serenity/AK/Array.h

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/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
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*/
#pragma once
#include <AK/Iterator.h>
#include <AK/Optional.h>
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#include <AK/Span.h>
#include <AK/StdLibExtras.h>
#include <AK/TypedTransfer.h>
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namespace AK {
namespace Detail {
// This type serves as the storage of 0-sized `AK::Array`s. While zero-length `T[0]`
// is accepted as a GNU extension, it causes problems with UBSan in Clang 16.
template<typename T>
struct EmptyArrayStorage {
T& operator[](size_t) const { VERIFY_NOT_REACHED(); }
constexpr operator T*() const { return nullptr; }
};
}
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template<typename T, size_t Size>
struct Array {
using ValueType = T;
// This is a static function because constructors mess up Array's POD-ness.
static Array from_span(ReadonlySpan<T> span)
{
Array array;
VERIFY(span.size() == Size);
TypedTransfer<T>::copy(array.data(), span.data(), Size);
return array;
}
[[nodiscard]] constexpr T const* data() const { return __data; }
[[nodiscard]] constexpr T* data() { return __data; }
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[[nodiscard]] constexpr size_t size() const { return Size; }
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[[nodiscard]] constexpr ReadonlySpan<T> span() const { return { __data, Size }; }
[[nodiscard]] constexpr Span<T> span() { return { __data, Size }; }
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[[nodiscard]] constexpr T const& at(size_t index) const
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{
VERIFY(index < size());
return __data[index];
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}
[[nodiscard]] constexpr T& at(size_t index)
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{
VERIFY(index < size());
return __data[index];
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}
[[nodiscard]] constexpr T const& first() const { return at(0); }
[[nodiscard]] constexpr T& first() { return at(0); }
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[[nodiscard]] constexpr T const& last() const
requires(Size > 0)
{
return at(Size - 1);
}
[[nodiscard]] constexpr T& last()
requires(Size > 0)
{
return at(Size - 1);
}
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[[nodiscard]] constexpr bool is_empty() const { return size() == 0; }
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[[nodiscard]] constexpr T const& operator[](size_t index) const { return at(index); }
[[nodiscard]] constexpr T& operator[](size_t index) { return at(index); }
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template<typename T2, size_t Size2>
[[nodiscard]] constexpr bool operator==(Array<T2, Size2> const& other) const { return span() == other.span(); }
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using ConstIterator = SimpleIterator<Array const, T const>;
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using Iterator = SimpleIterator<Array, T>;
[[nodiscard]] constexpr ConstIterator begin() const { return ConstIterator::begin(*this); }
[[nodiscard]] constexpr Iterator begin() { return Iterator::begin(*this); }
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[[nodiscard]] constexpr ConstIterator end() const { return ConstIterator::end(*this); }
[[nodiscard]] constexpr Iterator end() { return Iterator::end(*this); }
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[[nodiscard]] constexpr operator ReadonlySpan<T>() const { return span(); }
[[nodiscard]] constexpr operator Span<T>() { return span(); }
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constexpr size_t fill(T const& value)
{
for (size_t idx = 0; idx < Size; ++idx)
__data[idx] = value;
return Size;
}
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[[nodiscard]] constexpr T max() const
requires(requires(T x, T y) { x < y; })
{
static_assert(Size > 0, "No values to max() over");
T value = __data[0];
for (size_t i = 1; i < Size; ++i)
value = AK::max(__data[i], value);
return value;
}
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[[nodiscard]] constexpr T min() const
requires(requires(T x, T y) { x > y; })
{
static_assert(Size > 0, "No values to min() over");
T value = __data[0];
for (size_t i = 1; i < Size; ++i)
value = AK::min(__data[i], value);
return value;
}
bool contains_slow(T const& value) const
{
return first_index_of(value).has_value();
}
Optional<size_t> first_index_of(T const& value) const
{
for (size_t i = 0; i < Size; ++i) {
if (__data[i] == value)
return i;
}
return {};
}
Conditional<Size == 0, Detail::EmptyArrayStorage<T>, T[Size]> __data;
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};
template<typename T, typename... Types>
Array(T, Types...) -> Array<T, sizeof...(Types) + 1>;
namespace Detail {
template<typename T, size_t... Is>
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constexpr auto integer_sequence_generate_array([[maybe_unused]] T const offset, IntegerSequence<T, Is...>) -> Array<T, sizeof...(Is)>
{
return { { (offset + Is)... } };
}
}
template<typename T, T N>
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constexpr static auto iota_array(T const offset = {})
{
static_assert(N >= T {}, "Negative sizes not allowed in iota_array()");
return Detail::integer_sequence_generate_array<T>(offset, MakeIntegerSequence<T, N>());
}
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}
#if USING_AK_GLOBALLY
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using AK::Array;
using AK::iota_array;
#endif