UTF-8和Unicode互转

1、Unicode转UTF-8

void CodeCovertTool::UNICODE_to_UTF8(const CString& unicodeString, std::string& str)
{//Unicode转UTF8
    int stringLength = ::WideCharToMultiByte(CP_UTF8, NULL, unicodeString, wcslen(unicodeString), NULL, 0, NULL, NULL);

    char* buffer = new char[stringLength + 1];
    ::WideCharToMultiByte(CP_UTF8, NULL, unicodeString, wcslen(unicodeString), buffer, stringLength, NULL, NULL);
    buffer[stringLength] = '';

    str = buffer;

    delete[] buffer;
}

std::string CodeCovertTool::UnicodeToUtf8(const wchar_t* buf)  
{//Unicode转UTF8
    int len = ::WideCharToMultiByte(CP_UTF8, 0, buf, -1, NULL, 0, NULL, NULL);  
    if (len == 0) return "";  

    std::vector<char> utf8(len);  
    ::WideCharToMultiByte(CP_UTF8, 0, buf, -1, &utf8[0], len, NULL, NULL);  

    return &utf8[0];  
}  

2、UTF-8转Unicode

std::wstring CodeCovertTool::Utf8ToUnicode(const char* buf)  
{//UTF8转Unicode
    int len = ::MultiByteToWideChar(CP_UTF8, 0, buf, -1, NULL, 0);  
    if (len == 0) return _T("");  

    std::vector<wchar_t> unicode(len);  
    ::MultiByteToWideChar(CP_UTF8, 0, buf, -1, &unicode[0], len);  

    return &unicode[0];  
}  

CString CodeCovertTool::Utf8ToUnicode(const std::string &utf8_str)
{//UTF8转Unicode
    int len;
    len = MultiByteToWideChar(CP_UTF8, 0, (LPCSTR)utf8_str.c_str(), -1, NULL,0);
    WCHAR * wszUnicode = new WCHAR[len+1];
    memset(wszUnicode, 0, len * 2 + 2);
    MultiByteToWideChar(CP_UTF8, 0, (LPCSTR)utf8_str.c_str(), -1, wszUnicode, len);
    CString ss=wszUnicode;
    delete wszUnicode;
    return ss;
}

3、Ansi转Unicode

std::wstring CodeCovertTool::AnsiToUnicode(const char* buf)  
{//Ansi转Unicode
    int len = ::MultiByteToWideChar(CP_ACP, 0, buf, -1, NULL, 0);  
    if (len == 0) return L"";  

    std::vector<wchar_t> unicode(len);  
    ::MultiByteToWideChar(CP_ACP, 0, buf, -1, &unicode[0], len);  

    return &unicode[0];  
}

4、Unicode转Ansi

std::string CodeCovertTool::UnicodeToAnsi(const wchar_t* buf)  
{//Unicode转Ansi
    int len = ::WideCharToMultiByte(CP_ACP, 0, buf, -1, NULL, 0, NULL, NULL);  
    if (len == 0) return "";  

    std::vector<char> utf8(len);  
    ::WideCharToMultiByte(CP_ACP, 0, buf, -1, &utf8[0], len, NULL, NULL);  

    return &utf8[0];  
}