.. _program_listing_file__tmp_ws_src_rmf_utils_rmf_utils_include_rmf_utils_Modular.hpp:

Program Listing for File Modular.hpp
====================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_rmf_utils_rmf_utils_include_rmf_utils_Modular.hpp>` (``/tmp/ws/src/rmf_utils/rmf_utils/include/rmf_utils/Modular.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   /*
    * Copyright (C) 2020 Open Source Robotics Foundation
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
    * Unless required by applicable law or agreed to in writing, software
    * distributed under the License is distributed on an "AS IS" BASIS,
    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    * See the License for the specific language governing permissions and
    * limitations under the License.
    *
   */
   
   #ifndef RMF_UTILS__MODULAR_HPP
   #define RMF_UTILS__MODULAR_HPP
   
   #include <stdexcept>
   #include <limits>
   #include <type_traits>
   
   namespace rmf_utils {
   
   //==============================================================================
   template<typename V>
   class Modular
   {
   public:
   
     Modular(V basis)
     : _basis(basis)
     {
       // Do nothing
     }
   
     bool less_than(const V rhs) const
     {
       // "distance" here means how far the RHS is from the basis, adjusted back by
       // half of the maximum window size.
       const V distance = rhs - _basis + HalfWindow;
   
       // If the distance from the adjusted basis is greater than the maximum
       // window size, then we have an exception.
       if (Window < distance)
       {
         throw std::runtime_error(
                 "[rmf_traffic::schedule::Modular] modular distance between value ["
                 + std::to_string(
                   rhs) + "] and basis [" + std::to_string(_basis)
                 + "] is too big [" + std::to_string(distance) + "]. Maximum is "
                 + std::to_string(Window));
       }
   
       // If the distance from the adjusted basis is less than half the window
       // size, then RHS is below (i.e. less than) the original basis. Otherwise it
       // is not less than the original basis.
       return HalfWindow < distance;
     }
   
     bool less_than_or_equal(const V rhs) const
     {
       return (_basis == rhs) || less_than(rhs);
     }
   
     bool less_than(const V lhs, const V rhs) const
     {
       return (lhs - _basis) < (rhs - _basis);
     }
   
     bool less_than_or_equal(const V lhs, const V rhs) const
     {
       return (lhs == rhs) || less_than(lhs, rhs);
     }
   
   private:
   
     constexpr static V Window =
       static_cast<V>(std::numeric_limits<std::make_signed_t<V>>::max());
   
     constexpr static V HalfWindow = Window/2;
   
     V _basis = 0;
   
   };
   
   template<typename V>
   Modular<V> modular(V value)
   {
     return Modular<V>(value);
   }
   
   template<typename V>
   struct ModularLess
   {
     bool operator()(const V& lhs, const V& rhs) const
     {
       return modular(lhs).less_than(rhs);
     }
   };
   
   } // namespace rmf_utils
   
   #endif // RMF_UTILS__MODULAR_HPP