ladybird/AK/Checked.h
Lenny Maiorani d1fe6a0b53
Everywhere: Redundant inline specifier on constexpr functions (#3807)
Problem:
- `constexpr` functions are decorated with the `inline` specifier
  keyword. This is redundant because `constexpr` functions are
  implicitly `inline`.
- [dcl.constexpr], §7.1.5/2 in the C++11 standard): "constexpr
  functions and constexpr constructors are implicitly inline (7.1.2)".

Solution:
- Remove the redundant `inline` keyword.
2020-10-20 18:08:13 +02:00

381 lines
9.0 KiB
C++

/*
* Copyright (C) 2011-2019 Apple Inc. All rights reserved.
* Copyright (c) 2020, 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/Assertions.h>
#include <AK/NumericLimits.h>
#include <AK/StdLibExtras.h>
namespace AK {
template<typename Destination, typename Source, bool destination_is_wider = (sizeof(Destination) >= sizeof(Source)), bool destination_is_signed = NumericLimits<Destination>::is_signed(), bool source_is_signed = NumericLimits<Source>::is_signed()>
struct TypeBoundsChecker;
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, false, false, false> {
static constexpr bool is_within_range(Source value)
{
return value <= NumericLimits<Destination>::max();
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, false, true, true> {
static constexpr bool is_within_range(Source value)
{
return value <= NumericLimits<Destination>::max()
&& NumericLimits<Destination>::min() <= value;
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, false, false, true> {
static constexpr bool is_within_range(Source value)
{
return static_cast<MakeUnsigned<Source>>(value) <= NumericLimits<Destination>::max();
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, false, true, false> {
static constexpr bool is_within_range(Source value)
{
return value <= static_cast<Source>(NumericLimits<Destination>::max());
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, true, false, false> {
static constexpr bool is_within_range(Source)
{
return true;
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, true, true, true> {
static constexpr bool is_within_range(Source)
{
return true;
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, true, false, true> {
static constexpr bool is_within_range(Source value)
{
return value >= 0;
}
};
template<typename Destination, typename Source>
struct TypeBoundsChecker<Destination, Source, true, true, false> {
static constexpr bool is_within_range(Source value)
{
if (sizeof(Destination) > sizeof(Source))
return true;
return value <= static_cast<Source>(NumericLimits<Destination>::max());
}
};
template<typename Destination, typename Source>
constexpr bool is_within_range(Source value)
{
return TypeBoundsChecker<Destination, Source>::is_within_range(value);
}
template<typename T>
class Checked {
public:
constexpr Checked() = default;
constexpr Checked(T value)
: m_value(value)
{
}
template<typename U>
constexpr Checked(U value)
{
m_overflow = !is_within_range<T>(value);
m_value = value;
}
constexpr Checked(const Checked&) = default;
constexpr Checked(Checked&& other)
: m_value(exchange(other.m_value, 0))
, m_overflow(exchange(other.m_overflow, false))
{
}
template<typename U>
constexpr Checked& operator=(U value)
{
return *this = Checked(value);
}
constexpr Checked& operator=(const Checked& other) = default;
constexpr Checked& operator=(Checked&& other)
{
m_value = exchange(other.m_value, 0);
m_overflow = exchange(other.m_overflow, false);
return *this;
}
constexpr bool has_overflow() const
{
return m_overflow;
}
ALWAYS_INLINE constexpr bool operator!() const
{
ASSERT(!m_overflow);
return !m_value;
}
ALWAYS_INLINE constexpr T value() const
{
ASSERT(!m_overflow);
return m_value;
}
constexpr void add(T other)
{
m_overflow |= __builtin_add_overflow(m_value, other, &m_value);
}
constexpr void sub(T other)
{
m_overflow |= __builtin_sub_overflow(m_value, other, &m_value);
}
constexpr void mul(T other)
{
m_overflow |= __builtin_mul_overflow(m_value, other, &m_value);
}
constexpr void div(T other)
{
m_value /= other;
}
constexpr Checked& operator+=(T other)
{
add(other);
return *this;
}
constexpr Checked& operator-=(T other)
{
sub(other);
return *this;
}
constexpr Checked& operator*=(T other)
{
mul(other);
return *this;
}
constexpr Checked& operator/=(T other)
{
div(other);
return *this;
}
constexpr Checked& operator++()
{
add(1);
return *this;
}
constexpr Checked operator++(int)
{
Checked old { *this };
add(1);
return old;
}
template<typename U, typename V>
static constexpr bool addition_would_overflow(U u, V v)
{
#ifdef __clang__
Checked checked;
checked = u;
checked += v;
return checked.has_overflow();
#else
return __builtin_add_overflow_p(u, v, (T)0);
#endif
}
template<typename U, typename V>
static constexpr bool multiplication_would_overflow(U u, V v)
{
#ifdef __clang__
Checked checked;
checked = u;
checked *= v;
return checked.has_overflow();
#else
return __builtin_mul_overflow_p(u, v, (T)0);
#endif
}
template<typename U, typename V, typename X>
static constexpr bool multiplication_would_overflow(U u, V v, X x)
{
Checked checked;
checked = u;
checked *= v;
checked *= x;
return checked.has_overflow();
}
private:
T m_value {};
bool m_overflow { false };
};
template<typename T>
constexpr Checked<T> operator+(const Checked<T>& a, const Checked<T>& b)
{
Checked<T> c { a };
c.add(b.value());
return c;
}
template<typename T>
constexpr Checked<T> operator-(const Checked<T>& a, const Checked<T>& b)
{
Checked<T> c { a };
c.sub(b.value());
return c;
}
template<typename T>
constexpr Checked<T> operator*(const Checked<T>& a, const Checked<T>& b)
{
Checked<T> c { a };
c.mul(b.value());
return c;
}
template<typename T>
constexpr Checked<T> operator/(const Checked<T>& a, const Checked<T>& b)
{
Checked<T> c { a };
c.div(b.value());
return c;
}
template<typename T>
constexpr bool operator<(const Checked<T>& a, T b)
{
return a.value() < b;
}
template<typename T>
constexpr bool operator>(const Checked<T>& a, T b)
{
return a.value() > b;
}
template<typename T>
constexpr bool operator>=(const Checked<T>& a, T b)
{
return a.value() >= b;
}
template<typename T>
constexpr bool operator<=(const Checked<T>& a, T b)
{
return a.value() <= b;
}
template<typename T>
constexpr bool operator==(const Checked<T>& a, T b)
{
return a.value() == b;
}
template<typename T>
constexpr bool operator!=(const Checked<T>& a, T b)
{
return a.value() != b;
}
template<typename T>
constexpr bool operator<(T a, const Checked<T>& b)
{
return a < b.value();
}
template<typename T>
constexpr bool operator>(T a, const Checked<T>& b)
{
return a > b.value();
}
template<typename T>
constexpr bool operator>=(T a, const Checked<T>& b)
{
return a >= b.value();
}
template<typename T>
constexpr bool operator<=(T a, const Checked<T>& b)
{
return a <= b.value();
}
template<typename T>
constexpr bool operator==(T a, const Checked<T>& b)
{
return a == b.value();
}
template<typename T>
constexpr bool operator!=(T a, const Checked<T>& b)
{
return a != b.value();
}
template<typename T>
constexpr Checked<T> make_checked(T value)
{
return Checked<T>(value);
}
}
using AK::Checked;
using AK::make_checked;