summaryrefslogtreecommitdiff
path: root/sw/inc/ring.hxx
blob: e152899ec87a565aaeb35d4bdc52a743e7cf6615 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */
#ifndef INCLUDED_SW_INC_RING_HXX
#define INCLUDED_SW_INC_RING_HXX

#include <utility>
#include <sal/types.h>
#include <iterator>
#include <type_traits>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/intrusive/circular_list_algorithms.hpp>

namespace sw
{
    template <typename value_type> class RingContainer;
    template <typename value_type> class RingIterator;
    /**
     * An intrusive container class double linking the contained nodes
     * @example sw/qa/core/uwriter.cxx
     */
    template <typename value_type>
    class SAL_WARN_UNUSED Ring
    {
        public:
            typedef typename std::add_const<value_type>::type const_value_type;
            typedef RingContainer<value_type> ring_container;
            typedef RingContainer<const_value_type> const_ring_container;
            virtual ~Ring() COVERITY_NOEXCEPT_FALSE
                { unlink(); };
            /** algo::unlink is buggy! don't call it directly! */
            void unlink()
            {
                algo::unlink(this);
                m_pNext = this; // don't leave pointers to old list behind!
                m_pPrev = this;
            }
            /**
             * Removes this item from its current ring container and adds it to
             * another ring container. If the item was not alone in the original
             * ring container, the other items in the ring will stay in the old
             * ring container.
             * Note: the newly created item will be inserted just before item pDestRing.
             * @param pDestRing the container to add this item to
             */
            void MoveTo( value_type* pDestRing );
            /** @return a stl-like container with begin()/end() for iteration */
            ring_container GetRingContainer();
            /** @return a stl-like container with begin()/end() for const iteration */
            const_ring_container GetRingContainer() const;

        protected:
            /**
             * Creates a new item in a ring container all by itself.
             * Note: Ring instances can newer be outside a container. At most, they
             * are alone in one.
             */
            Ring()
                : m_pNext(this)
                , m_pPrev(this)
                { }
            /**
             * Creates a new item and add it to an existing ring container.
             * Note: the newly created item will be inserted just before item pRing.
             * @param pRing ring container to add the created item to
             */
            Ring( value_type* pRing );
            /** @return the next item in the ring container */
            value_type* GetNextInRing()
                { return static_cast<value_type *>(m_pNext); }
            /** @return the previous item in the ring container */
            value_type* GetPrevInRing()
                { return static_cast<value_type *>(m_pPrev); }
            /** @return the next item in the ring container */
            const_value_type* GetNextInRing() const
                { return static_cast<value_type *>(m_pNext); }
            /** @return the previous item in the ring container */
            const_value_type* GetPrevInRing() const
                { return static_cast<value_type *>(m_pPrev); }
            /** @return true if and only if this item is alone in its ring */
            bool unique() const
                { return algo::unique(static_cast< const_value_type* >(this)); }

        private:
            /** internal implementation class -- not for external use */
            struct Ring_node_traits
            {
                typedef Ring node;
                typedef Ring* node_ptr;
                typedef const Ring* const_node_ptr;
                static node_ptr get_next(const_node_ptr n) { return const_cast<node_ptr>(n)->m_pNext; };
                static void set_next(node_ptr n, node_ptr next) { n->m_pNext = next; };
                static node_ptr get_previous(const_node_ptr n) { return const_cast<node_ptr>(n)->m_pPrev; };
                static void set_previous(node_ptr n, node_ptr previous) { n->m_pPrev = previous; };
            };
            friend ring_container;
            friend const_ring_container;
            friend typename ring_container::iterator;
            friend typename ring_container::const_iterator;
            friend typename const_ring_container::iterator;
            friend typename const_ring_container::const_iterator;
            friend class boost::iterator_core_access;
            typedef boost::intrusive::circular_list_algorithms<Ring_node_traits> algo;
            Ring* m_pNext;
            Ring* m_pPrev;
    };

    template <typename value_type>
    inline Ring<value_type>::Ring( value_type* pObj )
        : m_pNext(this)
        , m_pPrev(this)
    {
        if( pObj )
        {
            algo::link_before(pObj, this);
        }
    }

    template <typename value_type>
    inline void Ring<value_type>::MoveTo(value_type* pDestRing)
    {
        value_type* pThis = static_cast< value_type* >(this);
        unlink();
        // insert into "new"
        if (pDestRing)
        {
            algo::link_before(pDestRing, pThis);
        }
    }

    /**
     * helper class that provides Svalue_typeL-style container iteration to the ring
     */
    template <typename value_type>
    class SAL_WARN_UNUSED RingContainer final
    {
        private:
            /** the item in the ring where iteration starts */
            value_type* m_pStart;
            typedef typename std::remove_const<value_type>::type nonconst_value_type;

        public:
            RingContainer( value_type* pRing ) : m_pStart(pRing) {};
            typedef RingIterator<value_type> iterator;
            typedef RingIterator<const value_type> const_iterator;
            /**
             * iterator access
             * @code
             * for(SwPaM& rCurrentPaM : pPaM->GetRingContainer())
             *     do_stuff(rCurrentPaM); // this gets called on every SwPaM in the same ring as pPaM
             * @endcode
             */
            iterator begin();
            iterator end();
            const_iterator begin() const;
            const_iterator end() const;
            /** @return the number of elements in the container */
            size_t size() const
                { return std::distance(begin(), end()); }
            /**
             * Merges two ring containers. All item from both ring containers will
             * be in the same ring container in the end.
             * Note: The items of this ring container will be inserted just before
             * item pDestRing
             * @param pDestRing the container to merge this container with
             */
            void merge( RingContainer< value_type > aDestRing )
            {
                // first check that we aren't merged already, swapping would
                // actually un-merge in this case!
                assert(m_pStart->m_pPrev != aDestRing.m_pStart);
                assert(m_pStart != aDestRing.m_pStart->m_pPrev);
                std::swap(m_pStart->m_pPrev->m_pNext, aDestRing.m_pStart->m_pPrev->m_pNext);
                std::swap(m_pStart->m_pPrev, aDestRing.m_pStart->m_pPrev);
            }
    };

    template <typename value_type>
    class RingIterator final : public boost::iterator_facade<
          RingIterator<value_type>
        , value_type
        , boost::forward_traversal_tag
        >
    {
        private:
            typedef typename std::remove_const<value_type>::type nonconst_value_type;
        public:
            RingIterator()
                : m_pCurrent(nullptr)
                , m_pStart(nullptr)
            {}
            explicit RingIterator(nonconst_value_type* pRing, bool bStart = true)
                : m_pCurrent(nullptr)
                , m_pStart(pRing)
            {
                if(!bStart)
                    m_pCurrent = m_pStart;
            }

        private:
            friend class boost::iterator_core_access;
            void increment()
                { m_pCurrent = m_pCurrent ? m_pCurrent->GetNextInRing() : m_pStart->GetNextInRing(); }
            bool equal(RingIterator const& other) const
            {
                // we never want to compare iterators from
                // different rings or starting points
                assert(m_pStart == other.m_pStart);
                return m_pCurrent == other.m_pCurrent;
            }
            value_type& dereference() const
                { return m_pCurrent ? *m_pCurrent : * m_pStart; }
            /**
             * value_type is:
             * - pointing to the current item in the iteration in general
             * - nullptr if on the first item (begin())
             * - m_pStart when beyond the last item (end())
             */
            nonconst_value_type* m_pCurrent;
            /** the first item of the iteration */
            nonconst_value_type* m_pStart;
    };

    template <typename value_type>
    inline typename Ring<value_type>::ring_container Ring<value_type>::GetRingContainer()
        { return Ring<value_type>::ring_container(static_cast< value_type* >(this)); };

    template <typename value_type>
    inline typename Ring<value_type>::const_ring_container Ring<value_type>::GetRingContainer() const
        { return Ring<value_type>::const_ring_container(static_cast< const_value_type* >(this)); };

    template <typename value_type>
    inline typename RingContainer<value_type>::iterator RingContainer<value_type>::begin()
        { return RingContainer<value_type>::iterator(const_cast< nonconst_value_type* >(m_pStart)); };

    template <typename value_type>
    inline typename RingContainer<value_type>::iterator RingContainer<value_type>::end()
        { return RingContainer<value_type>::iterator(const_cast< nonconst_value_type* >(m_pStart), false); };

    template <typename value_type>
    inline typename RingContainer<value_type>::const_iterator RingContainer<value_type>::begin() const
        { return RingContainer<value_type>::const_iterator(const_cast< nonconst_value_type* >(m_pStart)); };

    template <typename value_type>
    inline typename RingContainer<value_type>::const_iterator RingContainer<value_type>::end() const
        { return RingContainer<value_type>::const_iterator(const_cast< nonconst_value_type* >(m_pStart), false); };
}
#endif

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */