# trie_policy.hpp

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    00001 // -*- C++ -*-
    00002
    00003 // Copyright (C) 2005, 2006, 2007 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 terms
    00007 // of the GNU General Public License as published by the Free Software
    00008 // Foundation; either version 2, or (at your option) any later
    00009 // version.
    00010
    00011 // This library is distributed in the hope that it will be useful, but
    00012 // WITHOUT ANY WARRANTY; without even the implied warranty of
    00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00014 // General Public License for more details.
    00015
    00016 // You should have received a copy of the GNU General Public License
    00017 // along with this library; see the file COPYING.  If not, write to
    00018 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
    00019 // MA 02111-1307, USA.
    00020
    00021 // As a special exception, you may use this file as part of a free
    00022 // software library without restriction.  Specifically, if other files
    00023 // instantiate templates or use macros or inline functions from this
    00024 // file, or you compile this file and link it with other files to
    00025 // produce an executable, this file does not by itself cause the
    00026 // resulting executable to be covered by the GNU General Public
    00027 // License.  This exception does not however invalidate any other
    00028 // reasons why the executable file might be covered by the GNU General
    00029 // Public License.
    00030
    00031 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
    00032
    00033 // Permission to use, copy, modify, sell, and distribute this software
    00034 // is hereby granted without fee, provided that the above copyright
    00035 // notice appears in all copies, and that both that copyright notice
    00036 // and this permission notice appear in supporting documentation. None
    00037 // of the above authors, nor IBM Haifa Research Laboratories, make any
    00038 // representation about the suitability of this software for any
    00039 // purpose. It is provided "as is" without express or implied
    00040 // warranty.
    00041
    00042 /**
    00043  * @file trie_policy.hpp
    00044  * Contains trie-related policies.
    00045  */
    00046
    00047 #ifndef PB_DS_TRIE_POLICY_HPP
    00048 #define PB_DS_TRIE_POLICY_HPP
    00049
    00050 #include <string>
    00051 #include <ext/pb_ds/detail/type_utils.hpp>
    00052 #include <ext/pb_ds/detail/trie_policy/trie_policy_base.hpp>
    00053
    00054 namespace __gnu_pbds
    00055 {
    00056   // A null node updator, indicating that no node updates are required.
    00057   template<typename Const_Node_Iterator,
    00058        typename Node_Iterator,
    00059        typename E_Access_Traits,
    00060        typename Allocator>
    00061   struct null_trie_node_update
    00062   { };
    00063
    00064 #define PB_DS_CLASS_T_DEC                       \
    00065   template<typename String, typename String::value_type Min_E_Val, typename String::value_type Max_E_Val, bool Reverse, typename Allocator>
    00066
    00067 #define PB_DS_CLASS_C_DEC                       \
    00068   string_trie_e_access_traits<String, Min_E_Val,Max_E_Val,Reverse,Allocator>
    00069
    00070   // Element access traits for string types.
    00071   template<typename String = std::string,
    00072        typename String::value_type Min_E_Val = detail::__numeric_traits<typename String::value_type>::__min,
    00073        typename String::value_type Max_E_Val = detail::__numeric_traits<typename String::value_type>::__max,
    00074        bool Reverse = false,
    00075        typename Allocator = std::allocator<char> >
    00076   struct string_trie_e_access_traits
    00077   {
    00078   public:
    00079     typedef typename Allocator::size_type size_type;
    00080     typedef String key_type;
    00081     typedef typename Allocator::template rebind<key_type>::other key_rebind;
    00082     typedef typename key_rebind::const_reference const_key_reference;
    00083
    00084     enum
    00085       {
    00086     reverse = Reverse
    00087       };
    00088
    00089     // Element const iterator type.
    00090     typedef typename detail::__conditional_type<Reverse, typename String::const_reverse_iterator, typename String::const_iterator>::__type const_iterator;
    00091
    00092     // Element type.
    00093     typedef typename std::iterator_traits<const_iterator>::value_type e_type;
    00094
    00095     enum
    00096       {
    00097     min_e_val = Min_E_Val,
    00098     max_e_val = Max_E_Val,
    00099     max_size = max_e_val - min_e_val + 1
    00100       };
    00101     PB_DS_STATIC_ASSERT(min_max_size, max_size >= 2);
    00102
    00103     // Returns a const_iterator to the first element of
    00104     // const_key_reference agumnet.
    00105     inline static const_iterator
    00106     begin(const_key_reference);
    00107
    00108     // Returns a const_iterator to the after-last element of
    00109     // const_key_reference argument.
    00110     inline static const_iterator
    00111     end(const_key_reference);
    00112
    00113     // Maps an element to a position.
    00114     inline static size_type
    00115     e_pos(e_type e);
    00116
    00117   private:
    00118
    00119     inline static const_iterator
    00120     begin_imp(const_key_reference, detail::false_type);
    00121
    00122     inline static const_iterator
    00123     begin_imp(const_key_reference, detail::true_type);
    00124
    00125     inline static const_iterator
    00126     end_imp(const_key_reference, detail::false_type);
    00127
    00128     inline static const_iterator
    00129     end_imp(const_key_reference, detail::true_type);
    00130
    00131     static detail::integral_constant<int, Reverse> s_rev_ind;
    00132   };
    00133
    00134 #include <ext/pb_ds/detail/trie_policy/string_trie_e_access_traits_imp.hpp>
    00135
    00136 #undef PB_DS_CLASS_T_DEC
    00137 #undef PB_DS_CLASS_C_DEC
    00138
    00139 #define PB_DS_CLASS_T_DEC \
    00140   template<typename Const_Node_Iterator,typename Node_Iterator,class E_Access_Traits, typename Allocator>
    00141
    00142 #define PB_DS_CLASS_C_DEC \
    00143   trie_prefix_search_node_update<Const_Node_Iterator, Node_Iterator, E_Access_Traits,Allocator>
    00144
    00145 #define PB_DS_BASE_C_DEC \
    00146   detail::trie_policy_base<Const_Node_Iterator,Node_Iterator,E_Access_Traits, Allocator>
    00147
    00148   // A node updator that allows tries to be searched for the range of
    00149   // values that match a certain prefix.
    00150   template<typename Const_Node_Iterator,
    00151        typename Node_Iterator,
    00152        typename E_Access_Traits,
    00153        typename Allocator>
    00154   class trie_prefix_search_node_update : private PB_DS_BASE_C_DEC
    00155   {
    00156   private:
    00157     typedef PB_DS_BASE_C_DEC base_type;
    00158
    00159   public:
    00160     typedef typename base_type::key_type key_type;
    00161     typedef typename base_type::const_key_reference const_key_reference;
    00162
    00163     // Element access traits.
    00164     typedef E_Access_Traits e_access_traits;
    00165
    00166     // Const element iterator.
    00167     typedef typename e_access_traits::const_iterator const_e_iterator;
    00168
    00169     // Allocator type.
    00170     typedef Allocator allocator;
    00171
    00172     // Size type.
    00173     typedef typename allocator::size_type size_type;
    00174     typedef detail::null_node_metadata metadata_type;
    00175     typedef Const_Node_Iterator const_node_iterator;
    00176     typedef Node_Iterator node_iterator;
    00177     typedef typename const_node_iterator::value_type const_iterator;
    00178     typedef typename node_iterator::value_type iterator;
    00179
    00180     // Finds the const iterator range corresponding to all values
    00181     // whose prefixes match r_key.
    00182     std::pair<const_iterator, const_iterator>
    00183     prefix_range(const_key_reference) const;
    00184
    00185     // Finds the iterator range corresponding to all values whose
    00186     // prefixes match r_key.
    00187     std::pair<iterator, iterator>
    00188     prefix_range(const_key_reference);
    00189
    00190     // Finds the const iterator range corresponding to all values
    00191     // whose prefixes match [b, e).
    00192     std::pair<const_iterator, const_iterator>
    00193     prefix_range(const_e_iterator, const_e_iterator) const;
    00194
    00195     // Finds the iterator range corresponding to all values whose
    00196     // prefixes match [b, e).
    00197     std::pair<iterator, iterator>
    00198     prefix_range(const_e_iterator, const_e_iterator);
    00199
    00200   protected:
    00201     // Called to update a node's metadata.
    00202     inline void
    00203     operator()(node_iterator node_it, const_node_iterator end_nd_it) const;
    00204
    00205   private:
    00206     // Returns the const iterator associated with the just-after last element.
    00207     virtual const_iterator
    00208     end() const = 0;
    00209
    00210     // Returns the iterator associated with the just-after last element.
    00211     virtual iterator
    00212     end() = 0;
    00213
    00214     // Returns the const_node_iterator associated with the trie's root node.
    00215     virtual const_node_iterator
    00216     node_begin() const = 0;
    00217
    00218     // Returns the node_iterator associated with the trie's root node.
    00219     virtual node_iterator
    00220     node_begin() = 0;
    00221
    00222     // Returns the const_node_iterator associated with a just-after leaf node.
    00223     virtual const_node_iterator
    00224     node_end() const = 0;
    00225
    00226     // Returns the node_iterator associated with a just-after leaf node.
    00227     virtual node_iterator
    00228     node_end() = 0;
    00229
    00230     // Access to the cmp_fn object.
    00231     virtual const e_access_traits&
    00232     get_e_access_traits() const = 0;
    00233
    00234     node_iterator
    00235     next_child(node_iterator, const_e_iterator, const_e_iterator,
    00236            node_iterator, const e_access_traits&);
    00237   };
    00238
    00239 #include <ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp>
    00240
    00241 #undef PB_DS_CLASS_C_DEC
    00242
    00243 #define PB_DS_CLASS_C_DEC \
    00244   trie_order_statistics_node_update<Const_Node_Iterator, Node_Iterator,E_Access_Traits, Allocator>
    00245
    00246   // Functor updating ranks of entrees.
    00247   template<typename Const_Node_Iterator,
    00248        typename Node_Iterator,
    00249        typename E_Access_Traits,
    00250        typename Allocator>
    00251   class trie_order_statistics_node_update : private PB_DS_BASE_C_DEC
    00252   {
    00253   private:
    00254     typedef PB_DS_BASE_C_DEC base_type;
    00255
    00256   public:
    00257     typedef E_Access_Traits e_access_traits;
    00258     typedef typename e_access_traits::const_iterator const_e_iterator;
    00259     typedef Allocator allocator;
    00260     typedef typename allocator::size_type size_type;
    00261     typedef typename base_type::key_type key_type;
    00262     typedef typename base_type::const_key_reference const_key_reference;
    00263
    00264     typedef size_type metadata_type;
    00265     typedef Const_Node_Iterator const_node_iterator;
    00266     typedef Node_Iterator node_iterator;
    00267     typedef typename const_node_iterator::value_type const_iterator;
    00268     typedef typename node_iterator::value_type iterator;
    00269
    00270     // Finds an entry by __order. Returns a const_iterator to the
    00271     // entry with the __order order, or a const_iterator to the
    00272     // container object's end if order is at least the size of the
    00273     // container object.
    00274     inline const_iterator
    00275     find_by_order(size_type) const;
    00276
    00277     // Finds an entry by __order. Returns an iterator to the entry
    00278     // with the __order order, or an iterator to the container
    00279     // object's end if order is at least the size of the container
    00280     // object.
    00281     inline iterator
    00282     find_by_order(size_type);
    00283
    00284     // Returns the order of a key within a sequence. For exapmle, if
    00285     // r_key is the smallest key, this method will return 0; if r_key
    00286     // is a key between the smallest and next key, this method will
    00287     // return 1; if r_key is a key larger than the largest key, this
    00288     // method will return the size of r_c.
    00289     inline size_type
    00290     order_of_key(const_key_reference) const;
    00291
    00292     // Returns the order of a prefix within a sequence. For exapmle,
    00293     // if [b, e] is the smallest prefix, this method will return 0; if
    00294     // r_key is a key between the smallest and next key, this method
    00295     // will return 1; if r_key is a key larger than the largest key,
    00296     // this method will return the size of r_c.
    00297     inline size_type
    00298     order_of_prefix(const_e_iterator, const_e_iterator) const;
    00299
    00300   private:
    00301     typedef typename base_type::const_reference const_reference;
    00302     typedef typename base_type::const_pointer const_pointer;
    00303
    00304     typedef typename Allocator::template rebind<metadata_type>::other metadata_rebind;
    00305     typedef typename metadata_rebind::const_reference const_metadata_reference;
    00306     typedef typename metadata_rebind::reference metadata_reference;
    00307
    00308     // Returns true if the container is empty.
    00309     virtual bool
    00310     empty() const = 0;
    00311
    00312     // Returns the iterator associated with the trie's first element.
    00313     virtual iterator
    00314     begin() = 0;
    00315
    00316     // Returns the iterator associated with the trie's
    00317     // just-after-last element.
    00318     virtual iterator
    00319     end() = 0;
    00320
    00321     // Returns the const_node_iterator associated with the trie's root node.
    00322     virtual const_node_iterator
    00323     node_begin() const = 0;
    00324
    00325     // Returns the node_iterator associated with the trie's root node.
    00326     virtual node_iterator
    00327     node_begin() = 0;
    00328
    00329     // Returns the const_node_iterator associated with a just-after
    00330     // leaf node.
    00331     virtual const_node_iterator
    00332     node_end() const = 0;
    00333
    00334     // Returns the node_iterator associated with a just-after leaf node.
    00335     virtual node_iterator
    00336     node_end() = 0;
    00337
    00338     // Access to the cmp_fn object.
    00339     virtual e_access_traits&
    00340     get_e_access_traits() = 0;
    00341
    00342   protected:
    00343     // Updates the rank of a node through a node_iterator node_it;
    00344     // end_nd_it is the end node iterator.
    00345     inline void
    00346     operator()(node_iterator, const_node_iterator) const;
    00347
    00348     // Destructor.
    00349     virtual
    00350     ~trie_order_statistics_node_update();
    00351   };
    00352
    00353 #include <ext/pb_ds/detail/trie_policy/order_statistics_imp.hpp>
    00354
    00355 #undef PB_DS_CLASS_T_DEC
    00356 #undef PB_DS_CLASS_C_DEC
    00357 #undef PB_DS_BASE_C_DEC
    00358
    00359 } // namespace __gnu_pbds
    00360
    00361 #endif