gbk与utf-8转换

linux：

#include <iconv.h>

int code_convert(char *from_charset,char *to_charset,char *inbuf,int inlen,char *outbuf,int outlen)
{
        iconv_t cd;
        int rc;
        char **pin = &inbuf;
        char **pout = &outbuf;

        cd = iconv_open(to_charset,from_charset);
        if (cd==0)
                return -1;
        memset(outbuf,0,outlen);
        if (iconv(cd,pin,&inlen,pout,&outlen) == -1)
                return -1;
        iconv_close(cd);
        return 0;
}

int u2g(char *inbuf,int inlen,char *outbuf,int outlen)
{
        return code_convert("utf-8","gb2312",inbuf,inlen,outbuf,outlen);
}

int g2u(char *inbuf,size_t inlen,char *outbuf,size_t outlen)
{
        return code_convert("gb2312","utf-8",inbuf,inlen,outbuf,outlen);
}

解释：

其中

iconv函数族的头文件是iconv.h,使用前需包含之。
#include <iconv.h>
iconv函数族有三个函数,原型如下:
(1) iconv_t iconv_open(const char *tocode, const char *fromcode);
此函数说明将要进行哪两种编码的转换,tocode是目标编码,fromcode是原编码,该函数返回一个转换句柄,供以下两个函数使用。
(2) size_t iconv(iconv_t cd,char **inbuf,size_t *inbytesleft,char **outbuf,size_t *outbytesleft);
此函数从inbuf中读取字符,转换后输出到outbuf中,inbytesleft用以记录还未转换的字符数,outbytesleft用以记录输出缓冲的剩余空间。

(3) int iconv_close(iconv_t cd);
此函数用于关闭转换句柄,释放资源。

Windows：

    #include <iostream>  
    #include <string>  
    #include <fstream>  
    #include <windows.h>   
      
    using namespace std;  
      
    string GBKToUTF8(const std::string& strGBK)  
    {  
        string strOutUTF8 = "";  
        WCHAR * str1;  
        int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, NULL, 0);  
        str1 = new WCHAR[n];  
        MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, str1, n);  
        n = WideCharToMultiByte(CP_UTF8, 0, str1, -1, NULL, 0, NULL, NULL);  
        char * str2 = new char[n];  
        WideCharToMultiByte(CP_UTF8, 0, str1, -1, str2, n, NULL, NULL);  
        strOutUTF8 = str2;  
        delete[]str1;  
        str1 = NULL;  
        delete[]str2;  
        str2 = NULL;  
        return strOutUTF8;  
    }  
      
    string UTF8ToGBK(const std::string& strUTF8)  
    {  
        int len = MultiByteToWideChar(CP_UTF8, 0, strUTF8.c_str(), -1, NULL, 0);  
        unsigned short * wszGBK = new unsigned short[len + 1];  
        memset(wszGBK, 0, len * 2 + 2);  
        MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)strUTF8.c_str(), -1, wszGBK, len);  
      
        len = WideCharToMultiByte(CP_ACP, 0, wszGBK, -1, NULL, 0, NULL, NULL);  
        char *szGBK = new char[len + 1];  
        memset(szGBK, 0, len + 1);  
        WideCharToMultiByte(CP_ACP,0, wszGBK, -1, szGBK, len, NULL, NULL);  
        //strUTF8 = szGBK;  
        std::string strTemp(szGBK);  
        delete[]szGBK;  
        delete[]wszGBK;  
        return strTemp;  
    }  
      
    int _tmain(int argc, _TCHAR* argv[])  
    {  
        string test("我们中国是个强大的名族，强大的动力来自每个人的支持");  
        fstream output("test.txt",ios_base::out | ios_base::app);  
        output << GBKToUTF8(test);  
        //system("iconv -f GBK -t utf-8");  
        return 0;  
    }