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& mapped, unsigned hashCode)
 137         {
 138             Translator::translate(location.first, key, hashCode);
 139             location.second = mapped;
 140         }
 141     };
 142
 143     template<typename T, typename U, typename V, typename W, typename X>
 144     inline void HashMap<T, U, V, W, X>::swap(HashMap& other)
 145     {
 146         m_impl.swap(other.m_impl);
 147     }
 148
 149     template<typename T, typename U, typename V, typename W, typename X>
 150     inline int HashMap<T, U, V, W, X>::size() const
 151     {
 152         return m_impl.size();
 153     }
 154
 155     template<typename T, typename U, typename V, typename W, typename X>
 156     inline int HashMap<T, U, V, W, X>::capacity() const
 157     {
 158         return m_impl.capacity();
 159     }
 160
 161     template<typename T, typename U, typename V, typename W, typename X>
 162     inline bool HashMap<T, U, V, W, X>::isEmpty() const
 163     {
 164         return m_impl.isEmpty();
 165     }
 166
 167     template<typename T, typename U, typename V, typename W, typename X>
 168     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::begin()
 169     {
 170         return m_impl.begin();
 171     }
 172
 173     template<typename T, typename U, typename V, typename W, typename X>
 174     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::end()
 175     {
 176         return m_impl.end();
 177     }
 178
 179     template<typename T, typename U, typename V, typename W, typename X>
 180     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::begin() const
 181     {
 182         return m_impl.begin();
 183     }
 184
 185     template<typename T, typename U, typename V, typename W, typename X>
 186     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::end() const
 187     {
 188         return m_impl.end();
 189     }
 190
 191     template<typename T, typename U, typename V, typename W, typename X>
 192     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::find(const KeyType& key)
 193     {
 194         return m_impl.find(key);
 195     }
 196
 197     template<typename T, typename U, typename V, typename W, typename X>
 198     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::find(const KeyType& key) const
 199     {
 200         return m_impl.find(key);
 201     }
 202
 203     template<typename T, typename U, typename V, typename W, typename X>
 204     inline bool HashMap<T, U, V, W, X>::contains(const KeyType& key) const
 205     {
 206         return m_impl.contains(key);
 207     }
 208
 209     template<typename T, typename U, typename V, typename W, typename X>
 210     template<typename TYPE, typename HashTranslator>
 211     inline typename HashMap<T, U, V, W, X>::iterator
 212     HashMap<T, U, V, W, X>::find(const TYPE& value)
 213     {
 214         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 215         return m_impl.template find<TYPE, Adapter>(value);
 216     }
 217
 218     template<typename T, typename U, typename V, typename W, typename X>
 219     template<typename TYPE, typename HashTranslator>
 220     inline typename HashMap<T, U, V, W, X>::const_iterator
 221     HashMap<T, U, V, W, X>::find(const TYPE& value) const
 222     {
 223         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 224         return m_impl.template find<TYPE, Adapter>(value);
 225     }
 226
 227     template<typename T, typename U, typename V, typename W, typename X>
 228     template<typename TYPE, typename HashTranslator>
 229     inline bool
 230     HashMap<T, U, V, W, X>::contains(const TYPE& value) const
 231     {
 232         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 233         return m_impl.template contains<TYPE, Adapter>(value);
 234     }
 235
 236     template<typename T, typename U, typename V, typename W, typename X>
 237     inline pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 238     HashMap<T, U, V, W, X>::inlineAdd(const KeyType& key, const MappedType& mapped)
 239     {
 240         typedef HashMapTranslator<ValueType, ValueTraits, HashFunctions> TranslatorType;
 241         return m_impl.template add<KeyType, MappedType, TranslatorType>(key, mapped);
 242     }
 243
 244     template<typename T, typename U, typename V, typename W, typename X>
 245     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 246     HashMap<T, U, V, W, X>::set(const KeyType& key, const MappedType& mapped)
 247     {
 248         pair<iterator, bool> result = inlineAdd(key, mapped);
 249         if (!result.second) {
 250             // add call above didn't change anything, so set the mapped value
 251             result.first->second = mapped;
 252         }
 253         return result;
 254     }
 255
 256     template<typename T, typename U, typename V, typename W, typename X>
 257     template<typename TYPE, typename HashTranslator>
 258     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 259     HashMap<T, U, V, W, X>::add(const TYPE& key, const MappedType& value)
 260     {
 261         typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
 262         return m_impl.template addPassingHashCode<TYPE, MappedType, Adapter>(key, value);
 263     }
 264
 265     template<typename T, typename U, typename V, typename W, typename X>
 266     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 267     HashMap<T, U, V, W, X>::add(const KeyType& key, const MappedType& mapped)
 268     {
 269         return inlineAdd(key, mapped);
 270     }
 271
 272     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 273     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 274     HashMap<T, U, V, W, MappedTraits>::get(const KeyType& key) const
 275     {
 276         ValueType* entry = const_cast<HashTableType&>(m_impl).lookup(key);
 277         if (!entry)
 278             return MappedTraits::emptyValue();
 279         return entry->second;
 280     }
 281
 282     template<typename T, typename U, typename V, typename W, typename X>
 283     inline void HashMap<T, U, V, W, X>::remove(iterator it)
 284     {
 285         if (it.m_impl == m_impl.end())
 286             return;
 287         m_impl.internalCheckTableConsistency();
 288         m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
 289     }
 290
 291     template<typename T, typename U, typename V, typename W, typename X>
 292     inline void HashMap<T, U, V, W, X>::remove(const KeyType& key)
 293     {
 294         remove(find(key));
 295     }
 296
 297     template<typename T, typename U, typename V, typename W, typename X>
 298     inline void HashMap<T, U, V, W, X>::clear()
 299     {
 300         m_impl.clear();
 301     }
 302
 303     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 304     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 305     HashMap<T, U, V, W, MappedTraits>::take(const KeyType& key)
 306     {
 307         // This can probably be made more efficient to avoid ref/deref churn.
 308         iterator it = find(key);
 309         if (it == end())
 310             return MappedTraits::emptyValue();
 311         typename HashMap<T, U, V, W, MappedTraits>::MappedType result = it->second;
 312         remove(it);
 313         return result;
 314     }
 315
 316     template<typename T, typename U, typename V, typename W, typename X>
 317     inline void HashMap<T, U, V, W, X>::checkConsistency() const
 318     {
 319         m_impl.checkTableConsistency();
 320     }
 321
 322
 323     template<typename T, typename U, typename V, typename W, typename X>
 324     bool operator==(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 325     {
 326         if (a.size() != b.size())
 327             return false;
 328
 329         typedef typename HashMap<T, U, V, W, X>::const_iterator const_iterator;
 330
 331         const_iterator end = a.end();
 332         const_iterator notFound = b.end();
 333         for (const_iterator it = a.begin(); it != end; ++it) {
 334             const_iterator bPos = b.find(it->first);
 335             if (bPos == notFound || it->second != bPos->second)
 336                 return false;
 337         }
 338
 339         return true;
 340     }
 341
 342     template<typename T, typename U, typename V, typename W, typename X>
 343     inline bool operator!=(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 344     {
 345         return !(a == b);
 346     }
 347
 348     template<typename MappedType, typename HashTableType>
 349     void deleteAllPairSeconds(HashTableType& collection)
 350     {
 351         typedef typename HashTableType::const_iterator iterator;
 352         iterator end = collection.end();
 353         for (iterator it = collection.begin(); it != end; ++it)
 354             delete it->second;
 355     }
 356
 357     template<typename T, typename U, typename V, typename W, typename X>
 358     inline void deleteAllValues(const HashMap<T, U, V, W, X>& collection)
 359     {
 360         deleteAllPairSeconds<typename HashMap<T, U, V, W, X>::MappedType>(collection);
 361     }
 362
 363     template<typename KeyType, typename HashTableType>
 364     void deleteAllPairFirsts(HashTableType& collection)
 365     {
 366         typedef typename HashTableType::const_iterator iterator;
 367         iterator end = collection.end();
 368         for (iterator it = collection.begin(); it != end; ++it)
 369             delete it->first;
 370     }
 371
 372     template<typename T, typename U, typename V, typename W, typename X>
 373     inline void deleteAllKeys(const HashMap<T, U, V, W, X>& collection)
 374     {
 375         deleteAllPairFirsts<typename HashMap<T, U, V, W, X>::KeyType>(collection);
 376     }
 377
 378     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 379     inline void copyKeysToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 380     {
 381         typedef typename HashMap<T, U, V, W, X>::const_iterator::Keys iterator;
 382
 383         vector.resize(collection.size());
 384
 385         iterator it = collection.begin().keys();
 386         iterator end = collection.end().keys();
 387         for (unsigned i = 0; it != end; ++it, ++i)
 388             vector[i] = *it;
 389     }
 390
 391     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 392     inline void copyValuesToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 393     {
 394         typedef typename HashMap<T, U, V, W, X>::const_iterator::Values iterator;
 395
 396         vector.resize(collection.size());
 397
 398         iterator it = collection.begin().values();
 399         iterator end = collection.end().values();
 400         for (unsigned i = 0; it != end; ++it, ++i)
 401             vector[i] = *it;
 402     }
 403
 404 } // namespace WTF
 405
 406 using WTF::HashMap;
 407
 408 #include "RefPtrHashMap.h"
 409
 410 #endif /* WTF_HashMap_h */