libstdc++-v3/include/ext/array_allocator.h

   1 // array allocator -*- C++ -*-
   2
   3 // Copyright (C) 2004 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 #ifndef _ARRAY_ALLOCATOR_H
  31 #define _ARRAY_ALLOCATOR_H 1
  32
  33 #include <cstddef>
  34 #include <new>
  35 #include <bits/functexcept.h>
  36 #include <tr1/array>
  37
  38 namespace __gnu_cxx
  39 {
  40  template<typename _Tp>
  41     class array_allocator_base
  42     {
  43     public:
  44       typedef size_t     size_type;
  45       typedef ptrdiff_t  difference_type;
  46       typedef _Tp*       pointer;
  47       typedef const _Tp* const_pointer;
  48       typedef _Tp&       reference;
  49       typedef const _Tp& const_reference;
  50       typedef _Tp        value_type;
  51
  52       pointer
  53       address(reference __x) const { return &__x; }
  54
  55       const_pointer
  56       address(const_reference __x) const { return &__x; }
  57
  58       void
  59       deallocate(pointer, size_type)
  60       {
  61         // Does nothing.
  62       }
  63
  64       size_type
  65       max_size() const throw()
  66       { return size_t(-1) / sizeof(_Tp); }
  67
  68       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  69       // 402. wrong new expression in [some_] allocator::construct
  70       void
  71       construct(pointer __p, const _Tp& __val)
  72       { ::new(__p) value_type(__val); }
  73
  74       void
  75       destroy(pointer __p) { __p->~_Tp(); }
  76     };
  77
  78   /**
  79    *  @brief  An allocator that uses previously allocated memory.
  80    *  This memory can be externally, globally, or otherwise allocated.
  81    *
  82    *  (See @link Allocators allocators info @endlink for more.)
  83    */
  84   template<typename _Tp, typename _Array = std::tr1::array<_Tp> >
  85     class array_allocator : public array_allocator_base<_Tp>
  86     {
  87     public:
  88       typedef size_t     size_type;
  89       typedef ptrdiff_t  difference_type;
  90       typedef _Tp*       pointer;
  91       typedef const _Tp* const_pointer;
  92       typedef _Tp&       reference;
  93       typedef const _Tp& const_reference;
  94       typedef _Tp        value_type;
  95
  96       typedef _Array    array_type;
  97
  98       array_type* _M_array;
  99
 100      template<typename _Tp1, typename _Array1 = _Array>
 101         struct rebind
 102         { typedef array_allocator<_Tp1, _Array1> other; };
 103
 104       array_allocator(array_type* __array = NULL) throw()
 105       : _M_array(__array)
 106       { }
 107
 108       array_allocator(const array_allocator& __o)  throw()
 109       : _M_array(__o._M_array) { }
 110
 111       template<typename _Tp1, typename _Array1>
 112         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
 113         : _M_array(NULL) { }
 114
 115       ~array_allocator() throw() { }
 116
 117       pointer
 118       allocate(size_type __n, const void* = 0)
 119       {
 120         static size_type __used;
 121         if (_M_array == 0 || __used + __n > _M_array->size())
 122           std::__throw_bad_alloc();
 123         pointer __ret = _M_array->begin() + __used;
 124         __used += __n;
 125         return __ret;
 126       }
 127     };
 128
 129   template<typename _Tp, typename _Array>
 130     inline bool
 131     operator==(const array_allocator<_Tp, _Array>&,
 132                const array_allocator<_Tp, _Array>&)
 133     { return true; }
 134
 135   template<typename _Tp, typename _Array>
 136     inline bool
 137     operator!=(const array_allocator<_Tp, _Array>&,
 138                const array_allocator<_Tp, _Array>&)
 139     { return false; }
 140 } // namespace __gnu_cxx
 141
 142 #endif