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boost/interprocess/detail/transform_iterator.hpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2015.
// (C) Copyright Gennaro Prota 2003 - 2004.
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_INTERPROCESS_DETAIL_TRANSFORM_ITERATORS_HPP
#define BOOST_INTERPROCESS_DETAIL_TRANSFORM_ITERATORS_HPP

#ifndef BOOST_CONFIG_HPP
#  include <boost/config.hpp>
#endif
#
#if defined(BOOST_HAS_PRAGMA_ONCE)
#  pragma once
#endif

#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>

// interprocess
#include <boost/interprocess/interprocess_fwd.hpp>
// interprocess/detail
#include <boost/interprocess/detail/type_traits.hpp>
// move/detail
#include <boost/container/detail/iterator.hpp>

namespace boost {
namespace interprocess {

template <class PseudoReference>
struct operator_arrow_proxy
{
   operator_arrow_proxy(const PseudoReference &px)
      :  m_value(px)
   {}

   PseudoReference* operator->() const { return &m_value; }
   // This function is needed for MWCW and BCC, which won't call operator->
   // again automatically per 13.3.1.2 para 8
//   operator T*() const { return &m_value; }
   mutable PseudoReference m_value;
};

template <class T>
struct operator_arrow_proxy<T&>
{
   operator_arrow_proxy(T &px)
      :  m_value(px)
   {}

   T* operator->() const { return const_cast<T*>(&m_value); }
   // This function is needed for MWCW and BCC, which won't call operator->
   // again automatically per 13.3.1.2 para 8
//   operator T*() const { return &m_value; }
   T &m_value;
};

template <class Iterator, class UnaryFunction>
class transform_iterator
   : public UnaryFunction
{
   public:
   typedef typename ::boost::container::iterator_traits<Iterator>::iterator_category         iterator_category;
   typedef typename ipcdetail::remove_reference<typename UnaryFunction::result_type>::type   value_type;
   typedef typename ::boost::container::iterator_traits<Iterator>::difference_type           difference_type;
   typedef operator_arrow_proxy<typename UnaryFunction::result_type>                         pointer;
   typedef typename UnaryFunction::result_type                                               reference;

   explicit transform_iterator(const Iterator &it, const UnaryFunction &f = UnaryFunction())
      :  UnaryFunction(f), m_it(it)
   {}

   explicit transform_iterator()
      :  UnaryFunction(), m_it()
   {}

   //Constructors
   transform_iterator& operator++()
   { increment();   return *this;   }

   transform_iterator operator++(int)
   {
      transform_iterator result (*this);
      increment();
      return result;
   }

   transform_iterator& operator--()
   { decrement();   return *this;   }

   transform_iterator operator--(int)
   {
      transform_iterator result (*this);
      decrement();
      return result;
   }

   friend bool operator== (const transform_iterator& i, const transform_iterator& i2)
   { return i.equal(i2); }

   friend bool operator!= (const transform_iterator& i, const transform_iterator& i2)
   { return !(i == i2); }

   friend bool operator< (const transform_iterator& i, const transform_iterator& i2)
   { return i < i2; }

   friend bool operator> (const transform_iterator& i, const transform_iterator& i2)
   { return i2 < i; }

   friend bool operator<= (const transform_iterator& i, const transform_iterator& i2)
   { return !(i > i2); }

   friend bool operator>= (const transform_iterator& i, const transform_iterator& i2)
   { return !(i < i2); }

   friend difference_type operator- (const transform_iterator& i, const transform_iterator& i2)
   { return i2.distance_to(i); }

   //Arithmetic
   transform_iterator& operator+=(difference_type off)
   {  this->advance(off); return *this;   }

   transform_iterator operator+(difference_type off) const
   {
      transform_iterator other(*this);
      other.advance(off);
      return other;
   }

   friend transform_iterator operator+(difference_type off, const transform_iterator& right)
   {  return right + off; }

   transform_iterator& operator-=(difference_type off)
   {  this->advance(-off); return *this;   }

   transform_iterator operator-(difference_type off) const
   {  return *this + (-off);  }

   typename UnaryFunction::result_type operator*() const
   { return dereference(); }

   typename UnaryFunction::result_type operator[](difference_type off) const
   { return UnaryFunction::operator()(m_it[off]); }

   operator_arrow_proxy<typename UnaryFunction::result_type>
      operator->() const
   { return operator_arrow_proxy<typename UnaryFunction::result_type>(dereference());  }

   Iterator & base()
   {  return m_it;   }

   const Iterator & base() const
   {  return m_it;   }

   private:
   Iterator m_it;

   void increment()
   { ++m_it; }

   void decrement()
   { --m_it; }

   bool equal(const transform_iterator &other) const
   {  return m_it == other.m_it;   }

   bool less(const transform_iterator &other) const
   {  return other.m_it < m_it;   }

   typename UnaryFunction::result_type dereference() const
   { return UnaryFunction::operator()(*m_it); }

   void advance(difference_type n)
   {  ::boost::container::iterator_advance(m_it, n); }

   difference_type distance_to(const transform_iterator &other)const
   {  return ::boost::container::iterator_distance(other.m_it, m_it); }
};

template <class Iterator, class UnaryFunc>
transform_iterator<Iterator, UnaryFunc>
make_transform_iterator(Iterator it, UnaryFunc fun)
{
   return transform_iterator<Iterator, UnaryFunc>(it, fun);
}

}  //namespace interprocess {
}  //namespace boost {

#include <boost/interprocess/detail/config_end.hpp>

#endif   //#ifndef BOOST_INTERPROCESS_DETAIL_TRANSFORM_ITERATORS_HPP