# array_allocator.h

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    00001 // array allocator -*- C++ -*-
    00002
    00003 // Copyright (C) 2004, 2005, 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    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/array_allocator.h
    00031  *  This file is a GNU extension to the Standard C++ Library.
    00032  */
    00033
    00034 #ifndef _ARRAY_ALLOCATOR_H
    00035 #define _ARRAY_ALLOCATOR_H 1
    00036
    00037 #include <cstddef>
    00038 #include <new>
    00039 #include <bits/functexcept.h>
    00040 #include <tr1/array>
    00041
    00042 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00043
    00044  using std::size_t;
    00045  using std::ptrdiff_t;
    00046
    00047   /// @brief  Base class.
    00048  template<typename _Tp>
    00049     class array_allocator_base
    00050     {
    00051     public:
    00052       typedef size_t        size_type;
    00053       typedef ptrdiff_t     difference_type;
    00054       typedef _Tp*          pointer;
    00055       typedef const _Tp*    const_pointer;
    00056       typedef _Tp&          reference;
    00057       typedef const _Tp&    const_reference;
    00058       typedef _Tp           value_type;
    00059
    00060       pointer
    00061       address(reference __x) const { return &__x; }
    00062
    00063       const_pointer
    00064       address(const_reference __x) const { return &__x; }
    00065
    00066       void
    00067       deallocate(pointer, size_type)
    00068       {
    00069     // Does nothing.
    00070       }
    00071
    00072       size_type
    00073       max_size() const throw()
    00074       { return size_t(-1) / sizeof(_Tp); }
    00075
    00076       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00077       // 402. wrong new expression in [some_] allocator::construct
    00078       void
    00079       construct(pointer __p, const _Tp& __val)
    00080       { ::new(__p) value_type(__val); }
    00081
    00082       void
    00083       destroy(pointer __p) { __p->~_Tp(); }
    00084     };
    00085
    00086   /**
    00087    *  @brief  An allocator that uses previously allocated memory.
    00088    *  This memory can be externally, globally, or otherwise allocated.
    00089    */
    00090   template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
    00091     class array_allocator : public array_allocator_base<_Tp>
    00092     {
    00093     public:
    00094       typedef size_t        size_type;
    00095       typedef ptrdiff_t     difference_type;
    00096       typedef _Tp*          pointer;
    00097       typedef const _Tp*    const_pointer;
    00098       typedef _Tp&          reference;
    00099       typedef const _Tp&    const_reference;
    00100       typedef _Tp           value_type;
    00101       typedef _Array        array_type;
    00102
    00103     private:
    00104       array_type*   _M_array;
    00105       size_type     _M_used;
    00106
    00107     public:
    00108      template<typename _Tp1, typename _Array1 = _Array>
    00109         struct rebind
    00110         { typedef array_allocator<_Tp1, _Array1> other; };
    00111
    00112       array_allocator(array_type* __array = NULL) throw()
    00113       : _M_array(__array), _M_used(size_type()) { }
    00114
    00115       array_allocator(const array_allocator& __o)  throw()
    00116       : _M_array(__o._M_array), _M_used(__o._M_used) { }
    00117
    00118       template<typename _Tp1, typename _Array1>
    00119         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
    00120     : _M_array(NULL), _M_used(size_type()) { }
    00121
    00122       ~array_allocator() throw() { }
    00123
    00124       pointer
    00125       allocate(size_type __n, const void* = 0)
    00126       {
    00127     if (_M_array == 0 || _M_used + __n > _M_array->size())
    00128       std::__throw_bad_alloc();
    00129     pointer __ret = _M_array->begin() + _M_used;
    00130     _M_used += __n;
    00131     return __ret;
    00132       }
    00133     };
    00134
    00135   template<typename _Tp, typename _Array>
    00136     inline bool
    00137     operator==(const array_allocator<_Tp, _Array>&,
    00138            const array_allocator<_Tp, _Array>&)
    00139     { return true; }
    00140
    00141   template<typename _Tp, typename _Array>
    00142     inline bool
    00143     operator!=(const array_allocator<_Tp, _Array>&,
    00144            const array_allocator<_Tp, _Array>&)
    00145     { return false; }
    00146
    00147 _GLIBCXX_END_NAMESPACE
    00148
    00149 #endif