UTF-8与GB2312之间的互换

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UTF-8与GB2312之间的互换----源码下载网
www.hsip.cn/article/12/2006/200601093297.html

　　如果对UTF-8、Unicode、GB2312等还是很陌生的话，请查看http://www.linuxforum.net/books/UTF-8-Unicode.html 。下面介绍一下WinAPI的两个函数：WideCharToMultiByte、MultiByteToWideChar。

函数原型：
int WideCharToMultiByte(
UINT CodePage, // code page
DWORD dwFlags, // performance and mapping flags
LPCWSTR lpWideCharStr, // wide-character string
int cchWideChar, // number of chars in string
LPSTR lpMultiByteStr, // buffer for new string
int cbMultiByte, // size of buffer
LPCSTR lpDefaultChar, // default for unmappable chars
LPBOOL lpUsedDefaultChar // set when default char used
); //将宽字符转换成多个窄字符

int MultiByteToWideChar(
UINT CodePage, // code page
DWORD dwFlags, // character-type options
LPCSTR lpMultiByteStr, // string to map
int cbMultiByte, // number of bytes in string
LPWSTR lpWideCharStr, // wide-character buffer
int cchWideChar // size of buffer
);//将多个窄字符转换成宽字符
需要用到的一些函数：
CString CXmlProcess::HexToBin(CString string)//将16进制数转换成2进制
{
if( string == "0") return "0000";
if( string == "1") return "0001";
if( string == "2") return "0010";
if( string == "3") return "0011";
if( string == "4") return "0100";
if( string == "5") return "0101";
if( string == "6") return "0110";
if( string == "7") return "0111";
if( string == "8") return "1000";
if( string == "9") return "1001";
if( string == "a") return "1010";
if( string == "b") return "1011";
if( string == "c") return "1100";
if( string == "d") return "1101";
if( string == "e") return "1110";
if( string == "f") return "1111";
return "";
}

CString CXmlProcess::BinToHex(CString BinString)//将2进制数转换成16进制
{
if( BinString == "0000") return "0";
if( BinString == "0001") return "1";
if( BinString == "0010") return "2";
if( BinString == "0011") return "3";
if( BinString == "0100") return "4";
if( BinString == "0101") return "5";
if( BinString == "0110") return "6";
if( BinString == "0111") return "7";
if( BinString == "1000") return "8";
if( BinString == "1001") return "9";
if( BinString == "1010") return "a";
if( BinString == "1011") return "b";
if( BinString == "1100") return "c";
if( BinString == "1101") return "d";
if( BinString == "1110") return "e";
if( BinString == "1111") return "f";
return "";
}

int CXmlProcess::BinToInt(CString string)//2进制字符数据转换成10进制整型
{
int len =0;
int tempInt = 0;
int strInt = 0;
for(int i =0 ;i < string.GetLength() ;i ++)
{
         tempInt = 1;
         strInt = (int)string.GetAt(i)-48;
         for(int k =0 ;k < 7-i ; k++)
         {
   tempInt = 2*tempInt;
         }
         len += tempInt*strInt;
}
return len;
}
　　UTF-8转换成GB2312先把UTF-8转换成Unicode.然后再把Unicode通过函数WideCharToMultiByte转换成GB2312
WCHAR* CXmlProcess::UTF_8ToUnicode(char *ustart) //把UTF-8转换成Unicode
{
char char_one;
char char_two;
char char_three;
int Hchar;
int Lchar;
char uchar[2];
WCHAR *unicode;
CString string_one;
CString string_two;
CString string_three;
CString combiString;
char_one = *ustart;
char_two = *(ustart+1);
char_three = *(ustart+2);
string_one.Format("%x",char_one);
string_two.Format("%x",char_two);
string_three.Format("%x",char_three);
string_three = string_three.Right(2);
string_two = string_two.Right(2);
string_one = string_one.Right(2);
string_three = HexToBin(string_three.Left(1))+HexToBin(string_three.Right(1));
string_two = HexToBin(string_two.Left(1))+HexToBin(string_two.Right(1));
string_one = HexToBin(string_one.Left(1))+HexToBin(string_one.Right(1));
combiString = string_one +string_two +string_three;
combiString = combiString.Right(20);
combiString.Delete(4,2);
combiString.Delete(10,2);
Hchar = BinToInt(combiString.Left(8));
Lchar = BinToInt(combiString.Right(8));
uchar[1] = (char)Hchar;
uchar[0] = (char)Lchar;
unicode = (WCHAR *)uchar;
return unicode;
}

char * CXmlProcess::UnicodeToGB2312(unsigned short uData) //把Unicode 转换成 GB2312
{
char *buffer ;
buffer = new char[sizeof(WCHAR)];
WideCharToMultiByte(CP_ACP,NULL,&uData,1,buffer,sizeof(WCHAR),NULL,NULL);
return buffer;
}
　　GB2312转换成UTF-8：先把GB2312通过函数MultiByteToWideChar转换成Unicode.然后再把Unicode通过拆开Unicode后拼装成UTF-8。

WCHAR * CXmlProcess::Gb2312ToUnicode(char *gbBuffer) //GB2312 转换成　Unicode
{
WCHAR *uniChar;
uniChar = new WCHAR[1];
::MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,gbBuffer,2,uniChar,1);
return uniChar;
}
char * CXmlProcess::UnicodeToUTF_8(WCHAR *UniChar) // Unicode 转换成UTF-8
{
char *buffer;
CString strOne;
CString strTwo;
CString strThree;
CString strFour;
CString strAnd;
buffer = new char[3];
int hInt,lInt;
hInt = (int)((*UniChar)/256);
lInt = (*UniChar)%256;
CString string ;
string.Format("%x",hInt);
strTwo = HexToBin(string.Right(1));
string = string.Left(string.GetLength() - 1);
strOne = HexToBin(string.Right(1));
string.Format("%x",lInt);
strFour = HexToBin(string.Right(1));
string = string.Left(string.GetLength() -1);
strThree = HexToBin(string.Right(1));
strAnd = strOne +strTwo + strThree + strFour;
strAnd.Insert(0,"1110");
strAnd.Insert(8,"10");
strAnd.Insert(16,"10");
strOne = strAnd.Left(8);
strAnd = strAnd.Right(16);
strTwo = strAnd.Left(8);
strThree = strAnd.Right(8);
*buffer = (char)BinToInt(strOne);
buffer[1] = (char)BinToInt(strTwo);
buffer[2] = (char)BinToInt(strThree);
return buffer;
}
例子：将GB2312转换成UTF-8的调用：
char * CXmlProcess::translateCharToUTF_8(char *xmlStream, int len)
{
int newCharLen =0 ;
int oldCharLen = 0;
int revCharLen = len;
char* newCharBuffer;
char* finalCharBuffer;
char *buffer ;
CString string;
buffer = new char[sizeof(WCHAR)];
newCharBuffer = new char[int(1.5*revCharLen)];//设置最大的一个缓冲区
while(oldCharLen < revCharLen)
{
if( *(xmlStream + oldCharLen) >= 0)
{
   *(newCharBuffer+newCharLen) = *(xmlStream +oldCharLen);
   newCharLen ++;
   oldCharLen ++;
}//如果是英文直接复制就可以
else
{
   WCHAR *pbuffer = this->Gb2312ToUnicode(xmlStream+oldCharLen);
   buffer = this->UnicodeToUTF_8(pbuffer);
   *(newCharBuffer+newCharLen) = *buffer;
   *(newCharBuffer +newCharLen +1) = *(buffer + 1);
   *(newCharBuffer +newCharLen +2) = *(buffer + 2);
   newCharLen += 3;
   oldCharLen += 2;
}
}
newCharBuffer[newCharLen] = ''/0'';
CString string1 ;
string1.Format("%s",newCharBuffer);
finalCharBuffer = new char[newCharLen+1];
memcpy(finalCharBuffer,newCharBuffer,newCharLen+1);
return finalCharBuffer;
}
例子：将UTF-8转换成GB2312的调用：

char * CXmlProcess::TranslateUTF_8ToGB(char *xmlStream, int len)   //len 是xmlStream的长度
{
    char * newCharBuffer = new char[len];
    int index =0;
    int nCBIndex = 0;
    while(index < len)
    {
        if(xmlStream[index] > 0)     // 如果是GB2312的字符
        {
            newCharBuffer[nCBIndex] = xmlStream[index];    //直接复制
            index += 1;              //源字符串偏移量1
            nCBIndex += 1;           //目标字符串偏移量1
        }
        else                 //如果是UTF-8的字符
        {
            WCHAR * Wtemp = this->UTF_8ToUnicode(xmlStream + index); //先把UTF-8转成Unicode
            char * Ctemp = this->UnicodeToGB2312(*Wtemp);//再把Unicode 转成 GB2312
                    newCharBuffer[nCBIndex] = * Ctemp;         // 复制
            newCharBuffer[nCBIndex + 1] = *(Ctemp + 1);
            index += 3;     //源字符串偏移量3
            nCBIndex += 2;   //目标字符串偏移量2 因为一个中文UTF-8占3个字节，GB2312占两个字节
        }
    }
    newCharBuffer[nCBIndex] = 0; //结束符
    return newCharBuffer;
}