/*
* 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; }
void expand();
void shrink() { rehash(m_tableSize / 2); }
void rehash(unsigned newTableSize);
void 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 unsigned m_maxLoad = 2;
static const unsigned 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()) {
// 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();
AddResult result(find(enteredKey), true);
ASSERT(result.iterator != end());
return result;
}
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()) {
// 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();
AddResult result(find(enteredKey), true);
ASSERT(result.iterator != end());
return result;
}
return AddResult(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
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->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 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>
void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::expand()
{
unsigned newSize;
if (!m_tableSize) {
newSize = KeyTraits::minimumTableSize;
} else if (mustRehashInPlace()) {
newSize = m_tableSize;
} else {
newSize = m_tableSize * 2;
RELEASE_ASSERT(newSize > m_tableSize);
}
rehash(newSize);
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::rehash(unsigned newTableSize)
{
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);
for (unsigned i = 0; i != oldTableSize; ++i)
if (!isEmptyOrDeletedBucket(oldTable[i]))
reinsert(oldTable[i]);
m_deletedCount = 0;
deallocateTable(oldTable, oldTableSize);
}
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