ladybird/AK/Atomic.h

#pragma once

#ifndef KERNEL
#include <stddef.h>
#endif

namespace AK {

enum MemoryOrder
{
	memory_order_relaxed = __ATOMIC_RELAXED,
	memory_order_consume = __ATOMIC_CONSUME,
	memory_order_acquire = __ATOMIC_ACQUIRE,
	memory_order_release = __ATOMIC_RELEASE,
	memory_order_acq_rel = __ATOMIC_ACQ_REL,
	memory_order_seq_cst = __ATOMIC_SEQ_CST
};

template <typename T>
class Atomic
{
	T m_value { 0 };

public:
	Atomic() noexcept = default;
	Atomic(const Atomic&) = delete;
	Atomic& operator=(const Atomic&) volatile = delete;

	Atomic(T val) noexcept:
		m_value(val)
	{
	}
	
	T exchange(T desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_exchange_n(&m_value, desired, order);
	}
	
	bool compare_exchange_strong(T& expected, T desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		if (order == memory_order_acq_rel || order == memory_order_release)
			return __atomic_compare_exchange_n(&m_value, &expected, desired, false, memory_order_release, memory_order_acquire);
		else
			return __atomic_compare_exchange_n(&m_value, &expected, desired, false, order, order);
	}
	
	T operator++() volatile noexcept
	{
		return fetch_add(1) + 1;
	}
	
	T operator++(int) volatile noexcept
	{
		return fetch_add(1);
	}
	
	T operator+=(T val) volatile noexcept
	{
		return fetch_add(val) + val;
	}
	
	T fetch_add(T val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_add(&m_value, val, order);
	}
	
	T operator--() volatile noexcept
	{
		return fetch_sub(1) - 1;
	}
	
	T operator--(int) volatile noexcept
	{
		return fetch_sub(1);
	}
	
	T operator-=(T val) volatile noexcept
	{
		return fetch_sub(val) - val;
	}
	
	T fetch_sub(T val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_sub(&m_value, val, order);
	}
	
	T operator&=(T val) volatile noexcept
	{
		return fetch_and(val) & val;
	}
	
	T fetch_and(T val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_and(&m_value, val, order);
	}
	
	T operator|=(T val) volatile noexcept
	{
		return fetch_or(val) | val;
	}
	
	T fetch_or(T val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_or(&m_value, val, order);
	}
	
	T operator^=(T val) volatile noexcept
	{
		return fetch_xor(val) ^ val;
	}
	
	T fetch_xor(T val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_xor(&m_value, val, order);
	}
	
	operator T() const volatile noexcept
	{
		return load();
	}
	
	T load(MemoryOrder order = memory_order_seq_cst) const volatile noexcept
	{
		return __atomic_load_n(&m_value, order);
	}
	
	T operator=(T desired) volatile noexcept
	{
		store(desired);
		return desired;
	}
	
	void store(T desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		__atomic_store_n(&m_value, desired, order);
	}
	
	bool is_lock_free() const volatile noexcept
	{
		return __atomic_is_lock_free(sizeof(m_value), &m_value);
	}
};


template <typename T>
class Atomic<T*>
{
	T* m_value { nullptr };

public:
	Atomic() noexcept = default;
	Atomic(const Atomic&) = delete;
	Atomic& operator=(const Atomic&) volatile = delete;

	Atomic(T* val) noexcept:
		m_value(val)
	{
	}
	
	T* exchange(T* desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_exchange_n(&m_value, desired, order);
	}
	
	bool compare_exchange_strong(T*& expected, T* desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		if (order == memory_order_acq_rel || order == memory_order_release)
			return __atomic_compare_exchange_n(&m_value, &expected, desired, false, memory_order_release, memory_order_acquire);
		else
			return __atomic_compare_exchange_n(&m_value, &expected, desired, false, order, order);
	}
	
	T* operator++() volatile noexcept
	{
		return fetch_add(1) + 1;
	}
	
	T* operator++(int) volatile noexcept
	{
		return fetch_add(1);
	}
	
	T* operator+=(ptrdiff_t val) volatile noexcept
	{
		return fetch_add(val) + val;
	}
	
	T* fetch_add(ptrdiff_t val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_add(&m_value, val * sizeof(*m_value), order);
	}
	
	T* operator--() volatile noexcept
	{
		return fetch_sub(1) - 1;
	}
	
	T* operator--(int) volatile noexcept
	{
		return fetch_sub(1);
	}
	
	T* operator-=(ptrdiff_t val) volatile noexcept
	{
		return fetch_sub(val) - val;
	}
	
	T* fetch_sub(ptrdiff_t val, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		return __atomic_fetch_sub(&m_value, val * sizeof(*m_value), order);
	}
	
	operator T*() const volatile noexcept
	{
		return load();
	}
	
	T* load(MemoryOrder order = memory_order_seq_cst) const volatile noexcept
	{
		return __atomic_load_n(&m_value, order);
	}
	
	T* operator=(T* desired) volatile noexcept
	{
		store(desired);
		return desired;
	}
	
	void store(T* desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
	{
		__atomic_store_n(&m_value, desired, order);
	}
	
	bool is_lock_free() const volatile noexcept
	{
		return __atomic_is_lock_free(sizeof(m_value), &m_value);
	}
};

}

using AK::Atomic;