darling-WTF/wtf/HashTable.h
2018-01-05 13:44:16 -08:00

1539 lines
57 KiB
C++

/*
* Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012, 2015 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.
*
*/
#pragma once
#include <atomic>
#include <iterator>
#include <mutex>
#include <string.h>
#include <type_traits>
#include <utility>
#include <wtf/Assertions.h>
#include <wtf/FastMalloc.h>
#include <wtf/HashTraits.h>
#include <wtf/Lock.h>
#include <wtf/MathExtras.h>
#include <wtf/StdLibExtras.h>
#include <wtf/ValueCheck.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 {
// 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 {
// The following variables are all atomically incremented when modified.
WTF_EXPORTDATA static std::atomic<unsigned> numAccesses;
WTF_EXPORTDATA static std::atomic<unsigned> numRehashes;
WTF_EXPORTDATA static std::atomic<unsigned> numRemoves;
WTF_EXPORTDATA static std::atomic<unsigned> numReinserts;
// The following variables are only modified in the recordCollisionAtCount method within a mutex.
WTF_EXPORTDATA static unsigned maxCollisions;
WTF_EXPORTDATA static unsigned numCollisions;
WTF_EXPORTDATA static unsigned collisionGraph[4096];
WTF_EXPORT_PRIVATE static void recordCollisionAtCount(unsigned count);
WTF_EXPORT_PRIVATE 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;
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 : public std::iterator<std::forward_iterator_tag, Value, std::ptrdiff_t, const Value*, const Value&> {
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(static_cast<const HashTableType*>(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;
}
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:
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 { nullptr };
PointerType m_endPosition { nullptr };
#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 : public std::iterator<std::forward_iterator_tag, Value, std::ptrdiff_t, Value*, Value&> {
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;
};
template<typename ValueTraits, 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, typename V> static void translate(T& location, const U&, V&& value)
{
ValueTraits::assignToEmpty(location, std::forward<V>(value));
}
};
template<typename IteratorType> struct HashTableAddResult {
HashTableAddResult() : isNewEntry(false) { }
HashTableAddResult(IteratorType iter, bool isNewEntry) : iterator(iter), isNewEntry(isNewEntry) { }
IteratorType iterator;
bool isNewEntry;
explicit operator bool() const { return 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<ValueTraits, 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()
{
}
unsigned numAccesses;
unsigned numRehashes;
unsigned numRemoves;
unsigned numReinserts;
unsigned maxCollisions;
unsigned numCollisions;
unsigned collisionGraph[4096];
void recordCollisionAtCount(unsigned 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 (unsigned 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()
{
invalidateIterators();
if (m_table)
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&);
HashTable(HashTable&&);
HashTable& operator=(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); }
AddResult add(ValueType&& value) { return add<IdentityTranslatorType>(Extractor::extract(value), WTFMove(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(T&& key, Extra&&);
template<typename HashTranslator, typename T, typename Extra> AddResult addPassingHashCode(T&& key, 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 removeWithoutEntryConsistencyCheck(iterator);
void removeWithoutEntryConsistencyCheck(const_iterator);
template<typename Functor>
void removeIf(const Functor&);
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&);
template<typename HashTranslator, typename T> ValueType* inlineLookup(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(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&);
template<typename HashTranslator, typename T, typename Extra> void addUniqueForInitialization(T&& key, Extra&&);
template<typename HashTranslator, typename T> 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 > KeyTraits::minimumTableSize; }
ValueType* expand(ValueType* entry = nullptr);
void shrink() { rehash(m_tableSize / 2, nullptr); }
ValueType* rehash(unsigned newTableSize, ValueType* entry);
ValueType* reinsert(ValueType&&);
static void initializeBucket(ValueType& bucket);
static void deleteBucket(ValueType& bucket) { hashTraitsDeleteBucket<Traits>(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 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 CHECK_HASHTABLE_ITERATORS
public:
// All access to m_iterators should be guarded with m_mutex.
mutable const_iterator* m_iterators;
// Use std::unique_ptr so HashTable can still be memmove'd or memcpy'ed.
mutable std::unique_ptr<Lock> m_mutex;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
public:
mutable std::unique_ptr<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<unsigned>(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 CHECK_HASHTABLE_ITERATORS
, m_iterators(0)
, m_mutex(std::make_unique<Lock>())
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
, m_stats(std::make_unique<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;
}
#if ASSERT_DISABLED
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
template<typename HashTranslator, typename T>
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 HashTranslator, typename T>
void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::checkKey(const T& key)
{
if (!HashFunctions::safeToCompareToEmptyOrDeleted)
return;
ASSERT(!HashTranslator::equal(KeyTraits::emptyValue(), key));
typename std::aligned_storage<sizeof(ValueType), std::alignment_of<ValueType>::value>::type deletedValueBuffer;
ValueType* deletedValuePtr = reinterpret_cast_ptr<ValueType*>(&deletedValueBuffer);
ValueType& deletedValue = *deletedValuePtr;
Traits::constructDeletedValue(deletedValue);
ASSERT(!HashTranslator::equal(Extractor::extract(deletedValue), key));
}
#endif
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
template<typename HashTranslator, typename T>
inline auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::lookup(const T& key) -> ValueType*
{
return inlineLookup<HashTranslator>(key);
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
template<typename HashTranslator, typename T>
ALWAYS_INLINE auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::inlineLookup(const T& key) -> ValueType*
{
checkKey<HashTranslator>(key);
unsigned k = 0;
unsigned sizeMask = m_tableSizeMask;
ValueType* table = m_table;
unsigned h = HashTranslator::hash(key);
unsigned i = h & sizeMask;
if (!table)
return 0;
#if DUMP_HASHTABLE_STATS
++HashTableStats::numAccesses;
unsigned probeCount = 0;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->numAccesses;
#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
m_stats->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 HashTranslator, typename T>
inline auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::lookupForWriting(const T& key) -> LookupType
{
ASSERT(m_table);
checkKey<HashTranslator>(key);
unsigned k = 0;
ValueType* table = m_table;
unsigned sizeMask = m_tableSizeMask;
unsigned h = HashTranslator::hash(key);
unsigned i = h & sizeMask;
#if DUMP_HASHTABLE_STATS
++HashTableStats::numAccesses;
unsigned probeCount = 0;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->numAccesses;
#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
m_stats->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 HashTranslator, typename T>
inline auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::fullLookupForWriting(const T& key) -> FullLookupType
{
ASSERT(m_table);
checkKey<HashTranslator>(key);
unsigned k = 0;
ValueType* table = m_table;
unsigned sizeMask = m_tableSizeMask;
unsigned h = HashTranslator::hash(key);
unsigned i = h & sizeMask;
#if DUMP_HASHTABLE_STATS
++HashTableStats::numAccesses;
unsigned probeCount = 0;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->numAccesses;
#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
m_stats->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 HashTranslator, typename T, typename Extra>
ALWAYS_INLINE void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::addUniqueForInitialization(T&& key, Extra&& extra)
{
ASSERT(m_table);
checkKey<HashTranslator>(key);
invalidateIterators();
internalCheckTableConsistency();
unsigned k = 0;
ValueType* table = m_table;
unsigned sizeMask = m_tableSizeMask;
unsigned h = HashTranslator::hash(key);
unsigned i = h & sizeMask;
#if DUMP_HASHTABLE_STATS
++HashTableStats::numAccesses;
unsigned probeCount = 0;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->numAccesses;
#endif
ValueType* entry;
while (1) {
entry = table + i;
if (isEmptyBucket(*entry))
break;
#if DUMP_HASHTABLE_STATS
++probeCount;
HashTableStats::recordCollisionAtCount(probeCount);
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
m_stats->recordCollisionAtCount(probeCount);
#endif
if (k == 0)
k = 1 | doubleHash(h);
i = (i + k) & sizeMask;
}
HashTranslator::translate(*entry, std::forward<T>(key), std::forward<Extra>(extra));
internalCheckTableConsistency();
}
template<bool emptyValueIsZero> struct HashTableBucketInitializer;
template<> struct HashTableBucketInitializer<false> {
template<typename Traits, typename Value> static void initialize(Value& bucket)
{
new (NotNull, std::addressof(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(std::addressof(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>
ALWAYS_INLINE auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::add(T&& key, Extra&& extra) -> AddResult
{
checkKey<HashTranslator>(key);
invalidateIterators();
if (!m_table)
expand(nullptr);
internalCheckTableConsistency();
ASSERT(m_table);
unsigned k = 0;
ValueType* table = m_table;
unsigned sizeMask = m_tableSizeMask;
unsigned h = HashTranslator::hash(key);
unsigned i = h & sizeMask;
#if DUMP_HASHTABLE_STATS
++HashTableStats::numAccesses;
unsigned probeCount = 0;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->numAccesses;
#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
m_stats->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, std::forward<T>(key), std::forward<Extra>(extra));
++m_keyCount;
if (shouldExpand())
entry = expand(entry);
internalCheckTableConsistency();
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>
inline auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::addPassingHashCode(T&& key, Extra&& extra) -> AddResult
{
checkKey<HashTranslator>(key);
invalidateIterators();
if (!m_table)
expand();
internalCheckTableConsistency();
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, std::forward<T>(key), std::forward<Extra>(extra), h);
++m_keyCount;
if (shouldExpand())
entry = expand(entry);
internalCheckTableConsistency();
return AddResult(makeKnownGoodIterator(entry), true);
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
inline auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::reinsert(ValueType&& entry) -> ValueType*
{
ASSERT(m_table);
ASSERT(!lookupForWriting(Extractor::extract(entry)).second);
ASSERT(!isDeletedBucket(*(lookupForWriting(Extractor::extract(entry)).first)));
#if DUMP_HASHTABLE_STATS
++HashTableStats::numReinserts;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->numReinserts;
#endif
Value* newEntry = lookupForWriting(Extractor::extract(entry)).first;
newEntry->~Value();
new (NotNull, newEntry) ValueType(WTFMove(entry));
return newEntry;
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
template <typename HashTranslator, typename T>
auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::find(const T& key) -> iterator
{
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>
auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::find(const T& key) const -> const_iterator
{
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>::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
++HashTableStats::numRemoves;
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
++m_stats->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>
template<typename Functor>
inline void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::removeIf(const Functor& functor)
{
// We must use local copies in case "functor" or "deleteBucket"
// make a function call, which prevents the compiler from keeping
// the values in register.
unsigned removedBucketCount = 0;
ValueType* table = m_table;
for (unsigned i = m_tableSize; i--;) {
ValueType& bucket = table[i];
if (isEmptyOrDeletedBucket(bucket))
continue;
if (!functor(bucket))
continue;
deleteBucket(bucket);
++removedBucketCount;
}
m_deletedCount += removedBucketCount;
m_keyCount -= removedBucketCount;
if (shouldShrink())
shrink();
internalCheckTableConsistency();
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::allocateTable(unsigned size) -> ValueType*
{
// 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 (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)
{
for (unsigned 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>
auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::expand(ValueType* entry) -> ValueType*
{
unsigned newSize;
if (m_tableSize == 0)
newSize = KeyTraits::minimumTableSize;
else if (mustRehashInPlace())
newSize = m_tableSize;
else
newSize = m_tableSize * 2;
return rehash(newSize, entry);
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::rehash(unsigned newTableSize, ValueType* entry) -> ValueType*
{
internalCheckTableConsistencyExceptSize();
unsigned oldTableSize = m_tableSize;
ValueType* oldTable = m_table;
#if DUMP_HASHTABLE_STATS
if (oldTableSize != 0)
++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 = nullptr;
for (unsigned i = 0; i != oldTableSize; ++i) {
if (isDeletedBucket(oldTable[i])) {
ASSERT(std::addressof(oldTable[i]) != entry);
continue;
}
if (isEmptyBucket(oldTable[i])) {
ASSERT(std::addressof(oldTable[i]) != entry);
oldTable[i].~ValueType();
continue;
}
Value* reinsertedEntry = reinsert(WTFMove(oldTable[i]));
oldTable[i].~ValueType();
if (std::addressof(oldTable[i]) == entry) {
ASSERT(!newEntry);
newEntry = reinsertedEntry;
}
}
m_deletedCount = 0;
fastFree(oldTable);
internalCheckTableConsistency();
return newEntry;
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::clear()
{
invalidateIterators();
if (!m_table)
return;
deallocateTable(m_table, m_tableSize);
m_table = 0;
m_tableSize = 0;
m_tableSizeMask = 0;
m_keyCount = 0;
m_deletedCount = 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(nullptr)
, m_tableSize(0)
, m_tableSizeMask(0)
, m_keyCount(0)
, m_deletedCount(0)
#if CHECK_HASHTABLE_ITERATORS
, m_iterators(nullptr)
, m_mutex(std::make_unique<Lock>())
#endif
#if DUMP_HASHTABLE_STATS_PER_TABLE
, m_stats(std::make_unique<Stats>(*other.m_stats))
#endif
{
unsigned otherKeyCount = other.size();
if (!otherKeyCount)
return;
unsigned bestTableSize = WTF::roundUpToPowerOfTwo(otherKeyCount) * 2;
// With maxLoad at 1/2 and minLoad at 1/6, our average load is 2/6.
// If we are getting halfway between 2/6 and 1/2 (past 5/12), we double the size to avoid being too close to
// loadMax and bring the ratio close to 2/6. This give us a load in the bounds [3/12, 5/12).
bool aboveThreeQuarterLoad = otherKeyCount * 12 >= bestTableSize * 5;
if (aboveThreeQuarterLoad)
bestTableSize *= 2;
unsigned minimumTableSize = KeyTraits::minimumTableSize;
m_tableSize = std::max<unsigned>(bestTableSize, minimumTableSize);
m_tableSizeMask = m_tableSize - 1;
m_keyCount = otherKeyCount;
m_table = allocateTable(m_tableSize);
for (const auto& otherValue : other)
addUniqueForInitialization<IdentityTranslatorType>(Extractor::extract(otherValue), otherValue);
}
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();
std::swap(m_table, other.m_table);
std::swap(m_tableSize, other.m_tableSize);
std::swap(m_tableSizeMask, other.m_tableSizeMask);
std::swap(m_keyCount, other.m_keyCount);
std::swap(m_deletedCount, other.m_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>
auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::operator=(const HashTable& other) -> HashTable&
{
HashTable tmp(other);
swap(tmp);
return *this;
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
inline HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::HashTable(HashTable&& other)
#if CHECK_HASHTABLE_ITERATORS
: m_iterators(nullptr)
, m_mutex(std::make_unique<Lock>())
#endif
{
other.invalidateIterators();
m_table = other.m_table;
m_tableSize = other.m_tableSize;
m_tableSizeMask = other.m_tableSizeMask;
m_keyCount = other.m_keyCount;
m_deletedCount = other.m_deletedCount;
other.m_table = nullptr;
other.m_tableSize = 0;
other.m_tableSizeMask = 0;
other.m_keyCount = 0;
other.m_deletedCount = 0;
#if DUMP_HASHTABLE_STATS_PER_TABLE
m_stats = WTFMove(other.m_stats);
other.m_stats = nullptr;
#endif
}
template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits>
inline auto HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits>::operator=(HashTable&& other) -> HashTable&
{
HashTable temp = WTFMove(other);
swap(temp);
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;
unsigned count = 0;
unsigned deletedCount = 0;
for (unsigned 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->key);
}
ASSERT(count == m_keyCount);
ASSERT(deletedCount == m_deletedCount);
ASSERT(m_tableSize >= KeyTraits::minimumTableSize);
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()
{
std::lock_guard<Lock> 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 {
std::lock_guard<Lock> 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)
{
// Delete iterator from doubly-linked list of iterators.
if (!it->m_table) {
ASSERT(!it->m_next);
ASSERT(!it->m_previous);
} else {
std::lock_guard<Lock> 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 : public std::iterator<std::forward_iterator_tag, ValueType, std::ptrdiff_t, const ValueType*, const ValueType&> {
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 : public std::iterator<std::forward_iterator_tag, ValueType, std::ptrdiff_t, ValueType*, ValueType&> {
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>