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

// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

// 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 allocator.h

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 */

#ifndef _ALLOCATOR_H

#define _ALLOCATOR_H 1

// Define the base class to std::allocator.

#include <bits/c++allocator.h>

_GLIBCXX_BEGIN_NAMESPACE(std)

  /**

   * @defgroup allocators Allocators

   * @ingroup memory

   *

   * Classes encapsulating memory operations.

   */

  template<typename _Tp>

    class allocator;

  /// allocator<void> specialization.

  template<>

    class allocator<void>

    {

    public:

      typedef size_t      size_type;

      typedef ptrdiff_t   difference_type;

      typedef void*       pointer;

      typedef const void* const_pointer;

      typedef void        value_type;

      template<typename _Tp1>

        struct rebind

        { typedef allocator<_Tp1> other; };

    };

  /**

   * @brief  The @a standard allocator, as per [20.4].

   * @ingroup allocators

   *

   *  Further details:

   *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html

   */

  template<typename _Tp>

    class allocator: public __glibcxx_base_allocator<_Tp>

    {

   public:

      typedef size_t     size_type;

      typedef ptrdiff_t  difference_type;

      typedef _Tp*       pointer;

      typedef const _Tp* const_pointer;

      typedef _Tp&       reference;

      typedef const _Tp& const_reference;

      typedef _Tp        value_type;

      template<typename _Tp1>

        struct rebind

        { typedef allocator<_Tp1> other; };

      allocator() throw() { }

      allocator(const allocator& __a) throw()

      : __glibcxx_base_allocator<_Tp>(__a) { }

      template<typename _Tp1>

        allocator(const allocator<_Tp1>&) throw() { }

      ~allocator() throw() { }

      // Inherit everything else.

    };

  template<typename _T1, typename _T2>

    inline bool

    operator==(const allocator<_T1>&, const allocator<_T2>&)

    { return true; }

  template<typename _Tp>

    inline bool

    operator==(const allocator<_Tp>&, const allocator<_Tp>&)

    { return true; }

  template<typename _T1, typename _T2>

    inline bool

    operator!=(const allocator<_T1>&, const allocator<_T2>&)

    { return false; }

  template<typename _Tp>

    inline bool

    operator!=(const allocator<_Tp>&, const allocator<_Tp>&)

    { return false; }

  // Inhibit implicit instantiations for required instantiations,

  // which are defined via explicit instantiations elsewhere.

  // NB: This syntax is a GNU extension.

#if _GLIBCXX_EXTERN_TEMPLATE

  extern template class allocator<char>;

  extern template class allocator<wchar_t>;

#endif

  // Undefine.

#undef __glibcxx_base_allocator

  // To implement Option 3 of DR 431.

  template<typename _Alloc, bool = __is_empty(_Alloc)>

    struct __alloc_swap

    { static void _S_do_it(_Alloc&, _Alloc&) { } };

  template<typename _Alloc>

    struct __alloc_swap<_Alloc, false>

    {

      static void

      _S_do_it(_Alloc& __one, _Alloc& __two)

      {

        // Precondition: swappable allocators.

        if (__one != __two)

          swap(__one, __two);

      }

    };

  // Optimize for stateless allocators.

  template<typename _Alloc, bool = __is_empty(_Alloc)>

    struct __alloc_neq

    {

      static bool

      _S_do_it(const _Alloc&, const _Alloc&)

      { return false; }

    };

  template<typename _Alloc>

    struct __alloc_neq<_Alloc, false>

    {

      static bool

      _S_do_it(const _Alloc& __one, const _Alloc& __two)

      { return __one != __two; }

    };

#ifdef __GXX_EXPERIMENTAL_CXX0X__

   // A very basic implementation for now.  In general we have to wait for

   // the availability of the infrastructure described in N2983:  we should

   // try when either T has a move constructor which cannot throw or T is

   // CopyContructible.

   // NB: This code doesn't properly belong here, we should find a more

   // suited place common to std::vector and std::deque.

   template<typename _Tp,

            bool = __has_trivial_copy(typename _Tp::value_type)>

     struct __shrink_to_fit

     { static void _S_do_it(_Tp&) { } };

   template<typename _Tp>

     struct __shrink_to_fit<_Tp, true>

     {

       static void

       _S_do_it(_Tp& __v)

       {

         __try

           { _Tp(__v).swap(__v); }

         __catch(...) { }

       }

     };

#endif

_GLIBCXX_END_NAMESPACE

#endif