libstdc++
safe_sequence.h
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00001 // Safe sequence implementation  -*- C++ -*-
00002 
00003 // Copyright (C) 2003-2018 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /** @file debug/safe_sequence.h
00026  *  This file is a GNU debug extension to the Standard C++ Library.
00027  */
00028 
00029 #ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
00030 #define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
00031 
00032 #include <debug/assertions.h>
00033 #include <debug/macros.h>
00034 #include <debug/functions.h>
00035 #include <debug/safe_base.h>
00036 
00037 namespace __gnu_debug
00038 {
00039   /** A simple function object that returns true if the passed-in
00040    *  value is not equal to the stored value. It saves typing over
00041    *  using both bind1st and not_equal.
00042    */
00043   template<typename _Type>
00044     class _Not_equal_to
00045     {
00046       _Type __value;
00047 
00048     public:
00049       explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
00050 
00051       bool
00052       operator()(const _Type& __x) const
00053       { return __value != __x; }
00054     };
00055 
00056   /** A simple function object that returns true if the passed-in
00057    *  value is equal to the stored value. */
00058   template <typename _Type>
00059     class _Equal_to
00060     {
00061       _Type __value;
00062 
00063     public:
00064       explicit _Equal_to(const _Type& __v) : __value(__v) { }
00065 
00066       bool
00067       operator()(const _Type& __x) const
00068       { return __value == __x; }
00069     };
00070 
00071   /** A function object that returns true when the given random access
00072       iterator is at least @c n steps away from the given iterator. */
00073   template<typename _Iterator>
00074     class _After_nth_from
00075     {
00076       typedef typename std::iterator_traits<_Iterator>::difference_type
00077       difference_type;
00078 
00079       _Iterator _M_base;
00080       difference_type _M_n;
00081 
00082     public:
00083       _After_nth_from(const difference_type& __n, const _Iterator& __base)
00084       : _M_base(__base), _M_n(__n) { }
00085 
00086       bool
00087       operator()(const _Iterator& __x) const
00088       { return __x - _M_base >= _M_n; }
00089     };
00090 
00091   /**
00092    * @brief Base class for constructing a @a safe sequence type that
00093    * tracks iterators that reference it.
00094    *
00095    * The class template %_Safe_sequence simplifies the construction of
00096    * @a safe sequences that track the iterators that reference the
00097    * sequence, so that the iterators are notified of changes in the
00098    * sequence that may affect their operation, e.g., if the container
00099    * invalidates its iterators or is destructed. This class template
00100    * may only be used by deriving from it and passing the name of the
00101    * derived class as its template parameter via the curiously
00102    * recurring template pattern. The derived class must have @c
00103    * iterator and @c const_iterator types that are instantiations of
00104    * class template _Safe_iterator for this sequence. Iterators will
00105    * then be tracked automatically.
00106    */
00107   template<typename _Sequence>
00108     class _Safe_sequence : public _Safe_sequence_base
00109     {
00110     public:
00111       /** Invalidates all iterators @c x that reference this sequence,
00112           are not singular, and for which @c __pred(x) returns @c
00113           true. @c __pred will be invoked with the normal iterators nested
00114           in the safe ones. */
00115       template<typename _Predicate>
00116         void
00117         _M_invalidate_if(_Predicate __pred);
00118 
00119       /** Transfers all iterators @c x that reference @c from sequence,
00120           are not singular, and for which @c __pred(x) returns @c
00121           true. @c __pred will be invoked with the normal iterators nested
00122           in the safe ones. */
00123       template<typename _Predicate>
00124         void
00125         _M_transfer_from_if(_Safe_sequence& __from, _Predicate __pred);
00126     };
00127 
00128   /// Like _Safe_sequence but with a special _M_invalidate_all implementation
00129   /// not invalidating past-the-end iterators. Used by node based sequence.
00130   template<typename _Sequence>
00131     class _Safe_node_sequence
00132     : public _Safe_sequence<_Sequence>
00133     {
00134     protected:
00135       void
00136       _M_invalidate_all()
00137       {
00138         typedef typename _Sequence::const_iterator _Const_iterator;
00139         typedef typename _Const_iterator::iterator_type _Base_const_iterator;
00140         typedef __gnu_debug::_Not_equal_to<_Base_const_iterator> _Not_equal;
00141         const _Sequence& __seq = *static_cast<_Sequence*>(this);
00142         this->_M_invalidate_if(_Not_equal(__seq._M_base().end()));
00143       }
00144     };
00145 
00146 } // namespace __gnu_debug
00147 
00148 #include <debug/safe_sequence.tcc>
00149 
00150 #endif