# 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 Free Software Foundation, Inc.
    00004 //
    00005 // This file is part of the GNU ISO C++ Library.  This library is free
    00006 // software; you can redistribute it and/or modify it under the
    00007 // terms of the GNU General Public License as published by the
    00008 // Free Software Foundation; either version 2, or (at your option)
    00009 // any later version.
    00010
    00011 // This library is distributed in the hope that it will be useful,
    00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00014 // GNU General Public License for more details.
    00015
    00016 // You should have received a copy of the GNU General Public License along
    00017 // with this library; see the file COPYING.  If not, write to the Free
    00018 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    00019 // USA.
    00020
    00021 // As a special exception, you may use this file as part of a free software
    00022 // library without restriction.  Specifically, if other files instantiate
    00023 // templates or use macros or inline functions from this file, or you compile
    00024 // this file and link it with other files to produce an executable, this
    00025 // file does not by itself cause the resulting executable to be covered by
    00026 // the GNU General Public License.  This exception does not however
    00027 // invalidate any other reasons why the executable file might be covered by
    00028 // the GNU General Public License.
    00029
    00030 /** @file ext/malloc_allocator.h
    00031  *  This file is a GNU extension to the Standard C++ Library.
    00032  */
    00033
    00034 #ifndef _MALLOC_ALLOCATOR_H
    00035 #define _MALLOC_ALLOCATOR_H 1
    00036
    00037 #include <cstdlib>
    00038 #include <new>
    00039 #include <bits/functexcept.h>
    00040
    00041 namespace __gnu_cxx
    00042 {
    00043   /**
    00044    *  @brief  An allocator that uses malloc.
    00045    *
    00046    *  This is precisely the allocator defined in the C++ Standard.
    00047    *    - all allocation calls malloc
    00048    *    - all deallocation calls free
    00049    */
    00050   template<typename _Tp>
    00051     class malloc_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 malloc_allocator<_Tp1> other; };
    00065
    00066       malloc_allocator() throw() { }
    00067
    00068       malloc_allocator(const malloc_allocator&) throw() { }
    00069
    00070       template<typename _Tp1>
    00071         malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
    00072
    00073       ~malloc_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     pointer __ret = static_cast<_Tp*>(malloc(__n * sizeof(_Tp)));
    00090     if (!__ret)
    00091       std::__throw_bad_alloc();
    00092     return __ret;
    00093       }
    00094
    00095       // __p is not permitted to be a null pointer.
    00096       void
    00097       deallocate(pointer __p, size_type)
    00098       { free(static_cast<void*>(__p)); }
    00099
    00100       size_type
    00101       max_size() const throw()
    00102       { return size_t(-1) / sizeof(_Tp); }
    00103
    00104       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00105       // 402. wrong new expression in [some_] allocator::construct
    00106       void
    00107       construct(pointer __p, const _Tp& __val)
    00108       { ::new(__p) value_type(__val); }
    00109
    00110       void
    00111       destroy(pointer __p) { __p->~_Tp(); }
    00112     };
    00113
    00114   template<typename _Tp>
    00115     inline bool
    00116     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
    00117     { return true; }
    00118
    00119   template<typename _Tp>
    00120     inline bool
    00121     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
    00122     { return false; }
    00123 } // namespace __gnu_cxx
    00124
    00125 #endif