etl/include/etl/fixed_iterator.h

///\file

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com

Copyright(c) 2015 John Wellbelove

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/

#ifndef ETL_FIXED_ITERATOR_INCLUDED
#define ETL_FIXED_ITERATOR_INCLUDED

#include "platform.h"
#include "iterator.h"

///\defgroup iterator Iterator types

namespace etl
{
  /// A fixed iterator class.
  /// This iterator can be given an iterator value, which will not be allowed to
  /// be incremented or decremented. This can be useful when using STL
  /// algorithms to interact with fixed memory locations such as registers.
  ///\ingroup iterator
  template <typename TIterator>
  class fixed_iterator
    : etl::iterator<typename etl::iterator_traits<TIterator>::iterator_category, typename etl::iterator_traits<TIterator>::value_type>
  {
  public:

    //***************************************************************************
    /// Default constructor.
    //***************************************************************************
    ETL_CONSTEXPR fixed_iterator()
      : it(TIterator())
    {
    }

    //***************************************************************************
    /// Construct from iterator.
    //***************************************************************************
    ETL_CONSTEXPR fixed_iterator(TIterator it_)
      : it(it_)
    {
    }

    //***************************************************************************
    /// Copy constructor
    //***************************************************************************
    ETL_CONSTEXPR fixed_iterator(const fixed_iterator& other)
      : it(other.it)
    {
    }

    //***************************************************************************
    /// Increment (Does nothing).
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator& operator++()
    {
      return *this;
    }

    //***************************************************************************
    /// Increment (Does nothing).
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator operator++(int)
    {
      return *this;
    }

    //***************************************************************************
    /// Decrement (Does nothing).
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator& operator--()
    {
      return *this;
    }

    //***************************************************************************
    /// Decrement (Does nothing).
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator operator--(int)
    {
      return *this;
    }

    //***************************************************************************
    /// Dereference operator.
    //***************************************************************************
    ETL_CONSTEXPR14 typename etl::iterator_traits<TIterator>::value_type operator*()
    {
      return *it;
    }

    //***************************************************************************
    /// Dereference operator.
    //***************************************************************************
    ETL_CONSTEXPR const typename etl::iterator_traits<TIterator>::value_type operator*() const
    {
      return *it;
    }

    //***************************************************************************
    /// -> operator.
    //***************************************************************************
    ETL_CONSTEXPR14 TIterator operator->()
    {
      return it;
    }

    //***************************************************************************
    /// -> operator.
    //***************************************************************************
    ETL_CONSTEXPR const TIterator operator->() const
    {
      return it;
    }

    //***************************************************************************
    /// Conversion operator.
    //***************************************************************************
    ETL_CONSTEXPR operator TIterator() const
    {
      return it;
    }

    //***************************************************************************
    /// += operator.
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator& operator+=(typename etl::iterator_traits<TIterator>::difference_type /*offset*/)
    {
      return *this;
    }

    //***************************************************************************
    /// -= operator.
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator& operator-=(typename etl::iterator_traits<TIterator>::difference_type /*offset*/)
    {
      return *this;
    }

    //***************************************************************************
    /// Assignment from iterator.
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator& operator=(TIterator new_it)
    {
      it = new_it;
      return *this;
    }

    //***************************************************************************
    /// Assignment from fixed_iterator.
    //***************************************************************************
    ETL_CONSTEXPR14 fixed_iterator& operator=(fixed_iterator other)
    {
      it = other.it;
      return *this;
    }

  private:

    TIterator it; ///< The underlying iterator.
  };

  //*****************************************************************************
  /// + difference operator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR14 etl::fixed_iterator<TIterator>& operator+(etl::fixed_iterator<TIterator>& lhs,
                                                      typename etl::iterator_traits<TIterator>::difference_type /*rhs*/)
  {
    return lhs;
  }

  //*****************************************************************************
  /// - difference operator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR14 etl::fixed_iterator<TIterator>& operator-(etl::fixed_iterator<TIterator>& lhs,
                                                      typename etl::iterator_traits<TIterator>::difference_type /*rhs*/)
  {
    return lhs;
  }

  //*****************************************************************************
  /// - fixed_iterator operator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR typename etl::iterator_traits<TIterator>::difference_type operator-(const etl::fixed_iterator<TIterator>& lhs,
                                                                                const etl::fixed_iterator<TIterator>& rhs)
  {
    return TIterator(lhs) - TIterator(rhs);
  }

  //*****************************************************************************
  /// Equality operator. fixed_iterator == fixed_iterator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR bool operator==(const etl::fixed_iterator<TIterator>& lhs, const etl::fixed_iterator<TIterator>& rhs)
  {
    return TIterator(lhs) == TIterator(rhs);
  }

  //*****************************************************************************
  /// Equality operator. fixed_iterator == iterator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR bool operator==(const etl::fixed_iterator<TIterator>& lhs, TIterator rhs)
  {
    return TIterator(lhs) == rhs;
  }

  //*****************************************************************************
  /// Equality operator. iterator == fixed_iterator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR bool operator==(TIterator lhs, const etl::fixed_iterator<TIterator>& rhs)
  {
    return lhs == TIterator(rhs);
  }

  //*****************************************************************************
  /// Inequality operator. fixed_iterator == fixed_iterator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR bool operator!=(const etl::fixed_iterator<TIterator>& lhs, const etl::fixed_iterator<TIterator>& rhs)
  {
    return !(lhs == rhs);
  }

  //*****************************************************************************
  /// Inequality operator. fixed_iterator == iterator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR bool operator!=(const etl::fixed_iterator<TIterator>& lhs, TIterator rhs)
  {
    return !(lhs == rhs);
  }

  //*****************************************************************************
  /// Inequality operator. iterator == fixed_iterator.
  //*****************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR bool operator!=(TIterator& lhs, const etl::fixed_iterator<TIterator>& rhs)
  {
    return !(lhs == rhs);
  }
} // namespace etl

#endif