首先声明,这是一篇转载文章,转载自许伟群先生的文章。个人觉得这篇文章写 的比较周到。
http://blog.csdn.net/xuweiqun/archive/2006/11/07/1370420.aspx
文章如下:
特搜集了UTF-8,UNICODE,Gb2312他们3个之间的相互转换.
UTF-8: 1~3字节可变
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可以
- 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[i] > 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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