libstdc++-v3/include/bits/allocator.h - gcc - Git at Google

 // Allocators -*- C++ -*-

 // Copyright (C) 2001-2022 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
 // <http://www.gnu.org/licenses/>.

 /*
  * Copyright (c) 1996-1997
  * Silicon Graphics Computer Systems, Inc.
  *
  * Permission to use, copy, modify, distribute and sell this software
  * and its documentation for any purpose is hereby granted without fee,
  * provided that the above copyright notice appear in all copies and
  * that both that copyright notice and this permission notice appear
  * in supporting documentation.  Silicon Graphics makes no
  * representations about the suitability of this software for any
  * purpose.  It is provided "as is" without express or implied warranty.
  */

 /** @file bits/allocator.h
  *  This is an internal header file, included by other library headers.
  *  Do not attempt to use it directly. @headername{memory}
  */

 #ifndef _ALLOCATOR_H
 #define _ALLOCATOR_H 1

 #include <bits/c++allocator.h> // Define the base class to std::allocator.
 #include <bits/memoryfwd.h>
 #if __cplusplus >= 201103L
 #include <type_traits>
 #endif

 #define __cpp_lib_incomplete_container_elements 201505L

 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION

   /**
    *  @addtogroup allocators
    *  @{
    */

   // Since C++20 the primary template should be used for allocator<void>,
   // but then it would have a non-trivial default ctor and dtor for C++20,
   // but trivial for C++98-17, which would be an ABI incompatibiliy between
   // different standard dialects. So C++20 still uses the allocator<void>
   // explicit specialization, with the historical ABI properties, but with
   // the same members that are present in the primary template.

   /** std::allocator<void> specialization.
    *
    * @headerfile memory
    */
   template<>
     class allocator<void>
     {
     public:
       typedef void        value_type;
       typedef size_t      size_type;
       typedef ptrdiff_t   difference_type;

 #if __cplusplus <= 201703L
       // These were removed for C++20, allocator_traits does the right thing.
       typedef void*       pointer;
       typedef const void* const_pointer;

       template<typename _Tp1>
 	struct rebind
 	{ typedef allocator<_Tp1> other; };
 #endif

 #if __cplusplus >= 201103L
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 2103. std::allocator propagate_on_container_move_assignment
       using propagate_on_container_move_assignment = true_type;

       using is_always_equal
 	_GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal")
 	= true_type;

 #if __cplusplus >= 202002L
       // As noted above, these members are present for C++20 to provide the
       // same API as the primary template, but still trivial as in pre-C++20.
       allocator() = default;
       ~allocator() = default;

       template<typename _Up>
 	__attribute__((__always_inline__))
 	constexpr
 	allocator(const allocator<_Up>&) noexcept { }

       // No allocate member because it's ill-formed by LWG 3307.
       // No deallocate member because it would be undefined to call it
       // with any pointer which wasn't obtained from allocate.
 #endif // C++20
 #endif // C++11
     };

   /**
    * @brief  The @a standard allocator, as per C++03 [20.4.1].
    *
    *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator
    *  for further details.
    *
    *  @tparam  _Tp  Type of allocated object.
    *
    *  @headerfile memory
    */
   template<typename _Tp>
     class allocator : public __allocator_base<_Tp>
     {
     public:
       typedef _Tp        value_type;
       typedef size_t     size_type;
       typedef ptrdiff_t  difference_type;

 #if __cplusplus <= 201703L
       // These were removed for C++20.
       typedef _Tp*       pointer;
       typedef const _Tp* const_pointer;
       typedef _Tp&       reference;
       typedef const _Tp& const_reference;

       template<typename _Tp1>
 	struct rebind
 	{ typedef allocator<_Tp1> other; };
 #endif

 #if __cplusplus >= 201103L
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 2103. std::allocator propagate_on_container_move_assignment
       using propagate_on_container_move_assignment = true_type;

       using is_always_equal
 	_GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal")
 	= true_type;
 #endif

       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 3035. std::allocator's constructors should be constexpr
       __attribute__((__always_inline__))
       _GLIBCXX20_CONSTEXPR
       allocator() _GLIBCXX_NOTHROW { }

       __attribute__((__always_inline__))
       _GLIBCXX20_CONSTEXPR
       allocator(const allocator& __a) _GLIBCXX_NOTHROW
       : __allocator_base<_Tp>(__a) { }

 #if __cplusplus >= 201103L
       // Avoid implicit deprecation.
       allocator& operator=(const allocator&) = default;
 #endif

       template<typename _Tp1>
 	__attribute__((__always_inline__))
 	_GLIBCXX20_CONSTEXPR
 	allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { }

       __attribute__((__always_inline__))
 #if __cpp_constexpr_dynamic_alloc
       constexpr
 #endif
       ~allocator() _GLIBCXX_NOTHROW { }

 #if __cplusplus > 201703L
       [[nodiscard,__gnu__::__always_inline__]]
       constexpr _Tp*
       allocate(size_t __n)
       {
 	if (std::__is_constant_evaluated())
 	  {
 	    if (__builtin_mul_overflow(__n, sizeof(_Tp), &__n))
 	      std::__throw_bad_array_new_length();
 	    return static_cast<_Tp*>(::operator new(__n));
 	  }

 	return __allocator_base<_Tp>::allocate(__n, 0);
       }

       [[__gnu__::__always_inline__]]
       constexpr void
       deallocate(_Tp* __p, size_t __n)
       {
 	if (std::__is_constant_evaluated())
 	  {
 	    ::operator delete(__p);
 	    return;
 	  }
 	__allocator_base<_Tp>::deallocate(__p, __n);
       }
 #endif // C++20

       friend __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
       bool
       operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW
       { return true; }

 #if __cpp_impl_three_way_comparison < 201907L
       friend __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
       bool
       operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW
       { return false; }
 #endif

       // Inherit everything else.
     };

   /** Equality comparison for std::allocator objects
    *
    * @return true, for all std::allocator objects.
    * @relates std::allocator
    */
   template<typename _T1, typename _T2>
     __attribute__((__always_inline__))
     inline _GLIBCXX20_CONSTEXPR bool
     operator==(const allocator<_T1>&, const allocator<_T2>&)
     _GLIBCXX_NOTHROW
     { return true; }

 #if __cpp_impl_three_way_comparison < 201907L
   template<typename _T1, typename _T2>
     __attribute__((__always_inline__))
     inline _GLIBCXX20_CONSTEXPR bool
     operator!=(const allocator<_T1>&, const allocator<_T2>&)
     _GLIBCXX_NOTHROW
     { return false; }
 #endif

   /// @cond undocumented

   // Invalid allocator<cv T> partial specializations.
   // allocator_traits::rebind_alloc can be used to form a valid allocator type.
   template<typename _Tp>
     class allocator<const _Tp>
     {
     public:
       typedef _Tp value_type;
       template<typename _Up> allocator(const allocator<_Up>&) { }
     };

   template<typename _Tp>
     class allocator<volatile _Tp>
     {
     public:
       typedef _Tp value_type;
       template<typename _Up> allocator(const allocator<_Up>&) { }
     };

   template<typename _Tp>
     class allocator<const volatile _Tp>
     {
     public:
       typedef _Tp value_type;
       template<typename _Up> allocator(const allocator<_Up>&) { }
     };
   /// @endcond

   /// @} group allocator

   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class allocator<char>;
   extern template class allocator<wchar_t>;
 #endif

   // Undefine.
 #undef __allocator_base

 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std

 #endif
	// Allocators -- C++ --

	// Copyright (C) 2001-2022 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
	// <http://www.gnu.org/licenses/>.

	/*
	* Copyright (c) 1996-1997
	* Silicon Graphics Computer Systems, Inc.
	*
	* Permission to use, copy, modify, distribute and sell this software
	* and its documentation for any purpose is hereby granted without fee,
	* provided that the above copyright notice appear in all copies and
	* that both that copyright notice and this permission notice appear
	* in supporting documentation. Silicon Graphics makes no
	* representations about the suitability of this software for any
	* purpose. It is provided "as is" without express or implied warranty.
	*/

	/** @file bits/allocator.h
	* This is an internal header file, included by other library headers.
	* Do not attempt to use it directly. @headername{memory}
	*/

	#ifndef _ALLOCATOR_H
	#define _ALLOCATOR_H 1

	#include <bits/c++allocator.h> // Define the base class to std::allocator.
	#include <bits/memoryfwd.h>
	#if __cplusplus >= 201103L
	#include <type_traits>
	#endif

	#define __cpp_lib_incomplete_container_elements 201505L

	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION

	/**
	* @addtogroup allocators
	* @{
	*/

	// Since C++20 the primary template should be used for allocator<void>,
	// but then it would have a non-trivial default ctor and dtor for C++20,
	// but trivial for C++98-17, which would be an ABI incompatibiliy between
	// different standard dialects. So C++20 still uses the allocator<void>
	// explicit specialization, with the historical ABI properties, but with
	// the same members that are present in the primary template.

	/** std::allocator<void> specialization.
	*
	* @headerfile memory
	*/
	template<>
	class allocator<void>
	{
	public:
	typedef void value_type;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;

	#if __cplusplus <= 201703L
	// These were removed for C++20, allocator_traits does the right thing.
	typedef void* pointer;
	typedef const void* const_pointer;

	template<typename _Tp1>
	struct rebind
	{ typedef allocator<_Tp1> other; };
	#endif

	#if __cplusplus >= 201103L
	// _GLIBCXX_RESOLVE_LIB_DEFECTS
	// 2103. std::allocator propagate_on_container_move_assignment
	using propagate_on_container_move_assignment = true_type;

	using is_always_equal
	_GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal")
	= true_type;

	#if __cplusplus >= 202002L
	// As noted above, these members are present for C++20 to provide the
	// same API as the primary template, but still trivial as in pre-C++20.
	allocator() = default;
	~allocator() = default;

	template<typename _Up>
	__attribute__((__always_inline__))
	constexpr
	allocator(const allocator<_Up>&) noexcept { }

	// No allocate member because it's ill-formed by LWG 3307.
	// No deallocate member because it would be undefined to call it
	// with any pointer which wasn't obtained from allocate.
	#endif // C++20
	#endif // C++11
	};

	/**
	* @brief The @a standard allocator, as per C++03 [20.4.1].
	*
	* See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator
	* for further details.
	*
	* @tparam _Tp Type of allocated object.
	*
	* @headerfile memory
	*/
	template<typename _Tp>
	class allocator : public __allocator_base<_Tp>
	{
	public:
	typedef _Tp value_type;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;

	#if __cplusplus <= 201703L
	// These were removed for C++20.
	typedef _Tp* pointer;
	typedef const _Tp* const_pointer;
	typedef _Tp& reference;
	typedef const _Tp& const_reference;

	template<typename _Tp1>
	struct rebind
	{ typedef allocator<_Tp1> other; };
	#endif

	#if __cplusplus >= 201103L
	// _GLIBCXX_RESOLVE_LIB_DEFECTS
	// 2103. std::allocator propagate_on_container_move_assignment
	using propagate_on_container_move_assignment = true_type;

	using is_always_equal
	_GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal")
	= true_type;
	#endif

	// _GLIBCXX_RESOLVE_LIB_DEFECTS
	// 3035. std::allocator's constructors should be constexpr
	__attribute__((__always_inline__))
	_GLIBCXX20_CONSTEXPR
	allocator() _GLIBCXX_NOTHROW { }

	__attribute__((__always_inline__))
	_GLIBCXX20_CONSTEXPR
	allocator(const allocator& __a) _GLIBCXX_NOTHROW
	: __allocator_base<_Tp>(__a) { }

	#if __cplusplus >= 201103L
	// Avoid implicit deprecation.
	allocator& operator=(const allocator&) = default;
	#endif

	template<typename _Tp1>
	__attribute__((__always_inline__))
	_GLIBCXX20_CONSTEXPR
	allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { }

	__attribute__((__always_inline__))
	#if __cpp_constexpr_dynamic_alloc
	constexpr
	#endif
	~allocator() _GLIBCXX_NOTHROW { }

	#if __cplusplus > 201703L
	[[nodiscard,__gnu__::__always_inline__]]
	constexpr _Tp*
	allocate(size_t __n)
	{
	if (std::__is_constant_evaluated())
	{
	if (__builtin_mul_overflow(__n, sizeof(_Tp), &__n))
	std::__throw_bad_array_new_length();
	return static_cast<_Tp*>(::operator new(__n));
	}

	return __allocator_base<_Tp>::allocate(__n, 0);
	}

	[[__gnu__::__always_inline__]]
	constexpr void
	deallocate(_Tp* __p, size_t __n)
	{
	if (std::__is_constant_evaluated())
	{
	::operator delete(__p);
	return;
	}
	__allocator_base<_Tp>::deallocate(__p, __n);
	}
	#endif // C++20

	friend __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
	bool
	operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW
	{ return true; }

	#if __cpp_impl_three_way_comparison < 201907L
	friend __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
	bool
	operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW
	{ return false; }
	#endif

	// Inherit everything else.
	};

	/** Equality comparison for std::allocator objects
	*
	* @return true, for all std::allocator objects.
	* @relates std::allocator
	*/
	template<typename _T1, typename _T2>
	__attribute__((__always_inline__))
	inline _GLIBCXX20_CONSTEXPR bool
	operator==(const allocator<_T1>&, const allocator<_T2>&)
	_GLIBCXX_NOTHROW
	{ return true; }

	#if __cpp_impl_three_way_comparison < 201907L
	template<typename _T1, typename _T2>
	__attribute__((__always_inline__))
	inline _GLIBCXX20_CONSTEXPR bool
	operator!=(const allocator<_T1>&, const allocator<_T2>&)
	_GLIBCXX_NOTHROW
	{ return false; }
	#endif

	/// @cond undocumented

	// Invalid allocator<cv T> partial specializations.
	// allocator_traits::rebind_alloc can be used to form a valid allocator type.
	template<typename _Tp>
	class allocator<const _Tp>
	{
	public:
	typedef _Tp value_type;
	template<typename _Up> allocator(const allocator<_Up>&) { }
	};

	template<typename _Tp>
	class allocator<volatile _Tp>
	{
	public:
	typedef _Tp value_type;
	template<typename _Up> allocator(const allocator<_Up>&) { }
	};

	template<typename _Tp>
	class allocator<const volatile _Tp>
	{
	public:
	typedef _Tp value_type;
	template<typename _Up> allocator(const allocator<_Up>&) { }
	};
	/// @endcond

	/// @} group allocator

	// Inhibit implicit instantiations for required instantiations,
	// which are defined via explicit instantiations elsewhere.
	#if _GLIBCXX_EXTERN_TEMPLATE
	extern template class allocator<char>;
	extern template class allocator<wchar_t>;
	#endif

	// Undefine.
	#undef __allocator_base

	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace std

	#endif