吴康彬
　　相信一定有不少的程序开发人员时常会遇到字符编码的问题，而这个问题也是非常让人头痛的。因为这些都是潜在的错误，要找出这些错误也得要有这方面的开发经验才行。特别是在处理xml文档时 ，该问题的出现就更加的频繁了，有一次用java写服务器端程序，用vc写客户端与之交互。交互的协议都是用xml写的。结果在通讯时老是发现数据接受不正确。纳闷！于是用抓取网络数据包工具抓取数据，后来才发现原来是java上xml的头是这样的<?xml version="1.0" encoding="UTF-8"?>,而vc上默认的是GB2312。所以一遇到汉字数据就不正确了。去网上找资料，这方面的文章好象特别少，针对像这样的问题，下面我介绍一下我自己写的一个转换程序。当然，程序很简单。如果有画蛇添足的地方，还望各位高手一笑了之。
　　如果您对UTF-8、Unicode、GB2312等还是很陌生的话，请查看，我这里就不浪费口舌了。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;

}

　　程序都非常的简单，由于实在太穷。已经吃了两天的方便面。所以现在头昏，程序的详细说明就不写了。程序员到了像我这样的地步也真是少见。工资低没有办法。哎！！！！