ladybird/AK/StdLibExtras.h
Stephan Unverwerth a595345e7c AK: Make declaration of std::move and std::forward optional
This introduces a new define AK_DONT_REPLACE_STD that disables our own
implementation of std::move and std::forward. Some ports include both
STL and AK headers which causes conflicts when trying to resolve those
functions. The port can define AK_DONT_REPLACE_STD before including
Serenity headers in that case.
2021-09-04 16:32:54 +02:00

170 lines
3.7 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/StdLibExtraDetails.h>
#include <AK/Assertions.h>
template<typename T, typename U>
constexpr auto round_up_to_power_of_two(T value, U power_of_two) requires(IsIntegral<T>&& IsIntegral<U>)
{
return ((value - 1) & ~(power_of_two - 1)) + power_of_two;
}
// HACK: clang-format does not format this correctly because of the requires clause above.
// Disabling formatting for that doesn't help either.
//
// clang-format off
#ifndef AK_DONT_REPLACE_STD
namespace std {
// NOTE: These are in the "std" namespace since some compilers and static analyzers rely on it.
template<typename T>
constexpr T&& forward(AK::Detail::RemoveReference<T>& param)
{
return static_cast<T&&>(param);
}
template<typename T>
constexpr T&& forward(AK::Detail::RemoveReference<T>&& param) noexcept
{
static_assert(!IsLvalueReference<T>, "Can't forward an rvalue as an lvalue.");
return static_cast<T&&>(param);
}
template<typename T>
constexpr T&& move(T& arg)
{
return static_cast<T&&>(arg);
}
}
#endif
// clang-format on
using std::forward;
using std::move;
namespace AK::Detail {
template<typename T>
struct _RawPtr {
using Type = T*;
};
}
namespace AK {
template<typename T, typename SizeType = decltype(sizeof(T)), SizeType N>
constexpr SizeType array_size(T (&)[N])
{
return N;
}
template<typename T>
constexpr T min(const T& a, const IdentityType<T>& b)
{
return b < a ? b : a;
}
template<typename T>
constexpr T max(const T& a, const IdentityType<T>& b)
{
return a < b ? b : a;
}
template<typename T>
constexpr T clamp(const T& value, const IdentityType<T>& min, const IdentityType<T>& max)
{
VERIFY(max >= min);
if (value > max)
return max;
if (value < min)
return min;
return value;
}
template<typename T, typename U>
constexpr T ceil_div(T a, U b)
{
static_assert(sizeof(T) == sizeof(U));
T result = a / b;
if ((a % b) != 0)
++result;
return result;
}
template<typename T, typename U>
inline void swap(T& a, U& b)
{
if (&a == &b)
return;
U tmp = move((U&)a);
a = (T &&) move(b);
b = move(tmp);
}
template<typename T, typename U = T>
constexpr T exchange(T& slot, U&& value)
{
T old_value = move(slot);
slot = forward<U>(value);
return old_value;
}
template<typename T>
using RawPtr = typename Detail::_RawPtr<T>::Type;
template<typename V>
constexpr decltype(auto) to_underlying(V value) requires(IsEnum<V>)
{
return static_cast<UnderlyingType<V>>(value);
}
constexpr bool is_constant_evaluated()
{
#if __has_builtin(__builtin_is_constant_evaluated)
return __builtin_is_constant_evaluated();
#else
return false;
#endif
}
// These can't be exported into the global namespace as they would clash with the C standard library.
#define __DEFINE_GENERIC_ABS(type, zero, intrinsic) \
constexpr type abs(type num) \
{ \
if (is_constant_evaluated()) \
return num < zero ? -num : num; \
else \
return __builtin_##intrinsic(num); \
}
__DEFINE_GENERIC_ABS(int, 0, abs);
__DEFINE_GENERIC_ABS(long, 0l, labs);
__DEFINE_GENERIC_ABS(long long, 0ll, llabs);
#ifndef KERNEL
__DEFINE_GENERIC_ABS(float, 0.0f, fabsf);
__DEFINE_GENERIC_ABS(double, 0.0, fabs);
__DEFINE_GENERIC_ABS(long double, 0.0l, fabsl);
#endif
}
using AK::array_size;
using AK::ceil_div;
using AK::clamp;
using AK::exchange;
using AK::is_constant_evaluated;
using AK::max;
using AK::min;
using AK::RawPtr;
using AK::swap;
using AK::to_underlying;