Конвертирование utf-8 в windows-1251

string Utf8_to_cp1251(const char *str)
{
	string res;
	int result_u, result_c;

	result_u = MultiByteToWideChar(CP_UTF8,
		0,
		str,
		-1,
		0,
		0);

	if (!result_u)
		return 0;

	wchar_t *ures = new wchar_t[result_u];

	if(!MultiByteToWideChar(CP_UTF8,
		0,
		str,
		-1,
		ures,
		result_u))
	{
		delete[] ures;
		return 0;
	}

	result_c = WideCharToMultiByte(
		1251,
		0,
		ures,
		-1,
		0,
		0,
		0, 0);

	if(!result_c)
	{
		delete [] ures;
		return 0;
	}

	char *cres = new char[result_c];

	if(!WideCharToMultiByte(
		1251,
		0,
		ures,
		-1,
		cres,
		result_c,
		0, 0))
	{
		delete[] cres;
		return 0;
	}
	delete[] ures;
	res.append(cres);
	delete[] cres;
	return res;
}