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     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     private:
  87         pair<iterator, bool> inlineAdd(const KeyType&, const MappedType&);
  88
  89         HashTableType m_impl;
  90     };
  91
  92     template<typename PairType> struct PairFirstExtractor {
  93         static const typename PairType::first_type& extract(const PairType& p) { return p.first; }
  94     };
  95
  96     template<typename ValueType, typename ValueTraits, typename HashFunctions>
  97     struct HashMapTranslator {
  98         typedef typename ValueType::first_type KeyType;
  99         typedef typename ValueType::second_type MappedType;
 100
 101         static unsigned hash(const KeyType& key) { return HashFunctions::hash(key); }
 102         static bool equal(const KeyType& a, const KeyType& b) { return HashFunctions::equal(a, b); }
 103         static void translate(ValueType& location, const KeyType& key, const MappedType& mapped)
 104         {
 105             location.first = key;
 106             location.second = mapped;
 107         }
 108     };
 109
 110     template<typename T, typename U, typename V, typename W, typename X>
 111     inline void HashMap<T, U, V, W, X>::swap(HashMap& other)
 112     {
 113         m_impl.swap(other.m_impl);
 114     }
 115
 116     template<typename T, typename U, typename V, typename W, typename X>
 117     inline int HashMap<T, U, V, W, X>::size() const
 118     {
 119         return m_impl.size();
 120     }
 121
 122     template<typename T, typename U, typename V, typename W, typename X>
 123     inline int HashMap<T, U, V, W, X>::capacity() const
 124     {
 125         return m_impl.capacity();
 126     }
 127
 128     template<typename T, typename U, typename V, typename W, typename X>
 129     inline bool HashMap<T, U, V, W, X>::isEmpty() const
 130     {
 131         return m_impl.isEmpty();
 132     }
 133
 134     template<typename T, typename U, typename V, typename W, typename X>
 135     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::begin()
 136     {
 137         return m_impl.begin();
 138     }
 139
 140     template<typename T, typename U, typename V, typename W, typename X>
 141     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::end()
 142     {
 143         return m_impl.end();
 144     }
 145
 146     template<typename T, typename U, typename V, typename W, typename X>
 147     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::begin() const
 148     {
 149         return m_impl.begin();
 150     }
 151
 152     template<typename T, typename U, typename V, typename W, typename X>
 153     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::end() const
 154     {
 155         return m_impl.end();
 156     }
 157
 158     template<typename T, typename U, typename V, typename W, typename X>
 159     inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::find(const KeyType& key)
 160     {
 161         return m_impl.find(key);
 162     }
 163
 164     template<typename T, typename U, typename V, typename W, typename X>
 165     inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::find(const KeyType& key) const
 166     {
 167         return m_impl.find(key);
 168     }
 169
 170     template<typename T, typename U, typename V, typename W, typename X>
 171     inline bool HashMap<T, U, V, W, X>::contains(const KeyType& key) const
 172     {
 173         return m_impl.contains(key);
 174     }
 175
 176     template<typename T, typename U, typename V, typename W, typename X>
 177     inline pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 178     HashMap<T, U, V, W, X>::inlineAdd(const KeyType& key, const MappedType& mapped)
 179     {
 180         typedef HashMapTranslator<ValueType, ValueTraits, HashFunctions> TranslatorType;
 181         return m_impl.template add<KeyType, MappedType, TranslatorType>(key, mapped);
 182     }
 183
 184     template<typename T, typename U, typename V, typename W, typename X>
 185     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 186     HashMap<T, U, V, W, X>::set(const KeyType& key, const MappedType& mapped)
 187     {
 188         pair<iterator, bool> result = inlineAdd(key, mapped);
 189         if (!result.second) {
 190             // add call above didn't change anything, so set the mapped value
 191             result.first->second = mapped;
 192         }
 193         return result;
 194     }
 195
 196     template<typename T, typename U, typename V, typename W, typename X>
 197     pair<typename HashMap<T, U, V, W, X>::iterator, bool>
 198     HashMap<T, U, V, W, X>::add(const KeyType& key, const MappedType& mapped)
 199     {
 200         return inlineAdd(key, mapped);
 201     }
 202
 203     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 204     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 205     HashMap<T, U, V, W, MappedTraits>::get(const KeyType& key) const
 206     {
 207         ValueType* entry = const_cast<HashTableType&>(m_impl).lookup(key);
 208         if (!entry)
 209             return MappedTraits::emptyValue();
 210         return entry->second;
 211     }
 212
 213     template<typename T, typename U, typename V, typename W, typename X>
 214     inline void HashMap<T, U, V, W, X>::remove(iterator it)
 215     {
 216         if (it.m_impl == m_impl.end())
 217             return;
 218         m_impl.checkTableConsistency();
 219         m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
 220     }
 221
 222     template<typename T, typename U, typename V, typename W, typename X>
 223     inline void HashMap<T, U, V, W, X>::remove(const KeyType& key)
 224     {
 225         remove(find(key));
 226     }
 227
 228     template<typename T, typename U, typename V, typename W, typename X>
 229     inline void HashMap<T, U, V, W, X>::clear()
 230     {
 231         m_impl.clear();
 232     }
 233
 234     template<typename T, typename U, typename V, typename W, typename MappedTraits>
 235     typename HashMap<T, U, V, W, MappedTraits>::MappedType
 236     HashMap<T, U, V, W, MappedTraits>::take(const KeyType& key)
 237     {
 238         // This can probably be made more efficient to avoid ref/deref churn.
 239         iterator it = find(key);
 240         if (it == end())
 241             return MappedTraits::emptyValue();
 242         typename HashMap<T, U, V, W, MappedTraits>::MappedType result = it->second;
 243         remove(it);
 244         return result;
 245     }
 246
 247     template<typename T, typename U, typename V, typename W, typename X>
 248     bool operator==(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 249     {
 250         if (a.size() != b.size())
 251             return false;
 252
 253         typedef typename HashMap<T, U, V, W, X>::const_iterator const_iterator;
 254
 255         const_iterator end = a.end();
 256         const_iterator notFound = b.end();
 257         for (const_iterator it = a.begin(); it != end; ++it) {
 258             const_iterator bPos = b.find(it->first);
 259             if (bPos == notFound || it->second != bPos->second)
 260                 return false;
 261         }
 262
 263         return true;
 264     }
 265
 266     template<typename T, typename U, typename V, typename W, typename X>
 267     inline bool operator!=(const HashMap<T, U, V, W, X>& a, const HashMap<T, U, V, W, X>& b)
 268     {
 269         return !(a == b);
 270     }
 271
 272     template<typename MappedType, typename HashTableType>
 273     void deleteAllPairSeconds(HashTableType& collection)
 274     {
 275         typedef typename HashTableType::const_iterator iterator;
 276         iterator end = collection.end();
 277         for (iterator it = collection.begin(); it != end; ++it)
 278             delete it->second;
 279     }
 280
 281     template<typename T, typename U, typename V, typename W, typename X>
 282     inline void deleteAllValues(const HashMap<T, U, V, W, X>& collection)
 283     {
 284         deleteAllPairSeconds<typename HashMap<T, U, V, W, X>::MappedType>(collection);
 285     }
 286
 287     template<typename KeyType, typename HashTableType>
 288     void deleteAllPairFirsts(HashTableType& collection)
 289     {
 290         typedef typename HashTableType::const_iterator iterator;
 291         iterator end = collection.end();
 292         for (iterator it = collection.begin(); it != end; ++it)
 293             delete it->first;
 294     }
 295
 296     template<typename T, typename U, typename V, typename W, typename X>
 297     inline void deleteAllKeys(const HashMap<T, U, V, W, X>& collection)
 298     {
 299         deleteAllPairFirsts<typename HashMap<T, U, V, W, X>::KeyType>(collection);
 300     }
 301
 302     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 303     inline void copyKeysToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 304     {
 305         typedef typename HashMap<T, U, V, W, X>::const_iterator::Keys iterator;
 306
 307         vector.resize(collection.size());
 308
 309         iterator it = collection.begin().keys();
 310         iterator end = collection.end().keys();
 311         for (unsigned i = 0; it != end; ++it, ++i)
 312             vector[i] = *it;
 313     }
 314
 315     template<typename T, typename U, typename V, typename W, typename X, typename Y>
 316     inline void copyValuesToVector(const HashMap<T, U, V, W, X>& collection, Y& vector)
 317     {
 318         typedef typename HashMap<T, U, V, W, X>::const_iterator::Values iterator;
 319
 320         vector.resize(collection.size());
 321
 322         iterator it = collection.begin().values();
 323         iterator end = collection.end().values();
 324         for (unsigned i = 0; it != end; ++it, ++i)
 325             vector[i] = *it;
 326     }
 327
 328 } // namespace WTF
 329
 330 using WTF::HashMap;
 331
 332 #include "RefPtrHashMap.h"
 333
 334 #endif /* WTF_HashMap_h */