| // <memory> -*- C++ -*- |
| |
| // Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 2, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING. If not, write to the Free |
| // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
| // USA. |
| |
| // As a special exception, you may use this file as part of a free software |
| // library without restriction. Specifically, if other files instantiate |
| // templates or use macros or inline functions from this file, or you compile |
| // this file and link it with other files to produce an executable, this |
| // file does not by itself cause the resulting executable to be covered by |
| // the GNU General Public License. This exception does not however |
| // invalidate any other reasons why the executable file might be covered by |
| // the GNU General Public License. |
| |
| /* |
| * Copyright (c) 1997-1999 |
| * Silicon Graphics Computer Systems, Inc. |
| * |
| * Permission to use, copy, modify, distribute and sell this software |
| * and its documentation for any purpose is hereby granted without fee, |
| * provided that the above copyright notice appear in all copies and |
| * that both that copyright notice and this permission notice appear |
| * in supporting documentation. Silicon Graphics makes no |
| * representations about the suitability of this software for any |
| * purpose. It is provided "as is" without express or implied warranty. |
| * |
| */ |
| |
| /** @file memory |
| * This is a Standard C++ Library header. You should @c #include this header |
| * in your programs, rather than any of the "st[dl]_*.h" implementation files. |
| */ |
| |
| #ifndef _GLIBCXX_MEMORY |
| #define _GLIBCXX_MEMORY 1 |
| |
| #pragma GCC system_header |
| |
| #include <bits/stl_algobase.h> |
| #include <bits/allocator.h> |
| #include <bits/stl_construct.h> |
| #include <bits/stl_iterator_base_types.h> //for iterator_traits |
| #include <bits/stl_uninitialized.h> |
| #include <bits/stl_raw_storage_iter.h> |
| #include <debug/debug.h> |
| |
| namespace std |
| { |
| /** |
| * @if maint |
| * This is a helper function. The unused second parameter exists to |
| * permit the real get_temporary_buffer to use template parameter deduction. |
| * |
| * XXX This should perhaps use the pool. |
| * @endif |
| */ |
| template<typename _Tp> |
| pair<_Tp*, ptrdiff_t> |
| __get_temporary_buffer(ptrdiff_t __len, _Tp*) |
| { |
| if (__len > ptrdiff_t(INT_MAX / sizeof(_Tp))) |
| __len = INT_MAX / sizeof(_Tp); |
| |
| while (__len > 0) |
| { |
| _Tp* __tmp = static_cast<_Tp*>(::operator new(__len * sizeof(_Tp), |
| nothrow)); |
| if (__tmp != 0) |
| return pair<_Tp*, ptrdiff_t>(__tmp, __len); |
| __len /= 2; |
| } |
| return pair<_Tp*, ptrdiff_t>(static_cast<_Tp*>(0), 0); |
| } |
| |
| /** |
| * @brief Allocates a temporary buffer. |
| * @param len The number of objects of type Tp. |
| * @return See full description. |
| * |
| * Reinventing the wheel, but this time with prettier spokes! |
| * |
| * This function tries to obtain storage for @c len adjacent Tp |
| * objects. The objects themselves are not constructed, of course. |
| * A pair<> is returned containing "the buffer s address and |
| * capacity (in the units of sizeof(Tp)), or a pair of 0 values if |
| * no storage can be obtained." Note that the capacity obtained |
| * may be less than that requested if the memory is unavailable; |
| * you should compare len with the .second return value. |
| * |
| * Provides the nothrow exception guarantee. |
| */ |
| template<typename _Tp> |
| inline pair<_Tp*,ptrdiff_t> |
| get_temporary_buffer(ptrdiff_t __len) |
| { return std::__get_temporary_buffer(__len, static_cast<_Tp*>(0)); } |
| |
| /** |
| * @brief The companion to get_temporary_buffer(). |
| * @param p A buffer previously allocated by get_temporary_buffer. |
| * @return None. |
| * |
| * Frees the memory pointed to by p. |
| */ |
| template<typename _Tp> |
| void |
| return_temporary_buffer(_Tp* __p) |
| { ::operator delete(__p, nothrow); } |
| |
| /** |
| * A wrapper class to provide auto_ptr with reference semantics. |
| * For example, an auto_ptr can be assigned (or constructed from) |
| * the result of a function which returns an auto_ptr by value. |
| * |
| * All the auto_ptr_ref stuff should happen behind the scenes. |
| */ |
| template<typename _Tp1> |
| struct auto_ptr_ref |
| { |
| _Tp1* _M_ptr; |
| |
| explicit |
| auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { } |
| }; |
| |
| |
| /** |
| * @brief A simple smart pointer providing strict ownership semantics. |
| * |
| * The Standard says: |
| * <pre> |
| * An @c auto_ptr owns the object it holds a pointer to. Copying |
| * an @c auto_ptr copies the pointer and transfers ownership to the |
| * destination. If more than one @c auto_ptr owns the same object |
| * at the same time the behavior of the program is undefined. |
| * |
| * The uses of @c auto_ptr include providing temporary |
| * exception-safety for dynamically allocated memory, passing |
| * ownership of dynamically allocated memory to a function, and |
| * returning dynamically allocated memory from a function. @c |
| * auto_ptr does not meet the CopyConstructible and Assignable |
| * requirements for Standard Library <a |
| * href="tables.html#65">container</a> elements and thus |
| * instantiating a Standard Library container with an @c auto_ptr |
| * results in undefined behavior. |
| * </pre> |
| * Quoted from [20.4.5]/3. |
| * |
| * Good examples of what can and cannot be done with auto_ptr can |
| * be found in the libstdc++ testsuite. |
| * |
| * @if maint |
| * _GLIBCXX_RESOLVE_LIB_DEFECTS |
| * 127. auto_ptr<> conversion issues |
| * These resolutions have all been incorporated. |
| * @endif |
| */ |
| template<typename _Tp> |
| class auto_ptr |
| { |
| private: |
| _Tp* _M_ptr; |
| |
| public: |
| /// The pointed-to type. |
| typedef _Tp element_type; |
| |
| /** |
| * @brief An %auto_ptr is usually constructed from a raw pointer. |
| * @param p A pointer (defaults to NULL). |
| * |
| * This object now @e owns the object pointed to by @a p. |
| */ |
| explicit |
| auto_ptr(element_type* __p = 0) throw() : _M_ptr(__p) { } |
| |
| /** |
| * @brief An %auto_ptr can be constructed from another %auto_ptr. |
| * @param a Another %auto_ptr of the same type. |
| * |
| * This object now @e owns the object previously owned by @a a, |
| * which has given up ownsership. |
| */ |
| auto_ptr(auto_ptr& __a) throw() : _M_ptr(__a.release()) { } |
| |
| /** |
| * @brief An %auto_ptr can be constructed from another %auto_ptr. |
| * @param a Another %auto_ptr of a different but related type. |
| * |
| * A pointer-to-Tp1 must be convertible to a |
| * pointer-to-Tp/element_type. |
| * |
| * This object now @e owns the object previously owned by @a a, |
| * which has given up ownsership. |
| */ |
| template<typename _Tp1> |
| auto_ptr(auto_ptr<_Tp1>& __a) throw() : _M_ptr(__a.release()) { } |
| |
| /** |
| * @brief %auto_ptr assignment operator. |
| * @param a Another %auto_ptr of the same type. |
| * |
| * This object now @e owns the object previously owned by @a a, |
| * which has given up ownsership. The object that this one @e |
| * used to own and track has been deleted. |
| */ |
| auto_ptr& |
| operator=(auto_ptr& __a) throw() |
| { |
| reset(__a.release()); |
| return *this; |
| } |
| |
| /** |
| * @brief %auto_ptr assignment operator. |
| * @param a Another %auto_ptr of a different but related type. |
| * |
| * A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type. |
| * |
| * This object now @e owns the object previously owned by @a a, |
| * which has given up ownsership. The object that this one @e |
| * used to own and track has been deleted. |
| */ |
| template<typename _Tp1> |
| auto_ptr& |
| operator=(auto_ptr<_Tp1>& __a) throw() |
| { |
| reset(__a.release()); |
| return *this; |
| } |
| |
| /** |
| * When the %auto_ptr goes out of scope, the object it owns is |
| * deleted. If it no longer owns anything (i.e., @c get() is |
| * @c NULL), then this has no effect. |
| * |
| * @if maint |
| * The C++ standard says there is supposed to be an empty throw |
| * specification here, but omitting it is standard conforming. Its |
| * presence can be detected only if _Tp::~_Tp() throws, but this is |
| * prohibited. [17.4.3.6]/2 |
| * @end maint |
| */ |
| ~auto_ptr() { delete _M_ptr; } |
| |
| /** |
| * @brief Smart pointer dereferencing. |
| * |
| * If this %auto_ptr no longer owns anything, then this |
| * operation will crash. (For a smart pointer, "no longer owns |
| * anything" is the same as being a null pointer, and you know |
| * what happens when you dereference one of those...) |
| */ |
| element_type& |
| operator*() const throw() |
| { |
| _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); |
| return *_M_ptr; |
| } |
| |
| /** |
| * @brief Smart pointer dereferencing. |
| * |
| * This returns the pointer itself, which the language then will |
| * automatically cause to be dereferenced. |
| */ |
| element_type* |
| operator->() const throw() |
| { |
| _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); |
| return _M_ptr; |
| } |
| |
| /** |
| * @brief Bypassing the smart pointer. |
| * @return The raw pointer being managed. |
| * |
| * You can get a copy of the pointer that this object owns, for |
| * situations such as passing to a function which only accepts |
| * a raw pointer. |
| * |
| * @note This %auto_ptr still owns the memory. |
| */ |
| element_type* |
| get() const throw() { return _M_ptr; } |
| |
| /** |
| * @brief Bypassing the smart pointer. |
| * @return The raw pointer being managed. |
| * |
| * You can get a copy of the pointer that this object owns, for |
| * situations such as passing to a function which only accepts |
| * a raw pointer. |
| * |
| * @note This %auto_ptr no longer owns the memory. When this object |
| * goes out of scope, nothing will happen. |
| */ |
| element_type* |
| release() throw() |
| { |
| element_type* __tmp = _M_ptr; |
| _M_ptr = 0; |
| return __tmp; |
| } |
| |
| /** |
| * @brief Forcibly deletes the managed object. |
| * @param p A pointer (defaults to NULL). |
| * |
| * This object now @e owns the object pointed to by @a p. The |
| * previous object has been deleted. |
| */ |
| void |
| reset(element_type* __p = 0) throw() |
| { |
| if (__p != _M_ptr) |
| { |
| delete _M_ptr; |
| _M_ptr = __p; |
| } |
| } |
| |
| /** @{ |
| * @brief Automatic conversions |
| * |
| * These operations convert an %auto_ptr into and from an auto_ptr_ref |
| * automatically as needed. This allows constructs such as |
| * @code |
| * auto_ptr<Derived> func_returning_auto_ptr(.....); |
| * ... |
| * auto_ptr<Base> ptr = func_returning_auto_ptr(.....); |
| * @endcode |
| */ |
| auto_ptr(auto_ptr_ref<element_type> __ref) throw() |
| : _M_ptr(__ref._M_ptr) { } |
| |
| auto_ptr& |
| operator=(auto_ptr_ref<element_type> __ref) throw() |
| { |
| if (__ref._M_ptr != this->get()) |
| { |
| delete _M_ptr; |
| _M_ptr = __ref._M_ptr; |
| } |
| return *this; |
| } |
| |
| template<typename _Tp1> |
| operator auto_ptr_ref<_Tp1>() throw() |
| { return auto_ptr_ref<_Tp1>(this->release()); } |
| |
| template<typename _Tp1> |
| operator auto_ptr<_Tp1>() throw() |
| { return auto_ptr<_Tp1>(this->release()); } |
| /** @} */ |
| }; |
| } // namespace std |
| |
| #endif /* _GLIBCXX_MEMORY */ |
