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https://github.com/LadybirdBrowser/ladybird.git
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AK: Consolidate iterators for HashTable and DoublyLinkedList respectively.
Get rid of the ConstIterator classes for these containers and use templated FooIterator<T, ...> and FooIterator<const T, ...> helpers. This makes the HashTable class a lot easier to read.
This commit is contained in:
Andreas Kling
parent
50700c107f
commit
516d736afe
Notes:
sideshowbarker
2024-07-19 13:28:10 +09:00
Author: https://github.com/awesomekling
Commit: 516d736afe
5 changed files with 150 additions and 240 deletions
276
AK/HashTable.h
276
AK/HashTable.h
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@ -6,19 +6,76 @@
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#include "Traits.h"
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#include "kstdio.h"
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//#define HASHTABLE_DEBUG
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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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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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struct Bucket {
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DoublyLinkedList<T> chain;
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};
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using Bucket = DoublyLinkedList<T>;
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public:
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HashTable() {}
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@ -79,161 +136,13 @@ public:
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void dump() const;
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class Iterator {
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public:
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bool operator!=(const Iterator& 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 Iterator& other) const { return !(*this != other); }
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T& operator*()
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{
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#ifdef HASHTABLE_DEBUG
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kprintf("retrieve { bucket_index: %u, is_end: %u }\n", m_bucket_index, m_is_end);
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#endif
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return *m_bucket_iterator;
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}
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T* operator->() { return m_bucket_iterator.operator->(); }
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Iterator& 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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#ifdef HASHTABLE_DEBUG
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unsigned pass = 0;
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#endif
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while (!m_is_end) {
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#ifdef HASHTABLE_DEBUG
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++pass;
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kprintf("skip_to_next pass %u, m_bucket_index=%u\n", pass, m_bucket_index);
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#endif
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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.m_buckets[m_bucket_index].chain.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 class HashTable;
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explicit Iterator(HashTable& table, bool is_end, typename DoublyLinkedList<T>::Iterator bucket_iterator = DoublyLinkedList<T>::Iterator::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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if (!is_end && !m_table.is_empty() && !(m_bucket_iterator != DoublyLinkedList<T>::Iterator::universal_end())) {
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#ifdef HASHTABLE_DEBUG
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kprintf("bucket iterator init!\n");
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#endif
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m_bucket_iterator = m_table.m_buckets[0].chain.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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HashTable& m_table;
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int m_bucket_index { 0 };
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bool m_is_end { false };
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typename DoublyLinkedList<T>::Iterator m_bucket_iterator;
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};
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using Iterator = HashTableIterator<HashTable, T, typename DoublyLinkedList<T>::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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class ConstIterator {
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public:
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bool operator!=(const ConstIterator& 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 ConstIterator& other) const { return !(*this != other); }
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const T& operator*() const
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{
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#ifdef HASHTABLE_DEBUG
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kprintf("retrieve { bucket_index: %u, is_end: %u }\n", m_bucket_index, m_is_end);
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#endif
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return *m_bucket_iterator;
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}
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const T* operator->() const { return m_bucket_iterator.operator->(); }
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ConstIterator& 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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#ifdef HASHTABLE_DEBUG
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unsigned pass = 0;
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#endif
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while (!m_is_end) {
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#ifdef HASHTABLE_DEBUG
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++pass;
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kprintf("skip_to_next pass %u, m_bucket_index=%u\n", pass, m_bucket_index);
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#endif
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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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const DoublyLinkedList<T>& chain = m_table.m_buckets[m_bucket_index].chain;
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m_bucket_iterator = chain.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 class HashTable;
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ConstIterator(const HashTable& table, bool is_end, typename DoublyLinkedList<T>::ConstIterator bucket_iterator = DoublyLinkedList<T>::ConstIterator::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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if (!is_end && !m_table.is_empty() && !(m_bucket_iterator != DoublyLinkedList<T>::ConstIterator::universal_end())) {
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#ifdef HASHTABLE_DEBUG
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kprintf("const bucket iterator init!\n");
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#endif
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const DoublyLinkedList<T>& chain = m_table.m_buckets[0].chain;
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m_bucket_iterator = chain.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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const HashTable& m_table;
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int m_bucket_index { 0 };
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bool m_is_end { false };
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typename DoublyLinkedList<T>::ConstIterator m_bucket_iterator;
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};
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using ConstIterator = HashTableIterator<const HashTable, const T, typename DoublyLinkedList<T>::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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@ -256,6 +165,9 @@ private:
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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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@ -268,7 +180,7 @@ void HashTable<T, TraitsForT>::set(T&& value)
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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.chain) {
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for (auto& e : bucket) {
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if (e == value) {
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e = move(value);
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return;
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@ -278,7 +190,7 @@ void HashTable<T, TraitsForT>::set(T&& value)
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rehash(size() + 1);
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insert(move(value));
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} else {
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bucket.chain.append(move(value));
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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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@ -289,7 +201,7 @@ void HashTable<T, TraitsForT>::set(const T& value)
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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.chain) {
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for (auto& e : bucket) {
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if (e == value) {
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e = move(value);
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return;
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@ -299,7 +211,7 @@ void HashTable<T, TraitsForT>::set(const T& value)
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rehash(size() + 1);
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insert(value);
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} else {
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bucket.chain.append(value);
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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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@ -308,20 +220,14 @@ 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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new_capacity *= 2;
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#ifdef HASHTABLE_DEBUG
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kprintf("rehash to %u buckets\n", new_capacity);
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#endif
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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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#ifdef HASHTABLE_DEBUG
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kprintf("reinsert %u buckets\n", old_capacity);
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#endif
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for (int i = 0; i < old_capacity; ++i) {
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for (auto& value : old_buckets[i].chain) {
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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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@ -344,14 +250,14 @@ 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.chain.append(move(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.chain.append(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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@ -360,7 +266,7 @@ bool HashTable<T, TraitsForT>::contains(const T& value) const
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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.chain) {
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for (auto& e : bucket) {
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if (e == value)
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return true;
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}
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@ -374,8 +280,8 @@ auto HashTable<T, TraitsForT>::find(const T& value) -> Iterator
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return end();
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int bucket_index;
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auto& bucket = lookup(value, &bucket_index);
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auto bucket_iterator = bucket.chain.find(value);
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if (bucket_iterator != bucket.chain.end())
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auto bucket_iterator = bucket.find(value);
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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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@ -386,9 +292,9 @@ auto HashTable<T, TraitsForT>::find(const T& value) const -> ConstIterator
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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(value, &bucket_index);
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auto bucket_iterator = bucket.chain.find(value);
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if (bucket_iterator != bucket.chain.end())
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const auto& bucket = lookup(value, &bucket_index);
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auto bucket_iterator = bucket.find(value);
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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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@ -397,33 +303,23 @@ 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].chain.remove(it.m_bucket_iterator);
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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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typename HashTable<T, TraitsForT>::Bucket& HashTable<T, TraitsForT>::lookup(const T& value, int* bucket_index)
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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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#ifdef HASHTABLE_DEBUG
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kprintf("hash for ");
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TraitsForT::dump(value);
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kprintf(" is %u\n", hash);
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#endif
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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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const typename HashTable<T, TraitsForT>::Bucket& HashTable<T, TraitsForT>::lookup(const T& value, int* bucket_index) const
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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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#ifdef HASHTABLE_DEBUG
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kprintf("hash for ");
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TraitsForT::dump(value);
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kprintf(" is %u\n", hash);
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#endif
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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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@ -436,7 +332,7 @@ void HashTable<T, TraitsForT>::dump() const
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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.chain) {
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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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