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Diffstat (limited to 'libstdc++/include/std/std_memory.h')
| -rw-r--r-- | libstdc++/include/std/std_memory.h | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/libstdc++/include/std/std_memory.h b/libstdc++/include/std/std_memory.h new file mode 100644 index 0000000..b57a94f --- /dev/null +++ b/libstdc++/include/std/std_memory.h @@ -0,0 +1,374 @@ +// <memory> -*- C++ -*- + +// Copyright (C) 2001, 2002, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, +// 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 include/memory + * This is a Standard C++ Library header. + */ + +#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> +#include <limits> + +_GLIBCXX_BEGIN_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*) + { + const ptrdiff_t __max = numeric_limits<ptrdiff_t>::max() / sizeof(_Tp); + if (__len > __max) + __len = __max; + + 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 + * @endif + */ + ~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()); } + }; + +_GLIBCXX_END_NAMESPACE + +#endif /* _GLIBCXX_MEMORY */ |
