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 {
  33         WTF_MAKE_FAST_ALLOCATED;
  34     private:
  35         typedef KeyTraitsArg KeyTraits;
  36         typedef MappedTraitsArg MappedTraits;
  37         typedef PairHashTraits<KeyTraits, MappedTraits> ValueTraits;
  38
  39     public:
  40         typedef typename KeyTraits::TraitType KeyType;
  41         typedef typename MappedTraits::TraitType MappedType;
  42         typedef typename ValueTraits::TraitType ValueType;
  43
  44     private:
  45         typedef HashArg HashFunctions;
  46
  47         typedef HashTable<KeyType, ValueType, PairFirstExtractor<ValueType>,
  48             HashFunctions, ValueTraits, KeyTraits> HashTableType;
  49
  50     public:
  51         typedef HashTableIteratorAdapter<HashTableType, ValueType> iterator;
  52         typedef HashTableConstIteratorAdapter<HashTableType, ValueType> const_iterator;
  53
  54         void swap(HashMap&);
  55
  56         int size() const;
  57         int capacity() const;
  58         bool isEmpty() const;
  59
  60         // iterators iterate over pairs of keys and values
  61         iterator begin();
  62         iterator end();
  63         const_iterator begin() const;
  64         const_iterator end() const;
  65
  66         iterator find(const KeyType&);
  67         const_iterator find(const KeyType&) const;
  68         bool contains(const KeyType&) const;
  69         MappedType get(const KeyType&) const;
  70
  71         // replaces value but not key if key is already present
  72         // return value is a pair of the iterator to the key location,
  73         // and a boolean that's true if a new value was actually added
  74         pair<iterator, bool> set(const KeyType&, const MappedType&);
  75
  76         // does nothing if key is already present
  77         // return value is a pair of the iterator to the key location,
  78         // and a boolean that's true if a new value was actually added
  79         pair<iterator, bool> add(const KeyType&, const MappedType&);
  80
  81         void remove(const KeyType&);
  82         void remove(iterator);
  83         void clear();
  84
  85         MappedType take(const KeyType&); // efficient combination of get with remove
  86
  87         // An alternate version of find() that finds the object by hashing and comparing
  88         // with some other type, to avoid the cost of type conversion. HashTranslator
  89         // must have the following function members:
  90         //   static unsigned hash(const T&);
  91         //   static bool equal(const ValueType&, const T&);
  92         template<typename T, typename HashTranslator> iterator find(const T&);
  93         template<typename T, typename HashTranslator> const_iterator find(const T&) const;
  94         template<typename T, typename HashTranslator> bool contains(const T&) const;
  95
  96         // An alternate version of add() that finds the object by hashing and comparing
  97         // with some other type, to avoid the cost of type conversion if the object is already
  98         // in the table. HashTranslator must have the following function members:
  99         //   static unsigned hash(const T&);
 100         //   static bool equal(const ValueType&, const T&);
 101         //   static translate(ValueType&, const T&, unsigned hashCode);
 102         template<typename T, typename HashTranslator> pair<iterator, bool> add(const T&, const MappedType&);
 103
 104         void checkConsistency() const;
 105
 106     private:
 107         pair<iterator, bool> inlineAdd(const KeyType&, const MappedType&);
 108
 109         HashTableType m_impl;
 110     };
 111
 112     template<typename PairType> struct PairFirstExtractor {
 113         static const typename PairType::first_type& extract(const PairType& p) { return p.first; }
 114     };
 115
 116     template<typename ValueType, typename ValueTraits, typename HashFunctions>
 117     struct HashMapTranslator {
 118         typedef typename ValueType::first_type KeyType;
 119         typedef typename ValueType::second_type MappedType;
 120
 121         static unsigned hash(const KeyType& key) { return HashFunctions::hash(key); }
 122         static bool equal(const KeyType& a, const KeyType& b) { return HashFunctions::equal(a, b); }
 123         static void translate(ValueType& location, const KeyType& key, const MappedType& mapped)
 124         {
 125             location.first = key;
 126             location.second = mapped;
 127         }
 128     };
 129
 130     template<typename ValueType, typename ValueTraits, typename T, typename Translator>
 131     struct HashMapTranslatorAdapter {
 132         typedef typename ValueType::first_type KeyType;
 133         typedef typename ValueType::second_type MappedType;
 134
 135         static unsigned hash(const T& key) { return Translator::hash(key); }
 136         static bool equal(const KeyType& a, const T& b) { return Translator::equal(a, b); }
 137         static void translate(ValueType& location, const T& key, const MappedType& mapped, unsigned hashCode)
 138         {
 139             Translator::translate(location.first, key, hashCode);
 140             location.second = mapped;
 141         }
 142     };
 143
 144     template<typename T, typename U, typename V, typename W, typename X>
 145     inline void HashMap<T, U, V, W, X>::swap(HashMap& other)
 146     {
 147         m_impl.swap(other.m_impl);
 148     }
 149
 150     template<typename T, typename U, typename V, typename W, typename X>
 151     inline int HashMap<T, U, V, W, X>::size() const
 152     {
 153         return m_impl.size();
 154     }
 155
 156     template<typename T, typename U, typename V, typename W, typename X>
 157     inline int HashMap<T, U, V, W, X>::capacity() const
 158     {
 159         return m_impl.capacity();
 160     }
 161
 162     template<typename T, typename U, typename V, typename W, typename X>
 163     inline bool HashMap<T, U, V, W, X>::isEmpty() const
 164     {
 165         return m_impl.isEmpty();
 166     }
 167
 168     template<typename T, typename U, typename V, typename W, typename X>
 169     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::begin()
 170     {
 171         return m_impl.begin();
 172     }
 173
 174     template<typename T, typename U, typename V, typename W, typename X>
 175     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::end()
 176     {
 177         return m_impl.end();
 178     }
 179
 180     template<typename T, typename U, typename V, typename W, typename X>
 181     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::begin() const
 182     {
 183         return m_impl.begin();
 184     }
 185
 186     template<typename T, typename U, typename V, typename W, typename X>
 187     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::end() const
 188     {
 189         return m_impl.end();
 190     }
 191
 192     template<typename T, typename U, typename V, typename W, typename X>
 193     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::find(const KeyType& key)
 194     {
 195         return m_impl.find(key);
 196     }
 197
 198     template<typename T, typename U, typename V, typename W, typename X>
 199     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::find(const KeyType& key) const
 200     {
 201         return m_impl.find(key);
 202     }
 203
 204     template<typename T, typename U, typename V, typename W, typename X>
 205     inline bool HashMap<T, U, V, W, X>::contains(const KeyType& key) const
 206     {
 207         return m_impl.contains(key);
 208     }
 209
 210     template<typename T, typename U, typename V, typename W, typename X>
 211     template<typename TYPE, typename HashTranslator>
 212     inline typename HashMap<T, U, V, W, X>::iterator
 213     HashMap<T, U, V, W, X>::find(const TYPE& value)
 214     {
 215         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 216         return m_impl.template find<TYPE, Adapter>(value);
 217     }
 218
 219     template<typename T, typename U, typename V, typename W, typename X>
 220     template<typename TYPE, typename HashTranslator>
 221     inline typename HashMap<T, U, V, W, X>::const_iterator
 222     HashMap<T, U, V, W, X>::find(const TYPE& value) const
 223     {
 224         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 225         return m_impl.template find<TYPE, Adapter>(value);
 226     }
 227
 228     template<typename T, typename U, typename V, typename W, typename X>
 229     template<typename TYPE, typename HashTranslator>
 230     inline bool
 231     HashMap<T, U, V, W, X>::contains(const TYPE& value) const
 232     {
 233         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 234         return m_impl.template contains<TYPE, Adapter>(value);
 235     }
 236
 237     template<typename T, typename U, typename V, typename W, typename X>
 238     inline pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 239     HashMap<T, U, V, W, X>::inlineAdd(const KeyType& key, const MappedType& mapped)
 240     {
 241         typedef HashMapTranslator<ValueType, ValueTraits, HashFunctions> TranslatorType;
 242         return m_impl.template add<KeyType, MappedType, TranslatorType>(key, mapped);
 243     }
 244
 245     template<typename T, typename U, typename V, typename W, typename X>
 246     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 247     HashMap<T, U, V, W, X>::set(const KeyType& key, const MappedType& mapped)
 248     {
 249         pair<iterator, bool> result = inlineAdd(key, mapped);
 250         if (!result.second) {
 251             // add call above didn't change anything, so set the mapped value
 252             result.first->second = mapped;
 253         }
 254         return result;
 255     }
 256
 257     template<typename T, typename U, typename V, typename W, typename X>
 258     template<typename TYPE, typename HashTranslator>
 259     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 260     HashMap<T, U, V, W, X>::add(const TYPE& key, const MappedType& value)
 261     {
 262         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 263         return m_impl.template addPassingHashCode<TYPE, MappedType, Adapter>(key, value);
 264     }
 265
 266     template<typename T, typename U, typename V, typename W, typename X>
 267     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 268     HashMap<T, U, V, W, X>::add(const KeyType& key, const MappedType& mapped)
 269     {
 270         return inlineAdd(key, mapped);
 271     }
 272
 273     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 274     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 275     HashMap<T, U, V, W, MappedTraits>::get(const KeyType& key) const
 276     {
 277         ValueType* entry = const_cast<HashTableType&>(m_impl).lookup(key);
 278         if (!entry)
 279             return MappedTraits::emptyValue();
 280         return entry->second;
 281     }
 282
 283     template<typename T, typename U, typename V, typename W, typename X>
 284     inline void HashMap<T, U, V, W, X>::remove(iterator it)
 285     {
 286         if (it.m_impl == m_impl.end())
 287             return;
 288         m_impl.internalCheckTableConsistency();
 289         m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
 290     }
 291
 292     template<typename T, typename U, typename V, typename W, typename X>
 293     inline void HashMap<T, U, V, W, X>::remove(const KeyType& key)
 294     {
 295         remove(find(key));
 296     }
 297
 298     template<typename T, typename U, typename V, typename W, typename X>
 299     inline void HashMap<T, U, V, W, X>::clear()
 300     {
 301         m_impl.clear();
 302     }
 303
 304     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 305     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 306     HashMap<T, U, V, W, MappedTraits>::take(const KeyType& key)
 307     {
 308         // This can probably be made more efficient to avoid ref/deref churn.
 309         iterator it = find(key);
 310         if (it == end())
 311             return MappedTraits::emptyValue();
 312         typename HashMap<T, U, V, W, MappedTraits>::MappedType result = it->second;
 313         remove(it);
 314         return result;
 315     }
 316
 317     template<typename T, typename U, typename V, typename W, typename X>
 318     inline void HashMap<T, U, V, W, X>::checkConsistency() const
 319     {
 320         m_impl.checkTableConsistency();
 321     }
 322
 323
 324     template<typename T, typename U, typename V, typename W, typename X>
 325     bool operator==(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 326     {
 327         if (a.size() != b.size())
 328             return false;
 329
 330         typedef typename HashMap<T, U, V, W, X>::const_iterator const_iterator;
 331
 332         const_iterator end = a.end();
 333         const_iterator notFound = b.end();
 334         for (const_iterator it = a.begin(); it != end; ++it) {
 335             const_iterator bPos = b.find(it->first);
 336             if (bPos == notFound || it->second != bPos->second)
 337                 return false;
 338         }
 339
 340         return true;
 341     }
 342
 343     template<typename T, typename U, typename V, typename W, typename X>
 344     inline bool operator!=(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 345     {
 346         return !(a == b);
 347     }
 348
 349     template<typename MappedType, typename HashTableType>
 350     void deleteAllPairSeconds(HashTableType& collection)
 351     {
 352         typedef typename HashTableType::const_iterator iterator;
 353         iterator end = collection.end();
 354         for (iterator it = collection.begin(); it != end; ++it)
 355             delete it->second;
 356     }
 357
 358     template<typename T, typename U, typename V, typename W, typename X>
 359     inline void deleteAllValues(const HashMap<T, U, V, W, X>& collection)
 360     {
 361         deleteAllPairSeconds<typename HashMap<T, U, V, W, X>::MappedType>(collection);
 362     }
 363
 364     template<typename KeyType, typename HashTableType>
 365     void deleteAllPairFirsts(HashTableType& collection)
 366     {
 367         typedef typename HashTableType::const_iterator iterator;
 368         iterator end = collection.end();
 369         for (iterator it = collection.begin(); it != end; ++it)
 370             delete it->first;
 371     }
 372
 373     template<typename T, typename U, typename V, typename W, typename X>
 374     inline void deleteAllKeys(const HashMap<T, U, V, W, X>& collection)
 375     {
 376         deleteAllPairFirsts<typename HashMap<T, U, V, W, X>::KeyType>(collection);
 377     }
 378
 379     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 380     inline void copyKeysToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 381     {
 382         typedef typename HashMap<T, U, V, W, X>::const_iterator::Keys iterator;
 383
 384         vector.resize(collection.size());
 385
 386         iterator it = collection.begin().keys();
 387         iterator end = collection.end().keys();
 388         for (unsigned i = 0; it != end; ++it, ++i)
 389             vector[i] = *it;
 390     }
 391
 392     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 393     inline void copyValuesToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 394     {
 395         typedef typename HashMap<T, U, V, W, X>::const_iterator::Values iterator;
 396
 397         vector.resize(collection.size());
 398
 399         iterator it = collection.begin().values();
 400         iterator end = collection.end().values();
 401         for (unsigned i = 0; it != end; ++it, ++i)
 402             vector[i] = *it;
 403     }
 404
 405 } // namespace WTF
 406
 407 using WTF::HashMap;
 408
 409 #include "RefPtrHashMap.h"
 410
 411 #endif /* WTF_HashMap_h */