// Copyright (c) 2008  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
// SPDX-License-Identifier: LGPL-3.0+
//
// Author(s)     : Sylvain Pion

#ifndef CGAL_ARRAY_H
#define CGAL_ARRAY_H

#include <CGAL/config.h>
#ifndef CGAL_CFG_NO_CPP0X_ARRAY
#  include <array>
#else
#  include <boost/array.hpp>
#endif

namespace CGAL {

namespace cpp11 {

#ifndef CGAL_CFG_NO_CPP0X_ARRAY
using std::array;
#else
using boost::array;
#endif

} // cpp11

namespace cpp0x = cpp11;

// This using is just for short-term backward-compat, people should take the
// habit to use CGAL::cpp11::array.
using cpp11::array;


// The make_array() function simply constructs an std::array.
// It is needed for cases where a std::array is used as a class data
// member and you want to initialize it in the member initializers list.
// It is also optimized: no spurious copies of the objects are made,
// provided the compiler does the NRVO.  So this is better than
// default construction followed by assignment.

// I proposed it for Boost.Array, but it has not been integrated so far.
// See the thread starting at
// http://lists.boost.org/Archives/boost/2006/08/109003.php
//
// C++0x has it under discussion here :
// http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#851

// Hopefully C++0x will fix this properly with initializer_lists.
// So, it's temporary, therefore I do not document it and keep it internal.

// NOTE : The above is actually untrue !  It is possible to do :
//     struct S2 {
//       typedef boost::array<M,2> Ar;
//       Ar m;
//       S2 (const M&a) : m ((Ar) { { a, a } }) {}
//     };
// without spurious copies...  Except VC++ does not eat it :-(

// It's also untrue that this is not documented...  It is !

#ifndef CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES

template< typename T, typename... Args >
inline
cpp11::array< T, 1 + sizeof...(Args) >
make_array(const T & t, const Args & ... args)
{
  cpp11::array< T, 1 + sizeof...(Args) > a = { { t, static_cast<T>(args)... } };
  return a;
}


// Functor version
struct Construct_array
{
  template <typename T, typename... Args>
  cpp11::array<T, 1 + sizeof...(Args)> operator()(const T& t, const Args& ... args)
  {
    return make_array (t, args...);
  }
};

#else // CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES

template < typename T > inline
cpp11::array<T, 1>
make_array(const T& b1)
{
  cpp11::array<T, 1> a = { { b1 } };
  return a;
}

template < typename T > inline
cpp11::array<T, 2>
make_array(const T& b1, const T& b2)
{
  cpp11::array<T, 2> a = { { b1, b2 } };
  return a;
}

template < typename T > inline
cpp11::array<T, 3>
make_array(const T& b1, const T& b2, const T& b3)
{
  cpp11::array<T, 3> a = { { b1, b2, b3 } };
  return a;
}

template < typename T > inline
cpp11::array<T, 4>
make_array(const T& b1, const T& b2, const T& b3, const T& b4)
{
  cpp11::array<T, 4> a = { { b1, b2, b3, b4 } };
  return a;
}

template < typename T > inline
cpp11::array<T, 5>
make_array(const T& b1, const T& b2, const T& b3, const T& b4, const T& b5)
{
  cpp11::array<T, 5> a = { { b1, b2, b3, b4, b5 } };
  return a;
}

template < typename T > inline
cpp11::array<T, 6>
make_array(const T& b1, const T& b2, const T& b3, const T& b4, const T& b5,
           const T& b6)
{
  cpp11::array<T, 6> a = { { b1, b2, b3, b4, b5, b6 } };
  return a;
}

// Functor version
struct Construct_array
{
  template < typename T >
  cpp11::array<T, 1>
  operator()(const T& b1)
  {
    return make_array (b1);
  }

  template < typename T >
  cpp11::array<T, 2>
  operator()(const T& b1, const T& b2)
  {
    return make_array (b1, b2);
  }

  template < typename T >
  cpp11::array<T, 3>
  operator()(const T& b1, const T& b2, const T& b3)
  {
    return make_array (b1, b2, b3);
  }

  template < typename T >
  cpp11::array<T, 4>
  operator()(const T& b1, const T& b2, const T& b3, const T& b4)
  {
    return make_array (b1, b2, b3, b4);
  }

  template < typename T >
  cpp11::array<T, 5>
  operator()(const T& b1, const T& b2, const T& b3, const T& b4, const T& b5)
  {
    return make_array (b1, b2, b3, b4, b5);
  }

  template < typename T >
  cpp11::array<T, 6>
  operator()(const T& b1, const T& b2, const T& b3, const T& b4, const T& b5,
             const T& b6)
  {
    return make_array (b1, b2, b3, b4, b5, b6);
  }
};

  
#endif // CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES

} //namespace CGAL

#endif // CGAL_ARRAY_H