stringtempl.hpp

//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2020 OpenVPN Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Affero General Public License Version 3
//    as published by the Free Software Foundation.
//
//    This program is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Affero General Public License for more details.
//
//    You should have received a copy of the GNU Affero General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.


// Sometimes you want to accept a <typename STRING> in a
// method, without knowing whether it's a const char *,
// const std::string&, or nullptr.  These methods help with
// basic type-independent string operations.

#ifndef OPENVPN_COMMON_STRINGTEMPL_H
#define OPENVPN_COMMON_STRINGTEMPL_H

#include <string>
#include <cstddef> // for std::nullptr_t
#include <utility>

namespace openvpn {
  namespace StringTempl {

    // empty

    inline bool empty(std::nullptr_t)
    {
      return true;
    }

    inline bool empty(const char *str)
    {
      return !str || str[0] == '\0';
    }

    inline bool empty(const std::string& str)
    {
      return str.empty();
    }

    // to_string

    inline std::string to_string(std::nullptr_t)
    {
      return std::string();
    }

    inline std::string to_string(const char *str)
    {
      if (str)
	return std::string(str);
      else
	return to_string(nullptr);
    }

    inline std::string to_string(std::string&& str)
    {
      return std::move(str);
    }

    inline const std::string& to_string(const std::string& str)
    {
      return str;
    }

    // to_cstring

    inline const char *to_cstring(const std::string& str)
    {
      return str.c_str();
    }

    inline const char *to_cstring(const char *str)
    {
      return str;
    }
  }
}

#endif