# malloc_allocator.h

Go to the documentation of this file.

    00001 // Allocator that wraps "C" malloc -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 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/malloc_allocator.h
    00027  *  This file is a GNU extension to the Standard C++ Library.
    00028  */
    00029
    00030 #ifndef _MALLOC_ALLOCATOR_H
    00031 #define _MALLOC_ALLOCATOR_H 1
    00032
    00033 #include <cstdlib>
    00034 #include <new>
    00035 #include <bits/functexcept.h>
    00036 #include <bits/move.h>
    00037
    00038 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00039
    00040   using std::size_t;
    00041   using std::ptrdiff_t;
    00042
    00043   /**
    00044    *  @brief  An allocator that uses malloc.
    00045    *  @ingroup allocators
    00046    *
    00047    *  This is precisely the allocator defined in the C++ Standard.
    00048    *    - all allocation calls malloc
    00049    *    - all deallocation calls free
    00050    */
    00051   template<typename _Tp>
    00052     class malloc_allocator
    00053     {
    00054     public:
    00055       typedef size_t     size_type;
    00056       typedef ptrdiff_t  difference_type;
    00057       typedef _Tp*       pointer;
    00058       typedef const _Tp* const_pointer;
    00059       typedef _Tp&       reference;
    00060       typedef const _Tp& const_reference;
    00061       typedef _Tp        value_type;
    00062
    00063       template<typename _Tp1>
    00064         struct rebind
    00065         { typedef malloc_allocator<_Tp1> other; };
    00066
    00067       malloc_allocator() throw() { }
    00068
    00069       malloc_allocator(const malloc_allocator&) throw() { }
    00070
    00071       template<typename _Tp1>
    00072         malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
    00073
    00074       ~malloc_allocator() throw() { }
    00075
    00076       pointer
    00077       address(reference __x) const { return &__x; }
    00078
    00079       const_pointer
    00080       address(const_reference __x) const { return &__x; }
    00081
    00082       // NB: __n is permitted to be 0.  The C++ standard says nothing
    00083       // about what the return value is when __n == 0.
    00084       pointer
    00085       allocate(size_type __n, const void* = 0)
    00086       {
    00087     if (__n > this->max_size())
    00088       std::__throw_bad_alloc();
    00089
    00090     pointer __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
    00091     if (!__ret)
    00092       std::__throw_bad_alloc();
    00093     return __ret;
    00094       }
    00095
    00096       // __p is not permitted to be a null pointer.
    00097       void
    00098       deallocate(pointer __p, size_type)
    00099       { std::free(static_cast<void*>(__p)); }
    00100
    00101       size_type
    00102       max_size() const throw()
    00103       { return size_t(-1) / sizeof(_Tp); }
    00104
    00105       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00106       // 402. wrong new expression in [some_] allocator::construct
    00107       void
    00108       construct(pointer __p, const _Tp& __val)
    00109       { ::new((void *)__p) value_type(__val); }
    00110
    00111 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00112       template<typename... _Args>
    00113         void
    00114         construct(pointer __p, _Args&&... __args)
    00115     { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
    00116 #endif
    00117
    00118       void
    00119       destroy(pointer __p) { __p->~_Tp(); }
    00120     };
    00121
    00122   template<typename _Tp>
    00123     inline bool
    00124     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
    00125     { return true; }
    00126
    00127   template<typename _Tp>
    00128     inline bool
    00129     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
    00130     { return false; }
    00131
    00132 _GLIBCXX_END_NAMESPACE
    00133
    00134 #endif