| /* |
| * Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012 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 "wtf/Alignment.h" |
| #include "wtf/Assertions.h" |
| #include "wtf/HashTraits.h" |
| #include "wtf/PartitionAlloc.h" |
| #include "wtf/WTF.h" |
| #include <string.h> |
| |
| #define DUMP_HASHTABLE_STATS 0 |
| #define DUMP_HASHTABLE_STATS_PER_TABLE 0 |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| #include "wtf/DataLog.h" |
| #endif |
| |
| namespace WTF { |
| |
| #if DUMP_HASHTABLE_STATS |
| |
| struct HashTableStats { |
| // 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); |
| static void dumpStats(); |
| }; |
| |
| #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; |
| |
| 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) |
| { |
| skipEmptyBuckets(); |
| } |
| |
| HashTableConstIterator(const HashTableType* table, PointerType position, PointerType endPosition, HashItemKnownGoodTag) |
| : m_position(position), m_endPosition(endPosition) |
| { |
| } |
| |
| public: |
| HashTableConstIterator() |
| { |
| } |
| |
| PointerType get() const |
| { |
| return m_position; |
| } |
| ReferenceType operator*() const { return *get(); } |
| PointerType operator->() const { return get(); } |
| |
| const_iterator& operator++() |
| { |
| ASSERT(m_position != m_endPosition); |
| ++m_position; |
| skipEmptyBuckets(); |
| return *this; |
| } |
| |
| // postfix ++ intentionally omitted |
| |
| // Comparison. |
| bool operator==(const const_iterator& other) const |
| { |
| return m_position == other.m_position; |
| } |
| bool operator!=(const const_iterator& other) const |
| { |
| return m_position != other.m_position; |
| } |
| bool operator==(const iterator& other) const |
| { |
| return *this == static_cast<const_iterator>(other); |
| } |
| bool operator!=(const iterator& other) const |
| { |
| return *this != static_cast<const_iterator>(other); |
| } |
| |
| private: |
| PointerType m_position; |
| PointerType m_endPosition; |
| }; |
| |
| 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; } |
| bool operator==(const const_iterator& other) const { return m_iterator == other; } |
| bool operator!=(const const_iterator& other) const { return m_iterator != other; } |
| |
| operator const_iterator() const { return m_iterator; } |
| |
| private: |
| const_iterator m_iterator; |
| }; |
| |
| using std::swap; |
| |
| // Work around MSVC's standard library, whose swap for pairs does not swap by component. |
| template<typename T> inline void hashTableSwap(T& a, T& b) |
| { |
| swap(a, b); |
| } |
| |
| template<typename T, typename U> inline void hashTableSwap(KeyValuePair<T, U>& a, KeyValuePair<T, U>& b) |
| { |
| swap(a.key, b.key); |
| swap(a.value, b.value); |
| } |
| |
| template<typename T, bool useSwap> struct Mover; |
| template<typename T> struct Mover<T, true> { static void move(T& from, T& to) { hashTableSwap(from, to); } }; |
| template<typename T> struct Mover<T, false> { static void move(T& from, T& to) { to = from; } }; |
| |
| template<typename HashFunctions> class IdentityHashTranslator { |
| public: |
| template<typename T> static unsigned hash(const T& key) { return HashFunctions::hash(key); } |
| template<typename T, typename U> static bool equal(const T& a, const U& b) { return HashFunctions::equal(a, b); } |
| template<typename T, typename U> static void translate(T& location, const U&, const T& value) { location = value; } |
| }; |
| |
| template<typename IteratorType> struct HashTableAddResult { |
| HashTableAddResult(IteratorType iter, bool isNewEntry) : iterator(iter), isNewEntry(isNewEntry) { } |
| IteratorType iterator; |
| bool isNewEntry; |
| }; |
| |
| 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<HashFunctions> IdentityTranslatorType; |
| typedef HashTableAddResult<iterator> AddResult; |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| struct Stats { |
| Stats() |
| : numAccesses(0) |
| , numRehashes(0) |
| , numRemoves(0) |
| , numReinserts(0) |
| , maxCollisions(0) |
| , numCollisions(0) |
| , collisionGraph() |
| { |
| } |
| |
| int numAccesses; |
| int numRehashes; |
| int numRemoves; |
| int numReinserts; |
| |
| int maxCollisions; |
| int numCollisions; |
| int collisionGraph[4096]; |
| |
| void recordCollisionAtCount(int count) |
| { |
| if (count > maxCollisions) |
| maxCollisions = count; |
| numCollisions++; |
| collisionGraph[count]++; |
| } |
| |
| void dumpStats() |
| { |
| dataLogF("\nWTF::HashTable::Stats dump\n\n"); |
| dataLogF("%d accesses\n", numAccesses); |
| dataLogF("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses); |
| dataLogF("longest collision chain: %d\n", maxCollisions); |
| for (int i = 1; i <= maxCollisions; i++) { |
| dataLogF(" %d lookups with exactly %d collisions (%.2f%% , %.2f%% with this many or more)\n", collisionGraph[i], i, 100.0 * (collisionGraph[i] - collisionGraph[i+1]) / numAccesses, 100.0 * collisionGraph[i] / numAccesses); |
| } |
| dataLogF("%d rehashes\n", numRehashes); |
| dataLogF("%d reinserts\n", numReinserts); |
| } |
| }; |
| #endif |
| |
| HashTable(); |
| ~HashTable() |
| { |
| if (LIKELY(!m_table)) |
| return; |
| deallocateTable(m_table, m_tableSize); |
| m_table = 0; |
| } |
| |
| HashTable(const HashTable&); |
| void swap(HashTable&); |
| HashTable& operator=(const HashTable&); |
| |
| // When the hash table is empty, just return the same iterator for end as for begin. |
| // This is more efficient because we don't have to skip all the empty and deleted |
| // buckets, and iterating an empty table is a common case that's worth optimizing. |
| iterator begin() { return isEmpty() ? end() : makeIterator(m_table); } |
| iterator end() { return makeKnownGoodIterator(m_table + m_tableSize); } |
| const_iterator begin() const { return isEmpty() ? end() : makeConstIterator(m_table); } |
| const_iterator end() const { return makeKnownGoodConstIterator(m_table + m_tableSize); } |
| |
| unsigned size() const { return m_keyCount; } |
| unsigned capacity() const { return m_tableSize; } |
| bool isEmpty() const { return !m_keyCount; } |
| |
| AddResult add(const ValueType& value) { return add<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 HashTranslator, typename T, typename Extra> AddResult add(const T& key, const Extra&); |
| template<typename HashTranslator, typename T, typename Extra> AddResult addPassingHashCode(const T& key, const Extra&); |
| |
| iterator find(const KeyType& key) { return find<IdentityTranslatorType>(key); } |
| const_iterator find(const KeyType& key) const { return find<IdentityTranslatorType>(key); } |
| bool contains(const KeyType& key) const { return contains<IdentityTranslatorType>(key); } |
| |
| template<typename HashTranslator, typename T> iterator find(const T&); |
| template<typename HashTranslator, typename T> const_iterator find(const T&) const; |
| template<typename HashTranslator, typename T> bool contains(const T&) const; |
| |
| void remove(const KeyType&); |
| void remove(iterator); |
| void remove(const_iterator); |
| void clear(); |
| |
| static bool isEmptyBucket(const ValueType& value) { return isHashTraitsEmptyValue<KeyTraits>(Extractor::extract(value)); } |
| 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<IdentityTranslatorType>(key); } |
| template<typename HashTranslator, typename T> ValueType* lookup(const T&); |
| |
| private: |
| static ValueType* allocateTable(unsigned size); |
| static void deallocateTable(ValueType* table, unsigned size); |
| |
| typedef std::pair<ValueType*, bool> LookupType; |
| typedef std::pair<LookupType, unsigned> FullLookupType; |
| |
| LookupType lookupForWriting(const Key& key) { return lookupForWriting<IdentityTranslatorType>(key); }; |
| template<typename HashTranslator, typename T> FullLookupType fullLookupForWriting(const T&); |
| template<typename HashTranslator, typename T> LookupType lookupForWriting(const T&); |
| |
| 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 > KeyTraits::minimumTableSize; } |
| ValueType* expand(ValueType* entry = 0); |
| void shrink() { rehash(m_tableSize / 2, 0); } |
| |
| ValueType* rehash(unsigned newTableSize, ValueType* entry); |
| ValueType* reinsert(ValueType&); |
| |
| static void initializeBucket(ValueType& bucket); |
| 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); } |
| |
| static const int m_maxLoad = 2; |
| static const int m_minLoad = 6; |
| |
| ValueType* m_table; |
| unsigned m_tableSize; |
| unsigned m_tableSizeMask; |
| unsigned m_keyCount; |
| unsigned m_deletedCount; |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| public: |
| mutable OwnPtr<Stats> m_stats; |
| #endif |
| }; |
| |
| // Set all the bits to one after the most significant bit: 00110101010 -> 00111111111. |
| template<unsigned size> struct OneifyLowBits; |
| template<> |
| struct OneifyLowBits<0> { |
| static const unsigned value = 0; |
| }; |
| template<unsigned number> |
| struct OneifyLowBits { |
| static const unsigned value = number | OneifyLowBits<(number >> 1)>::value; |
| }; |
| // Compute the first power of two integer that is an upper bound of the parameter 'number'. |
| template<unsigned number> |
| struct UpperPowerOfTwoBound { |
| static const unsigned value = (OneifyLowBits<number - 1>::value + 1) * 2; |
| }; |
| |
| // Because power of two numbers are the limit of maxLoad, their capacity is twice the |
| // UpperPowerOfTwoBound, or 4 times their values. |
| template<unsigned size, bool isPowerOfTwo> struct HashTableCapacityForSizeSplitter; |
| template<unsigned size> |
| struct HashTableCapacityForSizeSplitter<size, true> { |
| static const unsigned value = size * 4; |
| }; |
| template<unsigned size> |
| struct HashTableCapacityForSizeSplitter<size, false> { |
| static const unsigned value = UpperPowerOfTwoBound<size>::value; |
| }; |
| |
| // HashTableCapacityForSize computes the upper power of two capacity to hold the size parameter. |
| // This is done at compile time to initialize the HashTraits. |
| template<unsigned size> |
| struct HashTableCapacityForSize { |
| static const unsigned value = HashTableCapacityForSizeSplitter<size, !(size & (size - 1))>::value; |
| COMPILE_ASSERT(size > 0, HashTableNonZeroMinimumCapacity); |
| COMPILE_ASSERT(!static_cast<int>(value >> 31), HashTableNoCapacityOverflow); |
| COMPILE_ASSERT(value > (2 * size), HashTableCapacityHoldsContentSize); |
| }; |
| |
| 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 DUMP_HASHTABLE_STATS_PER_TABLE |
| , m_stats(adoptPtr(new Stats)) |
| #endif |
| { |
| } |
| |
| inline unsigned doubleHash(unsigned key) |
| { |
| key = ~key + (key >> 23); |
| key ^= (key << 12); |
| key ^= (key >> 7); |
| key ^= (key << 2); |
| key ^= (key >> 20); |
| return key; |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template<typename HashTranslator, typename T> |
| inline Value* HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::lookup(const T& 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 |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++m_stats->numAccesses; |
| int perTableProbeCount = 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 DUMP_HASHTABLE_STATS_PER_TABLE |
| ++perTableProbeCount; |
| m_stats->recordCollisionAtCount(perTableProbeCount); |
| #endif |
| |
| if (!k) |
| k = 1 | doubleHash(h); |
| i = (i + k) & sizeMask; |
| } |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template<typename HashTranslator, typename T> |
| inline typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::LookupType HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::lookupForWriting(const T& key) |
| { |
| 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 |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++m_stats->numAccesses; |
| int perTableProbeCount = 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 DUMP_HASHTABLE_STATS_PER_TABLE |
| ++perTableProbeCount; |
| m_stats->recordCollisionAtCount(perTableProbeCount); |
| #endif |
| |
| if (!k) |
| k = 1 | doubleHash(h); |
| i = (i + k) & sizeMask; |
| } |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template<typename HashTranslator, typename T> |
| inline typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::FullLookupType HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::fullLookupForWriting(const T& key) |
| { |
| 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 |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++m_stats->numAccesses; |
| int perTableProbeCount = 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 DUMP_HASHTABLE_STATS_PER_TABLE |
| ++perTableProbeCount; |
| m_stats->recordCollisionAtCount(perTableProbeCount); |
| #endif |
| |
| if (!k) |
| k = 1 | doubleHash(h); |
| i = (i + k) & sizeMask; |
| } |
| } |
| |
| template<bool emptyValueIsZero> struct HashTableBucketInitializer; |
| |
| template<> struct HashTableBucketInitializer<false> { |
| template<typename Traits, typename Value> static void initialize(Value& bucket) |
| { |
| new (NotNull, &bucket) Value(Traits::emptyValue()); |
| } |
| }; |
| |
| template<> struct HashTableBucketInitializer<true> { |
| template<typename Traits, typename Value> static void initialize(Value& bucket) |
| { |
| // This initializes the bucket without copying the empty value. |
| // That makes it possible to use this with types that don't support copying. |
| // The memset to 0 looks like a slow operation but is optimized by the compilers. |
| memset(&bucket, 0, sizeof(bucket)); |
| } |
| }; |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::initializeBucket(ValueType& bucket) |
| { |
| HashTableBucketInitializer<Traits::emptyValueIsZero>::template initialize<Traits>(bucket); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template<typename HashTranslator, typename T, typename Extra> |
| typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::AddResult HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::add(const T& key, const Extra& extra) |
| { |
| if (!m_table) |
| expand(); |
| |
| 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 |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++m_stats->numAccesses; |
| int perTableProbeCount = 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 AddResult(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 AddResult(makeKnownGoodIterator(entry), false); |
| } |
| #if DUMP_HASHTABLE_STATS |
| ++probeCount; |
| HashTableStats::recordCollisionAtCount(probeCount); |
| #endif |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++perTableProbeCount; |
| m_stats->recordCollisionAtCount(perTableProbeCount); |
| #endif |
| |
| if (!k) |
| 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()) |
| entry = expand(entry); |
| |
| return AddResult(makeKnownGoodIterator(entry), true); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template<typename HashTranslator, typename T, typename Extra> |
| typename HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::AddResult HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::addPassingHashCode(const T& key, const Extra& extra) |
| { |
| if (!m_table) |
| expand(); |
| |
| FullLookupType lookupResult = fullLookupForWriting<HashTranslator>(key); |
| |
| ValueType* entry = lookupResult.first.first; |
| bool found = lookupResult.first.second; |
| unsigned h = lookupResult.second; |
| |
| if (found) |
| return AddResult(makeKnownGoodIterator(entry), false); |
| |
| if (isDeletedBucket(*entry)) { |
| initializeBucket(*entry); |
| --m_deletedCount; |
| } |
| |
| HashTranslator::translate(*entry, key, extra, h); |
| ++m_keyCount; |
| |
| if (shouldExpand()) |
| entry = expand(entry); |
| |
| return AddResult(makeKnownGoodIterator(entry), true); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| inline Value* 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 |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++m_stats->numReinserts; |
| #endif |
| Value* newEntry = lookupForWriting(Extractor::extract(entry)).first; |
| Mover<ValueType, Traits::needsDestruction>::move(entry, *newEntry); |
| |
| return newEntry; |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template <typename HashTranslator, typename T> |
| 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<HashTranslator>(key); |
| if (!entry) |
| return end(); |
| |
| return makeKnownGoodIterator(entry); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template <typename HashTranslator, typename T> |
| 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<HashTranslator>(key); |
| if (!entry) |
| return end(); |
| |
| return makeKnownGoodConstIterator(entry); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| template <typename HashTranslator, typename T> |
| bool HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::contains(const T& key) const |
| { |
| if (!m_table) |
| return false; |
| |
| return const_cast<HashTable*>(this)->lookup<HashTranslator>(key); |
| } |
| |
| 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 |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| ++m_stats->numRemoves; |
| #endif |
| |
| deleteBucket(*pos); |
| ++m_deletedCount; |
| --m_keyCount; |
| |
| if (shouldShrink()) |
| shrink(); |
| } |
| |
| 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; |
| |
| remove(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>::remove(const_iterator it) |
| { |
| if (it == end()) |
| return; |
| |
| remove(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(unsigned size) |
| { |
| size_t allocSize = size * sizeof(ValueType); |
| ValueType* result = static_cast<ValueType*>(partitionAllocGeneric(WTF::Partitions::getBufferPartition(), allocSize)); |
| if (Traits::emptyValueIsZero) { |
| memset(result, '\0', allocSize); |
| } else { |
| for (unsigned 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, unsigned size) |
| { |
| if (Traits::needsDestruction) { |
| for (unsigned i = 0; i < size; ++i) { |
| if (!isDeletedBucket(table[i])) |
| table[i].~ValueType(); |
| } |
| } |
| partitionFreeGeneric(WTF::Partitions::getBufferPartition(), table); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| Value* HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::expand(Value* entry) |
| { |
| unsigned newSize; |
| if (!m_tableSize) { |
| newSize = KeyTraits::minimumTableSize; |
| } else if (mustRehashInPlace()) { |
| newSize = m_tableSize; |
| } else { |
| newSize = m_tableSize * 2; |
| RELEASE_ASSERT(newSize > m_tableSize); |
| } |
| |
| return rehash(newSize, entry); |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| Value* HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::rehash(unsigned newTableSize, Value *entry) |
| { |
| unsigned oldTableSize = m_tableSize; |
| ValueType* oldTable = m_table; |
| |
| #if DUMP_HASHTABLE_STATS |
| if (oldTableSize != 0) |
| atomicIncrement(&HashTableStats::numRehashes); |
| #endif |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| if (oldTableSize != 0) |
| ++m_stats->numRehashes; |
| #endif |
| |
| m_tableSize = newTableSize; |
| m_tableSizeMask = newTableSize - 1; |
| m_table = allocateTable(newTableSize); |
| |
| Value* newEntry = 0; |
| for (unsigned i = 0; i != oldTableSize; ++i) { |
| if (isEmptyOrDeletedBucket(oldTable[i])) { |
| ASSERT(&oldTable[i] != entry); |
| continue; |
| } |
| |
| Value* reinsertedEntry = reinsert(oldTable[i]); |
| if (&oldTable[i] == entry) { |
| ASSERT(!newEntry); |
| newEntry = reinsertedEntry; |
| } |
| } |
| |
| m_deletedCount = 0; |
| |
| if (oldTable) |
| deallocateTable(oldTable, oldTableSize); |
| return newEntry; |
| } |
| |
| template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits> |
| void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::clear() |
| { |
| if (!m_table) |
| return; |
| |
| 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 DUMP_HASHTABLE_STATS_PER_TABLE |
| , m_stats(adoptPtr(new Stats(*other.m_stats))) |
| #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) |
| { |
| 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; |
| |
| #if DUMP_HASHTABLE_STATS_PER_TABLE |
| m_stats.swap(other.m_stats); |
| #endif |
| } |
| |
| 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; |
| } |
| |
| // iterator adapters |
| |
| template<typename HashTableType, typename ValueType> struct HashTableConstIteratorAdapter { |
| 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() {} |
| 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; |
| } |
| |
| // All 4 combinations of ==, != and Const,non const. |
| template<typename T, typename U> |
| inline bool operator==(const HashTableConstIteratorAdapter<T, U>& a, const HashTableIteratorAdapter<T, U>& b) |
| { |
| return a.m_impl == b.m_impl; |
| } |
| |
| template<typename T, typename U> |
| inline bool operator!=(const HashTableConstIteratorAdapter<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 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 HashTableConstIteratorAdapter<T, U>& b) |
| { |
| return a.m_impl != b.m_impl; |
| } |
| |
| } // namespace WTF |
| |
| #include "wtf/HashIterators.h" |
| |
| #endif // WTF_HashTable_h |
