c++字符集之间转换(UTF-8,UNICODE,Gb2312)

玩C++的同学经常要遇到汉字编码问题的处理,这是个大麻烦,本博文转了一篇文章介绍这个问题。

  • UTF-8:   3字节一个字符
  • UNICODE: 2字节一个字符
  • GB2312:  1字节一个字符

例子:
“你”字的UTF-8编码: E4 BD A0        11100100 10111101 10100000
“你”的Unicode编码: 4F 60            01001111 01100000

按照UTF-8的编码规则,分解如下:xxxx0100 xx111101 xx100000,把除了x之外的数字拼接在一起,就变成“你”的Unicode编码了。
注意UTF-8的最前面3个1,表示整个UTF-8串是由3个字节构成的。
经过UTF-8编码之后,再也不会出现敏感字符了,因为最高位始终为1。

类定义

class CChineseCode{
public:
    static void UTF_8ToUnicode(wchar_t* pOut,char *pText);  // 把UTF-8转换成Unicode
    static void UnicodeToUTF_8(char* pOut,wchar_t* pText);  //Unicode 转换成UTF-8
    static void UnicodeToGB2312(char* pOut,wchar_t uData);  // 把Unicode 转换成 GB2312 
    static void Gb2312ToUnicode(wchar_t* pOut,char *gbBuffer);// GB2312 转换成 Unicode
    static void GB2312ToUTF_8(string& pOut,char *pText, int pLen);//GB2312 转为 UTF-8
    static void UTF_8ToGB2312(string &pOut, char *pText, int pLen);//UTF-8 转为 GB2312
};
//类实现
void CChineseCode::UTF_8ToUnicode(wchar_t* pOut,char *pText){
    char* uchar = (char *)pOut;
    uchar[1] = ((pText[0] & 0x0F) << 4) + ((pText[1] >> 2) & 0x0F);
    uchar[0] = ((pText[1] & 0x03) << 6) + (pText[2] & 0x3F);
    return;
}
void CChineseCode::UnicodeToUTF_8(char* pOut,wchar_t* pText){
    // 注意 WCHAR高低字的顺序,低字节在前,高字节在后
    char* pchar = (char *)pText;
    pOut[0] = (0xE0 | ((pchar[1] & 0xF0) >> 4));
    pOut[1] = (0x80 | ((pchar[1] & 0x0F) << 2)) + ((pchar[0] & 0xC0) >> 6);
    pOut[2] = (0x80 | (pchar[0] & 0x3F));
    return;
}
void CChineseCode::UnicodeToGB2312(char* pOut,wchar_t uData){
    WideCharToMultiByte(CP_ACP,NULL,&uData,1,pOut,sizeof(wchar_t),NULL,NULL);
    return;
}     
void CChineseCode::Gb2312ToUnicode(wchar_t* pOut,char *gbBuffer){
    ::MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,gbBuffer,2,pOut,1);
    return ;
}
void CChineseCode::GB2312ToUTF_8(string& pOut,char *pText, int pLen){
    char buf[4];
    int nLength = pLen* 3;
    char* rst = new char[nLength];
    
    memset(buf,0,4);
    memset(rst,0,nLength);
    
    int i = 0;
    int j = 0;      
    while(i < pLen){
        //如果是英文直接复制就能
        if( *(pText + i) >= 0){
            rst[j++] = pText[i++]; 
        }else{
              wchar_t pbuffer;
              Gb2312ToUnicode(&pbuffer,pText+i);
              UnicodeToUTF_8(buf,&pbuffer);
              unsigned short int tmp = 0;
              tmp = rst[j] = buf[0];
              tmp = rst[j+1] = buf[1];
              tmp = rst[j+2] = buf[2];    
              j += 3;
            
              i += 2;
        
        }
    
    }
    
    rst[j] = ’’;
    //返回结果
    pOut = rst;             
    delete []rst;     
    return;
}
void CChineseCode::UTF_8ToGB2312(string &pOut, char *pText, int pLen){
    char * newBuf = new char[pLen];
    char Ctemp[4];
    memset(Ctemp,0,4);
    int i =0;
    int j = 0;
    while(i < pLen){
    
        if(pText > 0){
                 newBuf[j++] = pText[i++];                       
        }else{
              WCHAR Wtemp;
              UTF_8ToUnicode(&Wtemp,pText + i);
              UnicodeToGB2312(Ctemp,Wtemp);
              newBuf[j] = Ctemp[0];
              newBuf[j + 1] = Ctemp[1];
        
              i += 3;    
              j += 2;   
              }
        }
        newBuf[j] = ’’;
        pOut = newBuf;
        delete []newBuf;
        return; 
}

 


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