ASCII,UTF-8,Unicode字符串相互转换

#include<string>
#include<windows.h>
#include<vector>
using namespace std;  

//utf8 转 Unicode
std::wstring Utf82Unicode(const std::string& utf8string)
{
    int widesize = ::MultiByteToWideChar(CP_UTF8, , utf8string.c_str(), -, NULL, );
    if (widesize == ERROR_NO_UNICODE_TRANSLATION)
    {
        throw std::exception("Invalid UTF-8 sequence.");
    }
    if (widesize == )
    {
        throw std::exception("Error in conversion.");
    }  

    std::vector<wchar_t> resultstring(widesize);  

    int convresult = ::MultiByteToWideChar(CP_UTF8, , utf8string.c_str(), -, &resultstring[], widesize);  

    if (convresult != widesize)
    {
        throw std::exception("La falla!");
    }  

    return std::wstring(&resultstring[]);
}  

//unicode 转为 ascii
std::string WideByte2Acsi(std::wstring& wstrcode)
{
    int asciisize = ::WideCharToMultiByte(CP_OEMCP, , wstrcode.c_str(), -, NULL, , NULL, NULL);
    if (asciisize == ERROR_NO_UNICODE_TRANSLATION)
    {
        throw std::exception("Invalid UTF-8 sequence.");
    }
    if (asciisize == )
    {
        throw std::exception("Error in conversion.");
    }
    std::vector<char> resultstring(asciisize);
    int convresult =::WideCharToMultiByte(CP_OEMCP, , wstrcode.c_str(), -, &resultstring[], asciisize, NULL, NULL);  

    if (convresult != asciisize)
    {
        throw std::exception("La falla!");
    }  

    return std::string(&resultstring[]);
}  

//utf-8 转 ascii
std::string UTF_82ASCII(std::string& strUtf8Code)
{
    std::string strRet("");
    //先把 utf8 转为 unicode
    std::wstring wstr = Utf82Unicode(strUtf8Code);
    //最后把 unicode 转为 ascii
    strRet = WideByte2Acsi(wstr);
    return strRet;
}  

///////////////////////////////////////////////////////////////////////  

//ascii 转 Unicode
std::wstring Acsi2WideByte(std::string& strascii)
{
    int widesize = MultiByteToWideChar (CP_ACP, , (char*)strascii.c_str(), -, NULL, );
    if (widesize == ERROR_NO_UNICODE_TRANSLATION)
    {
        throw std::exception("Invalid UTF-8 sequence.");
    }
    if (widesize == )
    {
        throw std::exception("Error in conversion.");
    }
    std::vector<wchar_t> resultstring(widesize);
    int convresult = MultiByteToWideChar (CP_ACP, , (char*)strascii.c_str(), -, &resultstring[], widesize);  

    if (convresult != widesize)
    {
        throw std::exception("La falla!");
    }  

    return std::wstring(&resultstring[]);
}  

//Unicode 转 Utf8
std::string Unicode2Utf8(const std::wstring& widestring)
{
    int utf8size = ::WideCharToMultiByte(CP_UTF8, , widestring.c_str(), -, NULL, , NULL, NULL);
    if (utf8size == )
    {
        throw std::exception("Error in conversion.");
    }  

    std::vector<char> resultstring(utf8size);  

    int convresult = ::WideCharToMultiByte(CP_UTF8, , widestring.c_str(), -, &resultstring[], utf8size, NULL, NULL);  

    if (convresult != utf8size)
    {
        throw std::exception("La falla!");
    }  

    return std::string(&resultstring[]);
}  

//ascii 转 Utf8
std::string ASCII2UTF_8(std::string& strAsciiCode)
{
    std::string strRet("");
    //先把 ascii 转为 unicode
    std::wstring wstr = Acsi2WideByte(strAsciiCode);
    //最后把 unicode 转为 utf8
    strRet = Unicode2Utf8(wstr);
    return strRet;
}  

转载于：https://blog.csdn.net/Don211/article/details/51769515