# trie_policy.hpp

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    00001 // -*- C++ -*-
    00002
    00003 // Copyright (C) 2005, 2006, 2007, 2009 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
    00017 // permissions described in the GCC Runtime Library Exception, version
    00018 // 3.1, as published by the Free Software Foundation.
    00019
    00020 // You should have received a copy of the GNU General Public License and
    00021 // a copy of the GCC Runtime Library Exception along with this program;
    00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    00023 // <http://www.gnu.org/licenses/>.
    00024
    00025 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
    00026
    00027 // Permission to use, copy, modify, sell, and distribute this software
    00028 // is hereby granted without fee, provided that the above copyright
    00029 // notice appears in all copies, and that both that copyright notice
    00030 // and this permission notice appear in supporting documentation. None
    00031 // of the above authors, nor IBM Haifa Research Laboratories, make any
    00032 // representation about the suitability of this software for any
    00033 // purpose. It is provided "as is" without express or implied
    00034 // warranty.
    00035
    00036 /**
    00037  * @file trie_policy.hpp
    00038  * Contains trie-related policies.
    00039  */
    00040
    00041 #ifndef PB_DS_TRIE_POLICY_HPP
    00042 #define PB_DS_TRIE_POLICY_HPP
    00043
    00044 #include <string>
    00045 #include <ext/pb_ds/detail/type_utils.hpp>
    00046 #include <ext/pb_ds/detail/trie_policy/trie_policy_base.hpp>
    00047
    00048 namespace __gnu_pbds
    00049 {
    00050   // A null node updator, indicating that no node updates are required.
    00051   template<typename Const_Node_Iterator,
    00052        typename Node_Iterator,
    00053        typename E_Access_Traits,
    00054        typename Allocator>
    00055   struct null_trie_node_update
    00056   { };
    00057
    00058 #define PB_DS_CLASS_T_DEC                       \
    00059   template<typename String, typename String::value_type Min_E_Val, typename String::value_type Max_E_Val, bool Reverse, typename Allocator>
    00060
    00061 #define PB_DS_CLASS_C_DEC                       \
    00062   string_trie_e_access_traits<String, Min_E_Val,Max_E_Val,Reverse,Allocator>
    00063
    00064   // Element access traits for string types.
    00065   template<typename String = std::string,
    00066        typename String::value_type Min_E_Val = detail::__numeric_traits<typename String::value_type>::__min,
    00067        typename String::value_type Max_E_Val = detail::__numeric_traits<typename String::value_type>::__max,
    00068        bool Reverse = false,
    00069        typename Allocator = std::allocator<char> >
    00070   struct string_trie_e_access_traits
    00071   {
    00072   public:
    00073     typedef typename Allocator::size_type size_type;
    00074     typedef String key_type;
    00075     typedef typename Allocator::template rebind<key_type>::other key_rebind;
    00076     typedef typename key_rebind::const_reference const_key_reference;
    00077
    00078     enum
    00079       {
    00080     reverse = Reverse
    00081       };
    00082
    00083     // Element const iterator type.
    00084     typedef typename detail::__conditional_type<Reverse, typename String::const_reverse_iterator, typename String::const_iterator>::__type const_iterator;
    00085
    00086     // Element type.
    00087     typedef typename std::iterator_traits<const_iterator>::value_type e_type;
    00088
    00089     enum
    00090       {
    00091     min_e_val = Min_E_Val,
    00092     max_e_val = Max_E_Val,
    00093     max_size = max_e_val - min_e_val + 1
    00094       };
    00095     PB_DS_STATIC_ASSERT(min_max_size, max_size >= 2);
    00096
    00097     // Returns a const_iterator to the first element of
    00098     // const_key_reference agumnet.
    00099     inline static const_iterator
    00100     begin(const_key_reference);
    00101
    00102     // Returns a const_iterator to the after-last element of
    00103     // const_key_reference argument.
    00104     inline static const_iterator
    00105     end(const_key_reference);
    00106
    00107     // Maps an element to a position.
    00108     inline static size_type
    00109     e_pos(e_type e);
    00110
    00111   private:
    00112
    00113     inline static const_iterator
    00114     begin_imp(const_key_reference, detail::false_type);
    00115
    00116     inline static const_iterator
    00117     begin_imp(const_key_reference, detail::true_type);
    00118
    00119     inline static const_iterator
    00120     end_imp(const_key_reference, detail::false_type);
    00121
    00122     inline static const_iterator
    00123     end_imp(const_key_reference, detail::true_type);
    00124
    00125     static detail::integral_constant<int, Reverse> s_rev_ind;
    00126   };
    00127
    00128 #include <ext/pb_ds/detail/trie_policy/string_trie_e_access_traits_imp.hpp>
    00129
    00130 #undef PB_DS_CLASS_T_DEC
    00131 #undef PB_DS_CLASS_C_DEC
    00132
    00133 #define PB_DS_CLASS_T_DEC \
    00134   template<typename Const_Node_Iterator,typename Node_Iterator,class E_Access_Traits, typename Allocator>
    00135
    00136 #define PB_DS_CLASS_C_DEC \
    00137   trie_prefix_search_node_update<Const_Node_Iterator, Node_Iterator, E_Access_Traits,Allocator>
    00138
    00139 #define PB_DS_BASE_C_DEC \
    00140   detail::trie_policy_base<Const_Node_Iterator,Node_Iterator,E_Access_Traits, Allocator>
    00141
    00142   // A node updator that allows tries to be searched for the range of
    00143   // values that match a certain prefix.
    00144   template<typename Const_Node_Iterator,
    00145        typename Node_Iterator,
    00146        typename E_Access_Traits,
    00147        typename Allocator>
    00148   class trie_prefix_search_node_update : private PB_DS_BASE_C_DEC
    00149   {
    00150   private:
    00151     typedef PB_DS_BASE_C_DEC base_type;
    00152
    00153   public:
    00154     typedef typename base_type::key_type key_type;
    00155     typedef typename base_type::const_key_reference const_key_reference;
    00156
    00157     // Element access traits.
    00158     typedef E_Access_Traits e_access_traits;
    00159
    00160     // Const element iterator.
    00161     typedef typename e_access_traits::const_iterator const_e_iterator;
    00162
    00163     // Allocator type.
    00164     typedef Allocator allocator_type;
    00165
    00166     // Size type.
    00167     typedef typename allocator_type::size_type size_type;
    00168     typedef detail::null_node_metadata metadata_type;
    00169     typedef Const_Node_Iterator const_node_iterator;
    00170     typedef Node_Iterator node_iterator;
    00171     typedef typename const_node_iterator::value_type const_iterator;
    00172     typedef typename node_iterator::value_type iterator;
    00173
    00174     // Finds the const iterator range corresponding to all values
    00175     // whose prefixes match r_key.
    00176     std::pair<const_iterator, const_iterator>
    00177     prefix_range(const_key_reference) const;
    00178
    00179     // Finds the iterator range corresponding to all values whose
    00180     // prefixes match r_key.
    00181     std::pair<iterator, iterator>
    00182     prefix_range(const_key_reference);
    00183
    00184     // Finds the const iterator range corresponding to all values
    00185     // whose prefixes match [b, e).
    00186     std::pair<const_iterator, const_iterator>
    00187     prefix_range(const_e_iterator, const_e_iterator) const;
    00188
    00189     // Finds the iterator range corresponding to all values whose
    00190     // prefixes match [b, e).
    00191     std::pair<iterator, iterator>
    00192     prefix_range(const_e_iterator, const_e_iterator);
    00193
    00194   protected:
    00195     // Called to update a node's metadata.
    00196     inline void
    00197     operator()(node_iterator node_it, const_node_iterator end_nd_it) const;
    00198
    00199   private:
    00200     // Returns the const iterator associated with the just-after last element.
    00201     virtual const_iterator
    00202     end() const = 0;
    00203
    00204     // Returns the iterator associated with the just-after last element.
    00205     virtual iterator
    00206     end() = 0;
    00207
    00208     // Returns the const_node_iterator associated with the trie's root node.
    00209     virtual const_node_iterator
    00210     node_begin() const = 0;
    00211
    00212     // Returns the node_iterator associated with the trie's root node.
    00213     virtual node_iterator
    00214     node_begin() = 0;
    00215
    00216     // Returns the const_node_iterator associated with a just-after leaf node.
    00217     virtual const_node_iterator
    00218     node_end() const = 0;
    00219
    00220     // Returns the node_iterator associated with a just-after leaf node.
    00221     virtual node_iterator
    00222     node_end() = 0;
    00223
    00224     // Access to the cmp_fn object.
    00225     virtual const e_access_traits&
    00226     get_e_access_traits() const = 0;
    00227
    00228     node_iterator
    00229     next_child(node_iterator, const_e_iterator, const_e_iterator,
    00230            node_iterator, const e_access_traits&);
    00231   };
    00232
    00233 #include <ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp>
    00234
    00235 #undef PB_DS_CLASS_C_DEC
    00236
    00237 #define PB_DS_CLASS_C_DEC \
    00238   trie_order_statistics_node_update<Const_Node_Iterator, Node_Iterator,E_Access_Traits, Allocator>
    00239
    00240   // Functor updating ranks of entrees.
    00241   template<typename Const_Node_Iterator,
    00242        typename Node_Iterator,
    00243        typename E_Access_Traits,
    00244        typename Allocator>
    00245   class trie_order_statistics_node_update : private PB_DS_BASE_C_DEC
    00246   {
    00247   private:
    00248     typedef PB_DS_BASE_C_DEC base_type;
    00249
    00250   public:
    00251     typedef E_Access_Traits e_access_traits;
    00252     typedef typename e_access_traits::const_iterator const_e_iterator;
    00253     typedef Allocator allocator_type;
    00254     typedef typename allocator_type::size_type size_type;
    00255     typedef typename base_type::key_type key_type;
    00256     typedef typename base_type::const_key_reference const_key_reference;
    00257
    00258     typedef size_type metadata_type;
    00259     typedef Const_Node_Iterator const_node_iterator;
    00260     typedef Node_Iterator node_iterator;
    00261     typedef typename const_node_iterator::value_type const_iterator;
    00262     typedef typename node_iterator::value_type iterator;
    00263
    00264     // Finds an entry by __order. Returns a const_iterator to the
    00265     // entry with the __order order, or a const_iterator to the
    00266     // container object's end if order is at least the size of the
    00267     // container object.
    00268     inline const_iterator
    00269     find_by_order(size_type) const;
    00270
    00271     // Finds an entry by __order. Returns an iterator to the entry
    00272     // with the __order order, or an iterator to the container
    00273     // object's end if order is at least the size of the container
    00274     // object.
    00275     inline iterator
    00276     find_by_order(size_type);
    00277
    00278     // Returns the order of a key within a sequence. For exapmle, if
    00279     // r_key is the smallest key, this method will return 0; if r_key
    00280     // is a key between the smallest and next key, this method will
    00281     // return 1; if r_key is a key larger than the largest key, this
    00282     // method will return the size of r_c.
    00283     inline size_type
    00284     order_of_key(const_key_reference) const;
    00285
    00286     // Returns the order of a prefix within a sequence. For exapmle,
    00287     // if [b, e] is the smallest prefix, this method will return 0; if
    00288     // r_key is a key between the smallest and next key, this method
    00289     // will return 1; if r_key is a key larger than the largest key,
    00290     // this method will return the size of r_c.
    00291     inline size_type
    00292     order_of_prefix(const_e_iterator, const_e_iterator) const;
    00293
    00294   private:
    00295     typedef typename base_type::const_reference const_reference;
    00296     typedef typename base_type::const_pointer const_pointer;
    00297
    00298     typedef typename Allocator::template rebind<metadata_type>::other metadata_rebind;
    00299     typedef typename metadata_rebind::const_reference const_metadata_reference;
    00300     typedef typename metadata_rebind::reference metadata_reference;
    00301
    00302     // Returns true if the container is empty.
    00303     virtual bool
    00304     empty() const = 0;
    00305
    00306     // Returns the iterator associated with the trie's first element.
    00307     virtual iterator
    00308     begin() = 0;
    00309
    00310     // Returns the iterator associated with the trie's
    00311     // just-after-last element.
    00312     virtual iterator
    00313     end() = 0;
    00314
    00315     // Returns the const_node_iterator associated with the trie's root node.
    00316     virtual const_node_iterator
    00317     node_begin() const = 0;
    00318
    00319     // Returns the node_iterator associated with the trie's root node.
    00320     virtual node_iterator
    00321     node_begin() = 0;
    00322
    00323     // Returns the const_node_iterator associated with a just-after
    00324     // leaf node.
    00325     virtual const_node_iterator
    00326     node_end() const = 0;
    00327
    00328     // Returns the node_iterator associated with a just-after leaf node.
    00329     virtual node_iterator
    00330     node_end() = 0;
    00331
    00332     // Access to the cmp_fn object.
    00333     virtual e_access_traits&
    00334     get_e_access_traits() = 0;
    00335
    00336   protected:
    00337     // Updates the rank of a node through a node_iterator node_it;
    00338     // end_nd_it is the end node iterator.
    00339     inline void
    00340     operator()(node_iterator, const_node_iterator) const;
    00341
    00342     // Destructor.
    00343     virtual
    00344     ~trie_order_statistics_node_update();
    00345   };
    00346
    00347 #include <ext/pb_ds/detail/trie_policy/order_statistics_imp.hpp>
    00348
    00349 #undef PB_DS_CLASS_T_DEC
    00350 #undef PB_DS_CLASS_C_DEC
    00351 #undef PB_DS_BASE_C_DEC
    00352
    00353 } // namespace __gnu_pbds
    00354
    00355 #endif