#include <stdio.h>

#include <windows.h>

//GBK编码转换到UTF8编码

int GBKToUTF8(unsigned char * lpGBKStr,unsigned char * lpUTF8Str,int nUTF8StrLen)

{

    wchar_t * lpUnicodeStr = NULL;

    int nRetLen = 0;

    if(!lpGBKStr)  //如果GBK字符串为NULL则出错退出

        return 0;

    nRetLen = ::MultiByteToWideChar(CP_ACP,0,(char *)lpGBKStr,-1,NULL,NULL);  //获取转换到Unicode编码后所需要的字符空间长度

    lpUnicodeStr = new WCHAR[nRetLen + 1];  //为Unicode字符串空间

    nRetLen = ::MultiByteToWideChar(CP_ACP,0,(char *)lpGBKStr,-1,lpUnicodeStr,nRetLen);  //转换到Unicode编码

    if(!nRetLen)  //转换失败则出错退出

        return 0;

    nRetLen = ::WideCharToMultiByte(CP_UTF8,0,lpUnicodeStr,-1,NULL,0,NULL,NULL);  //获取转换到UTF8编码后所需要的字符空间长度

    if(!lpUTF8Str)  //输出缓冲区为空则返回转换后需要的空间大小

    {

        if(lpUnicodeStr)

  delete []lpUnicodeStr;

        return nRetLen;

    }

    if(nUTF8StrLen < nRetLen)  //如果输出缓冲区长度不够则退出

    {

        if(lpUnicodeStr)

            delete []lpUnicodeStr;

        return 0;

    }

    nRetLen = ::WideCharToMultiByte(CP_UTF8,0,lpUnicodeStr,-1,(char *)lpUTF8Str,nUTF8StrLen,NULL,NULL);  //转换到UTF8编码

    if(lpUnicodeStr)

        delete []lpUnicodeStr;

    return nRetLen;

}

 //使用这两个函数的例子

int main()

{

    char cGBKStr[] = "我是中国人!";

    char * lpGBKStr = NULL;

    char * lpUTF8Str = NULL;

    FILE * fp = NULL;

    int nRetLen = 0;

    nRetLen = GBKToUTF8((unsigned char *) cGBKStr,NULL,NULL);

    printf("转换后的字符串需要的空间长度为：%d ",nRetLen);

    lpUTF8Str = new char[nRetLen + 1];

    nRetLen = GBKToUTF8((unsigned char *)cGBKStr,(unsigned char *)lpUTF8Str,nRetLen);

    if(nRetLen)

    {

        printf("GBKToUTF8转换成功！");

    }

 else

    {

        printf("GBKToUTF8转换失败！");

        goto Ret0;

    }

 fp = fopen("C:\\GBKtoUTF8.txt","wb");  //保存到文本文件

    fwrite(lpUTF8Str,nRetLen,1,fp);

    fclose(fp);

    getchar();  //先去打开那个文本文件看看，单击记事本的“文件”-“另存为”菜单，在对话框中看到编码框变为了“UTF-8”说明转换成功了

    Ret0:

 {

  if(lpGBKStr)

         delete []lpGBKStr;

     if(lpUTF8Str)

         delete []lpUTF8Str;

 }

 return 0;

}

  1 class CChineseCode

  2

  3 {

  4

  5   public:

  6

  7       static void UTF_8ToUnicode(wchar_t* pOut,char *pText);  // 把UTF-8转换成Unicode

  8

  9       static void UnicodeToUTF_8(char* pOut,wchar_t* pText);  //Unicode 转换成UTF-8

 10

 11       static void UnicodeToGB2312(char* pOut,wchar_t uData);  // 把Unicode 转换成 GB2312

 12

 13       static void Gb2312ToUnicode(wchar_t* pOut,char *gbBuffer);// GB2312 转换成　Unicode

 14

 15       static void GB2312ToUTF_8(string& pOut,char *pText, int pLen);//GB2312 转为 UTF-8

 16

 17       static void UTF_8ToGB2312(string &pOut, char *pText, int pLen);//UTF-8 转为 GB2312

 18

 19 };

 20

 21 类实现

 22

 23 void CChineseCode::UTF_8ToUnicode(wchar_t* pOut,char *pText)

 24

 25 {

 26

 27    char* uchar = (char *)pOut;

 28

 29    uchar[1] = ((pText[0] & 0x0F) << 4) + ((pText[1] >> 2) & 0x0F);

 30

 31    uchar[0] = ((pText[1] & 0x03) << 6) + (pText[2] & 0x3F);

 32

 33    return;

 34

 35 }

 36

 37 void CChineseCode::UnicodeToUTF_8(char* pOut,wchar_t* pText)

 38

 39 {

 40

 41    // 注意 WCHAR高低字的顺序,低字节在前，高字节在后

 42

 43    char* pchar = (char *)pText;

 44

 45    pOut[0] = (0xE0 | ((pchar[1] & 0xF0) >> 4));

 46

 47    pOut[1] = (0x80 | ((pchar[1] & 0x0F) << 2)) + ((pchar[0] & 0xC0) >> 6);

 48

 49    pOut[2] = (0x80 | (pchar[0] & 0x3F));

 50

 51    return;

 52

 53 }

 54

 55 void CChineseCode::UnicodeToGB2312(char* pOut,wchar_t uData)

 56

 57 {

 58

 59   WideCharToMultiByte(CP_ACP,NULL,&uData,1,pOut,sizeof(wchar_t),NULL,NULL);

 60

 61    return;

 62

 63 }

 64

 65 void CChineseCode::Gb2312ToUnicode(wchar_t* pOut,char *gbBuffer)

 66

 67 {

 68

 69    ::MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,gbBuffer,2,pOut,1);

 70

 71    return ;

 72

 73 }

 74

 75 void CChineseCode::GB2312ToUTF_8(string& pOut,char *pText, int pLen)

 76

 77 {

 78

 79    char buf[4];

 80

 81    int nLength = pLen* 3;

 82

 83    char* rst = new char[nLength];

 84

 85    memset(buf,0,4);

 86

 87    memset(rst,0,nLength);

 88

 89    int i = 0;

 90

 91    int j = 0;

 92

 93    while(i < pLen)

 94

 95    {

 96

 97            //如果是英文直接复制就可以

 98

 99            if( *(pText + i) >= 0)

100

101            {

102

103                    rst[j++] = pText[i++];

104

105            }

106

107            else

108

109            {

110

111                    wchar_t pbuffer;

112

113                    Gb2312ToUnicode(&pbuffer,pText+i);

114

115                    UnicodeToUTF_8(buf,&pbuffer);

116

117                    unsigned short int tmp = 0;

118

119                    tmp = rst[j] = buf[0];

120

121                    tmp = rst[j+1] = buf[1];

122

123                    tmp = rst[j+2] = buf[2];

124

125                    j += 3;

126

127                    i += 2;

128

129            }

130

131    }

132

133    rst[j] = '';

134

135    //返回结果

136

137    pOut = rst;

138

139    delete []rst;

140

141    return;

142

143 }

144

145 void CChineseCode::UTF_8ToGB2312(string &pOut, char *pText, int pLen)

146

147 {

148

149    char * newBuf = new char[pLen];

150

151    char Ctemp[4];

152

153    memset(Ctemp,0,4);

154

155    int i =0;

156

157    int j = 0;

158

159    while(i < pLen)

160

161    {

162

163        if(pText > 0)

164

165        {

166

167                newBuf[j++] = pText[i++];

168

169        }

170

171        else

172

173        {

174

175                WCHAR Wtemp;

176

177                UTF_8ToUnicode(&Wtemp,pText + i);

178

179                UnicodeToGB2312(Ctemp,Wtemp);

180

181                newBuf[j] = Ctemp[0];

182

183                newBuf[j + 1] = Ctemp[1];

184

185                i += 3;

186

187                j += 2;

188

189        }

190

191    }

192

193    newBuf[j] = '';

194

195    pOut = newBuf;

196

197    delete []newBuf;

198

199    return;

200

201 }