// Copyright (C) 2007, 2008 Steven Watanabe, Joseph Gauterin, Niels Dekker

//

// 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)

// For more information, see http://www.boost.org

#ifndef BOOST_UTILITY_SWAP_HPP

#define BOOST_UTILITY_SWAP_HPP

// Note: the implementation of this utility contains various workarounds:

// - swap_impl is put outside the boost namespace, to avoid infinite

// recursion (causing stack overflow) when swapping objects of a primitive

// type.

// - swap_impl has a using-directive, rather than a using-declaration,

// because some compilers (including MSVC 7.1, Borland 5.9.3, and

// Intel 8.1) don't do argument-dependent lookup when it has a

// using-declaration instead.

// - boost::swap has two template arguments, instead of one, to

// avoid ambiguity when swapping objects of a Boost type that does

// not have its own boost::swap overload.

#include <algorithm> //for std::swap

#include <cstddef> //for std::size_t

namespace boost_swap_impl

{

  template<class T>

  void swap_impl(T& left, T& right)

  {

    using namespace std;//use std::swap if argument dependent lookup fails

    swap(left,right);

  }

  template<class T, std::size_t N>

  void swap_impl(T (& left)[N], T (& right)[N])

  {

    for (std::size_t i = 0; i < N; ++i)

    {

      ::boost_swap_impl::swap_impl(left[i], right[i]);

    }

  }

}

namespace boost

{

  template<class T1, class T2>

  void swap(T1& left, T2& right)

  {

    ::boost_swap_impl::swap_impl(left, right);

  }

}

#endif