wtf/HashMap.h

   1 /*
   2  * Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public License
  15  * along with this library; see the file COPYING.LIB.  If not, write to
  16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  *
  19  */
  20
  21 #ifndef WTF_HashMap_h
  22 #define WTF_HashMap_h
  23
  24 #include "HashTable.h"
  25
  26 namespace WTF {
  27
  28     template<typename PairType> struct PairFirstExtractor;
  29
  30     template<typename KeyArg, typename MappedArg, typename HashArg = typename DefaultHash<KeyArg>::Hash,
  31         typename KeyTraitsArg = HashTraits<KeyArg>, typename MappedTraitsArg = HashTraits<MappedArg> >
  32     class HashMap : public FastAllocBase {
  33     private:
  34         typedef KeyTraitsArg KeyTraits;
  35         typedef MappedTraitsArg MappedTraits;
  36         typedef PairHashTraits<KeyTraits, MappedTraits> ValueTraits;
  37
  38     public:
  39         typedef typename KeyTraits::TraitType KeyType;
  40         typedef typename MappedTraits::TraitType MappedType;
  41         typedef typename ValueTraits::TraitType ValueType;
  42
  43     private:
  44         typedef HashArg HashFunctions;
  45
  46         typedef HashTable<KeyType, ValueType, PairFirstExtractor<ValueType>,
  47             HashFunctions, ValueTraits, KeyTraits> HashTableType;
  48
  49     public:
  50         typedef HashTableIteratorAdapter<HashTableType, ValueType> iterator;
  51         typedef HashTableConstIteratorAdapter<HashTableType, ValueType> const_iterator;
  52
  53         void swap(HashMap&);
  54
  55         int size() const;
  56         int capacity() const;
  57         bool isEmpty() const;
  58
  59         // iterators iterate over pairs of keys and values
  60         iterator begin();
  61         iterator end();
  62         const_iterator begin() const;
  63         const_iterator end() const;
  64
  65         iterator find(const KeyType&);
  66         const_iterator find(const KeyType&) const;
  67         bool contains(const KeyType&) const;
  68         MappedType get(const KeyType&) const;
  69
  70         // replaces value but not key if key is already present
  71         // return value is a pair of the iterator to the key location,
  72         // and a boolean that's true if a new value was actually added
  73         pair<iterator, bool> set(const KeyType&, const MappedType&);
  74
  75         // does nothing if key is already present
  76         // return value is a pair of the iterator to the key location,
  77         // and a boolean that's true if a new value was actually added
  78         pair<iterator, bool> add(const KeyType&, const MappedType&);
  79
  80         void remove(const KeyType&);
  81         void remove(iterator);
  82         void clear();
  83
  84         MappedType take(const KeyType&); // efficient combination of get with remove
  85
  86         // An alternate version of find() that finds the object by hashing and comparing
  87         // with some other type, to avoid the cost of type conversion. HashTranslator
  88         // must have the following function members:
  89         //   static unsigned hash(const T&);
  90         //   static bool equal(const ValueType&, const T&);
  91         template<typename T, typename HashTranslator> iterator find(const T&);
  92         template<typename T, typename HashTranslator> const_iterator find(const T&) const;
  93         template<typename T, typename HashTranslator> bool contains(const T&) const;
  94
  95         // An alternate version of add() that finds the object by hashing and comparing
  96         // with some other type, to avoid the cost of type conversion if the object is already
  97         // in the table. HashTranslator must have the following function members:
  98         //   static unsigned hash(const T&);
  99         //   static bool equal(const ValueType&, const T&);
 100         //   static translate(ValueType&, const T&, unsigned hashCode);
 101         template<typename T, typename HashTranslator> pair<iterator, bool> add(const T&, const MappedType&);
 102
 103         void checkConsistency() const;
 104
 105     private:
 106         pair<iterator, bool> inlineAdd(const KeyType&, const MappedType&);
 107
 108         HashTableType m_impl;
 109     };
 110
 111     template<typename PairType> struct PairFirstExtractor {
 112         static const typename PairType::first_type& extract(const PairType& p) { return p.first; }
 113     };
 114
 115     template<typename ValueType, typename ValueTraits, typename HashFunctions>
 116     struct HashMapTranslator {
 117         typedef typename ValueType::first_type KeyType;
 118         typedef typename ValueType::second_type MappedType;
 119
 120         static unsigned hash(const KeyType& key) { return HashFunctions::hash(key); }
 121         static bool equal(const KeyType& a, const KeyType& b) { return HashFunctions::equal(a, b); }
 122         static void translate(ValueType& location, const KeyType& key, const MappedType& mapped)
 123         {
 124             location.first = key;
 125             location.second = mapped;
 126         }
 127     };
 128
 129     template<typename ValueType, typename ValueTraits, typename T, typename Translator>
 130     struct HashMapTranslatorAdapter {
 131         typedef typename ValueType::first_type KeyType;
 132         typedef typename ValueType::second_type MappedType;
 133
 134         static unsigned hash(const T& key) { return Translator::hash(key); }
 135         static bool equal(const KeyType& a, const T& b) { return Translator::equal(a, b); }
 136         static void translate(ValueType& location, const T& key, const MappedType&, unsigned hashCode)
 137         {
 138             Translator::translate(location.first, key, hashCode);
 139         }
 140     };
 141
 142     template<typename T, typename U, typename V, typename W, typename X>
 143     inline void HashMap<T, U, V, W, X>::swap(HashMap& other)
 144     {
 145         m_impl.swap(other.m_impl);
 146     }
 147
 148     template<typename T, typename U, typename V, typename W, typename X>
 149     inline int HashMap<T, U, V, W, X>::size() const
 150     {
 151         return m_impl.size();
 152     }
 153
 154     template<typename T, typename U, typename V, typename W, typename X>
 155     inline int HashMap<T, U, V, W, X>::capacity() const
 156     {
 157         return m_impl.capacity();
 158     }
 159
 160     template<typename T, typename U, typename V, typename W, typename X>
 161     inline bool HashMap<T, U, V, W, X>::isEmpty() const
 162     {
 163         return m_impl.isEmpty();
 164     }
 165
 166     template<typename T, typename U, typename V, typename W, typename X>
 167     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::begin()
 168     {
 169         return m_impl.begin();
 170     }
 171
 172     template<typename T, typename U, typename V, typename W, typename X>
 173     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::end()
 174     {
 175         return m_impl.end();
 176     }
 177
 178     template<typename T, typename U, typename V, typename W, typename X>
 179     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::begin() const
 180     {
 181         return m_impl.begin();
 182     }
 183
 184     template<typename T, typename U, typename V, typename W, typename X>
 185     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::end() const
 186     {
 187         return m_impl.end();
 188     }
 189
 190     template<typename T, typename U, typename V, typename W, typename X>
 191     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::find(const KeyType& key)
 192     {
 193         return m_impl.find(key);
 194     }
 195
 196     template<typename T, typename U, typename V, typename W, typename X>
 197     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::find(const KeyType& key) const
 198     {
 199         return m_impl.find(key);
 200     }
 201
 202     template<typename T, typename U, typename V, typename W, typename X>
 203     inline bool HashMap<T, U, V, W, X>::contains(const KeyType& key) const
 204     {
 205         return m_impl.contains(key);
 206     }
 207
 208     template<typename T, typename U, typename V, typename W, typename X>
 209     template<typename TYPE, typename HashTranslator>
 210     inline typename HashMap<T, U, V, W, X>::iterator
 211     HashMap<T, U, V, W, X>::find(const TYPE& value)
 212     {
 213         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 214         return m_impl.template find<TYPE, Adapter>(value);
 215     }
 216
 217     template<typename T, typename U, typename V, typename W, typename X>
 218     template<typename TYPE, typename HashTranslator>
 219     inline typename HashMap<T, U, V, W, X>::const_iterator
 220     HashMap<T, U, V, W, X>::find(const TYPE& value) const
 221     {
 222         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 223         return m_impl.template find<TYPE, Adapter>(value);
 224     }
 225
 226     template<typename T, typename U, typename V, typename W, typename X>
 227     template<typename TYPE, typename HashTranslator>
 228     inline bool
 229     HashMap<T, U, V, W, X>::contains(const TYPE& value) const
 230     {
 231         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 232         return m_impl.template contains<TYPE, Adapter>(value);
 233     }
 234
 235     template<typename T, typename U, typename V, typename W, typename X>
 236     inline pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 237     HashMap<T, U, V, W, X>::inlineAdd(const KeyType& key, const MappedType& mapped)
 238     {
 239         typedef HashMapTranslator<ValueType, ValueTraits, HashFunctions> TranslatorType;
 240         return m_impl.template add<KeyType, MappedType, TranslatorType>(key, mapped);
 241     }
 242
 243     template<typename T, typename U, typename V, typename W, typename X>
 244     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 245     HashMap<T, U, V, W, X>::set(const KeyType& key, const MappedType& mapped)
 246     {
 247         pair<iterator, bool> result = inlineAdd(key, mapped);
 248         if (!result.second) {
 249             // add call above didn't change anything, so set the mapped value
 250             result.first->second = mapped;
 251         }
 252         return result;
 253     }
 254
 255     template<typename T, typename U, typename V, typename W, typename X>
 256     template<typename TYPE, typename HashTranslator>
 257     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 258     HashMap<T, U, V, W, X>::add(const TYPE& key, const MappedType& value)
 259     {
 260         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 261         return m_impl.template addPassingHashCode<TYPE, MappedType, Adapter>(key, value);
 262     }
 263
 264     template<typename T, typename U, typename V, typename W, typename X>
 265     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 266     HashMap<T, U, V, W, X>::add(const KeyType& key, const MappedType& mapped)
 267     {
 268         return inlineAdd(key, mapped);
 269     }
 270
 271     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 272     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 273     HashMap<T, U, V, W, MappedTraits>::get(const KeyType& key) const
 274     {
 275         ValueType* entry = const_cast<HashTableType&>(m_impl).lookup(key);
 276         if (!entry)
 277             return MappedTraits::emptyValue();
 278         return entry->second;
 279     }
 280
 281     template<typename T, typename U, typename V, typename W, typename X>
 282     inline void HashMap<T, U, V, W, X>::remove(iterator it)
 283     {
 284         if (it.m_impl == m_impl.end())
 285             return;
 286         m_impl.internalCheckTableConsistency();
 287         m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
 288     }
 289
 290     template<typename T, typename U, typename V, typename W, typename X>
 291     inline void HashMap<T, U, V, W, X>::remove(const KeyType& key)
 292     {
 293         remove(find(key));
 294     }
 295
 296     template<typename T, typename U, typename V, typename W, typename X>
 297     inline void HashMap<T, U, V, W, X>::clear()
 298     {
 299         m_impl.clear();
 300     }
 301
 302     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 303     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 304     HashMap<T, U, V, W, MappedTraits>::take(const KeyType& key)
 305     {
 306         // This can probably be made more efficient to avoid ref/deref churn.
 307         iterator it = find(key);
 308         if (it == end())
 309             return MappedTraits::emptyValue();
 310         typename HashMap<T, U, V, W, MappedTraits>::MappedType result = it->second;
 311         remove(it);
 312         return result;
 313     }
 314
 315     template<typename T, typename U, typename V, typename W, typename X>
 316     inline void HashMap<T, U, V, W, X>::checkConsistency() const
 317     {
 318         m_impl.checkTableConsistency();
 319     }
 320
 321
 322     template<typename T, typename U, typename V, typename W, typename X>
 323     bool operator==(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 324     {
 325         if (a.size() != b.size())
 326             return false;
 327
 328         typedef typename HashMap<T, U, V, W, X>::const_iterator const_iterator;
 329
 330         const_iterator end = a.end();
 331         const_iterator notFound = b.end();
 332         for (const_iterator it = a.begin(); it != end; ++it) {
 333             const_iterator bPos = b.find(it->first);
 334             if (bPos == notFound || it->second != bPos->second)
 335                 return false;
 336         }
 337
 338         return true;
 339     }
 340
 341     template<typename T, typename U, typename V, typename W, typename X>
 342     inline bool operator!=(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 343     {
 344         return !(a == b);
 345     }
 346
 347     template<typename MappedType, typename HashTableType>
 348     void deleteAllPairSeconds(HashTableType& collection)
 349     {
 350         typedef typename HashTableType::const_iterator iterator;
 351         iterator end = collection.end();
 352         for (iterator it = collection.begin(); it != end; ++it)
 353             delete it->second;
 354     }
 355
 356     template<typename T, typename U, typename V, typename W, typename X>
 357     inline void deleteAllValues(const HashMap<T, U, V, W, X>& collection)
 358     {
 359         deleteAllPairSeconds<typename HashMap<T, U, V, W, X>::MappedType>(collection);
 360     }
 361
 362     template<typename KeyType, typename HashTableType>
 363     void deleteAllPairFirsts(HashTableType& collection)
 364     {
 365         typedef typename HashTableType::const_iterator iterator;
 366         iterator end = collection.end();
 367         for (iterator it = collection.begin(); it != end; ++it)
 368             delete it->first;
 369     }
 370
 371     template<typename T, typename U, typename V, typename W, typename X>
 372     inline void deleteAllKeys(const HashMap<T, U, V, W, X>& collection)
 373     {
 374         deleteAllPairFirsts<typename HashMap<T, U, V, W, X>::KeyType>(collection);
 375     }
 376
 377     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 378     inline void copyKeysToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 379     {
 380         typedef typename HashMap<T, U, V, W, X>::const_iterator::Keys iterator;
 381
 382         vector.resize(collection.size());
 383
 384         iterator it = collection.begin().keys();
 385         iterator end = collection.end().keys();
 386         for (unsigned i = 0; it != end; ++it, ++i)
 387             vector[i] = *it;
 388     }
 389
 390     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 391     inline void copyValuesToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 392     {
 393         typedef typename HashMap<T, U, V, W, X>::const_iterator::Values iterator;
 394
 395         vector.resize(collection.size());
 396
 397         iterator it = collection.begin().values();
 398         iterator end = collection.end().values();
 399         for (unsigned i = 0; it != end; ++it, ++i)
 400             vector[i] = *it;
 401     }
 402
 403 } // namespace WTF
 404
 405 using WTF::HashMap;
 406
 407 #include "RefPtrHashMap.h"
 408
 409 #endif /* WTF_HashMap_h */