74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
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// Copyright (c) 2008 INRIA Sophia-Antipolis (France).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/STL_Extension/include/CGAL/array.h $
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// $Id: array.h 52164b1 2019-10-19T15:34:59+02:00 Sébastien Loriot
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author(s) : Sylvain Pion
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#ifndef CGAL_ARRAY_H
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#define CGAL_ARRAY_H
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#include <CGAL/config.h>
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#ifndef CGAL_CFG_NO_CPP0X_ARRAY
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# include <array>
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#else
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# include <boost/array.hpp>
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#endif
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namespace CGAL {
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// The make_array() function simply constructs an std::array.
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// It is needed for cases where a std::array is used as a class data
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// member and you want to initialize it in the member initializers list.
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// It is also optimized: no spurious copies of the objects are made,
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// provided the compiler does the NRVO. So this is better than
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// default construction followed by assignment.
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// I proposed it for Boost.Array, but it has not been integrated so far.
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// See the thread starting at
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// https://lists.boost.org/Archives/boost/2006/08/109003.php
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//
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// C++0x has it under discussion here :
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// http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#851
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// Hopefully C++0x will fix this properly with initializer_lists.
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// So, it's temporary, therefore I do not document it and keep it internal.
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// NOTE : The above is actually untrue ! It is possible to do :
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// struct S2 {
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// typedef boost::array<M,2> Ar;
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// Ar m;
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// S2 (const M&a) : m ((Ar) { { a, a } }) {}
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// };
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// without spurious copies... Except VC++ does not eat it :-(
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// It's also untrue that this is not documented... It is !
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template< typename T, typename... Args >
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inline
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std::array< T, 1 + sizeof...(Args) >
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make_array(const T & t, const Args & ... args)
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{
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std::array< T, 1 + sizeof...(Args) > a = { { t, static_cast<T>(args)... } };
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return a;
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}
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// Functor version
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struct Construct_array
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{
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template <typename T, typename... Args>
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std::array<T, 1 + sizeof...(Args)> operator()(const T& t, const Args& ... args)
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{
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return make_array (t, args...);
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}
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};
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} //namespace CGAL
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#endif // CGAL_ARRAY_H
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