1 // -*- C++ -*-
2 
3 // Copyright (C) 2005-2020 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 terms
7 // of the GNU General Public License as published by the Free Software
8 // Foundation; either version 3, or (at your option) any later
9 // version.
10 
11 // This library is distributed in the hope that it will be useful, but
12 // WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 // General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
26 
27 // Permission to use, copy, modify, sell, and distribute this software
28 // is hereby granted without fee, provided that the above copyright
29 // notice appears in all copies, and that both that copyright notice
30 // and this permission notice appear in supporting documentation. None
31 // of the above authors, nor IBM Haifa Research Laboratories, make any
32 // representation about the suitability of this software for any
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34 // warranty.
35 
36 /**
37  * @file ov_tree_map_/node_iterators.hpp
38  * Contains an implementation class for ov_tree_.
39  */
40 
41 #ifndef PB_DS_OV_TREE_NODE_ITERATORS_HPP
42 #define PB_DS_OV_TREE_NODE_ITERATORS_HPP
43 
44 #include <ext/pb_ds/tag_and_trait.hpp>
45 #include <ext/pb_ds/detail/type_utils.hpp>
46 #include <debug/debug.h>
47 
48 namespace __gnu_pbds
49 {
50   namespace detail
51   {
52 #define PB_DS_OV_TREE_CONST_NODE_ITERATOR_C_DEC	\
53     ov_tree_node_const_it_<Value_Type, Metadata_Type, _Alloc>
54 
55     /// Const node reference.
56     template<typename Value_Type, typename Metadata_Type, typename _Alloc>
57     class ov_tree_node_const_it_
58     {
59 
60     protected:
61       typedef typename rebind_traits<_Alloc, Value_Type>::pointer
62 	pointer;
63 
64       typedef typename rebind_traits<_Alloc, Value_Type>::const_pointer
65 	const_pointer;
66 
67       typedef typename rebind_traits<_Alloc, Metadata_Type>::const_pointer
68 	const_metadata_pointer;
69 
70       typedef PB_DS_OV_TREE_CONST_NODE_ITERATOR_C_DEC this_type;
71 
72     protected:
73 
74       template<typename Ptr>
75       inline static Ptr
mid_pointer(Ptr p_begin,Ptr p_end)76       mid_pointer(Ptr p_begin, Ptr p_end)
77       {
78 	_GLIBCXX_DEBUG_ASSERT(p_end >= p_begin);
79 	return (p_begin + (p_end - p_begin) / 2);
80       }
81 
82     public:
83 
84       typedef trivial_iterator_tag iterator_category;
85 
86       typedef trivial_iterator_difference_type difference_type;
87 
88       typedef typename rebind_traits<_Alloc, Value_Type>::const_pointer
89 	value_type;
90 
91       typedef typename rebind_traits<_Alloc,
92 	      typename remove_const<Value_Type>::type>::const_pointer
93 	reference;
94 
95       typedef typename rebind_traits<_Alloc,
96 	      typename remove_const<Value_Type>::type>::const_pointer
97 	const_reference;
98 
99       typedef Metadata_Type metadata_type;
100 
101       typedef typename rebind_traits<_Alloc, metadata_type>::const_reference
102 	metadata_const_reference;
103 
104     public:
105       inline
ov_tree_node_const_it_(const_pointer p_nd=0,const_pointer p_begin_nd=0,const_pointer p_end_nd=0,const_metadata_pointer p_metadata=0)106       ov_tree_node_const_it_(const_pointer p_nd = 0,
107 			     const_pointer p_begin_nd = 0,
108 			     const_pointer p_end_nd = 0,
109 			     const_metadata_pointer p_metadata = 0)
110       : m_p_value(const_cast<pointer>(p_nd)),
111 	m_p_begin_value(const_cast<pointer>(p_begin_nd)),
112 	m_p_end_value(const_cast<pointer>(p_end_nd)),
113 	m_p_metadata(p_metadata)
114       { }
115 
116       inline const_reference
operator *() const117       operator*() const
118       { return m_p_value; }
119 
120       inline metadata_const_reference
get_metadata() const121       get_metadata() const
122       {
123 	enum
124 	  {
125 	    has_metadata = !is_same<Metadata_Type, null_type>::value
126 	  };
127 
128 	PB_DS_STATIC_ASSERT(should_have_metadata, has_metadata);
129 	_GLIBCXX_DEBUG_ASSERT(m_p_metadata != 0);
130 	return *m_p_metadata;
131       }
132 
133       /// Returns the node iterator associated with the left node.
134       inline this_type
get_l_child() const135       get_l_child() const
136       {
137 	if (m_p_begin_value == m_p_value)
138 	  return (this_type(m_p_begin_value, m_p_begin_value, m_p_begin_value));
139 
140 	const_metadata_pointer p_begin_metadata =
141 	  m_p_metadata - (m_p_value - m_p_begin_value);
142 
143 	return (this_type(mid_pointer(m_p_begin_value, m_p_value),
144 			  m_p_begin_value,
145 			  m_p_value,
146 			  mid_pointer(p_begin_metadata, m_p_metadata)));
147       }
148 
149       /// Returns the node iterator associated with the right node.
150       inline this_type
get_r_child() const151       get_r_child() const
152       {
153 	if (m_p_value == m_p_end_value)
154 	  return (this_type(m_p_end_value, m_p_end_value, m_p_end_value));
155 
156 	const_metadata_pointer p_end_metadata =
157 	  m_p_metadata + (m_p_end_value - m_p_value);
158 
159 	return (this_type(mid_pointer(m_p_value + 1, m_p_end_value),
160 			  m_p_value + 1,
161 			  m_p_end_value,(m_p_metadata == 0) ?
162 			  0 : mid_pointer(m_p_metadata + 1, p_end_metadata)));
163       }
164 
165       inline bool
operator ==(const this_type & other) const166       operator==(const this_type& other) const
167       {
168 	const bool is_end = m_p_begin_value == m_p_end_value;
169 	const bool is_other_end = other.m_p_begin_value == other.m_p_end_value;
170 
171 	if (is_end)
172 	  return (is_other_end);
173 
174 	if (is_other_end)
175 	  return (is_end);
176 
177 	return m_p_value == other.m_p_value;
178       }
179 
180       inline bool
operator !=(const this_type & other) const181       operator!=(const this_type& other) const
182       { return !operator==(other); }
183 
184     public:
185       pointer m_p_value;
186       pointer m_p_begin_value;
187       pointer m_p_end_value;
188 
189       const_metadata_pointer m_p_metadata;
190     };
191 
192 #define PB_DS_OV_TREE_NODE_ITERATOR_C_DEC \
193     ov_tree_node_it_<Value_Type, Metadata_Type, _Alloc>
194 
195     /// Node reference.
196     template<typename Value_Type, typename Metadata_Type, typename _Alloc>
197     class ov_tree_node_it_ : public PB_DS_OV_TREE_CONST_NODE_ITERATOR_C_DEC
198     {
199     private:
200       typedef PB_DS_OV_TREE_NODE_ITERATOR_C_DEC this_type;
201 
202       typedef PB_DS_OV_TREE_CONST_NODE_ITERATOR_C_DEC base_type;
203 
204       typedef typename base_type::pointer pointer;
205 
206       typedef typename base_type::const_pointer const_pointer;
207 
208       typedef
209       typename base_type::const_metadata_pointer
210       const_metadata_pointer;
211 
212     public:
213       typedef trivial_iterator_tag iterator_category;
214 
215       typedef trivial_iterator_difference_type difference_type;
216 
217       typedef typename rebind_traits<_Alloc, Value_Type>::pointer
218 	value_type;
219 
220       typedef typename rebind_traits<_Alloc,
221 	      typename remove_const<Value_Type>::type>::pointer
222 	reference;
223 
224       typedef typename rebind_traits<_Alloc,
225 	      typename remove_const<Value_Type>::type>::pointer
226 	const_reference;
227 
228       inline
ov_tree_node_it_(const_pointer p_nd=0,const_pointer p_begin_nd=0,const_pointer p_end_nd=0,const_metadata_pointer p_metadata=0)229       ov_tree_node_it_(const_pointer p_nd = 0,  const_pointer p_begin_nd = 0,  const_pointer p_end_nd = 0,  const_metadata_pointer p_metadata = 0) : base_type(p_nd,  p_begin_nd,  p_end_nd,  p_metadata)
230       { }
231 
232       /// Access.
233       inline reference
operator *() const234       operator*() const
235       { return reference(base_type::m_p_value); }
236 
237       /// Returns the node reference associated with the left node.
238       inline ov_tree_node_it_
get_l_child() const239       get_l_child() const
240       {
241 	if (base_type::m_p_begin_value == base_type::m_p_value)
242 	  return (this_type(base_type::m_p_begin_value,  base_type::m_p_begin_value,  base_type::m_p_begin_value));
243 
244 	const_metadata_pointer p_begin_metadata =
245 	  base_type::m_p_metadata - (base_type::m_p_value - base_type::m_p_begin_value);
246 
247 	return (this_type(base_type::mid_pointer(base_type::m_p_begin_value, base_type::m_p_value),
248 			  base_type::m_p_begin_value,
249 			  base_type::m_p_value,
250 			  base_type::mid_pointer(p_begin_metadata, base_type::m_p_metadata)));
251       }
252 
253       /// Returns the node reference associated with the right node.
254       inline ov_tree_node_it_
get_r_child() const255       get_r_child() const
256       {
257 	if (base_type::m_p_value == base_type::m_p_end_value)
258 	  return this_type(base_type::m_p_end_value, base_type::m_p_end_value,
259 			   base_type::m_p_end_value);
260 
261 	const_metadata_pointer p_end_metadata =
262 	  base_type::m_p_metadata + (base_type::m_p_end_value - base_type::m_p_value);
263 
264 	return (this_type(base_type::mid_pointer(base_type::m_p_value + 1, base_type::m_p_end_value),
265 			  base_type::m_p_value + 1,
266 			  base_type::m_p_end_value,(base_type::m_p_metadata == 0)?
267 			  0 : base_type::mid_pointer(base_type::m_p_metadata + 1, p_end_metadata)));
268       }
269 
270     };
271 
272 #undef PB_DS_OV_TREE_NODE_ITERATOR_C_DEC
273 #undef PB_DS_OV_TREE_CONST_NODE_ITERATOR_C_DEC
274 
275 } // namespace detail
276 } // namespace __gnu_pbds
277 
278 #endif
279