C++ wstring和string相互转换

不支持中文

std::wstring wide = L"wide";
std::string str(wide.begin(), wide.end());

std::string s = "hello";
std::wstring ws(s.begin(), s.end());

支持中文

// Windows
#include <comdef.h>
#include <string>
#include <windows.h>

// -------方式一---------
std::string Wstring2String(std::wstring wstr)
{
    // support chinese
    std::string res;
    int len = WideCharToMultiByte(CP_ACP, 0, wstr.c_str(), wstr.size(), nullptr, 0, nullptr, nullptr);
    if (len <= 0){
        return res;
    }
    char* buffer = new char[len + 1];
    if (buffer == nullptr){
        return res;
    }
    WideCharToMultiByte(CP_ACP, 0, wstr.c_str(), wstr.size(), buffer, len, nullptr, nullptr);
    buffer[len] = '\0';
    res.append(buffer);
    delete[] buffer;
    return res;
}

std::wstring String2Wstring(std::string wstr)
{
    std::wstring res;
    int len = MultiByteToWideChar(CP_ACP, 0, wstr.c_str(), wstr.size(), nullptr, 0);
    if( len < 0 ){
        return res;
    }
    wchar_t* buffer = new wchar_t[len + 1];
    if( buffer == nullptr){
        return res;
    }
    MultiByteToWideChar(CP_ACP, 0, wstr.c_str(), wstr.size(), buffer, len);
    buffer[len] = '\0';
    res.append(buffer);
    delete[] buffer;
    return res;
}

// -------方式二---------
std::string WString2String(const std::wstring& wstr) {
    std::string strLocale = setlocale(LC_ALL, "");   // use the default locale set in the environment
    const wchar_t* wchSrc = wstr.c_str();
    size_t nWStr = wcstombs(NULL, wchSrc, 0) + 1;    // get the string len, zh has two byte
    char* chDest = new char[nWStr];
    memset(chDest, 0, nWStr);                        // is chDest[nWStr - 1] = 0;
    wcstombs(chDest, wchSrc, nWStr);                 // translates wide characters from the sequence pointed by src to the multibyte equivalent sequence
    std::string strRes = chDest;
    delete[] chDest;
    setlocale(LC_ALL, strLocale.c_str());

    bool bUtf8 = IsUtf8((unsigned char*)(strRes.c_str()), strRes.size());
    if (bUtf8) {
        std::string strGbk;
        char c[MAX_PATH_LEN];
        strcpy(c, strRes.c_str());
        strGbk = Utf8ToGbk(c);
        return strGbk;
    }
    return strRes;
}

std::wstring String2WString(const std::string& str) 
{
    std::string strGbk = str;
    bool bUtf8 = IsUtf8((unsigned char*)(str.c_str()), str.size());
    if (bUtf8) {
        char c[MAX_PATH_LEN];
        strcpy(c, str.c_str());
        strGbk = Utf8ToGbk(c);
    }
    std::string strLocale = setlocale(LC_ALL, "");
    const char* chSrc = strGbk.c_str();
    size_t nStr = mbstowcs(NULL, chSrc, 0) + 1;
    wchar_t* wchDest = new wchar_t[nStr];
    memset(wchDest, 0, nStr);
    mbstowcs(wchDest, chSrc, nStr);
    std::wstring wStrRes = wchDest;
    delete[] wchDest;
    setlocale(LC_ALL, strLocale.c_str());
    
    return wStrRes;
}


// -------方式三---------
std::string WString2String(const std::wstring& wstr){
    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
    return converter.to_bytes(wstr);
}

std::wstring String2WString(const std::string& mbs) {
    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
    return converter.from_bytes(mbs);
}

// Linux
#include <unistd.h>
#include <sys/stat.h>
#include <iconv.h>

std::string WString2String(const std::wstring& wstr) {
    setlocale(LC_ALL, "en_US.UTF-8");
    const wchar_t* wchSrc = wstr.c_str();
    size_t nWStr = wcstombs(NULL, wchSrc, 0) + 1;   
    char* chDest = new char[nWStr];
    memset(chDest, 0, nWStr);                       
    wcstombs(chDest, wchSrc, nWStr);                
    std::string strRes = chDest;
    delete[] chDest;

    return strRes;
}

std::wstring String2WString(const std::string& str) 
{
    std::string strUtf8 = str;
    setlocale(LC_ALL, "en_US.UTF-8");
    const char* chSrc = strUtf8.c_str();
    size_t nStr = mbstowcs(NULL, chSrc, 0) + 1;
    wchar_t* wchDest = new wchar_t[nStr];
    memset(wchDest, 0, nStr);
    mbstowcs(wchDest, chSrc, nStr);
    std::wstring wStrRes = wchDest;
    delete[] wchDest;
    return wStrRes;
}

参考链接

https://stackoverflow.com/questions/4804298/how-to-convert-wstring-into-string
https://www.cnblogs.com/bookdrip/p/9987099.html
https://www.jianshu.com/p/495fb979a1de
https://newbedev.com/how-to-convert-wstring-into-string
https://stackoverflow.com/questions/402283/stdwstring-vs-stdstring/402918#402918

gbk utf8

https://blog.csdn.net/u012234115/article/details/83186386
https://blog.csdn.net/taiyang1987912/article/details/103187978
https://www.jianshu.com/p/a83d398e3606