# new_allocator.h

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    00001 // Allocator that wraps operator new -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 3, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // Under Section 7 of GPL version 3, you are granted additional
    00018 // permissions described in the GCC Runtime Library Exception, version
    00019 // 3.1, as published by the Free Software Foundation.
    00020
    00021 // You should have received a copy of the GNU General Public License and
    00022 // a copy of the GCC Runtime Library Exception along with this program;
    00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    00024 // <http://www.gnu.org/licenses/>.
    00025
    00026 /** @file ext/new_allocator.h
    00027  *  This file is a GNU extension to the Standard C++ Library.
    00028  */
    00029
    00030 #ifndef _NEW_ALLOCATOR_H
    00031 #define _NEW_ALLOCATOR_H 1
    00032
    00033 #include <new>
    00034 #include <bits/functexcept.h>
    00035 #include <bits/move.h>
    00036
    00037 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00038
    00039   using std::size_t;
    00040   using std::ptrdiff_t;
    00041
    00042   /**
    00043    *  @brief  An allocator that uses global new, as per [20.4].
    00044    *  @ingroup allocators
    00045    *
    00046    *  This is precisely the allocator defined in the C++ Standard.
    00047    *    - all allocation calls operator new
    00048    *    - all deallocation calls operator delete
    00049    */
    00050   template<typename _Tp>
    00051     class new_allocator
    00052     {
    00053     public:
    00054       typedef size_t     size_type;
    00055       typedef ptrdiff_t  difference_type;
    00056       typedef _Tp*       pointer;
    00057       typedef const _Tp* const_pointer;
    00058       typedef _Tp&       reference;
    00059       typedef const _Tp& const_reference;
    00060       typedef _Tp        value_type;
    00061
    00062       template<typename _Tp1>
    00063         struct rebind
    00064         { typedef new_allocator<_Tp1> other; };
    00065
    00066       new_allocator() throw() { }
    00067
    00068       new_allocator(const new_allocator&) throw() { }
    00069
    00070       template<typename _Tp1>
    00071         new_allocator(const new_allocator<_Tp1>&) throw() { }
    00072
    00073       ~new_allocator() throw() { }
    00074
    00075       pointer
    00076       address(reference __x) const { return &__x; }
    00077
    00078       const_pointer
    00079       address(const_reference __x) const { return &__x; }
    00080
    00081       // NB: __n is permitted to be 0.  The C++ standard says nothing
    00082       // about what the return value is when __n == 0.
    00083       pointer
    00084       allocate(size_type __n, const void* = 0)
    00085       {
    00086     if (__builtin_expect(__n > this->max_size(), false))
    00087       std::__throw_bad_alloc();
    00088
    00089     return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
    00090       }
    00091
    00092       // __p is not permitted to be a null pointer.
    00093       void
    00094       deallocate(pointer __p, size_type)
    00095       { ::operator delete(__p); }
    00096
    00097       size_type
    00098       max_size() const throw()
    00099       { return size_t(-1) / sizeof(_Tp); }
    00100
    00101       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00102       // 402. wrong new expression in [some_] allocator::construct
    00103       void
    00104       construct(pointer __p, const _Tp& __val)
    00105       { ::new((void *)__p) _Tp(__val); }
    00106
    00107 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00108       template<typename... _Args>
    00109         void
    00110         construct(pointer __p, _Args&&... __args)
    00111     { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
    00112 #endif
    00113
    00114       void
    00115       destroy(pointer __p) { __p->~_Tp(); }
    00116     };
    00117
    00118   template<typename _Tp>
    00119     inline bool
    00120     operator==(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
    00121     { return true; }
    00122
    00123   template<typename _Tp>
    00124     inline bool
    00125     operator!=(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
    00126     { return false; }
    00127
    00128 _GLIBCXX_END_NAMESPACE
    00129
    00130 #endif