C++中实现类似php的UTF8和UrlEncode函数

#include <string>
#include <vector>
  
inline BYTE toHex(const BYTE x)
{
    return x>9?x+55:x+48;
}
  
std::string WC2UT(const wchar_t* buf)
{
    int len=WideCharToMultiByte(CP_UTF8,buf,-1,NULL,NULL);
    std::vector<char> utf8(len);
    WideCharToMultiByte(CP_UTF8,&utf8[0],len,NULL);
    return std::string(&utf8[0]);
}
  
std::wstring MB2WC(const char* buf)
{
    int len=MultiByteToWideChar(CP_ACP,0);
    std::vector<wchar_t> unicode(len);
    MultiByteToWideChar(CP_ACP,&unicode[0],len);
    return std::wstring(&unicode[0]);
}
  
//参数要用指针。
void URLEncode(CString* str)
{
    std::string sln=str->GetBuffer(0);
    sln=WC2UT(MB2WC(sln.c_str()).c_str());
    std::string sOut;
    for (size_t ix=0;ix<sln.size();ix++)
    {
        BYTE buf[4];
        memset(buf,4);
        if (isalnum((BYTE)sln[ix]))
            buf[0]=sln[ix];
        else if (isspace((BYTE)sln[ix]))
            buf[0]='+';
        else
        {
            buf[0]='%';
            buf[1]=toHex((BYTE)sln[ix]>>4);
            buf[2]=toHex((BYTE)sln[ix]);
        }
        sOut+=(char*)buf;
    }
    CString out=sOut.c_str();
    *str=out;
}