ladybird/AK/StdLibExtras.h

/*
 * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <AK/StdLibExtraDetails.h>

#include <AK/Assertions.h>

constexpr unsigned round_up_to_power_of_two(unsigned value, unsigned power_of_two)
{
    return ((value - 1) & ~(power_of_two - 1)) + power_of_two;
}

namespace std {

// NOTE: This is in the "std" namespace since some compiler features rely on it.

template<typename T>
constexpr T&& move(T& arg)
{
    return static_cast<T&&>(arg);
}

}

using std::move;

namespace AK::Detail {
template<typename T>
struct _RawPtr {
    using Type = T*;
};
}

namespace AK {

template<typename T>
auto declval() -> T;

template<class T>
constexpr T&& forward(RemoveReference<T>& param)
{
    return static_cast<T&&>(param);
}

template<class T>
constexpr T&& forward(RemoveReference<T>&& param) noexcept
{
    static_assert(!IsLvalueReference<T>, "Can't forward an rvalue as an lvalue.");
    return static_cast<T&&>(param);
}

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 T& b)
{
    return b < a ? b : a;
}

template<typename T>
constexpr T max(const T& a, const T& b)
{
    return a < b ? b : a;
}

template<typename T>
constexpr T clamp(const T& value, const T& min, const 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)
{
    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;

}

using AK::array_size;
using AK::ceil_div;
using AK::clamp;
using AK::declval;
using AK::exchange;
using AK::forward;
using AK::max;
using AK::min;
using AK::RawPtr;
using AK::swap;