mirror of
https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
375 lines
9.9 KiB
C++
375 lines
9.9 KiB
C++
#pragma once
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#include <AK/Assertions.h>
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#include <AK/SinglyLinkedList.h>
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#include <AK/StdLibExtras.h>
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#include <AK/TemporaryChange.h>
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#include <AK/Traits.h>
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#include <AK/kstdio.h>
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namespace AK {
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template<typename T, typename = Traits<T>>
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class HashTable;
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template<typename HashTableType, typename ElementType, typename BucketIteratorType>
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class HashTableIterator {
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public:
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bool operator!=(const HashTableIterator& other) const
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{
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if (m_is_end && other.m_is_end)
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return false;
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return &m_table != &other.m_table
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|| m_is_end != other.m_is_end
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|| m_bucket_index != other.m_bucket_index
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|| m_bucket_iterator != other.m_bucket_iterator;
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}
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bool operator==(const HashTableIterator& other) const { return !(*this != other); }
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ElementType& operator*() { return *m_bucket_iterator; }
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ElementType* operator->() { return m_bucket_iterator.operator->(); }
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HashTableIterator& operator++()
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{
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skip_to_next();
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return *this;
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}
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void skip_to_next()
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{
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while (!m_is_end) {
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if (m_bucket_iterator.is_end()) {
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++m_bucket_index;
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if (m_bucket_index >= m_table.capacity()) {
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m_is_end = true;
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return;
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}
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m_bucket_iterator = m_table.bucket(m_bucket_index).begin();
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} else {
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++m_bucket_iterator;
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}
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if (!m_bucket_iterator.is_end())
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return;
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}
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}
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private:
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friend HashTableType;
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explicit HashTableIterator(HashTableType& table, bool is_end, BucketIteratorType bucket_iterator = BucketIteratorType::universal_end(), int bucket_index = 0)
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: m_table(table)
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, m_bucket_index(bucket_index)
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, m_is_end(is_end)
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, m_bucket_iterator(bucket_iterator)
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{
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ASSERT(!table.m_clearing);
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ASSERT(!table.m_rehashing);
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if (!is_end && !m_table.is_empty() && !(m_bucket_iterator != BucketIteratorType::universal_end())) {
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m_bucket_iterator = m_table.bucket(0).begin();
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if (m_bucket_iterator.is_end())
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skip_to_next();
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}
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}
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HashTableType& m_table;
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int m_bucket_index { 0 };
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bool m_is_end { false };
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BucketIteratorType m_bucket_iterator;
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};
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template<typename T, typename TraitsForT>
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class HashTable {
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private:
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using Bucket = SinglyLinkedList<T>;
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public:
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HashTable() {}
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HashTable(const HashTable& other)
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{
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ensure_capacity(other.size());
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for (auto& it : other)
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set(it);
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}
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HashTable& operator=(const HashTable& other)
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{
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if (this != &other) {
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clear();
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ensure_capacity(other.size());
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for (auto& it : other)
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set(it);
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}
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return *this;
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}
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HashTable(HashTable&& other)
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: m_buckets(other.m_buckets)
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, m_size(other.m_size)
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, m_capacity(other.m_capacity)
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{
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other.m_size = 0;
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other.m_capacity = 0;
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other.m_buckets = nullptr;
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}
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HashTable& operator=(HashTable&& other)
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{
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if (this != &other) {
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clear();
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m_buckets = other.m_buckets;
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m_size = other.m_size;
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m_capacity = other.m_capacity;
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other.m_size = 0;
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other.m_capacity = 0;
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other.m_buckets = nullptr;
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}
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return *this;
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}
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~HashTable() { clear(); }
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bool is_empty() const { return !m_size; }
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int size() const { return m_size; }
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int capacity() const { return m_capacity; }
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void ensure_capacity(int capacity)
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{
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ASSERT(capacity >= size());
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rehash(capacity);
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}
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void set(const T&);
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void set(T&&);
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bool contains(const T&) const;
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void clear();
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void dump() const;
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using Iterator = HashTableIterator<HashTable, T, typename Bucket::Iterator>;
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friend Iterator;
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Iterator begin() { return Iterator(*this, is_empty()); }
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Iterator end() { return Iterator(*this, true); }
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using ConstIterator = HashTableIterator<const HashTable, const T, typename Bucket::ConstIterator>;
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friend ConstIterator;
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ConstIterator begin() const { return ConstIterator(*this, is_empty()); }
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ConstIterator end() const { return ConstIterator(*this, true); }
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template<typename Finder>
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Iterator find(unsigned hash, Finder finder)
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{
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if (is_empty())
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return end();
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int bucket_index;
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auto& bucket = lookup_with_hash(hash, &bucket_index);
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auto bucket_iterator = bucket.find(finder);
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if (bucket_iterator != bucket.end())
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return Iterator(*this, false, bucket_iterator, bucket_index);
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return end();
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}
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template<typename Finder>
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ConstIterator find(unsigned hash, Finder finder) const
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{
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if (is_empty())
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return end();
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int bucket_index;
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auto& bucket = lookup_with_hash(hash, &bucket_index);
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auto bucket_iterator = bucket.find(finder);
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if (bucket_iterator != bucket.end())
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return ConstIterator(*this, false, bucket_iterator, bucket_index);
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return end();
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}
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Iterator find(const T& value)
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{
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return find(TraitsForT::hash(value), [&](auto& other) { return TraitsForT::equals(value, other); });
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}
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ConstIterator find(const T& value) const
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{
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return find(TraitsForT::hash(value), [&](auto& other) { return TraitsForT::equals(value, other); });
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}
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void remove(const T& value)
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{
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auto it = find(value);
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if (it != end())
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remove(it);
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}
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void remove(Iterator);
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private:
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Bucket& lookup(const T&, int* bucket_index = nullptr);
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const Bucket& lookup(const T&, int* bucket_index = nullptr) const;
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Bucket& lookup_with_hash(unsigned hash, int* bucket_index)
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{
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if (bucket_index)
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*bucket_index = hash % m_capacity;
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return m_buckets[hash % m_capacity];
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}
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const Bucket& lookup_with_hash(unsigned hash, int* bucket_index) const
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{
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if (bucket_index)
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*bucket_index = hash % m_capacity;
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return m_buckets[hash % m_capacity];
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}
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void rehash(int capacity);
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void insert(const T&);
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void insert(T&&);
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Bucket& bucket(int index) { return m_buckets[index]; }
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const Bucket& bucket(int index) const { return m_buckets[index]; }
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Bucket* m_buckets { nullptr };
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int m_size { 0 };
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int m_capacity { 0 };
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bool m_clearing { false };
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bool m_rehashing { false };
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};
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::set(T&& value)
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{
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if (!m_capacity)
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rehash(1);
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auto& bucket = lookup(value);
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for (auto& e : bucket) {
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if (TraitsForT::equals(e, value)) {
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e = move(value);
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return;
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}
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}
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if (size() >= capacity()) {
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rehash(size() + 1);
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insert(move(value));
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} else {
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bucket.append(move(value));
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}
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m_size++;
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::set(const T& value)
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{
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if (!m_capacity)
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rehash(1);
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auto& bucket = lookup(value);
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for (auto& e : bucket) {
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if (TraitsForT::equals(e, value)) {
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e = value;
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return;
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}
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}
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if (size() >= capacity()) {
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rehash(size() + 1);
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insert(value);
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} else {
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bucket.append(value);
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}
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m_size++;
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::rehash(int new_capacity)
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{
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TemporaryChange<bool> change(m_rehashing, true);
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new_capacity *= 2;
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auto* new_buckets = new Bucket[new_capacity];
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auto* old_buckets = m_buckets;
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int old_capacity = m_capacity;
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m_buckets = new_buckets;
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m_capacity = new_capacity;
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for (int i = 0; i < old_capacity; ++i) {
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for (auto& value : old_buckets[i]) {
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insert(move(value));
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}
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}
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delete[] old_buckets;
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::clear()
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{
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TemporaryChange<bool> change(m_clearing, true);
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if (m_buckets) {
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delete[] m_buckets;
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m_buckets = nullptr;
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}
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m_capacity = 0;
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m_size = 0;
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::insert(T&& value)
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{
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auto& bucket = lookup(value);
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bucket.append(move(value));
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::insert(const T& value)
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{
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auto& bucket = lookup(value);
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bucket.append(value);
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}
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template<typename T, typename TraitsForT>
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bool HashTable<T, TraitsForT>::contains(const T& value) const
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{
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if (is_empty())
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return false;
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auto& bucket = lookup(value);
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for (auto& e : bucket) {
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if (TraitsForT::equals(e, value))
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return true;
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}
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return false;
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::remove(Iterator it)
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{
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ASSERT(!is_empty());
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m_buckets[it.m_bucket_index].remove(it.m_bucket_iterator);
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--m_size;
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}
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template<typename T, typename TraitsForT>
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auto HashTable<T, TraitsForT>::lookup(const T& value, int* bucket_index) -> Bucket&
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{
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unsigned hash = TraitsForT::hash(value);
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if (bucket_index)
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*bucket_index = hash % m_capacity;
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return m_buckets[hash % m_capacity];
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}
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template<typename T, typename TraitsForT>
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auto HashTable<T, TraitsForT>::lookup(const T& value, int* bucket_index) const -> const Bucket&
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{
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unsigned hash = TraitsForT::hash(value);
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if (bucket_index)
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*bucket_index = hash % m_capacity;
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return m_buckets[hash % m_capacity];
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}
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template<typename T, typename TraitsForT>
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void HashTable<T, TraitsForT>::dump() const
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{
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kprintf("HashTable{%p} m_size=%u, m_capacity=%u, m_buckets=%p\n", this, m_size, m_capacity, m_buckets);
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for (int i = 0; i < m_capacity; ++i) {
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auto& bucket = m_buckets[i];
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kprintf("Bucket %u\n", i);
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for (auto& e : bucket) {
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kprintf(" > ");
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TraitsForT::dump(e);
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kprintf("\n");
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}
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}
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}
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}
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using AK::HashTable;
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