# 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
    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 2, 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 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 /** @file ext/malloc_allocator.h
    00032  *  This file is a GNU extension to the Standard C++ Library.
    00033  */
    00034
    00035 #ifndef _MALLOC_ALLOCATOR_H
    00036 #define _MALLOC_ALLOCATOR_H 1
    00037
    00038 #include <cstdlib>
    00039 #include <new>
    00040 #include <bits/functexcept.h>
    00041 #include <bits/stl_move.h>
    00042
    00043 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00044
    00045   using std::size_t;
    00046   using std::ptrdiff_t;
    00047
    00048   /**
    00049    *  @brief  An allocator that uses malloc.
    00050    *
    00051    *  This is precisely the allocator defined in the C++ Standard.
    00052    *    - all allocation calls malloc
    00053    *    - all deallocation calls free
    00054    */
    00055   template<typename _Tp>
    00056     class malloc_allocator
    00057     {
    00058     public:
    00059       typedef size_t     size_type;
    00060       typedef ptrdiff_t  difference_type;
    00061       typedef _Tp*       pointer;
    00062       typedef const _Tp* const_pointer;
    00063       typedef _Tp&       reference;
    00064       typedef const _Tp& const_reference;
    00065       typedef _Tp        value_type;
    00066
    00067       template<typename _Tp1>
    00068         struct rebind
    00069         { typedef malloc_allocator<_Tp1> other; };
    00070
    00071       malloc_allocator() throw() { }
    00072
    00073       malloc_allocator(const malloc_allocator&) throw() { }
    00074
    00075       template<typename _Tp1>
    00076         malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
    00077
    00078       ~malloc_allocator() throw() { }
    00079
    00080       pointer
    00081       address(reference __x) const { return &__x; }
    00082
    00083       const_pointer
    00084       address(const_reference __x) const { return &__x; }
    00085
    00086       // NB: __n is permitted to be 0.  The C++ standard says nothing
    00087       // about what the return value is when __n == 0.
    00088       pointer
    00089       allocate(size_type __n, const void* = 0)
    00090       {
    00091     if (__builtin_expect(__n > this->max_size(), false))
    00092       std::__throw_bad_alloc();
    00093
    00094     pointer __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
    00095     if (!__ret)
    00096       std::__throw_bad_alloc();
    00097     return __ret;
    00098       }
    00099
    00100       // __p is not permitted to be a null pointer.
    00101       void
    00102       deallocate(pointer __p, size_type)
    00103       { std::free(static_cast<void*>(__p)); }
    00104
    00105       size_type
    00106       max_size() const throw()
    00107       { return size_t(-1) / sizeof(_Tp); }
    00108
    00109       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00110       // 402. wrong new expression in [some_] allocator::construct
    00111       void
    00112       construct(pointer __p, const _Tp& __val)
    00113       { ::new((void *)__p) value_type(__val); }
    00114
    00115 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00116       template<typename... _Args>
    00117         void
    00118         construct(pointer __p, _Args&&... __args)
    00119     { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
    00120 #endif
    00121
    00122       void
    00123       destroy(pointer __p) { __p->~_Tp(); }
    00124     };
    00125
    00126   template<typename _Tp>
    00127     inline bool
    00128     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
    00129     { return true; }
    00130
    00131   template<typename _Tp>
    00132     inline bool
    00133     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
    00134     { return false; }
    00135
    00136 _GLIBCXX_END_NAMESPACE
    00137
    00138 #endif