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      1 // -*- C++ -*-
      2 
      3 // Copyright (C) 2005-2013 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
     33 // purpose. It is provided "as is" without express or implied
     34 // warranty.
     35 
     36 /**
     37  * @file trie_policy.hpp
     38  * Contains trie-related policies.
     39  */
     40 
     41 #ifndef PB_DS_TRIE_POLICY_HPP
     42 #define PB_DS_TRIE_POLICY_HPP
     43 
     44 #include <bits/c++config.h>
     45 #include <string>
     46 #include <ext/pb_ds/detail/type_utils.hpp>
     47 #include <ext/pb_ds/detail/trie_policy/trie_policy_base.hpp>
     48 
     49 namespace __gnu_pbds
     50 {
     51 #define PB_DS_CLASS_T_DEC \
     52   template<typename String, typename String::value_type Min_E_Val, \
     53 	   typename String::value_type Max_E_Val, bool Reverse, \
     54 	   typename _Alloc>
     55 
     56 #define PB_DS_CLASS_C_DEC \
     57   trie_string_access_traits<String, Min_E_Val,Max_E_Val,Reverse,_Alloc>
     58 
     59   /**
     60    *  Element access traits for string types.
     61    *
     62    *  @tparam String 	    	String type.
     63    *  @tparam Min_E_Val        	Minimal element value.
     64    *  @tparam Max_E_Val	    	Maximum element value.
     65    *  @tparam Reverse	        Reverse iteration should be used.
     66    *                            Default: false.
     67    *  @tparam _Alloc 	    	Allocator type.
     68    */
     69   template<typename String = std::string,
     70 	   typename String::value_type Min_E_Val = detail::__numeric_traits<typename String::value_type>::__min,
     71 	   typename String::value_type Max_E_Val = detail::__numeric_traits<typename String::value_type>::__max,
     72 	   bool Reverse = false,
     73 	   typename _Alloc = std::allocator<char> >
     74   struct trie_string_access_traits
     75   {
     76   public:
     77     typedef typename _Alloc::size_type			  size_type;
     78     typedef String 					  key_type;
     79     typedef typename _Alloc::template rebind<key_type>	  __rebind_k;
     80     typedef typename __rebind_k::other::const_reference   key_const_reference;
     81 
     82     enum
     83       {
     84 	reverse = Reverse
     85       };
     86 
     87     /// Element const iterator type.
     88     typedef typename detail::__conditional_type<Reverse, \
     89 		       typename String::const_reverse_iterator, \
     90 		       typename String::const_iterator>::__type const_iterator;
     91 
     92     /// Element type.
     93     typedef typename std::iterator_traits<const_iterator>::value_type e_type;
     94 
     95     enum
     96       {
     97 	min_e_val = Min_E_Val,
     98 	max_e_val = Max_E_Val,
     99 	max_size = max_e_val - min_e_val + 1
    100       };
    101     PB_DS_STATIC_ASSERT(min_max_size, max_size >= 2);
    102 
    103     /// Returns a const_iterator to the first element of
    104     /// key_const_reference agumnet.
    105     inline static const_iterator
    106     begin(key_const_reference);
    107 
    108     /// Returns a const_iterator to the after-last element of
    109     /// key_const_reference argument.
    110     inline static const_iterator
    111     end(key_const_reference);
    112 
    113     /// Maps an element to a position.
    114     inline static size_type
    115     e_pos(e_type e);
    116 
    117   private:
    118     inline static const_iterator
    119     begin_imp(key_const_reference, detail::false_type);
    120 
    121     inline static const_iterator
    122     begin_imp(key_const_reference, detail::true_type);
    123 
    124     inline static const_iterator
    125     end_imp(key_const_reference, detail::false_type);
    126 
    127     inline static const_iterator
    128     end_imp(key_const_reference, detail::true_type);
    129 
    130     static detail::integral_constant<int, Reverse> s_rev_ind;
    131   };
    132 
    133 #include <ext/pb_ds/detail/trie_policy/trie_string_access_traits_imp.hpp>
    134 
    135 #undef PB_DS_CLASS_T_DEC
    136 #undef PB_DS_CLASS_C_DEC
    137 
    138 #define PB_DS_CLASS_T_DEC \
    139   template<typename Node_CItr,typename Node_Itr, \
    140 	   typename _ATraits, typename _Alloc>
    141 
    142 #define PB_DS_CLASS_C_DEC \
    143   trie_prefix_search_node_update<Node_CItr, Node_Itr, \
    144 				 _ATraits,_Alloc>
    145 
    146 #define PB_DS_TRIE_POLICY_BASE \
    147   detail::trie_policy_base<Node_CItr,Node_Itr,_ATraits, _Alloc>
    148 
    149   /// A node updator that allows tries to be searched for the range of
    150   /// values that match a certain prefix.
    151   template<typename Node_CItr,
    152 	   typename Node_Itr,
    153 	   typename _ATraits,
    154 	   typename _Alloc>
    155   class trie_prefix_search_node_update : private PB_DS_TRIE_POLICY_BASE
    156   {
    157   private:
    158     typedef PB_DS_TRIE_POLICY_BASE 		       	base_type;
    159 
    160   public:
    161     typedef typename base_type::key_type 		key_type;
    162     typedef typename base_type::key_const_reference 	key_const_reference;
    163 
    164     /// Element access traits.
    165     typedef _ATraits 				access_traits;
    166 
    167     /// Const element iterator.
    168     typedef typename access_traits::const_iterator 	a_const_iterator;
    169 
    170     /// _Alloc type.
    171     typedef _Alloc 	       				allocator_type;
    172 
    173     /// Size type.
    174     typedef typename allocator_type::size_type 		size_type;
    175     typedef null_type 					metadata_type;
    176     typedef Node_Itr 					node_iterator;
    177     typedef Node_CItr 					node_const_iterator;
    178     typedef typename node_iterator::value_type 		iterator;
    179     typedef typename node_const_iterator::value_type 	const_iterator;
    180 
    181     /// Finds the const iterator range corresponding to all values
    182     /// whose prefixes match r_key.
    183     std::pair<const_iterator, const_iterator>
    184     prefix_range(key_const_reference) const;
    185 
    186     /// Finds the iterator range corresponding to all values whose
    187     /// prefixes match r_key.
    188     std::pair<iterator, iterator>
    189     prefix_range(key_const_reference);
    190 
    191     /// Finds the const iterator range corresponding to all values
    192     /// whose prefixes match [b, e).
    193     std::pair<const_iterator, const_iterator>
    194     prefix_range(a_const_iterator, a_const_iterator) const;
    195 
    196     /// Finds the iterator range corresponding to all values whose
    197     /// prefixes match [b, e).
    198     std::pair<iterator, iterator>
    199     prefix_range(a_const_iterator, a_const_iterator);
    200 
    201   protected:
    202     /// Called to update a node's metadata.
    203     inline void
    204     operator()(node_iterator node_it, node_const_iterator end_nd_it) const;
    205 
    206   private:
    207     node_iterator
    208     next_child(node_iterator, a_const_iterator, a_const_iterator,
    209 	       node_iterator, const access_traits&);
    210 
    211     /// Returns the const iterator associated with the just-after last element.
    212     virtual const_iterator
    213     end() const = 0;
    214 
    215     /// Returns the iterator associated with the just-after last element.
    216     virtual iterator
    217     end() = 0;
    218 
    219     /// Returns the node_const_iterator associated with the trie's root node.
    220     virtual node_const_iterator
    221     node_begin() const = 0;
    222 
    223     /// Returns the node_iterator associated with the trie's root node.
    224     virtual node_iterator
    225     node_begin() = 0;
    226 
    227     /// Returns the node_const_iterator associated with a just-after leaf node.
    228     virtual node_const_iterator
    229     node_end() const = 0;
    230 
    231     /// Returns the node_iterator associated with a just-after leaf node.
    232     virtual node_iterator
    233     node_end() = 0;
    234 
    235     /// Access to the cmp_fn object.
    236     virtual const access_traits&
    237     get_access_traits() const = 0;
    238   };
    239 
    240 #include <ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp>
    241 
    242 #undef PB_DS_CLASS_C_DEC
    243 
    244 #define PB_DS_CLASS_C_DEC \
    245   trie_order_statistics_node_update<Node_CItr, Node_Itr, \
    246 				    _ATraits, _Alloc>
    247 
    248   /// Functor updating ranks of entrees.
    249   template<typename Node_CItr,
    250 	   typename Node_Itr,
    251 	   typename _ATraits,
    252 	   typename _Alloc>
    253   class trie_order_statistics_node_update : private PB_DS_TRIE_POLICY_BASE
    254   {
    255   private:
    256     typedef PB_DS_TRIE_POLICY_BASE 		       	base_type;
    257 
    258   public:
    259     typedef _ATraits 				access_traits;
    260     typedef typename access_traits::const_iterator 	a_const_iterator;
    261     typedef _Alloc 					allocator_type;
    262     typedef typename allocator_type::size_type 		size_type;
    263     typedef typename base_type::key_type 		key_type;
    264     typedef typename base_type::key_const_reference 	key_const_reference;
    265 
    266     typedef size_type 					metadata_type;
    267     typedef Node_CItr 					node_const_iterator;
    268     typedef Node_Itr 					node_iterator;
    269     typedef typename node_const_iterator::value_type 	const_iterator;
    270     typedef typename node_iterator::value_type 		iterator;
    271 
    272     /// Finds an entry by __order. Returns a const_iterator to the
    273     /// entry with the __order order, or a const_iterator to the
    274     /// container object's end if order is at least the size of the
    275     /// container object.
    276     inline const_iterator
    277     find_by_order(size_type) const;
    278 
    279     /// Finds an entry by __order. Returns an iterator to the entry
    280     /// with the __order order, or an iterator to the container
    281     /// object's end if order is at least the size of the container
    282     /// object.
    283     inline iterator
    284     find_by_order(size_type);
    285 
    286     /// Returns the order of a key within a sequence. For exapmle, if
    287     /// r_key is the smallest key, this method will return 0; if r_key
    288     /// is a key between the smallest and next key, this method will
    289     /// return 1; if r_key is a key larger than the largest key, this
    290     /// method will return the size of r_c.
    291     inline size_type
    292     order_of_key(key_const_reference) const;
    293 
    294     /// Returns the order of a prefix within a sequence. For exapmle,
    295     /// if [b, e] is the smallest prefix, this method will return 0; if
    296     /// r_key is a key between the smallest and next key, this method
    297     /// will return 1; if r_key is a key larger than the largest key,
    298     /// this method will return the size of r_c.
    299     inline size_type
    300     order_of_prefix(a_const_iterator, a_const_iterator) const;
    301 
    302   protected:
    303     /// Updates the rank of a node through a node_iterator node_it;
    304     /// end_nd_it is the end node iterator.
    305     inline void
    306     operator()(node_iterator, node_const_iterator) const;
    307 
    308   private:
    309     typedef typename base_type::const_reference 	const_reference;
    310     typedef typename base_type::const_pointer 		const_pointer;
    311 
    312     typedef typename _Alloc::template rebind<metadata_type> __rebind_m;
    313     typedef typename __rebind_m::other 			__rebind_ma;
    314     typedef typename __rebind_ma::const_reference      metadata_const_reference;
    315     typedef typename __rebind_ma::reference 		metadata_reference;
    316 
    317     /// Returns true if the container is empty.
    318     virtual bool
    319     empty() const = 0;
    320 
    321     /// Returns the iterator associated with the trie's first element.
    322     virtual iterator
    323     begin() = 0;
    324 
    325     /// Returns the iterator associated with the trie's
    326     /// just-after-last element.
    327     virtual iterator
    328     end() = 0;
    329 
    330     /// Returns the node_const_iterator associated with the trie's root node.
    331     virtual node_const_iterator
    332     node_begin() const = 0;
    333 
    334     /// Returns the node_iterator associated with the trie's root node.
    335     virtual node_iterator
    336     node_begin() = 0;
    337 
    338     /// Returns the node_const_iterator associated with a just-after
    339     /// leaf node.
    340     virtual node_const_iterator
    341     node_end() const = 0;
    342 
    343     /// Returns the node_iterator associated with a just-after leaf node.
    344     virtual node_iterator
    345     node_end() = 0;
    346 
    347     /// Access to the cmp_fn object.
    348     virtual access_traits&
    349     get_access_traits() = 0;
    350   };
    351 
    352 #include <ext/pb_ds/detail/trie_policy/order_statistics_imp.hpp>
    353 
    354 #undef PB_DS_CLASS_T_DEC
    355 #undef PB_DS_CLASS_C_DEC
    356 #undef PB_DS_TRIE_POLICY_BASE
    357 
    358 } // namespace __gnu_pbds
    359 
    360 #endif
    361