<h2>Editing File: /usr/include/c++/8/experimental/any</h2><form method='post'><textarea name='content' class='file-edit'>// &lt;experimental/any&gt; -*- C++ -*-

// Copyright (C) 2014-2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// &lt;http://www.gnu.org/licenses/&gt;.

/** @file experimental/any
 *  This is a TS C++ Library header.
 */

#ifndef _GLIBCXX_EXPERIMENTAL_ANY
#define _GLIBCXX_EXPERIMENTAL_ANY 1

#pragma GCC system_header

#if __cplusplus &gt;= 201402L

#include &lt;typeinfo&gt;
#include &lt;new&gt;
#include &lt;utility&gt;
#include &lt;type_traits&gt;
#include &lt;experimental/bits/lfts_config.h&gt;

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

namespace experimental
{
inline namespace fundamentals_v1
{
  /**
   * @defgroup any Type-safe container of any type
   * @ingroup experimental
   *
   * A type-safe container for single values of value types, as
   * described in n3804 &quot;Any Library Proposal (Revision 3)&quot;.
   *
   * @{
   */

#define __cpp_lib_experimental_any 201411

  /**
   *  @brief Exception class thrown by a failed @c any_cast
   *  @ingroup exceptions
   */
  class bad_any_cast : public bad_cast
  {
  public:
    virtual const char* what() const noexcept { return &quot;bad any_cast&quot;; }
  };

  [[gnu::noreturn]] inline void __throw_bad_any_cast()
  {
#if __cpp_exceptions
    throw bad_any_cast{};
#else
    __builtin_abort();
#endif
  }

  /**
   *  @brief A type-safe container of any type.
   * 
   *  An @c any object's state is either empty or it stores a contained object
   *  of CopyConstructible type.
   */
  class any
  {
    // Holds either pointer to a heap object or the contained object itself.
    union _Storage
    {
      // This constructor intentionally doesn't initialize anything.
      _Storage() = default;

      // Prevent trivial copies of this type, buffer might hold a non-POD.
      _Storage(const _Storage&amp;) = delete;
      _Storage&amp; operator=(const _Storage&amp;) = delete;

      void* _M_ptr;
      aligned_storage&lt;sizeof(_M_ptr), alignof(void*)&gt;::type _M_buffer;
    };

    template&lt;typename _Tp, typename _Safe = is_nothrow_move_constructible&lt;_Tp&gt;,
	     bool _Fits = (sizeof(_Tp) &lt;= sizeof(_Storage))
			  &amp;&amp; (alignof(_Tp) &lt;= alignof(_Storage))&gt;
      using _Internal = std::integral_constant&lt;bool, _Safe::value &amp;&amp; _Fits&gt;;

    template&lt;typename _Tp&gt;
      struct _Manager_internal; // uses small-object optimization

    template&lt;typename _Tp&gt;
      struct _Manager_external; // creates contained object on the heap

    template&lt;typename _Tp&gt;
      using _Manager = conditional_t&lt;_Internal&lt;_Tp&gt;::value,
				     _Manager_internal&lt;_Tp&gt;,
				     _Manager_external&lt;_Tp&gt;&gt;;

    template&lt;typename _Tp, typename _Decayed = decay_t&lt;_Tp&gt;&gt;
      using _Decay = enable_if_t&lt;!is_same&lt;_Decayed, any&gt;::value, _Decayed&gt;;

  public:
    // construct/destruct

    /// Default constructor, creates an empty object.
    any() noexcept : _M_manager(nullptr) { }

    /// Copy constructor, copies the state of @p __other
    any(const any&amp; __other)
    {
      if (__other.empty())
	_M_manager = nullptr;
      else
	{
	  _Arg __arg;
	  __arg._M_any = this;
	  __other._M_manager(_Op_clone, &amp;__other, &amp;__arg);
	}
    }

    /**
     * @brief Move constructor, transfer the state from @p __other
     *
     * @post @c __other.empty() (this postcondition is a GNU extension)
     */
    any(any&amp;&amp; __other) noexcept
    {
      if (__other.empty())
	_M_manager = nullptr;
      else
	{
	  _Arg __arg;
	  __arg._M_any = this;
	  __other._M_manager(_Op_xfer, &amp;__other, &amp;__arg);
	}
    }

    /// Construct with a copy of @p __value as the contained object.
    template &lt;typename _ValueType, typename _Tp = _Decay&lt;_ValueType&gt;,
	      typename _Mgr = _Manager&lt;_Tp&gt;,
              typename enable_if&lt;is_constructible&lt;_Tp, _ValueType&amp;&amp;&gt;::value,
                                 bool&gt;::type = true&gt;
      any(_ValueType&amp;&amp; __value)
      : _M_manager(&amp;_Mgr::_S_manage)
      {
        _Mgr::_S_create(_M_storage, std::forward&lt;_ValueType&gt;(__value));
	static_assert(is_copy_constructible&lt;_Tp&gt;::value,
		      &quot;The contained object must be CopyConstructible&quot;);
      }

    /// Construct with a copy of @p __value as the contained object.
    template &lt;typename _ValueType, typename _Tp = _Decay&lt;_ValueType&gt;,
	      typename _Mgr = _Manager&lt;_Tp&gt;,
              typename enable_if&lt;!is_constructible&lt;_Tp, _ValueType&amp;&amp;&gt;::value,
                                 bool&gt;::type = false&gt;
      any(_ValueType&amp;&amp; __value)
      : _M_manager(&amp;_Mgr::_S_manage)
      {
        _Mgr::_S_create(_M_storage, __value);
	static_assert(is_copy_constructible&lt;_Tp&gt;::value,
		      &quot;The contained object must be CopyConstructible&quot;);
      }

    /// Destructor, calls @c clear()
    ~any() { clear(); }

    // assignments

    /// Copy the state of another object.
    any&amp; operator=(const any&amp; __rhs)
    {
      *this = any(__rhs);
      return *this;
    }

    /**
     * @brief Move assignment operator
     *
     * @post @c __rhs.empty() (not guaranteed for other implementations)
     */
    any&amp; operator=(any&amp;&amp; __rhs) noexcept
    {
      if (__rhs.empty())
	clear();
      else if (this != &amp;__rhs)
	{
	  clear();
	  _Arg __arg;
	  __arg._M_any = this;
	  __rhs._M_manager(_Op_xfer, &amp;__rhs, &amp;__arg);
	}
      return *this;
    }

    /// Store a copy of @p __rhs as the contained object.
    template&lt;typename _ValueType&gt;
      enable_if_t&lt;!is_same&lt;any, decay_t&lt;_ValueType&gt;&gt;::value, any&amp;&gt;
      operator=(_ValueType&amp;&amp; __rhs)
      {
	*this = any(std::forward&lt;_ValueType&gt;(__rhs));
	return *this;
      }

    // modifiers

    /// If not empty, destroy the contained object.
    void clear() noexcept
    {
      if (!empty())
      {
	_M_manager(_Op_destroy, this, nullptr);
	_M_manager = nullptr;
      }
    }

    /// Exchange state with another object.
    void swap(any&amp; __rhs) noexcept
    {
      if (empty() &amp;&amp; __rhs.empty())
	return;

      if (!empty() &amp;&amp; !__rhs.empty())
	{
	  if (this == &amp;__rhs)
	    return;

	  any __tmp;
	  _Arg __arg;
	  __arg._M_any = &amp;__tmp;
	  __rhs._M_manager(_Op_xfer, &amp;__rhs, &amp;__arg);
	  __arg._M_any = &amp;__rhs;
	  _M_manager(_Op_xfer, this, &amp;__arg);
	  __arg._M_any = this;
	  __tmp._M_manager(_Op_xfer, &amp;__tmp, &amp;__arg);
	}
      else
	{
	  any* __empty = empty() ? this : &amp;__rhs;
	  any* __full = empty() ? &amp;__rhs : this;
	  _Arg __arg;
	  __arg._M_any = __empty;
	  __full-&gt;_M_manager(_Op_xfer, __full, &amp;__arg);
	}
    }

    // observers

    /// Reports whether there is a contained object or not.
    bool empty() const noexcept { return _M_manager == nullptr; }

#if __cpp_rtti
    /// The @c typeid of the contained object, or @c typeid(void) if empty.
    const type_info&amp; type() const noexcept
    {
      if (empty())
	return typeid(void);
      _Arg __arg;
      _M_manager(_Op_get_type_info, this, &amp;__arg);
      return *__arg._M_typeinfo;
    }
#endif

    template&lt;typename _Tp&gt;
      static constexpr bool __is_valid_cast()
      { return __or_&lt;is_reference&lt;_Tp&gt;, is_copy_constructible&lt;_Tp&gt;&gt;::value; }

  private:
    enum _Op {
	_Op_access, _Op_get_type_info, _Op_clone, _Op_destroy, _Op_xfer
    };

    union _Arg
    {
	void* _M_obj;
	const std::type_info* _M_typeinfo;
	any* _M_any;
    };

    void (*_M_manager)(_Op, const any*, _Arg*);
    _Storage _M_storage;

    template&lt;typename _Tp&gt;
      friend enable_if_t&lt;is_object&lt;_Tp&gt;::value, void*&gt;
      __any_caster(const any* __any);

    // Manage in-place contained object.
    template&lt;typename _Tp&gt;
      struct _Manager_internal
      {
	static void
	_S_manage(_Op __which, const any* __anyp, _Arg* __arg);

	template&lt;typename _Up&gt;
	  static void
	  _S_create(_Storage&amp; __storage, _Up&amp;&amp; __value)
	  {
	    void* __addr = &amp;__storage._M_buffer;
	    ::new (__addr) _Tp(std::forward&lt;_Up&gt;(__value));
	  }
      };

    // Manage external contained object.
    template&lt;typename _Tp&gt;
      struct _Manager_external
      {
	static void
	_S_manage(_Op __which, const any* __anyp, _Arg* __arg);

	template&lt;typename _Up&gt;
	  static void
	  _S_create(_Storage&amp; __storage, _Up&amp;&amp; __value)
	  {
	    __storage._M_ptr = new _Tp(std::forward&lt;_Up&gt;(__value));
	  }
      };
  };

  /// Exchange the states of two @c any objects.
  inline void swap(any&amp; __x, any&amp; __y) noexcept { __x.swap(__y); }

  /**
   * @brief Access the contained object.
   *
   * @tparam  _ValueType  A const-reference or CopyConstructible type.
   * @param   __any       The object to access.
   * @return  The contained object.
   * @throw   bad_any_cast If &lt;code&gt;
   *          __any.type() != typeid(remove_reference_t&lt;_ValueType&gt;)
   *          &lt;/code&gt;
   */
  template&lt;typename _ValueType&gt;
    inline _ValueType any_cast(const any&amp; __any)
    {
      static_assert(any::__is_valid_cast&lt;_ValueType&gt;(),
	  &quot;Template argument must be a reference or CopyConstructible type&quot;);
      auto __p = any_cast&lt;add_const_t&lt;remove_reference_t&lt;_ValueType&gt;&gt;&gt;(&amp;__any);
      if (__p)
	return *__p;
      __throw_bad_any_cast();
    }

  /**
   * @brief Access the contained object.
   *
   * @tparam  _ValueType  A reference or CopyConstructible type.
   * @param   __any       The object to access.
   * @return  The contained object.
   * @throw   bad_any_cast If &lt;code&gt;
   *          __any.type() != typeid(remove_reference_t&lt;_ValueType&gt;)
   *          &lt;/code&gt;
   *
   * @{
   */
  template&lt;typename _ValueType&gt;
    inline _ValueType any_cast(any&amp; __any)
    {
      static_assert(any::__is_valid_cast&lt;_ValueType&gt;(),
	  &quot;Template argument must be a reference or CopyConstructible type&quot;);
      auto __p = any_cast&lt;remove_reference_t&lt;_ValueType&gt;&gt;(&amp;__any);
      if (__p)
	return *__p;
      __throw_bad_any_cast();
    }

  template&lt;typename _ValueType,
           typename enable_if&lt;!is_move_constructible&lt;_ValueType&gt;::value
                              || is_lvalue_reference&lt;_ValueType&gt;::value,
                              bool&gt;::type = true&gt;
    inline _ValueType any_cast(any&amp;&amp; __any)
    {
      static_assert(any::__is_valid_cast&lt;_ValueType&gt;(),
	  &quot;Template argument must be a reference or CopyConstructible type&quot;);
      auto __p = any_cast&lt;remove_reference_t&lt;_ValueType&gt;&gt;(&amp;__any);
      if (__p)
	return *__p;
      __throw_bad_any_cast();
    }

  template&lt;typename _ValueType,
           typename enable_if&lt;is_move_constructible&lt;_ValueType&gt;::value
                              &amp;&amp; !is_lvalue_reference&lt;_ValueType&gt;::value,
                              bool&gt;::type = false&gt;
    inline _ValueType any_cast(any&amp;&amp; __any)
    {
      static_assert(any::__is_valid_cast&lt;_ValueType&gt;(),
	  &quot;Template argument must be a reference or CopyConstructible type&quot;);
      auto __p = any_cast&lt;remove_reference_t&lt;_ValueType&gt;&gt;(&amp;__any);
      if (__p)
	return std::move(*__p);
      __throw_bad_any_cast();
    }
  // @}

  /// @cond undocumented
  template&lt;typename _Tp&gt;
    enable_if_t&lt;is_object&lt;_Tp&gt;::value, void*&gt;
    __any_caster(const any* __any)
    {
      // any_cast&lt;T&gt; returns non-null if __any-&gt;type() == typeid(T) and
      // typeid(T) ignores cv-qualifiers so remove them:
      using _Up = remove_cv_t&lt;_Tp&gt;;
      // The contained value has a decayed type, so if decay_t&lt;U&gt; is not U,
      // then it's not possible to have a contained value of type U.
      using __does_not_decay = is_same&lt;decay_t&lt;_Up&gt;, _Up&gt;;
      // Only copy constructible types can be used for contained values.
      using __is_copyable = is_copy_constructible&lt;_Up&gt;;
      // If the type _Tp could never be stored in an any we don't want to
      // instantiate _Manager&lt;_Tp&gt;, so use _Manager&lt;any::_Op&gt; instead, which
      // is explicitly specialized and has a no-op _S_manage function.
      using _Vp = conditional_t&lt;__and_&lt;__does_not_decay, __is_copyable&gt;::value,
				_Up, any::_Op&gt;;
      // First try comparing function addresses, which works without RTTI
      if (__any-&gt;_M_manager == &amp;any::_Manager&lt;_Vp&gt;::_S_manage
#if __cpp_rtti
	  || __any-&gt;type() == typeid(_Tp)
#endif
	  )
	{
	  any::_Arg __arg;
	  __any-&gt;_M_manager(any::_Op_access, __any, &amp;__arg);
	  return __arg._M_obj;
	}
      return nullptr;
    }

  // This overload exists so that std::any_cast&lt;void(*)()&gt;(a) is well-formed.
  template&lt;typename _Tp&gt;
    enable_if_t&lt;!is_object&lt;_Tp&gt;::value, _Tp*&gt;
    __any_caster(const any*) noexcept
    { return nullptr; }
  /// @endcond

  /**
   * @brief Access the contained object.
   *
   * @tparam  _ValueType  The type of the contained object.
   * @param   __any       A pointer to the object to access.
   * @return  The address of the contained object if &lt;code&gt;
   *          __any != nullptr &amp;&amp; __any.type() == typeid(_ValueType)
   *          &lt;/code&gt;, otherwise a null pointer.
   *
   * @{
   */
  template&lt;typename _ValueType&gt;
    inline const _ValueType* any_cast(const any* __any) noexcept
    {
      if (__any)
	return static_cast&lt;_ValueType*&gt;(__any_caster&lt;_ValueType&gt;(__any));
      return nullptr;
    }

  template&lt;typename _ValueType&gt;
    inline _ValueType* any_cast(any* __any) noexcept
    {
      if (__any)
	return static_cast&lt;_ValueType*&gt;(__any_caster&lt;_ValueType&gt;(__any));
      return nullptr;
    }
  // @}

  template&lt;typename _Tp&gt;
    void
    any::_Manager_internal&lt;_Tp&gt;::
    _S_manage(_Op __which, const any* __any, _Arg* __arg)
    {
      // The contained object is in _M_storage._M_buffer
      auto __ptr = reinterpret_cast&lt;const _Tp*&gt;(&amp;__any-&gt;_M_storage._M_buffer);
      switch (__which)
      {
      case _Op_access:
	__arg-&gt;_M_obj = const_cast&lt;_Tp*&gt;(__ptr);
	break;
      case _Op_get_type_info:
#if __cpp_rtti
	__arg-&gt;_M_typeinfo = &amp;typeid(_Tp);
#endif
	break;
      case _Op_clone:
	::new(&amp;__arg-&gt;_M_any-&gt;_M_storage._M_buffer) _Tp(*__ptr);
	__arg-&gt;_M_any-&gt;_M_manager = __any-&gt;_M_manager;
	break;
      case _Op_destroy:
	__ptr-&gt;~_Tp();
	break;
      case _Op_xfer:
	::new(&amp;__arg-&gt;_M_any-&gt;_M_storage._M_buffer) _Tp
	  (std::move(*const_cast&lt;_Tp*&gt;(__ptr)));
	__ptr-&gt;~_Tp();
	__arg-&gt;_M_any-&gt;_M_manager = __any-&gt;_M_manager;
	const_cast&lt;any*&gt;(__any)-&gt;_M_manager = nullptr;
	break;
      }
    }

  template&lt;typename _Tp&gt;
    void
    any::_Manager_external&lt;_Tp&gt;::
    _S_manage(_Op __which, const any* __any, _Arg* __arg)
    {
      // The contained object is *_M_storage._M_ptr
      auto __ptr = static_cast&lt;const _Tp*&gt;(__any-&gt;_M_storage._M_ptr);
      switch (__which)
      {
      case _Op_access:
	__arg-&gt;_M_obj = const_cast&lt;_Tp*&gt;(__ptr);
	break;
      case _Op_get_type_info:
#if __cpp_rtti
	__arg-&gt;_M_typeinfo = &amp;typeid(_Tp);
#endif
	break;
      case _Op_clone:
	__arg-&gt;_M_any-&gt;_M_storage._M_ptr = new _Tp(*__ptr);
	__arg-&gt;_M_any-&gt;_M_manager = __any-&gt;_M_manager;
	break;
      case _Op_destroy:
	delete __ptr;
	break;
      case _Op_xfer:
	__arg-&gt;_M_any-&gt;_M_storage._M_ptr = __any-&gt;_M_storage._M_ptr;
	__arg-&gt;_M_any-&gt;_M_manager = __any-&gt;_M_manager;
	const_cast&lt;any*&gt;(__any)-&gt;_M_manager = nullptr;
	break;
      }
    }

  // Dummy specialization used by __any_caster.
  template&lt;&gt;
    struct any::_Manager_internal&lt;any::_Op&gt;
    {
      static void
      _S_manage(_Op, const any*, _Arg*) { }
    };

  // @} group any
} // namespace fundamentals_v1
} // namespace experimental

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // C++14

#endif // _GLIBCXX_EXPERIMENTAL_ANY
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