certain key. pTable: the hash table. return value: none. ***************************************************************************************************/ void HashInsertOne(cp_int8* pKey,cp_int32 nKeyLength,void* pVal,struct HashTable *pTable)//insert { cp_int32 nPos = 0; struct Node** pNode = NULL; struct Node* pTmp = NULL; //if the input parameter is invalid, return. if(!pTable || !pKey || nKeyLength<1) { return ; } //comment it because when it expands, the same key's position changed and the original key position CAN'T be found. /*if((pTable->m_EleNum + 1) + ((pTable->m_EleNum + 1)>>1) > pTable->m_nLength) { HashExpand(pTable, 1); }*/ //compute the hash position. pTable->m_nEleNum++; nPos = HashGetValue(pKey,nKeyLength,pTable->m_nLength); pNode = &pTable->m_ppHead[nPos]; //if this key is NOT exist, insert it. if(HashFindOne(pKey,nKeyLength,pTable) == NULL) { //malloc a new node and set the value. pTmp=(struct Node*)MALLOCFUN(sizeof(struct Node)); MEMSETFUN(pTmp,0,sizeof(struct Node)); pTmp->m_pKey = (char*)MALLOCFUN(nKeyLength+2);//for Unicode, two bytes zero is needed. MEMSETFUN(pTmp->m_pKey,0,nKeyLength+2); MEMCPYFUN(pTmp->m_pKey,pKey,nKeyLength); pTmp->m_nKeyLength = nKeyLength; pTmp->m_pVal = pVal; pTmp->m_pNext=NULL; //if there is a list, then insert to the tail. while(*pNode) { pNode = &((*pNode)->m_pNext); } *pNode = pTmp; } } /************************************************************************************************** function name: HashInsertOneKeyredund description: insert the node of the certain key. parameter: pKey: the symbol which is related to a data block in hash table. nKeyLength: the key string's length. pVal: the node pointer of the certain key. pTable: the hash table. return value: none. ***************************************************************************************************/ void HashInsertOneKeyredund(cp_int8* pKey,cp_int32 nKeyLength,void* pVal,struct HashTable *pTable) //insert,key is redundant. { cp_int32 nPos = 0; struct Node** pNode = NULL; struct Node* pTmp = NULL; //if the input parameter is invalid, return. if(!pTable || !pKey || nKeyLength<1) { return ; } //comment it because when it expands, the same key's position changed and the original key position CAN'T be found. /*if((table->ele_num + 1) + ((table->ele_num + 1)>>1) > table->length) { hash_expand(table, 1); }*/ //compute the hash position. pTable->m_nEleNum++; nPos= HashGetValue(pKey,nKeyLength,pTable->m_nLength); pNode = &pTable->m_ppHead[nPos]; //compare with HashInsertOne, comment this line. if(hash_find_one(key,key_length,table) == NULL) { //malloc a new node and set the value. pTmp=(struct Node*)MALLOCFUN(sizeof(struct Node)); MEMSETFUN(pTmp,0,sizeof(struct Node)); pTmp->m_pKey = (char*)MALLOCFUN(nKeyLength+2);//for Unicode, two bytes zero is needed. MEMSETFUN(pTmp->m_pKey,0,nKeyLength+2); MEMCPYFUN(pTmp->m_pKey,pKey,nKeyLength); pTmp->m_nKeyLength = nKeyLength; pTmp->m_pVal = pVal; pTmp->m_pNext=NULL; //if has a link list, then insert the new node to the tail. while(*pNode) { pNode = &((*pNode)->m_pNext); } *pNode = pTmp; } } /************************************************************************************************** function name: HashTableCreate description: create the hash table when the program starts. parameter: nKeyNum: the key count of the program's data. return value: the hash table. ***************************************************************************************************/ struct HashTable * HashTableCreate(cp_int32 nKeyNum) { struct HashTable * pTable = NULL; cp_int32 i; cp_int32 nPrime[MAX_HASH_PRIME_ARRAY_NUM] = { 17, //0 37, //1 79, //2 163, //3 331, //4 673, //5 1361 //6 };//The prime table used to be the length of hash table to decrease conflict. //if the input parameter is invalid, return. if(nKeyNum < 1) { return NULL; } pTable = (struct HashTable *)MALLOCFUN(sizeof(struct HashTable)); if(!pTable) { return NULL; } MEMSETFUN(pTable,0,sizeof(struct HashTable)); //The default length is 1.5 times of key's number. pTable->m_nLength = nKeyNum + (nKeyNum<<1); //find the nearest size of prime array. for(i=0; i<MAX_HASH_PRIME_ARRAY_NUM; i++) { if(nPrime[i] > pTable->m_nLength) { pTable->m_nLength = nPrime[i]; break; } } pTable->m_ppHead = (struct Node **) MALLOCFUN(sizeof(struct Node *)*pTable->m_nLength); if(!pTable->m_ppHead) { FREEFUN(pTable); return NULL; } MEMSETFUN(pTable->m_ppHead,0,sizeof(struct Node *)*pTable->m_nLength); return pTable; } /************************************************************************************************** function name: HashTableVisit description: visit all the elements of the hash table. parameter: pTable: the hash table. pVisitFunc: the visit function for each element of the hash table, the first parameter is hash's element, the second parameter is 'agent' which is to pass to caller. pAgent: used to pass to the call back funtion. return value: none ***************************************************************************************************/ void HashTableVisit(struct HashTable * pTable,void (*pVisitFunc) (void *,void *),void *pAgent) { cp_int32 i; struct Node * pTmp = NULL; //if the input parameter is invalid, return. if(!pTable) { return ; } //visit each position if it's not null. for(i=0; i<pTable->m_nLength; i++) { if(pTable->m_ppHead[i] == NULL) { continue; } if(pTable->m_ppHead[i]->m_pKey) { if(pVisitFunc) { pVisitFunc(pTable->m_ppHead[i]->m_pVal,pAgent); } pTmp = pTable->m_ppHead[i]->m_pNext; //if has link list, then visit the whole list. while(pTmp) { if(pVisitFunc) { pVisitFunc(pTmp->m_pVal,pAgent); } pTmp = pTmp->m_pNext; } } } return ; } /************************************************************************************************** function name: HashGetFirst description: get the first element of the hash table. parameter: pTable: the hash table. return value: the first element ***************************************************************************************************/ struct Node* HashGetFirst(struct HashTable *pTable) { cp_int32 i; //if the input parameter is invalid, return. if(!pTable) { return NULL; } //find the first not null element of head array. for(i=0; i<pTable->m_nLength; i++) { if(pTable->m_ppHead[i] == NULL) { continue; } if(pTable->m_ppHead[i]->m_pKey) { return pTable->m_ppHead[i]; } } return NULL; } /************************************************************************************************** function name: HashGetNext description: get the next element of the current node which key is given. parameter: pTable: the hash table. pKey: the exclusive symbol which is related to a data block in hash table. nKeyLength: the key string's length. return value: the next element ***************************************************************************************************/ struct Node* HashGetNext(struct HashTable *pTable,cp_int8* pKey,cp_int32 nKeyLength) { struct Node* pNext = NULL; struct Node* pCur = NULL; cp_int32 nPos; cp_int32 i; //if the input parameter is invalid, return. if(!pTable) { return NULL; } //get the position of the key. nPos = HashGetValue(pKey,nKeyLength,pTable->m_nLength); if(nPos == -1) { return NULL; } pCur = pTable->m_ppHead[nPos]; if(!pCur) { return NULL;//the related node of the pKey is NOT exist, so return null. } //find the right one whose key is same with pKey. while(pCur) { if(pCur->m_nKeyLength == nKeyLength && MEMCMPFUN(pCur->m_pKey,pKey,nKeyLength) == 0) { break; } pCur = pCur->m_pNext; } //get the next pointer directly. if(pCur && pCur->m_pNext) { pNext = pCur->m_pNext; } else { //get the next not null one from the head array. nPos++; for(i=nPos; i<pTable->m_nLength; i++) { if(pTable->m_ppHead[i] == NULL) { continue; } if(pTable->m_ppHead[i]->m_pKey) { pNext = pTable->m_ppHead[i]; break; } } } return pNext; } /************************************************************************************************** function name: HashTableReset description: clear the hash table. parameter: pTable: the hash table. pFreeFunc: the free function for hash data "val" which is given by caller. return value: none ***************************************************************************************************/ void HashTableReset(struct HashTable * pTable,void (*pFreeFunc) (void *)) { cp_int32 i; struct Node * pTmp = NULL; struct Node * pTmp1 = NULL; //if the input parameter is invalid, return. if(!pTable) { return; } //reset each element of the head array and free related memory. for(i=0; i<pTable->m_nLength; i++) { if(pTable->m_ppHead[i] == NULL) { continue; } if(pTable->m_ppHead[i]->m_pKey) { FREEFUN(pTable->m_ppHead[i]->m_pKey); if(pFreeFunc) { pFreeFunc(pTable->m_ppHead[i]->m_pVal); } pTmp = pTable->m_ppHead[i]->m_pNext; FREEFUN(pTable->m_ppHead[i]); pTable->m_ppHead[i] = NULL; //free all the link list. while(pTmp) { FREEFUN(pTmp->m_pKey); if(pFreeFunc) { pFreeFunc(pTmp->m_pVal); } pTmp1 = pTmp; pTmp = pTmp->m_pNext; FREEFUN(pTmp1); } } } //clear the table. MEMSETFUN(pTable->m_ppHead,0,sizeof(struct Node *)*pTable->m_nLength); pTable->m_nEleNum = 0; return ; } /************************************************************************************************** function name: HashTableDestroy description: destroy the hash table when the program exits. parameter: pTable: the hash table. pFreeFunc: the free function for hash data "val" which is given by caller. return value: none ***************************************************************************************************/ void HashTableDestroy(struct HashTable * pTable,void (*pFreeFunc) (void *)) { cp_int32 i; struct Node * pTmp = NULL; struct Node * pTmp1 = NULL; //if the input parameter is invalid, return. if(!pTable) { return; } //clear each element and free its memory. for(i=0; i<pTable->m_nLength; i++) { if(pTable->m_ppHead[i] == NULL) { continue; } if(pTable->m_ppHead[i]->m_pKey) { FREEFUN(pTable->m_ppHead[i]->m_pKey); if(pFreeFunc) { pFreeFunc(pTable->m_ppHead[i]->m_pVal); } pTmp = pTable->m_ppHead[i]->m_pNext; FREEFUN(pTable->m_ppHead[i]); pTable->m_ppHead[i] = NULL; //free the link list. while(pTmp) { FREEFUN(pTmp->m_pKey); if(pFreeFunc) { pFreeFunc(pTmp->m_pVal); } pTmp1 = pTmp; pTmp = pTmp->m_pNext; FREEFUN(pTmp1); } } } //free the table. FREEFUN(pTable->m_ppHead); pTable->m_ppHead = NULL; FREEFUN(pTable); return ; } /************************************************************************************************** function name: HashDelOne description: delete one node of hash table. parameter: pTable: the hash table. pFreeFunc: the free function for hash data "val" which is given by caller. pKey: the exclusive symbol which is related to a data block in hash table. nKeyLength: the key string's length. return value: none ***************************************************************************************************/ void HashDelOne(struct HashTable * pTable,void (*pFreeFunc) (void *),char *pKey,cp_int32 nKeyLength) { cp_int32 nPos = 0; struct Node *pTmp = NULL; struct Node **pTmp1 = NULL; struct Node *pTmp2 = NULL; //if the input parameter is invalid, return. if(!pTable || !pKey || nKeyLength<1) { return; } //compute the hash position. nPos = HashGetValue(pKey,nKeyLength,pTable->m_nLength); if(!pTable->m_ppHead[nPos]) { return;//the related node of the key is NOT exist, return. } //the first one is the right one. if(pTable->m_ppHead[nPos]->m_nKeyLength == nKeyLength && MEMCMPFUN(pTable->m_ppHead[nPos]->m_pKey,pKey,nKeyLength) == 0) { pTable->m_nEleNum--; FREEFUN(pTable->m_ppHead[nPos]->m_pKey); pTable->m_ppHead[nPos]->m_pKey = NULL; if(pFreeFunc) pFreeFunc(pTable->m_ppHead[nPos]->m_pVal); pTable->m_ppHead[nPos]->m_pVal = NULL; if(pTable->m_ppHead[nPos]->m_pNext) { pTmp = pTable->m_ppHead[nPos]; pTable->m_ppHead[nPos] = pTable->m_ppHead[nPos]->m_pNext; FREEFUN(pTmp); } else { FREEFUN(pTable->m_ppHead[nPos]); pTable->m_ppHead[nPos] = NULL; } } else { //find the right one in the link list. pTmp1 = &(pTable->m_ppHead[nPos]->m_pNext); while(*pTmp1) { if((*pTmp1)->m_nKeyLength == nKeyLength && MEMCMPFUN((*pTmp1)->m_pKey,pKey,nKeyLength) == 0) { //find it, free it and relink the link list. pTable->m_nEleNum--; FREEFUN((*pTmp1)->m_pKey); (*pTmp1)->m_pKey = NULL; if(pFreeFunc) pFreeFunc((*pTmp1)->m_pVal); (*pTmp1)->m_pVal = NULL; if((*pTmp1)->m_pNext) { pTmp2 = *pTmp1; *pTmp1 = (*pTmp1)->m_pNext; FREEFUN(pTmp2); } else { FREEFUN(*pTmp1); *pTmp1 = NULL; } break; } else { pTmp1 = &((*pTmp1)->m_pNext); } } } return ; } /************************************************************************************************** function name: HashGetLength description: get the total length of the hash table. parameter: pTable: the hash table. return value: none ***************************************************************************************************/ cp_int32 HashGetLength(struct HashTable *pTable) { return pTable ? pTable->m_nEleNum : -1; }
c语言实现hashtable,类似C++的map和iOS的NSDictionary
时间: 2024-10-05 23:22:42