trie_policy.hpp

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00001 // -*- C++ -*-
00002 
00003 // Copyright (C) 2005, 2006 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 pb_ds
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_STATIC_ASSERT(UNIQUE, E)                  \
00065   typedef detail::static_assert_dumclass<sizeof(detail::static_assert<bool(E)>)> UNIQUE##_static_assert_type
00066 
00067 #define PB_DS_CLASS_T_DEC                       \
00068   template<typename String, typename String::value_type Min_E_Val, typename String::value_type Max_E_Val, bool Reverse, typename Allocator>
00069 
00070 #define PB_DS_CLASS_C_DEC                       \
00071   string_trie_e_access_traits<String, Min_E_Val,Max_E_Val,Reverse,Allocator>
00072 
00073   // Element access traits for string types.
00074   template<typename String = std::string,
00075        typename String::value_type Min_E_Val = detail::__numeric_traits<typename String::value_type>::__min, 
00076        typename String::value_type Max_E_Val = detail::__numeric_traits<typename String::value_type>::__max, 
00077        bool Reverse = false,
00078        typename Allocator = std::allocator<char> >
00079   struct string_trie_e_access_traits
00080   {
00081   public:
00082     typedef typename Allocator::size_type size_type;
00083     typedef String key_type;
00084     typedef typename Allocator::template rebind<key_type>::other key_rebind;
00085     typedef typename key_rebind::const_reference const_key_reference;
00086 
00087     enum
00088       {
00089     reverse = Reverse
00090       };
00091 
00092     // Element const iterator type.
00093     typedef typename detail::__conditional_type<Reverse, typename String::const_reverse_iterator, typename String::const_iterator>::__type const_iterator;
00094 
00095     // Element type.
00096     typedef typename std::iterator_traits<const_iterator>::value_type e_type;
00097 
00098     enum
00099       {
00100     min_e_val = Min_E_Val,
00101     max_e_val = Max_E_Val,
00102     max_size = max_e_val - min_e_val + 1
00103       };
00104     PB_DS_STATIC_ASSERT(min_max_size, max_size >= 2);
00105 
00106     // Returns a const_iterator to the first element of
00107     // const_key_reference agumnet.
00108     inline static const_iterator
00109     begin(const_key_reference);
00110 
00111     // Returns a const_iterator to the after-last element of
00112     // const_key_reference argument.
00113     inline static const_iterator
00114     end(const_key_reference);
00115 
00116     // Maps an element to a position.
00117     inline static size_type
00118     e_pos(e_type e);
00119 
00120   private:
00121 
00122     inline static const_iterator
00123     begin_imp(const_key_reference, detail::false_type);
00124 
00125     inline static const_iterator
00126     begin_imp(const_key_reference, detail::true_type);
00127 
00128     inline static const_iterator
00129     end_imp(const_key_reference, detail::false_type);
00130 
00131     inline static const_iterator
00132     end_imp(const_key_reference, detail::true_type);
00133 
00134     static detail::integral_constant<int, Reverse> s_rev_ind;
00135   };
00136 
00137 #include <ext/pb_ds/detail/trie_policy/string_trie_e_access_traits_imp.hpp>
00138 
00139 #undef PB_DS_CLASS_T_DEC
00140 #undef PB_DS_CLASS_C_DEC
00141 
00142 #define PB_DS_CLASS_T_DEC \
00143   template<typename Const_Node_Iterator,typename Node_Iterator,class E_Access_Traits, typename Allocator>
00144 
00145 #define PB_DS_CLASS_C_DEC \
00146   trie_prefix_search_node_update<Const_Node_Iterator, Node_Iterator, E_Access_Traits,Allocator>
00147 
00148 #define PB_DS_BASE_C_DEC \
00149   detail::trie_policy_base<Const_Node_Iterator,Node_Iterator,E_Access_Traits, Allocator>
00150 
00151   // A node updator that allows tries to be searched for the range of
00152   // values that match a certain prefix.
00153   template<typename Const_Node_Iterator,
00154        typename Node_Iterator,
00155        typename E_Access_Traits,
00156        typename Allocator>
00157   class trie_prefix_search_node_update : private PB_DS_BASE_C_DEC
00158   {
00159   private:
00160     typedef PB_DS_BASE_C_DEC base_type;
00161 
00162   public:
00163     typedef typename base_type::key_type key_type;
00164     typedef typename base_type::const_key_reference const_key_reference;
00165 
00166     // Element access traits.
00167     typedef E_Access_Traits e_access_traits;
00168 
00169     // Const element iterator.
00170     typedef typename e_access_traits::const_iterator const_e_iterator;
00171 
00172     // Allocator type.
00173     typedef Allocator allocator;
00174 
00175     // Size type.
00176     typedef typename allocator::size_type size_type;
00177     typedef detail::null_node_metadata metadata_type;
00178     typedef Const_Node_Iterator const_node_iterator;
00179     typedef Node_Iterator node_iterator;
00180     typedef typename const_node_iterator::value_type const_iterator;
00181     typedef typename node_iterator::value_type iterator;
00182 
00183     // Finds the const iterator range corresponding to all values
00184     // whose prefixes match r_key.
00185     std::pair<const_iterator, const_iterator>
00186     prefix_range(const_key_reference) const;
00187 
00188     // Finds the iterator range corresponding to all values whose
00189     // prefixes match r_key.
00190     std::pair<iterator, iterator>
00191     prefix_range(const_key_reference);
00192 
00193     // Finds the const iterator range corresponding to all values
00194     // whose prefixes match [b, e).
00195     std::pair<const_iterator, const_iterator>
00196     prefix_range(const_e_iterator, const_e_iterator) const;
00197 
00198     // Finds the iterator range corresponding to all values whose
00199     // prefixes match [b, e).
00200     std::pair<iterator, iterator>
00201     prefix_range(const_e_iterator, const_e_iterator);
00202 
00203   protected:
00204     // Called to update a node's metadata.
00205     inline void
00206     operator()(node_iterator node_it, const_node_iterator end_nd_it) const;
00207 
00208   private:
00209     // Returns the const iterator associated with the just-after last element.
00210     virtual const_iterator
00211     end() const = 0;
00212 
00213     // Returns the iterator associated with the just-after last element.
00214     virtual iterator
00215     end() = 0;
00216 
00217     // Returns the const_node_iterator associated with the trie's root node.
00218     virtual const_node_iterator
00219     node_begin() const = 0;
00220 
00221     // Returns the node_iterator associated with the trie's root node.
00222     virtual node_iterator
00223     node_begin() = 0;
00224 
00225     // Returns the const_node_iterator associated with a just-after leaf node.
00226     virtual const_node_iterator
00227     node_end() const = 0;
00228 
00229     // Returns the node_iterator associated with a just-after leaf node.
00230     virtual node_iterator
00231     node_end() = 0;
00232 
00233     // Access to the cmp_fn object.
00234     virtual const e_access_traits& 
00235     get_e_access_traits() const = 0;
00236 
00237     node_iterator
00238     next_child(node_iterator, const_e_iterator, const_e_iterator, 
00239            node_iterator, const e_access_traits&);
00240   };
00241 
00242 #include <ext/pb_ds/detail/trie_policy/prefix_search_node_update_imp.hpp>
00243 
00244 #undef PB_DS_CLASS_C_DEC
00245 
00246 #define PB_DS_CLASS_C_DEC \
00247   trie_order_statistics_node_update<Const_Node_Iterator, Node_Iterator,E_Access_Traits, Allocator>
00248 
00249   // Functor updating ranks of entrees.
00250   template<typename Const_Node_Iterator,
00251        typename Node_Iterator,
00252        typename E_Access_Traits,
00253        typename Allocator>
00254   class trie_order_statistics_node_update : private PB_DS_BASE_C_DEC
00255   {
00256   private:
00257     typedef PB_DS_BASE_C_DEC base_type;
00258 
00259   public:
00260     typedef E_Access_Traits e_access_traits;
00261     typedef typename e_access_traits::const_iterator const_e_iterator;
00262     typedef Allocator allocator;
00263     typedef typename allocator::size_type size_type;
00264     typedef typename base_type::key_type key_type;
00265     typedef typename base_type::const_key_reference const_key_reference;
00266 
00267     typedef size_type metadata_type;
00268     typedef Const_Node_Iterator const_node_iterator;
00269     typedef Node_Iterator node_iterator;
00270     typedef typename const_node_iterator::value_type const_iterator;
00271     typedef typename node_iterator::value_type iterator;
00272 
00273     // Finds an entry by __order. Returns a const_iterator to the
00274     // entry with the __order order, or a const_iterator to the
00275     // container object's end if order is at least the size of the
00276     // container object.
00277     inline const_iterator
00278     find_by_order(size_type) const;
00279 
00280     // Finds an entry by __order. Returns an iterator to the entry
00281     // with the __order order, or an iterator to the container
00282     // object's end if order is at least the size of the container
00283     // object.
00284     inline iterator
00285     find_by_order(size_type);
00286 
00287     // Returns the order of a key within a sequence. For exapmle, if
00288     // r_key is the smallest key, this method will return 0; if r_key
00289     // is a key between the smallest and next key, this method will
00290     // return 1; if r_key is a key larger than the largest key, this
00291     // method will return the size of r_c.
00292     inline size_type
00293     order_of_key(const_key_reference) const;
00294 
00295     // Returns the order of a prefix within a sequence. For exapmle,
00296     // if [b, e] is the smallest prefix, this method will return 0; if
00297     // r_key is a key between the smallest and next key, this method
00298     // will return 1; if r_key is a key larger than the largest key,
00299     // this method will return the size of r_c.
00300     inline size_type
00301     order_of_prefix(const_e_iterator, const_e_iterator) const;
00302 
00303   private:
00304     typedef typename base_type::const_reference const_reference;
00305     typedef typename base_type::const_pointer const_pointer;
00306 
00307     typedef typename Allocator::template rebind<metadata_type>::other metadata_rebind;
00308     typedef typename metadata_rebind::const_reference const_metadata_reference;
00309     typedef typename metadata_rebind::reference metadata_reference;
00310 
00311     // Returns true if the container is empty.
00312     virtual bool
00313     empty() const = 0;
00314 
00315     // Returns the iterator associated with the trie's first element.
00316     virtual iterator
00317     begin() = 0;
00318 
00319     // Returns the iterator associated with the trie's
00320     // just-after-last element.
00321     virtual iterator
00322     end() = 0;
00323 
00324     // Returns the const_node_iterator associated with the trie's root node.
00325     virtual const_node_iterator
00326     node_begin() const = 0;
00327 
00328     // Returns the node_iterator associated with the trie's root node.
00329     virtual node_iterator
00330     node_begin() = 0;
00331 
00332     // Returns the const_node_iterator associated with a just-after
00333     // leaf node.
00334     virtual const_node_iterator
00335     node_end() const = 0;
00336 
00337     // Returns the node_iterator associated with a just-after leaf node.
00338     virtual node_iterator
00339     node_end() = 0;
00340 
00341     // Access to the cmp_fn object.
00342     virtual e_access_traits& 
00343     get_e_access_traits() = 0;
00344 
00345   protected:
00346     // Updates the rank of a node through a node_iterator node_it;
00347     // end_nd_it is the end node iterator.
00348     inline void
00349     operator()(node_iterator, const_node_iterator) const;
00350 
00351     // Destructor.
00352     virtual
00353     ~trie_order_statistics_node_update();
00354   };
00355 
00356 #include <ext/pb_ds/detail/trie_policy/order_statistics_imp.hpp>
00357 
00358 #undef PB_DS_CLASS_T_DEC
00359 #undef PB_DS_CLASS_C_DEC
00360 #undef PB_DS_BASE_C_DEC
00361 #undef PB_DS_STATIC_ASSERT
00362 
00363 } // namespace pb_ds
00364 
00365 #endif

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