C++ 简单 Hash容器的实现

主要实现了以整数为关键字的hash，以key%m_nSize为哈希函数，以(hash(key)+i)%m_nSize重新寻址，并附带了elf_hash的实现，使用过程中可灵活修改。

 #ifndef _MY_HASH_INT_H_
 #define _MY_HASH_INT_H_

 template<class T,class K>
 class HashInt{
 public:
     HashInt();
     virtual ~HashInt();
 private:
     typedef struct tagElement
     {
         T data;
         K key;
         bool use;
         tagElement(){use = false;}
         ~tagElement(){}
     }Element;
     unsigned int m_nSize;
     Element *m_arrT;
     unsigned int m_nElementCnt;
     // 查找
     bool find(K key,unsigned int &index);
 public:
     // 初始化，分配内存
     bool init(const unsigned int size);
     // 哈希函数
     unsigned int hash(K key);
     // ELF哈希函数
     unsigned int hash_elf(char *str);
     // 插入
     bool insert(T data,K key);
     // 删除
     bool remove(K key);
     // 查找
     bool find(K key,T &data);
     // 修改
     bool modify(T data,K key);
     void dump();
 };

 template<class T,class K>
 unsigned int HashInt<T, K>::hash_elf( char *str)
 {
     unsigned int locate = ;
     unsigned int x = ;
     while (*str)
     {
         locate = (locate << ) + (*str++);//hash左移4位，当前字符ASCII存入hash低四位。
         if ((x = locate & 0xF0000000L) != )
         {//如果最高的四位不为0，则说明字符多余7个，如果不处理，再加第九个字符时，第一个字符会被移出，因此要有如下处理。
             locate ^= (x >> );
             //清空28-31位。
             locate &= ~x;
         }
     }
     return locate%m_nSize;
 }

 template<class T,class K>
 HashInt<T, K>::~HashInt()
 {
     if(m_arrT != NULL)
     {
         delete[] m_arrT;
     }
 }

 template<class T,class K>
 HashInt<T, K>::HashInt()
 {
     m_arrT = NULL;
     m_nSize = ;
     m_nElementCnt = ;
 }

 template<class T,class K>
 void HashInt<T, K>::dump()
 {
     cout<<"m_nElementCnt="<<m_nElementCnt<<",m_nSize="<<m_nSize<<endl;
     for(unsigned int i = ;i < m_nSize;i++)
     {
         if(m_arrT[i].use == true)
         {
             cout<<i<<"-";
             m_arrT[i].data->display();
         }
     }
     cout<<endl;
 }

 template<class T,class K>
 bool HashInt<T, K>::modify( T data,K key )
 {
     if( m_nElementCnt == )
     {
         return false;
     }
     bool exist = false;
     unsigned int index;
     exist = find(key,index);
     if( exist == true )
     {
         m_arrT[index].data = data;
     }
     return false;
 }

 template<class T,class K>
 bool HashInt<T, K>::find( K key,T &data )
 {
     if( m_nElementCnt == )
     {
         return false;
     }
     bool exist = false;
     unsigned int index;
     exist = find(key,index);
     if( exist == true )
     {
         data = m_arrT[index].data;
     }
     return false;
 }

 template<class T,class K>
 bool HashInt<T, K>::find( K key,unsigned int &index )
 {
     if( m_nElementCnt == )
     {
         return false;
     }
     unsigned int locate = hash(key),i = ;
     while(i < m_nSize)
     {
         if( m_arrT[locate].use == true &&  m_arrT[locate].key == key)
         {
             index = locate;
             return true;
         }
         locate = (locate + i)%m_nSize;
         i++;
     }
     return false;
 }

 template<class T,class K>
 bool HashInt<T, K>::remove( K key )
 {
     // 表为空
     if( m_nElementCnt ==  )
     {
         return false;
     }
     bool exist = false;
     unsigned int index;
     exist = find(key,index);
     if( exist == true )
     {
         m_arrT[index].use = false;
         m_nElementCnt--;
         return true;
     }
     return false;
 }

 template<class T,class K>
 bool HashInt<T, K>::insert( T data,K key)
 {
     // 表已满
     if( m_nElementCnt == m_nSize )
     {
         return false;
     }
     unsigned int locate = hash(key),i = ;
     while(i < m_nSize)
     {
         if( m_arrT[locate].use == false)
         {
             m_arrT[locate].data = data;
             m_arrT[locate].key = key;
             m_arrT[locate].use = true;
             m_nElementCnt++;
             return true;
         }
         locate = (locate + i)%m_nSize;
         i++;
     }
     return false;
 }

 template<class T,class K>
 unsigned int HashInt<T, K>::hash( K key )
 {
     return key%m_nSize;
 }

 template<class T,class K>
 bool HashInt<T, K>::init( const unsigned int size )
 {
     m_nSize = size;
     m_arrT = new Element[m_nSize];
     m_nElementCnt = ;
     cout<<"size = "<<sizeof(Element)*m_nSize<<endl;
     return true;
 }

 #endif