libstdc++-v3/include/std/std_memory.h

   1 // <memory> -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002 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 /*
  31  * Copyright (c) 1997-1999
  32  * Silicon Graphics Computer Systems, Inc.
  33  *
  34  * Permission to use, copy, modify, distribute and sell this software
  35  * and its documentation for any purpose is hereby granted without fee,
  36  * provided that the above copyright notice appear in all copies and
  37  * that both that copyright notice and this permission notice appear
  38  * in supporting documentation.  Silicon Graphics makes no
  39  * representations about the suitability of this software for any
  40  * purpose.  It is provided "as is" without express or implied warranty.
  41  *
  42  */
  43
  44 /** @file memory
  45  *  This is a Standard C++ Library header.  You should @c #include this header
  46  *  in your programs, rather than any of the "st[dl]_*.h" implementation files.
  47  */
  48
  49 #ifndef _CPP_MEMORY
  50 #define _CPP_MEMORY 1
  51
  52 #pragma GCC system_header
  53
  54 #include <bits/stl_algobase.h>
  55 #include <bits/stl_alloc.h>
  56 #include <bits/stl_construct.h>
  57 #include <bits/stl_iterator_base_types.h> //for iterator_traits
  58 #include <bits/stl_uninitialized.h>
  59 #include <bits/stl_raw_storage_iter.h>
  60
  61 namespace std
  62 {
  63
  64   /**
  65    *  @maint
  66    *  This is a helper function.  The unused second parameter exists to
  67    *  permit the real get_temporary_buffer to use template parameter deduction.
  68    *  @endmaint
  69   */
  70   template <class _Tp>
  71   pair<_Tp*, ptrdiff_t>
  72   __get_temporary_buffer(ptrdiff_t __len, _Tp*)
  73   {
  74     if (__len > ptrdiff_t(INT_MAX / sizeof(_Tp)))
  75       __len = INT_MAX / sizeof(_Tp);
  76
  77     while (__len > 0) {
  78       _Tp* __tmp = (_Tp*) std::malloc((std::size_t)__len * sizeof(_Tp));
  79       if (__tmp != 0)
  80         return pair<_Tp*, ptrdiff_t>(__tmp, __len);
  81       __len /= 2;
  82     }
  83
  84     return pair<_Tp*, ptrdiff_t>((_Tp*)0, 0);
  85   }
  86
  87   /**
  88    *  @brief This is a mostly-useless wrapper around malloc().
  89    *  @param  len  The number of objects of type Tp.
  90    *  @return   See full description.
  91    *
  92    *  Reinventing the wheel, but this time with prettier spokes!
  93    *
  94    *  This function tries to obtain storage for @c len adjacent Tp objects.
  95    *  The objects themselves are not constructed, of course.  A pair<> is
  96    *  returned containing "the buffer s address and capacity (in the units of
  97    *  sizeof(Tp)), or a pair of 0 values if no storage can be obtained."
  98    *  Note that the capacity obtained may be less than that requested if the
  99    *  memory is unavailable; you should compare len with the .second return
 100    *  value.
 101   */
 102   template <class _Tp>
 103   inline pair<_Tp*, ptrdiff_t> get_temporary_buffer(ptrdiff_t __len) {
 104     return __get_temporary_buffer(__len, (_Tp*) 0);
 105   }
 106
 107   /**
 108    *  @brief The companion to get_temporary_buffer().
 109    *  @param  p  A buffer previously allocated by get_temporary_buffer.
 110    *  @return   None.
 111    *
 112    *  Frees the memory pointed to by p.
 113    */
 114   template <class _Tp>
 115   void return_temporary_buffer(_Tp* __p) {
 116     std::free(__p);
 117   }
 118
 119
 120 template <class _Tp1>
 121   struct auto_ptr_ref
 122 {
 123    _Tp1* _M_ptr;
 124    auto_ptr_ref(_Tp1* __p) : _M_ptr(__p) {}
 125 };
 126
 127 /**
 128  *  A simple smart pointer providing strict ownership semantics.  (More later.)
 129 */
 130 template <class _Tp>
 131   class auto_ptr
 132 {
 133 private:
 134   _Tp* _M_ptr;
 135
 136 public:
 137   typedef _Tp element_type;
 138
 139   explicit auto_ptr(_Tp* __p = 0) throw() : _M_ptr(__p) {}
 140   auto_ptr(auto_ptr& __a) throw() : _M_ptr(__a.release()) {}
 141
 142   template <class _Tp1> auto_ptr(auto_ptr<_Tp1>& __a) throw()
 143     : _M_ptr(__a.release()) {}
 144
 145   auto_ptr& operator=(auto_ptr& __a) throw() {
 146     reset(__a.release());
 147     return *this;
 148   }
 149
 150   template <class _Tp1>
 151   auto_ptr& operator=(auto_ptr<_Tp1>& __a) throw() {
 152     reset(__a.release());
 153     return *this;
 154   }
 155
 156   // Note: The C++ standard says there is supposed to be an empty throw
 157   // specification here, but omitting it is standard conforming.  Its
 158   // presence can be detected only if _Tp::~_Tp() throws, but (17.4.3.6/2)
 159   // this is prohibited.
 160   ~auto_ptr() { delete _M_ptr; }
 161
 162   _Tp& operator*() const throw() {
 163     return *_M_ptr;
 164   }
 165   _Tp* operator->() const throw() {
 166     return _M_ptr;
 167   }
 168   _Tp* get() const throw() {
 169     return _M_ptr;
 170   }
 171   _Tp* release() throw() {
 172     _Tp* __tmp = _M_ptr;
 173     _M_ptr = 0;
 174     return __tmp;
 175   }
 176   void reset(_Tp* __p = 0) throw() {
 177     if (__p != _M_ptr) {
 178       delete _M_ptr;
 179       _M_ptr = __p;
 180     }
 181   }
 182
 183 public:
 184   auto_ptr(auto_ptr_ref<_Tp> __ref) throw()
 185     : _M_ptr(__ref._M_ptr) {}
 186
 187   auto_ptr& operator=(auto_ptr_ref<_Tp> __ref) throw() {
 188     if (__ref._M_ptr != this->get()) {
 189       delete _M_ptr;
 190       _M_ptr = __ref._M_ptr;
 191     }
 192     return *this;
 193   }
 194
 195   template <class _Tp1> operator auto_ptr_ref<_Tp1>() throw()
 196     { return auto_ptr_ref<_Tp>(this->release()); }
 197   template <class _Tp1> operator auto_ptr<_Tp1>() throw()
 198     { return auto_ptr<_Tp1>(this->release()); }
 199 };
 200
 201 } // namespace std
 202
 203 #endif /* _CPP_MEMORY */
 204
 205
 206 // Local Variables:
 207 // mode:C++
 208 // End: