src/core/container_func.hpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD 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.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file container_func.hpp Some simple functions to help with accessing containers. */
   9
  10 #ifndef CONTAINER_FUNC_HPP
  11 #define CONTAINER_FUNC_HPP
  12
  13 /**
  14  * Helper function to append an item to a container if it is not already contained.
  15  * The container must have a \c emplace_back function.
  16  * Consider using std::set, std::unordered_set or std::flat_set in new code.
  17  *
  18  * @param container A reference to the container to be extended
  19  * @param item Reference to the item to be copy-constructed if not found
  20  *
  21  * @return Whether the item was already present
  22  */
  23 template <typename Container>
  24 inline bool include(Container &container, typename Container::const_reference &item)
  25 {
  26         const bool is_member = std::find(container.begin(), container.end(), item) != container.end();
  27         if (!is_member) container.emplace_back(item);
  28         return is_member;
  29 }
  30
  31 /**
  32  * Helper function to get the index of an item
  33  * Consider using std::set, std::unordered_set or std::flat_set in new code.
  34  *
  35  * @param container A reference to the container to be searched.
  36  * @param item Reference to the item to be search for
  37  *
  38  * @return Index of element if found, otherwise -1
  39  */
  40 template <typename Container>
  41 int find_index(Container const &container, typename Container::const_reference item)
  42 {
  43         auto const it = std::find(container.begin(), container.end(), item);
  44         if (it != container.end()) return std::distance(container.begin(), it);
  45
  46         return -1;
  47 }
  48
  49 #endif /* CONTAINER_FUNC_HPP */