EnumIface.hh

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/*
 * Copyright (C) 2015-2016 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 _GAZEBO_ENUMITERATOR_HH_
#define _GAZEBO_ENUMITERATOR_HH_

#include <string>
#include <vector>
#include <algorithm>
#include "gazebo/common/Assert.hh"

namespace gazebo
{
  namespace common
  {
    #define GZ_ENUM(enumType, begin, end, ...) \
    template<> enumType common::EnumIface<enumType>::range[] = {begin, end}; \
    template<> std::vector<std::string> common::EnumIface<enumType>::names = \
    {__VA_ARGS__};

    template<typename T>
    class EnumIface
    {
      public: static T Begin()
      {
        return range[0];
      }

      public: static T End()
      {
        return range[1];
      }

      static std::string Str(T const &_e)
      {
        if (_e < names.size())
          return names[_e];
        else
          return "";
      }

      static void Set(T &_e, const std::string &_str)
      {
        static auto begin = std::begin(names);
        static auto end = std::end(names);

        auto find = std::find(begin, end, _str);
        if (find != end)
        {
          _e = static_cast<T>(std::distance(begin, find));
        }
      }

      public: static T range[2];

      public: static std::vector<std::string> names;
    };

    template<typename Enum>
    class EnumIterator
    : std::iterator<std::bidirectional_iterator_tag, Enum>
    {
      public: EnumIterator() : c(this->End())
      {
      }

      public: EnumIterator(const Enum _c) : c(_c)
      {
        GZ_ASSERT(this->c >= this->Begin() && this->c <= this->End(),
            "Invalid enum value in EnumIterator constructor");
      }

      public: EnumIterator &operator=(const Enum _c)
      {
        GZ_ASSERT(_c >= this->Begin() && _c <= this->End(),
            "Invalid operator= value in EnumIterator");
        this->c = _c;
        return *this;
      }

      public: static Enum Begin()
      {
        return EnumIface<Enum>::Begin();
      }

      public: static Enum End()
      {
        return EnumIface<Enum>::End();
      }

      public: EnumIterator &operator++()
      {
        GZ_ASSERT(this->c != this->End(), "Incrementing past end of enum");
        this->c = static_cast<Enum>(this->c + 1);
        return *this;
      }

      public: EnumIterator operator++(const int)
      {
        GZ_ASSERT(this->c != this->End(), "Incrementing past end of enum");
        EnumIterator cpy(*this);
        ++*this;
        return cpy;
      }

      public: EnumIterator &operator--()
      {
        GZ_ASSERT(this->c != this->Begin(), "decrementing beyond begin?");
        this->c = static_cast<Enum>(this->c - 1);
        return *this;
      }

      public: EnumIterator operator--(const int)
      {
        GZ_ASSERT(this->c != this->Begin(), "Decrementing beyond beginning.");
        EnumIterator cpy(*this);
        --*this;
        return cpy;
      }

      public: Enum operator*() const
      {
        GZ_ASSERT(this->c != this->End(), "Cannot dereference end iterator");
        return c;
      }

      public: Enum Value() const
      {
        return this->c;
      }

      private: Enum c;
    };

    template<typename Enum>
    bool operator==(EnumIterator<Enum> _e1, EnumIterator<Enum> _e2)
    {
      return _e1.Value() == _e2.Value();
    }

    template<typename Enum>
    bool operator!=(EnumIterator<Enum> _e1, EnumIterator<Enum> _e2)
    {
      return !(_e1 == _e2);
    }
  }
}
#endif