WCHAR to String, how do i do it?

String* Adder::downloadUrl(String* url)
{
    DWORD dwSize = 0;
    LPVOID lpOutBuffer = NULL;
    BOOL  bResults = FALSE;
    HINTERNET hSession = NULL,
              hConnect = NULL,
开发者_StackOverflow社区              hRequest = NULL;

    // Use WinHttpOpen to obtain a session handle.
    hSession = WinHttpOpen(  L"A WinHTTP Example Program/1.0",
                             WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
                             WINHTTP_NO_PROXY_NAME,
                             WINHTTP_NO_PROXY_BYPASS, 0);

    // Specify an HTTP server.
    if (hSession)
        hConnect = WinHttpConnect( hSession, L"www.google.com",
                                   INTERNET_DEFAULT_HTTP_PORT, 0);

    // Create an HTTP request handle.
    if (hConnect)
        hRequest = WinHttpOpenRequest( hConnect, L"GET", NULL,
                                       NULL, WINHTTP_NO_REFERER,
                                       WINHTTP_DEFAULT_ACCEPT_TYPES,
                                       0);

    // Send a request.
    if (hRequest)
        bResults = WinHttpSendRequest( hRequest,
                                       WINHTTP_NO_ADDITIONAL_HEADERS,
                                       0, WINHTTP_NO_REQUEST_DATA, 0,
                                       0, 0);

    // End the request.
    if (bResults)
        bResults = WinHttpReceiveResponse( hRequest, NULL);

    // First, use WinHttpQueryHeaders to obtain the size of the buffer.
    if (bResults)
    {
        WinHttpQueryHeaders( hRequest, WINHTTP_QUERY_RAW_HEADERS_CRLF,
                             WINHTTP_HEADER_NAME_BY_INDEX, NULL,
                             &dwSize, WINHTTP_NO_HEADER_INDEX);

        // Allocate memory for the buffer.
        if( GetLastError( ) == ERROR_INSUFFICIENT_BUFFER )
        {
            lpOutBuffer = new WCHAR[dwSize/sizeof(WCHAR)];

            // Now, use WinHttpQueryHeaders to retrieve the header.
            bResults = WinHttpQueryHeaders( hRequest,
                                       WINHTTP_QUERY_RAW_HEADERS_CRLF,
                                       WINHTTP_HEADER_NAME_BY_INDEX,
                                       lpOutBuffer, &dwSize,
                                       WINHTTP_NO_HEADER_INDEX);
        }
    }

    // Print the header contents.
    if (bResults)
        printf("Header contents: \n%S",lpOutBuffer);

    // Free the allocated memory.
    delete [] lpOutBuffer;

    // Report any errors.
    if (!bResults)
        printf("Error %d has occurred.\n",GetLastError());

    // Close any open handles.
    if (hRequest) WinHttpCloseHandle(hRequest);
    if (hConnect) WinHttpCloseHandle(hConnect);
    if (hSession) WinHttpCloseHandle(hSession);


    String* retOne;

    return retOne;
}

I want to get response as string i am using dll in C#, dont know vc++ at all, please suggest a way.

String* retOne //how to get response;

return retOne;

UPDATE

// Convert a wide Unicode string to an UTF8 string
std::string utf8_encode(const std::wstring &wstr)
{
    int size_needed = WideCharToMultiByte(CP_UTF8, 0, &wstr[0], (int)wstr.size(), NULL, 0, NULL, NULL);
    std::string strTo( size_needed, 0 );
    WideCharToMultiByte (CP_UTF8, 0, &wstr[0], (int)wstr.size(), &strTo[0], size_needed, NULL, NULL);
    return strTo;
}

String* retOne = utf8_encode(lpOutBuffer);

Gives error: 'utf8_encode' : cannot convert parameter 1 from 'LPVOID' to 'const std::wstring

Please don't post comments suggesting use of .net libraries.

Looks like you need the WideCharToMultiByte function

Whats hard in this process is to understand the function WideCharToMultiByte.

Basically what you need to do in order to get the whole string (and avoid garbage as a result of not having a null terminating string) is first use:

int size_needed = WideCharToMultiByte(CP_UTF8, 0, (LPCWCH)lpOutBuffer, -1, NULL, 0, NULL, NULL);
char *stringMe = new char[size_needed + 1];

While size_needed will be the required buffer size for lpMultiByteStr in the WideCharToMultiByte function.

Afterwards you just need to use that function again, since now you have the complete size:

WideCharToMultiByte(CP_UTF8, 0, (LPCWCH)lpOutBuffer, -1, stringMe, size_needed, NULL, NULL);
stringMe[size_needed + 1] = NULL;

Now you can also convert it to String:

std::string serverOutput(stringMe);

Try this:

 String* retOne = utf8_encode(std::wstring(lpOutBuffer));

or

 String* retOne = utf8_encode(std::wstring((WCHAR*)lpOutBuffer));