diff -r 000000000000 -r 4f2f89ce4247 JavaScriptCore/wtf/HashTable.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/wtf/HashTable.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,1179 @@
+/*
+ * Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2008 David Levin <levin@chromium.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef WTF_HashTable_h
+#define WTF_HashTable_h
+
+#include "FastMalloc.h"
+#include "HashTraits.h"
+#include "ValueCheck.h"
+#include <wtf/Assertions.h>
+#include <wtf/Threading.h>
+
+namespace WTF {
+
+#define DUMP_HASHTABLE_STATS 0
+// Enables internal WTF consistency checks that are invoked automatically. Non-WTF callers can call checkTableConsistency() even if internal checks are disabled.
+#define CHECK_HASHTABLE_CONSISTENCY 0
+
+#ifdef NDEBUG
+#define CHECK_HASHTABLE_ITERATORS 0
+#define CHECK_HASHTABLE_USE_AFTER_DESTRUCTION 0
+#else
+#define CHECK_HASHTABLE_ITERATORS 1
+#define CHECK_HASHTABLE_USE_AFTER_DESTRUCTION 1
+#endif
+
+#if DUMP_HASHTABLE_STATS
+
+    struct HashTableStats {
+        ~HashTableStats();
+        // All of the variables are accessed in ~HashTableStats when the static struct is destroyed.
+
+        // The following variables are all atomically incremented when modified.
+        static int numAccesses;
+        static int numRehashes;
+        static int numRemoves;
+        static int numReinserts;
+
+        // The following variables are only modified in the recordCollisionAtCount method within a mutex.
+        static int maxCollisions;
+        static int numCollisions;
+        static int collisionGraph[4096];
+
+        static void recordCollisionAtCount(int count);
+    };
+
+#endif
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    class HashTable;
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    class HashTableIterator;
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    class HashTableConstIterator;
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void addIterator(const HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>*,
+        HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>*);
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void removeIterator(HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>*);
+
+#if !CHECK_HASHTABLE_ITERATORS
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void addIterator(const HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>*,
+        HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>*) { }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void removeIterator(HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>*) { }
+
+#endif
+
+    typedef enum { HashItemKnownGood } HashItemKnownGoodTag;
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    class HashTableConstIterator {
+    private:
+        typedef HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> HashTableType;
+        typedef HashTableIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> iterator;
+        typedef HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> const_iterator;
+        typedef Value ValueType;
+        typedef const ValueType& ReferenceType;
+        typedef const ValueType* PointerType;
+
+        friend class HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>;
+        friend class HashTableIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>;
+
+        void skipEmptyBuckets()
+        {
+            while (m_position != m_endPosition && HashTableType::isEmptyOrDeletedBucket(*m_position))
+                ++m_position;
+        }
+
+        HashTableConstIterator(const HashTableType* table, PointerType position, PointerType endPosition)
+            : m_position(position), m_endPosition(endPosition)
+        {
+            addIterator(table, this);
+            skipEmptyBuckets();
+        }
+
+        HashTableConstIterator(const HashTableType* table, PointerType position, PointerType endPosition, HashItemKnownGoodTag)
+            : m_position(position), m_endPosition(endPosition)
+        {
+            addIterator(table, this);
+        }
+
+    public:
+        HashTableConstIterator()
+        {
+            addIterator(0, this);
+        }
+
+        // default copy, assignment and destructor are OK if CHECK_HASHTABLE_ITERATORS is 0
+
+#if CHECK_HASHTABLE_ITERATORS
+        ~HashTableConstIterator()
+        {
+            removeIterator(this);
+        }
+
+        HashTableConstIterator(const const_iterator& other)
+            : m_position(other.m_position), m_endPosition(other.m_endPosition)
+        {
+            addIterator(other.m_table, this);
+        }
+
+        const_iterator& operator=(const const_iterator& other)
+        {
+            m_position = other.m_position;
+            m_endPosition = other.m_endPosition;
+
+            removeIterator(this);
+            addIterator(other.m_table, this);
+
+            return *this;
+        }
+#endif
+
+        PointerType get() const
+        {
+            checkValidity();
+            return m_position;
+        }
+        ReferenceType operator*() const { return *get(); }
+        PointerType operator->() const { return get(); }
+
+        const_iterator& operator++()
+        {
+            checkValidity();
+            ASSERT(m_position != m_endPosition);
+            ++m_position;
+            skipEmptyBuckets();
+            return *this;
+        }
+
+        // postfix ++ intentionally omitted
+
+        // Comparison.
+        bool operator==(const const_iterator& other) const
+        {
+            checkValidity(other);
+            return m_position == other.m_position;
+        }
+        bool operator!=(const const_iterator& other) const
+        {
+            checkValidity(other);
+            return m_position != other.m_position;
+        }
+
+    private:
+        void checkValidity() const
+        {
+#if CHECK_HASHTABLE_ITERATORS
+            ASSERT(m_table);
+#endif
+        }
+
+
+#if CHECK_HASHTABLE_ITERATORS
+        void checkValidity(const const_iterator& other) const
+        {
+            ASSERT(m_table);
+            ASSERT_UNUSED(other, other.m_table);
+            ASSERT(m_table == other.m_table);
+        }
+#else
+        void checkValidity(const const_iterator&) const { }
+#endif
+
+        PointerType m_position;
+        PointerType m_endPosition;
+
+#if CHECK_HASHTABLE_ITERATORS
+    public:
+        // Any modifications of the m_next or m_previous of an iterator that is in a linked list of a HashTable::m_iterator,
+        // should be guarded with m_table->m_mutex.
+        mutable const HashTableType* m_table;
+        mutable const_iterator* m_next;
+        mutable const_iterator* m_previous;
+#endif
+    };
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    class HashTableIterator {
+    private:
+        typedef HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> HashTableType;
+        typedef HashTableIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> iterator;
+        typedef HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> const_iterator;
+        typedef Value ValueType;
+        typedef ValueType& ReferenceType;
+        typedef ValueType* PointerType;
+
+        friend class HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>;
+
+        HashTableIterator(HashTableType* table, PointerType pos, PointerType end) : m_iterator(table, pos, end) { }
+        HashTableIterator(HashTableType* table, PointerType pos, PointerType end, HashItemKnownGoodTag tag) : m_iterator(table, pos, end, tag) { }
+
+    public:
+        HashTableIterator() { }
+
+        // default copy, assignment and destructor are OK
+
+        PointerType get() const { return const_cast<PointerType>(m_iterator.get()); }
+        ReferenceType operator*() const { return *get(); }
+        PointerType operator->() const { return get(); }
+
+        iterator& operator++() { ++m_iterator; return *this; }
+
+        // postfix ++ intentionally omitted
+
+        // Comparison.
+        bool operator==(const iterator& other) const { return m_iterator == other.m_iterator; }
+        bool operator!=(const iterator& other) const { return m_iterator != other.m_iterator; }
+
+        operator const_iterator() const { return m_iterator; }
+
+    private:
+        const_iterator m_iterator;
+    };
+
+    using std::swap;
+
+#if !COMPILER(MSVC)
+    // Visual C++ has a swap for pairs defined.
+
+    // swap pairs by component, in case of pair members that specialize swap
+    template<typename T, typename U> inline void swap(pair<T, U>& a, pair<T, U>& b)
+    {
+        swap(a.first, b.first);
+        swap(a.second, b.second);
+    }
+#endif
+
+    template<typename T, bool useSwap> struct Mover;
+    template<typename T> struct Mover<T, true> { static void move(T& from, T& to) { swap(from, to); } };
+    template<typename T> struct Mover<T, false> { static void move(T& from, T& to) { to = from; } };
+
+    template<typename Key, typename Value, typename HashFunctions> class IdentityHashTranslator {
+    public:
+        static unsigned hash(const Key& key) { return HashFunctions::hash(key); }
+        static bool equal(const Key& a, const Key& b) { return HashFunctions::equal(a, b); }
+        static void translate(Value& location, const Key&, const Value& value) { location = value; }
+    };
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    class HashTable {
+    public:
+        typedef HashTableIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> iterator;
+        typedef HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> const_iterator;
+        typedef Traits ValueTraits;
+        typedef Key KeyType;
+        typedef Value ValueType;
+        typedef IdentityHashTranslator<Key, Value, HashFunctions> IdentityTranslatorType;
+
+        HashTable();
+        ~HashTable() 
+        {
+            invalidateIterators(); 
+            deallocateTable(m_table, m_tableSize); 
+#if CHECK_HASHTABLE_USE_AFTER_DESTRUCTION
+            m_table = (ValueType*)(uintptr_t)0xbbadbeef;
+#endif
+        }
+
+        HashTable(const HashTable&);
+        void swap(HashTable&);
+        HashTable& operator=(const HashTable&);
+
+        iterator begin() { return makeIterator(m_table); }
+        iterator end() { return makeKnownGoodIterator(m_table + m_tableSize); }
+        const_iterator begin() const { return makeConstIterator(m_table); }
+        const_iterator end() const { return makeKnownGoodConstIterator(m_table + m_tableSize); }
+
+        int size() const { return m_keyCount; }
+        int capacity() const { return m_tableSize; }
+        bool isEmpty() const { return !m_keyCount; }
+
+        pair<iterator, bool> add(const ValueType& value) { return add<KeyType, ValueType, IdentityTranslatorType>(Extractor::extract(value), value); }
+
+        // A special version of add() that finds the object by hashing and comparing
+        // with some other type, to avoid the cost of type conversion if the object is already
+        // in the table.
+        template<typename T, typename Extra, typename HashTranslator> pair<iterator, bool> add(const T& key, const Extra&);
+        template<typename T, typename Extra, typename HashTranslator> pair<iterator, bool> addPassingHashCode(const T& key, const Extra&);
+
+        iterator find(const KeyType& key) { return find<KeyType, IdentityTranslatorType>(key); }
+        const_iterator find(const KeyType& key) const { return find<KeyType, IdentityTranslatorType>(key); }
+        bool contains(const KeyType& key) const { return contains<KeyType, IdentityTranslatorType>(key); }
+
+        template <typename T, typename HashTranslator> iterator find(const T&);
+        template <typename T, typename HashTranslator> const_iterator find(const T&) const;
+        template <typename T, typename HashTranslator> bool contains(const T&) const;
+
+        void remove(const KeyType&);
+        void remove(iterator);
+        void removeWithoutEntryConsistencyCheck(iterator);
+        void removeWithoutEntryConsistencyCheck(const_iterator);
+        void clear();
+
+        static bool isEmptyBucket(const ValueType& value) { return Extractor::extract(value) == KeyTraits::emptyValue(); }
+        static bool isDeletedBucket(const ValueType& value) { return KeyTraits::isDeletedValue(Extractor::extract(value)); }
+        static bool isEmptyOrDeletedBucket(const ValueType& value) { return isEmptyBucket(value) || isDeletedBucket(value); }
+
+        ValueType* lookup(const Key& key) { return lookup<Key, IdentityTranslatorType>(key); }
+        template<typename T, typename HashTranslator> ValueType* lookup(const T&);
+
+#if !ASSERT_DISABLED
+        void checkTableConsistency() const;
+#else
+        static void checkTableConsistency() { }
+#endif
+#if CHECK_HASHTABLE_CONSISTENCY
+        void internalCheckTableConsistency() const { checkTableConsistency(); }
+        void internalCheckTableConsistencyExceptSize() const { checkTableConsistencyExceptSize(); }
+#else
+        static void internalCheckTableConsistencyExceptSize() { }
+        static void internalCheckTableConsistency() { }
+#endif
+
+    private:
+        static ValueType* allocateTable(int size);
+        static void deallocateTable(ValueType* table, int size);
+
+        typedef pair<ValueType*, bool> LookupType;
+        typedef pair<LookupType, unsigned> FullLookupType;
+
+        LookupType lookupForWriting(const Key& key) { return lookupForWriting<Key, IdentityTranslatorType>(key); };
+        template<typename T, typename HashTranslator> FullLookupType fullLookupForWriting(const T&);
+        template<typename T, typename HashTranslator> LookupType lookupForWriting(const T&);
+
+        template<typename T, typename HashTranslator> void checkKey(const T&);
+
+        void removeAndInvalidateWithoutEntryConsistencyCheck(ValueType*);
+        void removeAndInvalidate(ValueType*);
+        void remove(ValueType*);
+
+        bool shouldExpand() const { return (m_keyCount + m_deletedCount) * m_maxLoad >= m_tableSize; }
+        bool mustRehashInPlace() const { return m_keyCount * m_minLoad < m_tableSize * 2; }
+        bool shouldShrink() const { return m_keyCount * m_minLoad < m_tableSize && m_tableSize > m_minTableSize; }
+        void expand();
+        void shrink() { rehash(m_tableSize / 2); }
+
+        void rehash(int newTableSize);
+        void reinsert(ValueType&);
+
+        static void initializeBucket(ValueType& bucket) { new (&bucket) ValueType(Traits::emptyValue()); }
+        static void deleteBucket(ValueType& bucket) { bucket.~ValueType(); Traits::constructDeletedValue(bucket); }
+
+        FullLookupType makeLookupResult(ValueType* position, bool found, unsigned hash)
+            { return FullLookupType(LookupType(position, found), hash); }
+
+        iterator makeIterator(ValueType* pos) { return iterator(this, pos, m_table + m_tableSize); }
+        const_iterator makeConstIterator(ValueType* pos) const { return const_iterator(this, pos, m_table + m_tableSize); }
+        iterator makeKnownGoodIterator(ValueType* pos) { return iterator(this, pos, m_table + m_tableSize, HashItemKnownGood); }
+        const_iterator makeKnownGoodConstIterator(ValueType* pos) const { return const_iterator(this, pos, m_table + m_tableSize, HashItemKnownGood); }
+
+#if !ASSERT_DISABLED
+        void checkTableConsistencyExceptSize() const;
+#else
+        static void checkTableConsistencyExceptSize() { }
+#endif
+
+#if CHECK_HASHTABLE_ITERATORS
+        void invalidateIterators();
+#else
+        static void invalidateIterators() { }
+#endif
+
+        static const int m_minTableSize = 64;
+        static const int m_maxLoad = 2;
+        static const int m_minLoad = 6;
+
+        ValueType* m_table;
+        int m_tableSize;
+        int m_tableSizeMask;
+        int m_keyCount;
+        int m_deletedCount;
+
+#if CHECK_HASHTABLE_ITERATORS
+    public:
+        // All access to m_iterators should be guarded with m_mutex.
+        mutable const_iterator* m_iterators;
+        mutable Mutex m_mutex;
+#endif
+    };
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::HashTable()
+        : m_table(0)
+        , m_tableSize(0)
+        , m_tableSizeMask(0)
+        , m_keyCount(0)
+        , m_deletedCount(0)
+#if CHECK_HASHTABLE_ITERATORS
+        , m_iterators(0)
+#endif
+    {
+    }
+
+    static inline unsigned doubleHash(unsigned key)
+    {
+        key = ~key + (key >> 23);
+        key ^= (key << 12);
+        key ^= (key >> 7);
+        key ^= (key << 2);
+        key ^= (key >> 20);
+        return key;
+    }
+
+#if ASSERT_DISABLED
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename HashTranslator>
+    inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::checkKey(const T&)
+    {
+    }
+
+#else
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename HashTranslator>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::checkKey(const T& key)
+    {
+        if (!HashFunctions::safeToCompareToEmptyOrDeleted)
+            return;
+        ASSERT(!HashTranslator::equal(KeyTraits::emptyValue(), key));
+        ValueType deletedValue = Traits::emptyValue();
+        deletedValue.~ValueType();
+        Traits::constructDeletedValue(deletedValue);
+        ASSERT(!HashTranslator::equal(Extractor::extract(deletedValue), key));
+        new (&deletedValue) ValueType(Traits::emptyValue());
+    }
+
+#endif
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename HashTranslator>
+    inline Value* HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::lookup(const T& key)
+    {
+        checkKey<T, HashTranslator>(key);
+
+        int k = 0;
+        int sizeMask = m_tableSizeMask;
+        ValueType* table = m_table;
+        unsigned h = HashTranslator::hash(key);
+        int i = h & sizeMask;
+
+        if (!table)
+            return 0;
+
+#if DUMP_HASHTABLE_STATS
+        atomicIncrement(&HashTableStats::numAccesses);
+        int probeCount = 0;
+#endif
+
+        while (1) {
+            ValueType* entry = table + i;
+                
+            // we count on the compiler to optimize out this branch
+            if (HashFunctions::safeToCompareToEmptyOrDeleted) {
+                if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return entry;
+                
+                if (isEmptyBucket(*entry))
+                    return 0;
+            } else {
+                if (isEmptyBucket(*entry))
+                    return 0;
+                
+                if (!isDeletedBucket(*entry) && HashTranslator::equal(Extractor::extract(*entry), key))
+                    return entry;
+            }
+#if DUMP_HASHTABLE_STATS
+            ++probeCount;
+            HashTableStats::recordCollisionAtCount(probeCount);
+#endif
+            if (k == 0)
+                k = 1 | doubleHash(h);
+            i = (i + k) & sizeMask;
+        }
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename HashTranslator>
+    inline typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::LookupType HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::lookupForWriting(const T& key)
+    {
+        ASSERT(m_table);
+        checkKey<T, HashTranslator>(key);
+
+        int k = 0;
+        ValueType* table = m_table;
+        int sizeMask = m_tableSizeMask;
+        unsigned h = HashTranslator::hash(key);
+        int i = h & sizeMask;
+
+#if DUMP_HASHTABLE_STATS
+        atomicIncrement(&HashTableStats::numAccesses);
+        int probeCount = 0;
+#endif
+
+        ValueType* deletedEntry = 0;
+
+        while (1) {
+            ValueType* entry = table + i;
+            
+            // we count on the compiler to optimize out this branch
+            if (HashFunctions::safeToCompareToEmptyOrDeleted) {
+                if (isEmptyBucket(*entry))
+                    return LookupType(deletedEntry ? deletedEntry : entry, false);
+                
+                if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return LookupType(entry, true);
+                
+                if (isDeletedBucket(*entry))
+                    deletedEntry = entry;
+            } else {
+                if (isEmptyBucket(*entry))
+                    return LookupType(deletedEntry ? deletedEntry : entry, false);
+            
+                if (isDeletedBucket(*entry))
+                    deletedEntry = entry;
+                else if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return LookupType(entry, true);
+            }
+#if DUMP_HASHTABLE_STATS
+            ++probeCount;
+            HashTableStats::recordCollisionAtCount(probeCount);
+#endif
+            if (k == 0)
+                k = 1 | doubleHash(h);
+            i = (i + k) & sizeMask;
+        }
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename HashTranslator>
+    inline typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::FullLookupType HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::fullLookupForWriting(const T& key)
+    {
+        ASSERT(m_table);
+        checkKey<T, HashTranslator>(key);
+
+        int k = 0;
+        ValueType* table = m_table;
+        int sizeMask = m_tableSizeMask;
+        unsigned h = HashTranslator::hash(key);
+        int i = h & sizeMask;
+
+#if DUMP_HASHTABLE_STATS
+        atomicIncrement(&HashTableStats::numAccesses);
+        int probeCount = 0;
+#endif
+
+        ValueType* deletedEntry = 0;
+
+        while (1) {
+            ValueType* entry = table + i;
+            
+            // we count on the compiler to optimize out this branch
+            if (HashFunctions::safeToCompareToEmptyOrDeleted) {
+                if (isEmptyBucket(*entry))
+                    return makeLookupResult(deletedEntry ? deletedEntry : entry, false, h);
+                
+                if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return makeLookupResult(entry, true, h);
+                
+                if (isDeletedBucket(*entry))
+                    deletedEntry = entry;
+            } else {
+                if (isEmptyBucket(*entry))
+                    return makeLookupResult(deletedEntry ? deletedEntry : entry, false, h);
+            
+                if (isDeletedBucket(*entry))
+                    deletedEntry = entry;
+                else if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return makeLookupResult(entry, true, h);
+            }
+#if DUMP_HASHTABLE_STATS
+            ++probeCount;
+            HashTableStats::recordCollisionAtCount(probeCount);
+#endif
+            if (k == 0)
+                k = 1 | doubleHash(h);
+            i = (i + k) & sizeMask;
+        }
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename Extra, typename HashTranslator>
+    inline pair<typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::iterator, bool> HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::add(const T& key, const Extra& extra)
+    {
+        checkKey<T, HashTranslator>(key);
+
+        invalidateIterators();
+
+        if (!m_table)
+            expand();
+
+        internalCheckTableConsistency();
+
+        ASSERT(m_table);
+
+        int k = 0;
+        ValueType* table = m_table;
+        int sizeMask = m_tableSizeMask;
+        unsigned h = HashTranslator::hash(key);
+        int i = h & sizeMask;
+
+#if DUMP_HASHTABLE_STATS
+        atomicIncrement(&HashTableStats::numAccesses);
+        int probeCount = 0;
+#endif
+
+        ValueType* deletedEntry = 0;
+        ValueType* entry;
+        while (1) {
+            entry = table + i;
+            
+            // we count on the compiler to optimize out this branch
+            if (HashFunctions::safeToCompareToEmptyOrDeleted) {
+                if (isEmptyBucket(*entry))
+                    break;
+                
+                if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return std::make_pair(makeKnownGoodIterator(entry), false);
+                
+                if (isDeletedBucket(*entry))
+                    deletedEntry = entry;
+            } else {
+                if (isEmptyBucket(*entry))
+                    break;
+            
+                if (isDeletedBucket(*entry))
+                    deletedEntry = entry;
+                else if (HashTranslator::equal(Extractor::extract(*entry), key))
+                    return std::make_pair(makeKnownGoodIterator(entry), false);
+            }
+#if DUMP_HASHTABLE_STATS
+            ++probeCount;
+            HashTableStats::recordCollisionAtCount(probeCount);
+#endif
+            if (k == 0)
+                k = 1 | doubleHash(h);
+            i = (i + k) & sizeMask;
+        }
+
+        if (deletedEntry) {
+            initializeBucket(*deletedEntry);
+            entry = deletedEntry;
+            --m_deletedCount; 
+        }
+
+        HashTranslator::translate(*entry, key, extra);
+
+        ++m_keyCount;
+        
+        if (shouldExpand()) {
+            // FIXME: This makes an extra copy on expand. Probably not that bad since
+            // expand is rare, but would be better to have a version of expand that can
+            // follow a pivot entry and return the new position.
+            KeyType enteredKey = Extractor::extract(*entry);
+            expand();
+            pair<iterator, bool> p = std::make_pair(find(enteredKey), true);
+            ASSERT(p.first != end());
+            return p;
+        }
+        
+        internalCheckTableConsistency();
+        
+        return std::make_pair(makeKnownGoodIterator(entry), true);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template<typename T, typename Extra, typename HashTranslator>
+    inline pair<typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::iterator, bool> HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::addPassingHashCode(const T& key, const Extra& extra)
+    {
+        checkKey<T, HashTranslator>(key);
+
+        invalidateIterators();
+
+        if (!m_table)
+            expand();
+
+        internalCheckTableConsistency();
+
+        FullLookupType lookupResult = fullLookupForWriting<T, HashTranslator>(key);
+
+        ValueType* entry = lookupResult.first.first;
+        bool found = lookupResult.first.second;
+        unsigned h = lookupResult.second;
+        
+        if (found)
+            return std::make_pair(makeKnownGoodIterator(entry), false);
+        
+        if (isDeletedBucket(*entry)) {
+            initializeBucket(*entry);
+            --m_deletedCount;
+        }
+        
+        HashTranslator::translate(*entry, key, extra, h);
+        ++m_keyCount;
+        if (shouldExpand()) {
+            // FIXME: This makes an extra copy on expand. Probably not that bad since
+            // expand is rare, but would be better to have a version of expand that can
+            // follow a pivot entry and return the new position.
+            KeyType enteredKey = Extractor::extract(*entry);
+            expand();
+            pair<iterator, bool> p = std::make_pair(find(enteredKey), true);
+            ASSERT(p.first != end());
+            return p;
+        }
+
+        internalCheckTableConsistency();
+
+        return std::make_pair(makeKnownGoodIterator(entry), true);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::reinsert(ValueType& entry)
+    {
+        ASSERT(m_table);
+        ASSERT(!lookupForWriting(Extractor::extract(entry)).second);
+        ASSERT(!isDeletedBucket(*(lookupForWriting(Extractor::extract(entry)).first)));
+#if DUMP_HASHTABLE_STATS
+        atomicIncrement(&HashTableStats::numReinserts);
+#endif
+
+        Mover<ValueType, Traits::needsDestruction>::move(entry, *lookupForWriting(Extractor::extract(entry)).first);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template <typename T, typename HashTranslator> 
+    typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::iterator HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::find(const T& key)
+    {
+        if (!m_table)
+            return end();
+
+        ValueType* entry = lookup<T, HashTranslator>(key);
+        if (!entry)
+            return end();
+
+        return makeKnownGoodIterator(entry);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template <typename T, typename HashTranslator> 
+    typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::const_iterator HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::find(const T& key) const
+    {
+        if (!m_table)
+            return end();
+
+        ValueType* entry = const_cast<HashTable*>(this)->lookup<T, HashTranslator>(key);
+        if (!entry)
+            return end();
+
+        return makeKnownGoodConstIterator(entry);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    template <typename T, typename HashTranslator> 
+    bool HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::contains(const T& key) const
+    {
+        if (!m_table)
+            return false;
+
+        return const_cast<HashTable*>(this)->lookup<T, HashTranslator>(key);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::removeAndInvalidateWithoutEntryConsistencyCheck(ValueType* pos)
+    {
+        invalidateIterators();
+        remove(pos);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::removeAndInvalidate(ValueType* pos)
+    {
+        invalidateIterators();
+        internalCheckTableConsistency();
+        remove(pos);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::remove(ValueType* pos)
+    {
+#if DUMP_HASHTABLE_STATS
+        atomicIncrement(&HashTableStats::numRemoves);
+#endif
+
+        deleteBucket(*pos);
+        ++m_deletedCount;
+        --m_keyCount;
+
+        if (shouldShrink())
+            shrink();
+
+        internalCheckTableConsistency();
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::remove(iterator it)
+    {
+        if (it == end())
+            return;
+
+        removeAndInvalidate(const_cast<ValueType*>(it.m_iterator.m_position));
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::removeWithoutEntryConsistencyCheck(iterator it)
+    {
+        if (it == end())
+            return;
+
+        removeAndInvalidateWithoutEntryConsistencyCheck(const_cast<ValueType*>(it.m_iterator.m_position));
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::removeWithoutEntryConsistencyCheck(const_iterator it)
+    {
+        if (it == end())
+            return;
+
+        removeAndInvalidateWithoutEntryConsistencyCheck(const_cast<ValueType*>(it.m_position));
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::remove(const KeyType& key)
+    {
+        remove(find(key));
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    Value* HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::allocateTable(int size)
+    {
+        // would use a template member function with explicit specializations here, but
+        // gcc doesn't appear to support that
+        if (Traits::emptyValueIsZero)
+            return static_cast<ValueType*>(fastZeroedMalloc(size * sizeof(ValueType)));
+        ValueType* result = static_cast<ValueType*>(fastMalloc(size * sizeof(ValueType)));
+        for (int i = 0; i < size; i++)
+            initializeBucket(result[i]);
+        return result;
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::deallocateTable(ValueType* table, int size)
+    {
+        if (Traits::needsDestruction) {
+            for (int i = 0; i < size; ++i) {
+                if (!isDeletedBucket(table[i]))
+                    table[i].~ValueType();
+            }
+        }
+        fastFree(table);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::expand()
+    {
+        int newSize;
+        if (m_tableSize == 0)
+            newSize = m_minTableSize;
+        else if (mustRehashInPlace())
+            newSize = m_tableSize;
+        else
+            newSize = m_tableSize * 2;
+
+        rehash(newSize);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::rehash(int newTableSize)
+    {
+        internalCheckTableConsistencyExceptSize();
+
+        int oldTableSize = m_tableSize;
+        ValueType* oldTable = m_table;
+
+#if DUMP_HASHTABLE_STATS
+        if (oldTableSize != 0)
+            atomicIncrement(&HashTableStats::numRehashes);
+#endif
+
+        m_tableSize = newTableSize;
+        m_tableSizeMask = newTableSize - 1;
+        m_table = allocateTable(newTableSize);
+
+        for (int i = 0; i != oldTableSize; ++i)
+            if (!isEmptyOrDeletedBucket(oldTable[i]))
+                reinsert(oldTable[i]);
+
+        m_deletedCount = 0;
+
+        deallocateTable(oldTable, oldTableSize);
+
+        internalCheckTableConsistency();
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::clear()
+    {
+        invalidateIterators();
+        deallocateTable(m_table, m_tableSize);
+        m_table = 0;
+        m_tableSize = 0;
+        m_tableSizeMask = 0;
+        m_keyCount = 0;
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::HashTable(const HashTable& other)
+        : m_table(0)
+        , m_tableSize(0)
+        , m_tableSizeMask(0)
+        , m_keyCount(0)
+        , m_deletedCount(0)
+#if CHECK_HASHTABLE_ITERATORS
+        , m_iterators(0)
+#endif
+    {
+        // Copy the hash table the dumb way, by adding each element to the new table.
+        // It might be more efficient to copy the table slots, but it's not clear that efficiency is needed.
+        const_iterator end = other.end();
+        for (const_iterator it = other.begin(); it != end; ++it)
+            add(*it);
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::swap(HashTable& other)
+    {
+        invalidateIterators();
+        other.invalidateIterators();
+
+        ValueType* tmp_table = m_table;
+        m_table = other.m_table;
+        other.m_table = tmp_table;
+
+        int tmp_tableSize = m_tableSize;
+        m_tableSize = other.m_tableSize;
+        other.m_tableSize = tmp_tableSize;
+
+        int tmp_tableSizeMask = m_tableSizeMask;
+        m_tableSizeMask = other.m_tableSizeMask;
+        other.m_tableSizeMask = tmp_tableSizeMask;
+
+        int tmp_keyCount = m_keyCount;
+        m_keyCount = other.m_keyCount;
+        other.m_keyCount = tmp_keyCount;
+
+        int tmp_deletedCount = m_deletedCount;
+        m_deletedCount = other.m_deletedCount;
+        other.m_deletedCount = tmp_deletedCount;
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>& HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::operator=(const HashTable& other)
+    {
+        HashTable tmp(other);
+        swap(tmp);
+        return *this;
+    }
+
+#if !ASSERT_DISABLED
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::checkTableConsistency() const
+    {
+        checkTableConsistencyExceptSize();
+        ASSERT(!m_table || !shouldExpand());
+        ASSERT(!shouldShrink());
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::checkTableConsistencyExceptSize() const
+    {
+        if (!m_table)
+            return;
+
+        int count = 0;
+        int deletedCount = 0;
+        for (int j = 0; j < m_tableSize; ++j) {
+            ValueType* entry = m_table + j;
+            if (isEmptyBucket(*entry))
+                continue;
+
+            if (isDeletedBucket(*entry)) {
+                ++deletedCount;
+                continue;
+            }
+
+            const_iterator it = find(Extractor::extract(*entry));
+            ASSERT(entry == it.m_position);
+            ++count;
+
+            ValueCheck<Key>::checkConsistency(it->first);
+        }
+
+        ASSERT(count == m_keyCount);
+        ASSERT(deletedCount == m_deletedCount);
+        ASSERT(m_tableSize >= m_minTableSize);
+        ASSERT(m_tableSizeMask);
+        ASSERT(m_tableSize == m_tableSizeMask + 1);
+    }
+
+#endif // ASSERT_DISABLED
+
+#if CHECK_HASHTABLE_ITERATORS
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::invalidateIterators()
+    {
+        MutexLocker lock(m_mutex);
+        const_iterator* next;
+        for (const_iterator* p = m_iterators; p; p = next) {
+            next = p->m_next;
+            p->m_table = 0;
+            p->m_next = 0;
+            p->m_previous = 0;
+        }
+        m_iterators = 0;
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void addIterator(const HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>* table,
+        HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>* it)
+    {
+        it->m_table = table;
+        it->m_previous = 0;
+
+        // Insert iterator at head of doubly-linked list of iterators.
+        if (!table) {
+            it->m_next = 0;
+        } else {
+            MutexLocker lock(table->m_mutex);
+            ASSERT(table->m_iterators != it);
+            it->m_next = table->m_iterators;
+            table->m_iterators = it;
+            if (it->m_next) {
+                ASSERT(!it->m_next->m_previous);
+                it->m_next->m_previous = it;
+            }
+        }
+    }
+
+    template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
+    void removeIterator(HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>* it)
+    {
+        typedef HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> HashTableType;
+        typedef HashTableConstIterator<Key, Value, Extractor, HashFunctions, Traits, KeyTraits> const_iterator;
+
+        // Delete iterator from doubly-linked list of iterators.
+        if (!it->m_table) {
+            ASSERT(!it->m_next);
+            ASSERT(!it->m_previous);
+        } else {
+            MutexLocker lock(it->m_table->m_mutex);
+            if (it->m_next) {
+                ASSERT(it->m_next->m_previous == it);
+                it->m_next->m_previous = it->m_previous;
+            }
+            if (it->m_previous) {
+                ASSERT(it->m_table->m_iterators != it);
+                ASSERT(it->m_previous->m_next == it);
+                it->m_previous->m_next = it->m_next;
+            } else {
+                ASSERT(it->m_table->m_iterators == it);
+                it->m_table->m_iterators = it->m_next;
+            }
+        }
+
+        it->m_table = 0;
+        it->m_next = 0;
+        it->m_previous = 0;
+    }
+
+#endif // CHECK_HASHTABLE_ITERATORS
+
+    // iterator adapters
+
+    template<typename HashTableType, typename ValueType> struct HashTableConstIteratorAdapter {
+        HashTableConstIteratorAdapter(const typename HashTableType::const_iterator& impl) : m_impl(impl) {}
+
+        const ValueType* get() const { return (const ValueType*)m_impl.get(); }
+        const ValueType& operator*() const { return *get(); }
+        const ValueType* operator->() const { return get(); }
+
+        HashTableConstIteratorAdapter& operator++() { ++m_impl; return *this; }
+        // postfix ++ intentionally omitted
+
+        typename HashTableType::const_iterator m_impl;
+    };
+
+    template<typename HashTableType, typename ValueType> struct HashTableIteratorAdapter {
+        HashTableIteratorAdapter(const typename HashTableType::iterator& impl) : m_impl(impl) {}
+
+        ValueType* get() const { return (ValueType*)m_impl.get(); }
+        ValueType& operator*() const { return *get(); }
+        ValueType* operator->() const { return get(); }
+
+        HashTableIteratorAdapter& operator++() { ++m_impl; return *this; }
+        // postfix ++ intentionally omitted
+
+        operator HashTableConstIteratorAdapter<HashTableType, ValueType>() {
+            typename HashTableType::const_iterator i = m_impl;
+            return i;
+        }
+
+        typename HashTableType::iterator m_impl;
+    };
+
+    template<typename T, typename U>
+    inline bool operator==(const HashTableConstIteratorAdapter<T, U>& a, const HashTableConstIteratorAdapter<T, U>& b)
+    {
+        return a.m_impl == b.m_impl;
+    }
+
+    template<typename T, typename U>
+    inline bool operator!=(const HashTableConstIteratorAdapter<T, U>& a, const HashTableConstIteratorAdapter<T, U>& b)
+    {
+        return a.m_impl != b.m_impl;
+    }
+
+    template<typename T, typename U>
+    inline bool operator==(const HashTableIteratorAdapter<T, U>& a, const HashTableIteratorAdapter<T, U>& b)
+    {
+        return a.m_impl == b.m_impl;
+    }
+
+    template<typename T, typename U>
+    inline bool operator!=(const HashTableIteratorAdapter<T, U>& a, const HashTableIteratorAdapter<T, U>& b)
+    {
+        return a.m_impl != b.m_impl;
+    }
+
+} // namespace WTF
+
+#include "HashIterators.h"
+
+#endif // WTF_HashTable_h