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/*
* Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
*
* 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_HashCountedSet_h
#define WTF_HashCountedSet_h
#include "wtf/Assertions.h"
#include "wtf/HashMap.h"
#include "wtf/Vector.h"
namespace WTF {
// An unordered hash set that keeps track of how many times you added an item to
// the set. The iterators have fields ->key and ->value that return the set
// members and their counts, respectively.
template <
typename Value,
typename HashFunctions = typename DefaultHash<Value>::Hash,
typename Traits = HashTraits<Value>,
typename Allocator = PartitionAllocator>
class HashCountedSet {
WTF_USE_ALLOCATOR(HashCountedSet, Allocator);
WTF_MAKE_NONCOPYABLE(HashCountedSet);
private:
typedef HashMap<Value, unsigned, HashFunctions, Traits, HashTraits<unsigned>, Allocator> ImplType;
public:
typedef Value ValueType;
typedef typename ImplType::iterator iterator;
typedef typename ImplType::const_iterator const_iterator;
typedef typename ImplType::AddResult AddResult;
HashCountedSet() {}
void swap(HashCountedSet& other) { m_impl.swap(other.m_impl); }
unsigned size() const { return m_impl.size(); }
unsigned capacity() const { return m_impl.capacity(); }
bool isEmpty() const { return m_impl.isEmpty(); }
// Iterators iterate over pairs of values (called key) and counts (called
// value).
iterator begin() { return m_impl.begin(); }
iterator end() { return m_impl.end(); }
const_iterator begin() const { return m_impl.begin(); }
const_iterator end() const { return m_impl.end(); }
iterator find(const ValueType& value) { return m_impl.find(value); }
const_iterator find(const ValueType& value) const { return m_impl.find(value); }
bool contains(const ValueType& value ) const { return m_impl.contains(value); }
unsigned count(const ValueType& value ) const { return m_impl.get(value); }
// Increases the count if an equal value is already present the return value
// is a pair of an iterator to the new value's location, and a bool that is
// true if an new entry was added.
AddResult add(const ValueType&);
// Reduces the count of the value, and removes it if count goes down to
// zero, returns true if the value is removed.
bool remove(const ValueType& value) { return remove(find(value)); }
bool remove(iterator);
// Removes the value, regardless of its count.
void removeAll(const ValueType& value) { removeAll(find(value)); }
void removeAll(iterator);
// Clears the whole set.
void clear() { m_impl.clear(); }
template <typename VisitorDispatcher>
void trace(VisitorDispatcher visitor) { m_impl.trace(visitor); }
private:
ImplType m_impl;
};
template <typename T, typename U, typename V, typename W>
inline typename HashCountedSet<T, U, V, W>::AddResult HashCountedSet<T, U, V, W>::add(const ValueType& value)
{
AddResult result = m_impl.add(value, 0);
++result.storedValue->value;
return result;
}
template <typename T, typename U, typename V, typename W>
inline bool HashCountedSet<T, U, V, W>::remove(iterator it)
{
if (it == end())
return false;
unsigned oldVal = it->value;
ASSERT(oldVal);
unsigned newVal = oldVal - 1;
if (newVal) {
it->value = newVal;
return false;
}
m_impl.remove(it);
return true;
}
template <typename T, typename U, typename V, typename W>
inline void HashCountedSet<T, U, V, W>::removeAll(iterator it)
{
if (it == end())
return;
m_impl.remove(it);
}
template <typename T, typename U, typename V, typename W, typename VectorType>
inline void copyToVector(const HashCountedSet<T, U, V, W>& collection, VectorType& vector)
{
typedef typename HashCountedSet<T, U, V, W>::const_iterator iterator;
{
// Disallow GC across resize allocation, see crbug.com/568173
typename VectorType::GCForbiddenScope scope;
vector.resize(collection.size());
}
iterator it = collection.begin();
iterator end = collection.end();
for (unsigned i = 0; it != end; ++it, ++i)
vector[i] = *it;
}
template <typename Value, typename HashFunctions, typename Traits, typename Allocator, size_t inlineCapacity, typename VectorAllocator>
inline void copyToVector(const HashCountedSet<Value, HashFunctions, Traits, Allocator>& collection, Vector<Value, inlineCapacity, VectorAllocator>& vector)
{
typedef typename HashCountedSet<Value, HashFunctions, Traits, Allocator>::const_iterator iterator;
{
// Disallow GC across resize allocation, see crbug.com/568173
typename Vector<Value, inlineCapacity, VectorAllocator>::GCForbiddenScope scope;
vector.resize(collection.size());
}
iterator it = collection.begin();
iterator end = collection.end();
for (unsigned i = 0; it != end; ++it, ++i)
vector[i] = (*it).key;
}
#if !ENABLE(OILPAN)
template <typename T, typename U, typename V>
struct NeedsTracing<HashCountedSet<T, U, V>> {
static const bool value = false;
};
#endif
} // namespace WTF
using WTF::HashCountedSet;
#endif // WTF_HashCountedSet_h
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