ladybird/AK/HashMap.h
2021-07-21 18:18:29 +02:00

159 lines
4.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashTable.h>
#include <AK/Optional.h>
#include <AK/Vector.h>
// NOTE: We can't include <initializer_list> during the toolchain bootstrap,
// since it's part of libstdc++, and libstdc++ depends on LibC.
// For this reason, we don't support HashMap(initializer_list) in LibC.
#ifndef SERENITY_LIBC_BUILD
# include <initializer_list>
#endif
namespace AK {
template<typename K, typename V, typename KeyTraits, bool IsOrdered>
class HashMap {
private:
struct Entry {
K key;
V value;
};
struct EntryTraits {
static unsigned hash(const Entry& entry) { return KeyTraits::hash(entry.key); }
static bool equals(const Entry& a, const Entry& b) { return KeyTraits::equals(a.key, b.key); }
};
public:
using KeyType = K;
using ValueType = V;
HashMap() = default;
#ifndef SERENITY_LIBC_BUILD
HashMap(std::initializer_list<Entry> list)
{
ensure_capacity(list.size());
for (auto& item : list)
set(item.key, item.value);
}
#endif
[[nodiscard]] bool is_empty() const
{
return m_table.is_empty();
}
[[nodiscard]] size_t size() const { return m_table.size(); }
[[nodiscard]] size_t capacity() const { return m_table.capacity(); }
void clear() { m_table.clear(); }
HashSetResult set(const K& key, const V& value) { return m_table.set({ key, value }); }
HashSetResult set(const K& key, V&& value) { return m_table.set({ key, move(value) }); }
bool remove(const K& key)
{
auto it = find(key);
if (it != end()) {
m_table.remove(it);
return true;
}
return false;
}
using HashTableType = HashTable<Entry, EntryTraits, IsOrdered>;
using IteratorType = typename HashTableType::Iterator;
using ConstIteratorType = typename HashTableType::ConstIterator;
[[nodiscard]] IteratorType begin() { return m_table.begin(); }
[[nodiscard]] IteratorType end() { return m_table.end(); }
[[nodiscard]] IteratorType find(const K& key)
{
return m_table.find(KeyTraits::hash(key), [&](auto& entry) { return KeyTraits::equals(key, entry.key); });
}
template<typename TUnaryPredicate>
[[nodiscard]] IteratorType find(unsigned hash, TUnaryPredicate predicate)
{
return m_table.find(hash, predicate);
}
[[nodiscard]] ConstIteratorType begin() const { return m_table.begin(); }
[[nodiscard]] ConstIteratorType end() const { return m_table.end(); }
[[nodiscard]] ConstIteratorType find(const K& key) const
{
return m_table.find(KeyTraits::hash(key), [&](auto& entry) { return KeyTraits::equals(key, entry.key); });
}
template<typename TUnaryPredicate>
[[nodiscard]] ConstIteratorType find(unsigned hash, TUnaryPredicate predicate) const
{
return m_table.find(hash, predicate);
}
void ensure_capacity(size_t capacity) { m_table.ensure_capacity(capacity); }
Optional<typename Traits<V>::PeekType> get(const K& key) const requires(!IsPointer<typename Traits<V>::PeekType>)
{
auto it = find(key);
if (it == end())
return {};
return (*it).value;
}
Optional<typename Traits<V>::ConstPeekType> get(const K& key) const requires(IsPointer<typename Traits<V>::PeekType>)
{
auto it = find(key);
if (it == end())
return {};
return (*it).value;
}
Optional<typename Traits<V>::PeekType> get(const K& key) requires(!IsConst<typename Traits<V>::PeekType>)
{
auto it = find(key);
if (it == end())
return {};
return (*it).value;
}
[[nodiscard]] bool contains(const K& key) const
{
return find(key) != end();
}
void remove(IteratorType it)
{
m_table.remove(it);
}
V& ensure(const K& key)
{
auto it = find(key);
if (it == end())
set(key, V());
return find(key)->value;
}
[[nodiscard]] Vector<K> keys() const
{
Vector<K> list;
list.ensure_capacity(size());
for (auto& it : *this)
list.unchecked_append(it.key);
return list;
}
private:
HashTableType m_table;
};
}
using AK::HashMap;
using AK::OrderedHashMap;