wtf/HashSet.h

   1 // -*- mode: c++; c-basic-offset: 4 -*-
   2 /*
   3  * Copyright (C) 2005, 2006, 2007 Apple Inc. All rights reserved.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Library General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Library General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Library General Public License
  16  * along with this library; see the file COPYING.LIB.  If not, write to
  17  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18  * Boston, MA 02110-1301, USA.
  19  *
  20  */
  21
  22 #ifndef WTF_HashSet_h
  23 #define WTF_HashSet_h
  24
  25 #include "HashTable.h"
  26
  27 namespace WTF {
  28
  29     template<typename T> struct IdentityExtractor;
  30
  31     template<typename Value, typename HashFunctions, typename Traits> class HashSet;
  32     template<typename Value, typename HashFunctions, typename Traits>
  33     void deleteAllValues(const HashSet<Value, HashFunctions, Traits>&);
  34
  35     template<typename ValueArg, typename HashArg = typename DefaultHash<ValueArg>::Hash,
  36         typename TraitsArg = HashTraits<ValueArg> > class HashSet {
  37     private:
  38         typedef HashArg HashFunctions;
  39         typedef TraitsArg ValueTraits;
  40
  41         typedef typename HashKeyStorageTraits<HashFunctions, ValueTraits>::Hash StorageHashFunctions;
  42
  43         typedef typename HashKeyStorageTraits<HashFunctions, ValueTraits>::Traits StorageTraits;
  44         typedef typename StorageTraits::TraitType StorageType;
  45
  46         typedef HashTable<StorageType, StorageType, IdentityExtractor<StorageType>,
  47             StorageHashFunctions, StorageTraits, StorageTraits> HashTableType;
  48
  49     public:
  50         typedef typename ValueTraits::TraitType ValueType;
  51         typedef HashTableIteratorAdapter<HashTableType, ValueType> iterator;
  52         typedef HashTableConstIteratorAdapter<HashTableType, ValueType> const_iterator;
  53
  54         HashSet();
  55         HashSet(const HashSet&);
  56         HashSet& operator=(const HashSet&);
  57         ~HashSet();
  58
  59         void swap(HashSet&);
  60
  61         int size() const;
  62         int capacity() const;
  63         bool isEmpty() const;
  64
  65         iterator begin();
  66         iterator end();
  67         const_iterator begin() const;
  68         const_iterator end() const;
  69
  70         iterator find(const ValueType&);
  71         const_iterator find(const ValueType&) const;
  72         bool contains(const ValueType&) const;
  73
  74         // the return value is a pair of an interator to the new value's location,
  75         // and a bool that is true if an new entry was added
  76         pair<iterator, bool> add(const ValueType&);
  77
  78         // a special version of add() that finds the object by hashing and comparing
  79         // with some other type, to avoid the cost of type conversion if the object is already
  80         // in the table. HashTranslator should have the following methods:
  81         //   static unsigned hash(const T&);
  82         //   static bool equal(const ValueType&, const T&);
  83         //   static translate(ValueType&, const T&, unsigned hashCode);
  84         template<typename T, typename HashTranslator> pair<iterator, bool> add(const T&);
  85
  86         void remove(const ValueType&);
  87         void remove(iterator);
  88         void clear();
  89
  90     private:
  91         void refAll();
  92         void derefAll();
  93
  94         friend void deleteAllValues<>(const HashSet&);
  95
  96         HashTableType m_impl;
  97     };
  98
  99     template<typename T> struct IdentityExtractor {
 100         static const T& extract(const T& t) { return t; }
 101     };
 102
 103     template<bool canReplaceDeletedValue, typename ValueType, typename ValueTraits, typename StorageTraits, typename HashFunctions>
 104     struct HashSetTranslator;
 105
 106     template<typename ValueType, typename ValueTraits, typename StorageTraits, typename HashFunctions>
 107     struct HashSetTranslator<true, ValueType, ValueTraits, StorageTraits, HashFunctions> {
 108         typedef typename StorageTraits::TraitType StorageType;
 109         static unsigned hash(const ValueType& key) { return HashFunctions::hash(key); }
 110         static bool equal(const StorageType& a, const ValueType& b) { return HashFunctions::equal(*(const ValueType*)&a, b); }
 111         static void translate(StorageType& location, const ValueType& key, const ValueType&)
 112         {
 113             Assigner<ValueTraits::needsRef, ValueType, StorageType, ValueTraits>::assign(key, location);
 114         }
 115     };
 116
 117     template<typename ValueType, typename ValueTraits, typename StorageTraits, typename HashFunctions>
 118     struct HashSetTranslator<false, ValueType, ValueTraits, StorageTraits, HashFunctions> {
 119         typedef typename StorageTraits::TraitType StorageType;
 120         static unsigned hash(const ValueType& key) { return HashFunctions::hash(key); }
 121         static bool equal(const StorageType& a, const ValueType& b) { return HashFunctions::equal(*(const ValueType*)&a, b); }
 122         static void translate(StorageType& location, const ValueType& key, const ValueType&)
 123         {
 124             if (location == StorageTraits::deletedValue())
 125                 location = StorageTraits::emptyValue();
 126             Assigner<ValueTraits::needsRef, ValueType, StorageType, ValueTraits>::assign(key, location);
 127         }
 128     };
 129
 130     template<bool canReplaceDeletedValue, typename ValueType, typename StorageTraits, typename T, typename Translator>
 131     struct HashSetTranslatorAdapter;
 132
 133     template<typename ValueType, typename StorageTraits, typename T, typename Translator>
 134     struct HashSetTranslatorAdapter<true, ValueType, StorageTraits, T, Translator> {
 135         typedef typename StorageTraits::TraitType StorageType;
 136         static unsigned hash(const T& key) { return Translator::hash(key); }
 137         static bool equal(const StorageType& a, const T& b) { return Translator::equal(*(const ValueType*)&a, b); }
 138         static void translate(StorageType& location, const T& key, const T&, unsigned hashCode)
 139         {
 140             Translator::translate(*(ValueType*)&location, key, hashCode);
 141         }
 142     };
 143
 144     template<typename ValueType, typename StorageTraits, typename T, typename Translator>
 145     struct HashSetTranslatorAdapter<false, ValueType, StorageTraits, T, Translator> {
 146         typedef typename StorageTraits::TraitType StorageType;
 147         static unsigned hash(const T& key) { return Translator::hash(key); }
 148         static bool equal(const StorageType& a, const T& b) { return Translator::equal(*(const ValueType*)&a, b); }
 149         static void translate(StorageType& location, const T& key, const T&, unsigned hashCode)
 150         {
 151             if (location == StorageTraits::deletedValue())
 152                 location = StorageTraits::emptyValue();
 153             Translator::translate(*(ValueType*)&location, key, hashCode);
 154         }
 155     };
 156
 157     template<typename T, typename U, typename V>
 158     inline void HashSet<T, U, V>::refAll()
 159     {
 160         HashTableRefCounter<HashTableType, ValueTraits>::refAll(m_impl);
 161     }
 162
 163     template<typename T, typename U, typename V>
 164     inline void HashSet<T, U, V>::derefAll()
 165     {
 166         HashTableRefCounter<HashTableType, ValueTraits>::derefAll(m_impl);
 167     }
 168
 169     template<typename T, typename U, typename V>
 170     inline HashSet<T, U, V>::HashSet()
 171     {
 172     }
 173
 174     template<typename T, typename U, typename V>
 175     inline HashSet<T, U, V>::HashSet(const HashSet& other)
 176         : m_impl(other.m_impl)
 177     {
 178         refAll();
 179     }
 180
 181     template<typename T, typename U, typename V>
 182     inline HashSet<T, U, V>& HashSet<T, U, V>::operator=(const HashSet& other)
 183     {
 184         HashSet tmp(other);
 185         swap(tmp);
 186         return *this;
 187     }
 188
 189     template<typename T, typename U, typename V>
 190     inline void HashSet<T, U, V>::swap(HashSet& other)
 191     {
 192         m_impl.swap(other.m_impl);
 193     }
 194
 195     template<typename T, typename U, typename V>
 196     inline HashSet<T, U, V>::~HashSet()
 197     {
 198         derefAll();
 199     }
 200
 201     template<typename T, typename U, typename V>
 202     inline int HashSet<T, U, V>::size() const
 203     {
 204         return m_impl.size();
 205     }
 206
 207     template<typename T, typename U, typename V>
 208     inline int HashSet<T, U, V>::capacity() const
 209     {
 210         return m_impl.capacity();
 211     }
 212
 213     template<typename T, typename U, typename V>
 214     inline bool HashSet<T, U, V>::isEmpty() const
 215     {
 216         return m_impl.isEmpty();
 217     }
 218
 219     template<typename T, typename U, typename V>
 220     inline typename HashSet<T, U, V>::iterator HashSet<T, U, V>::begin()
 221     {
 222         return m_impl.begin();
 223     }
 224
 225     template<typename T, typename U, typename V>
 226     inline typename HashSet<T, U, V>::iterator HashSet<T, U, V>::end()
 227     {
 228         return m_impl.end();
 229     }
 230
 231     template<typename T, typename U, typename V>
 232     inline typename HashSet<T, U, V>::const_iterator HashSet<T, U, V>::begin() const
 233     {
 234         return m_impl.begin();
 235     }
 236
 237     template<typename T, typename U, typename V>
 238     inline typename HashSet<T, U, V>::const_iterator HashSet<T, U, V>::end() const
 239     {
 240         return m_impl.end();
 241     }
 242
 243     template<typename T, typename U, typename V>
 244     inline typename HashSet<T, U, V>::iterator HashSet<T, U, V>::find(const ValueType& value)
 245     {
 246         return m_impl.find(*(const StorageType*)&value);
 247     }
 248
 249     template<typename T, typename U, typename V>
 250     inline typename HashSet<T, U, V>::const_iterator HashSet<T, U, V>::find(const ValueType& value) const
 251     {
 252         return m_impl.find(*(const StorageType*)&value);
 253     }
 254
 255     template<typename T, typename U, typename V>
 256     inline bool HashSet<T, U, V>::contains(const ValueType& value) const
 257     {
 258         return m_impl.contains(*(const StorageType*)&value);
 259     }
 260
 261     template<typename T, typename U, typename V>
 262     pair<typename HashSet<T, U, V>::iterator, bool> HashSet<T, U, V>::add(const ValueType &value)
 263     {
 264         const bool canReplaceDeletedValue = !ValueTraits::needsDestruction || StorageTraits::needsDestruction;
 265         typedef HashSetTranslator<canReplaceDeletedValue, ValueType, ValueTraits, StorageTraits, HashFunctions> Translator;
 266         return m_impl.template add<ValueType, ValueType, Translator>(value, value);
 267     }
 268
 269     template<typename Value, typename HashFunctions, typename Traits>
 270     template<typename T, typename Translator>
 271     pair<typename HashSet<Value, HashFunctions, Traits>::iterator, bool>
 272     HashSet<Value, HashFunctions, Traits>::add(const T& value)
 273     {
 274         const bool canReplaceDeletedValue = !ValueTraits::needsDestruction || StorageTraits::needsDestruction;
 275         typedef HashSetTranslatorAdapter<canReplaceDeletedValue, ValueType, StorageTraits, T, Translator> Adapter;
 276         return m_impl.template addPassingHashCode<T, T, Adapter>(value, value);
 277     }
 278
 279     template<typename T, typename U, typename V>
 280     inline void HashSet<T, U, V>::remove(iterator it)
 281     {
 282         if (it.m_impl == m_impl.end())
 283             return;
 284         m_impl.checkTableConsistency();
 285         RefCounter<ValueTraits, StorageTraits>::deref(*it.m_impl);
 286         m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
 287     }
 288
 289     template<typename T, typename U, typename V>
 290     inline void HashSet<T, U, V>::remove(const ValueType& value)
 291     {
 292         remove(find(value));
 293     }
 294
 295     template<typename T, typename U, typename V>
 296     inline void HashSet<T, U, V>::clear()
 297     {
 298         derefAll();
 299         m_impl.clear();
 300     }
 301
 302     template<typename ValueType, typename HashTableType>
 303     void deleteAllValues(HashTableType& collection)
 304     {
 305         typedef typename HashTableType::const_iterator iterator;
 306         iterator end = collection.end();
 307         for (iterator it = collection.begin(); it != end; ++it)
 308             delete *(ValueType*)&*it;
 309     }
 310
 311     template<typename T, typename U, typename V>
 312     inline void deleteAllValues(const HashSet<T, U, V>& collection)
 313     {
 314         deleteAllValues<typename HashSet<T, U, V>::ValueType>(collection.m_impl);
 315     }
 316
 317     template<typename T, typename U, typename V, typename W>
 318     inline void copyToVector(const HashSet<T, U, V>& collection, W& vector)
 319     {
 320         typedef typename HashSet<T, U, V>::const_iterator iterator;
 321
 322         vector.resize(collection.size());
 323
 324         iterator it = collection.begin();
 325         iterator end = collection.end();
 326         for (unsigned i = 0; it != end; ++it, ++i)
 327             vector[i] = *it;
 328     }
 329
 330 } // namespace WTF
 331
 332 using WTF::HashSet;
 333
 334 #endif /* WTF_HashSet_h */