1 // -*- C++ -*-
2 
3 // Copyright (C) 2005, 2006, 2007, 2009, 2010, 2011
4 // Free Software Foundation, Inc.
5 //
6 // This file is part of the GNU ISO C++ Library.  This library is free
7 // software; you can redistribute it and/or modify it under the terms
8 // of the GNU General Public License as published by the Free Software
9 // Foundation; either version 3, or (at your option) any later
10 // version.
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12 // This library is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
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15 // General Public License for more details.
16 
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
20 
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24 // <http://www.gnu.org/licenses/>.
25 
26 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
27 
28 // Permission to use, copy, modify, sell, and distribute this software
29 // is hereby granted without fee, provided that the above copyright
30 // notice appears in all copies, and that both that copyright notice
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35 // warranty.
36 
37 /**
38  * @file trie_policy.hpp
39  * Contains trie-related policies.
40  */
41 
42 #ifndef PB_DS_TRIE_POLICY_HPP
43 #define PB_DS_TRIE_POLICY_HPP
44 
45 #include <bits/c++config.h>
46 #include <string>
47 #include <ext/pb_ds/detail/type_utils.hpp>
48 #include <ext/pb_ds/detail/trie_policy/trie_policy_base.hpp>
49 
50 namespace __gnu_pbds
51 {
52 #define PB_DS_CLASS_T_DEC \
53   template<typename String, typename String::value_type Min_E_Val, \
54 	   typename String::value_type Max_E_Val, bool Reverse, \
55 	   typename _Alloc>
56 
57 #define PB_DS_CLASS_C_DEC \
58   trie_string_access_traits<String, Min_E_Val,Max_E_Val,Reverse,_Alloc>
59 
60   /**
61    *  Element access traits for string types.
62    *
63    *  @tparam String 	    	String type.
64    *  @tparam Min_E_Val        	Minimal element value.
65    *  @tparam Max_E_Val	    	Maximum element value.
66    *  @tparam Reverse	        Reverse iteration should be used.
67    *                            Default: false.
68    *  @tparam _Alloc 	    	Allocator type.
69    */
70   template<typename String = std::string,
71 	   typename String::value_type Min_E_Val = detail::__numeric_traits<typename String::value_type>::__min,
72 	   typename String::value_type Max_E_Val = detail::__numeric_traits<typename String::value_type>::__max,
73 	   bool Reverse = false,
74 	   typename _Alloc = std::allocator<char> >
75   struct trie_string_access_traits
76   {
77   public:
78     typedef typename _Alloc::size_type			  size_type;
79     typedef String 					  key_type;
80     typedef typename _Alloc::template rebind<key_type>	  __rebind_k;
81     typedef typename __rebind_k::other::const_reference   key_const_reference;
82 
83     enum
84       {
85 	reverse = Reverse
86       };
87 
88     /// Element const iterator type.
89     typedef typename detail::__conditional_type<Reverse, \
90 		       typename String::const_reverse_iterator, \
91 		       typename String::const_iterator>::__type const_iterator;
92 
93     /// Element type.
94     typedef typename std::iterator_traits<const_iterator>::value_type e_type;
95 
96     enum
97       {
98 	min_e_val = Min_E_Val,
99 	max_e_val = Max_E_Val,
100 	max_size = max_e_val - min_e_val + 1
101       };
102     PB_DS_STATIC_ASSERT(min_max_size, max_size >= 2);
103 
104     /// Returns a const_iterator to the first element of
105     /// key_const_reference agumnet.
106     inline static const_iterator
107     begin(key_const_reference);
108 
109     /// Returns a const_iterator to the after-last element of
110     /// key_const_reference argument.
111     inline static const_iterator
112     end(key_const_reference);
113 
114     /// Maps an element to a position.
115     inline static size_type
116     e_pos(e_type e);
117 
118   private:
119     inline static const_iterator
120     begin_imp(key_const_reference, detail::false_type);
121 
122     inline static const_iterator
123     begin_imp(key_const_reference, detail::true_type);
124 
125     inline static const_iterator
126     end_imp(key_const_reference, detail::false_type);
127 
128     inline static const_iterator
129     end_imp(key_const_reference, detail::true_type);
130 
131     static detail::integral_constant<int, Reverse> s_rev_ind;
132   };
133 
134 #include <ext/pb_ds/detail/trie_policy/trie_string_access_traits_imp.hpp>
135 
136 #undef PB_DS_CLASS_T_DEC
137 #undef PB_DS_CLASS_C_DEC
138 
139 #define PB_DS_CLASS_T_DEC \
140   template<typename Node_CItr,typename Node_Itr, \
141 	   typename _ATraits, typename _Alloc>
142 
143 #define PB_DS_CLASS_C_DEC \
144   trie_prefix_search_node_update<Node_CItr, Node_Itr, \
145 				 _ATraits,_Alloc>
146 
147 #define PB_DS_TRIE_POLICY_BASE \
148   detail::trie_policy_base<Node_CItr,Node_Itr,_ATraits, _Alloc>
149 
150   /// A node updator that allows tries to be searched for the range of
151   /// values that match a certain prefix.
152   template<typename Node_CItr,
153 	   typename Node_Itr,
154 	   typename _ATraits,
155 	   typename _Alloc>
156   class trie_prefix_search_node_update : private PB_DS_TRIE_POLICY_BASE
157   {
158   private:
159     typedef PB_DS_TRIE_POLICY_BASE 		       	base_type;
160 
161   public:
162     typedef typename base_type::key_type 		key_type;
163     typedef typename base_type::key_const_reference 	key_const_reference;
164 
165     /// Element access traits.
166     typedef _ATraits 				access_traits;
167 
168     /// Const element iterator.
169     typedef typename access_traits::const_iterator 	a_const_iterator;
170 
171     /// _Alloc type.
172     typedef _Alloc 	       				allocator_type;
173 
174     /// Size type.
175     typedef typename allocator_type::size_type 		size_type;
176     typedef null_type 					metadata_type;
177     typedef Node_Itr 					node_iterator;
178     typedef Node_CItr 					node_const_iterator;
179     typedef typename node_iterator::value_type 		iterator;
180     typedef typename node_const_iterator::value_type 	const_iterator;
181 
182     /// Finds the const iterator range corresponding to all values
183     /// whose prefixes match r_key.
184     std::pair<const_iterator, const_iterator>
185     prefix_range(key_const_reference) const;
186 
187     /// Finds the iterator range corresponding to all values whose
188     /// prefixes match r_key.
189     std::pair<iterator, iterator>
190     prefix_range(key_const_reference);
191 
192     /// Finds the const iterator range corresponding to all values
193     /// whose prefixes match [b, e).
194     std::pair<const_iterator, const_iterator>
195     prefix_range(a_const_iterator, a_const_iterator) const;
196 
197     /// Finds the iterator range corresponding to all values whose
198     /// prefixes match [b, e).
199     std::pair<iterator, iterator>
200     prefix_range(a_const_iterator, a_const_iterator);
201 
202   protected:
203     /// Called to update a node's metadata.
204     inline void
205     operator()(node_iterator node_it, node_const_iterator end_nd_it) const;
206 
207   private:
208     node_iterator
209     next_child(node_iterator, a_const_iterator, a_const_iterator,
210 	       node_iterator, const access_traits&);
211 
212     /// Returns the const iterator associated with the just-after last element.
213     virtual const_iterator
214     end() const = 0;
215 
216     /// Returns the iterator associated with the just-after last element.
217     virtual iterator
218     end() = 0;
219 
220     /// Returns the node_const_iterator associated with the trie's root node.
221     virtual node_const_iterator
222     node_begin() const = 0;
223 
224     /// Returns the node_iterator associated with the trie's root node.
225     virtual node_iterator
226     node_begin() = 0;
227 
228     /// Returns the node_const_iterator associated with a just-after leaf node.
229     virtual node_const_iterator
230     node_end() const = 0;
231 
232     /// Returns the node_iterator associated with a just-after leaf node.
233     virtual node_iterator
234     node_end() = 0;
235 
236     /// Access to the cmp_fn object.
237     virtual const access_traits&
238     get_access_traits() const = 0;
239   };
240 
241 #include <ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp>
242 
243 #undef PB_DS_CLASS_C_DEC
244 
245 #define PB_DS_CLASS_C_DEC \
246   trie_order_statistics_node_update<Node_CItr, Node_Itr, \
247 				    _ATraits, _Alloc>
248 
249   /// Functor updating ranks of entrees.
250   template<typename Node_CItr,
251 	   typename Node_Itr,
252 	   typename _ATraits,
253 	   typename _Alloc>
254   class trie_order_statistics_node_update : private PB_DS_TRIE_POLICY_BASE
255   {
256   private:
257     typedef PB_DS_TRIE_POLICY_BASE 		       	base_type;
258 
259   public:
260     typedef _ATraits 				access_traits;
261     typedef typename access_traits::const_iterator 	a_const_iterator;
262     typedef _Alloc 					allocator_type;
263     typedef typename allocator_type::size_type 		size_type;
264     typedef typename base_type::key_type 		key_type;
265     typedef typename base_type::key_const_reference 	key_const_reference;
266 
267     typedef size_type 					metadata_type;
268     typedef Node_CItr 					node_const_iterator;
269     typedef Node_Itr 					node_iterator;
270     typedef typename node_const_iterator::value_type 	const_iterator;
271     typedef typename node_iterator::value_type 		iterator;
272 
273     /// Finds an entry by __order. Returns a const_iterator to the
274     /// entry with the __order order, or a const_iterator to the
275     /// container object's end if order is at least the size of the
276     /// container object.
277     inline const_iterator
278     find_by_order(size_type) const;
279 
280     /// Finds an entry by __order. Returns an iterator to the entry
281     /// with the __order order, or an iterator to the container
282     /// object's end if order is at least the size of the container
283     /// object.
284     inline iterator
285     find_by_order(size_type);
286 
287     /// Returns the order of a key within a sequence. For exapmle, if
288     /// r_key is the smallest key, this method will return 0; if r_key
289     /// is a key between the smallest and next key, this method will
290     /// return 1; if r_key is a key larger than the largest key, this
291     /// method will return the size of r_c.
292     inline size_type
293     order_of_key(key_const_reference) const;
294 
295     /// Returns the order of a prefix within a sequence. For exapmle,
296     /// if [b, e] is the smallest prefix, this method will return 0; if
297     /// r_key is a key between the smallest and next key, this method
298     /// will return 1; if r_key is a key larger than the largest key,
299     /// this method will return the size of r_c.
300     inline size_type
301     order_of_prefix(a_const_iterator, a_const_iterator) const;
302 
303   protected:
304     /// Updates the rank of a node through a node_iterator node_it;
305     /// end_nd_it is the end node iterator.
306     inline void
307     operator()(node_iterator, node_const_iterator) const;
308 
309   private:
310     typedef typename base_type::const_reference 	const_reference;
311     typedef typename base_type::const_pointer 		const_pointer;
312 
313     typedef typename _Alloc::template rebind<metadata_type> __rebind_m;
314     typedef typename __rebind_m::other 			__rebind_ma;
315     typedef typename __rebind_ma::const_reference      metadata_const_reference;
316     typedef typename __rebind_ma::reference 		metadata_reference;
317 
318     /// Returns true if the container is empty.
319     virtual bool
320     empty() const = 0;
321 
322     /// Returns the iterator associated with the trie's first element.
323     virtual iterator
324     begin() = 0;
325 
326     /// Returns the iterator associated with the trie's
327     /// just-after-last element.
328     virtual iterator
329     end() = 0;
330 
331     /// Returns the node_const_iterator associated with the trie's root node.
332     virtual node_const_iterator
333     node_begin() const = 0;
334 
335     /// Returns the node_iterator associated with the trie's root node.
336     virtual node_iterator
337     node_begin() = 0;
338 
339     /// Returns the node_const_iterator associated with a just-after
340     /// leaf node.
341     virtual node_const_iterator
342     node_end() const = 0;
343 
344     /// Returns the node_iterator associated with a just-after leaf node.
345     virtual node_iterator
346     node_end() = 0;
347 
348     /// Access to the cmp_fn object.
349     virtual access_traits&
350     get_access_traits() = 0;
351   };
352 
353 #include <ext/pb_ds/detail/trie_policy/order_statistics_imp.hpp>
354 
355 #undef PB_DS_CLASS_T_DEC
356 #undef PB_DS_CLASS_C_DEC
357 #undef PB_DS_TRIE_POLICY_BASE
358 
359 } // namespace __gnu_pbds
360 
361 #endif
362