ladybird/AK/Span.h
Timothy Flynn e4213f5767 AK: Generalize Span::contains_slow to use the Traits infrastructure
This allows, for example, checking if a Span<String> contains a value
without having to allocate a String.
2024-03-16 08:42:33 +01:00

350 lines
8.8 KiB
C++

/*
* Copyright (c) 2020-2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Array.h>
#include <AK/Assertions.h>
#include <AK/Iterator.h>
#include <AK/TypedTransfer.h>
#include <AK/Types.h>
namespace AK {
namespace Detail {
template<typename T>
class Span {
public:
ALWAYS_INLINE constexpr Span() = default;
ALWAYS_INLINE constexpr Span(T* values, size_t size)
: m_values(values)
, m_size(size)
{
}
template<size_t size>
ALWAYS_INLINE constexpr Span(T (&values)[size])
: m_values(values)
, m_size(size)
{
}
template<size_t size>
ALWAYS_INLINE constexpr Span(Array<T, size>& array)
: m_values(array.data())
, m_size(size)
{
}
template<size_t size>
requires(IsConst<T>)
ALWAYS_INLINE constexpr Span(Array<T, size> const& array)
: m_values(array.data())
, m_size(size)
{
}
protected:
T* m_values { nullptr };
size_t m_size { 0 };
};
template<>
class Span<u8> {
public:
ALWAYS_INLINE constexpr Span() = default;
ALWAYS_INLINE constexpr Span(u8* values, size_t size)
: m_values(values)
, m_size(size)
{
}
ALWAYS_INLINE Span(void* values, size_t size)
: m_values(reinterpret_cast<u8*>(values))
, m_size(size)
{
}
template<size_t size>
ALWAYS_INLINE constexpr Span(u8 (&values)[size])
: m_values(values)
, m_size(size)
{
}
protected:
u8* m_values { nullptr };
size_t m_size { 0 };
};
template<>
class Span<u8 const> {
public:
ALWAYS_INLINE constexpr Span() = default;
ALWAYS_INLINE constexpr Span(u8 const* values, size_t size)
: m_values(values)
, m_size(size)
{
}
ALWAYS_INLINE Span(void const* values, size_t size)
: m_values(reinterpret_cast<u8 const*>(values))
, m_size(size)
{
}
ALWAYS_INLINE Span(char const* values, size_t size)
: m_values(reinterpret_cast<u8 const*>(values))
, m_size(size)
{
}
template<size_t size>
ALWAYS_INLINE constexpr Span(u8 const (&values)[size])
: m_values(values)
, m_size(size)
{
}
protected:
u8 const* m_values { nullptr };
size_t m_size { 0 };
};
}
template<typename T>
class Span : public Detail::Span<T> {
public:
using Detail::Span<T>::Span;
constexpr Span() = default;
[[nodiscard]] ALWAYS_INLINE constexpr T const* data() const { return this->m_values; }
[[nodiscard]] ALWAYS_INLINE constexpr T* data() { return this->m_values; }
[[nodiscard]] ALWAYS_INLINE constexpr T const* offset_pointer(size_t offset) const { return this->m_values + offset; }
[[nodiscard]] ALWAYS_INLINE constexpr T* offset_pointer(size_t offset) { return this->m_values + offset; }
using ConstIterator = SimpleIterator<Span const, T const>;
using Iterator = SimpleIterator<Span, T>;
constexpr ConstIterator begin() const { return ConstIterator::begin(*this); }
constexpr Iterator begin() { return Iterator::begin(*this); }
constexpr ConstIterator end() const { return ConstIterator::end(*this); }
constexpr Iterator end() { return Iterator::end(*this); }
[[nodiscard]] ALWAYS_INLINE constexpr size_t size() const { return this->m_size; }
[[nodiscard]] ALWAYS_INLINE constexpr bool is_null() const { return this->m_values == nullptr; }
[[nodiscard]] ALWAYS_INLINE constexpr bool is_empty() const { return this->m_size == 0; }
[[nodiscard]] ALWAYS_INLINE constexpr Span slice(size_t start, size_t length) const
{
VERIFY(start + length <= size());
return { this->m_values + start, length };
}
[[nodiscard]] ALWAYS_INLINE constexpr Span slice(size_t start) const
{
VERIFY(start <= size());
return { this->m_values + start, size() - start };
}
[[nodiscard]] ALWAYS_INLINE constexpr Span slice_from_end(size_t count) const
{
VERIFY(count <= size());
return { this->m_values + size() - count, count };
}
[[nodiscard]] ALWAYS_INLINE constexpr Span trim(size_t length) const
{
return { this->m_values, min(size(), length) };
}
[[nodiscard]] Span align_to(size_t alignment) const
{
auto* start = reinterpret_cast<T*>(align_up_to((FlatPtr)data(), alignment));
auto* end = reinterpret_cast<T*>(align_down_to((FlatPtr)(data() + size()), alignment));
if (end < start)
return {};
size_t length = end - start;
return { start, length };
}
[[nodiscard]] ALWAYS_INLINE constexpr T* offset(size_t start) const
{
VERIFY(start < this->m_size);
return this->m_values + start;
}
ALWAYS_INLINE constexpr void overwrite(size_t offset, void const* data, size_t data_size)
{
// make sure we're not told to write past the end
VERIFY(offset + data_size <= size());
__builtin_memmove(this->data() + offset, data, data_size);
}
ALWAYS_INLINE constexpr size_t copy_to(Span<RemoveConst<T>> other) const
{
VERIFY(other.size() >= size());
return TypedTransfer<RemoveConst<T>>::copy(other.data(), data(), size());
}
ALWAYS_INLINE constexpr size_t copy_trimmed_to(Span<RemoveConst<T>> other) const
{
auto const count = min(size(), other.size());
return TypedTransfer<RemoveConst<T>>::copy(other.data(), data(), count);
}
ALWAYS_INLINE constexpr size_t fill(T const& value)
{
for (size_t idx = 0; idx < size(); ++idx)
data()[idx] = value;
return size();
}
template<typename V>
[[nodiscard]] constexpr bool contains_slow(V const& value) const
{
for (size_t i = 0; i < size(); ++i) {
if (Traits<RemoveReference<T>>::equals(at(i), value))
return true;
}
return false;
}
[[nodiscard]] constexpr bool starts_with(ReadonlySpan<T> other) const
{
if (size() < other.size())
return false;
return TypedTransfer<T>::compare(data(), other.data(), other.size());
}
[[nodiscard]] constexpr size_t matching_prefix_length(ReadonlySpan<T> other) const
{
auto maximum_length = min(size(), other.size());
for (size_t i = 0; i < maximum_length; i++) {
if (data()[i] != other.data()[i])
return i;
}
return maximum_length;
}
[[nodiscard]] ALWAYS_INLINE constexpr T const& at(size_t index) const
{
VERIFY(index < this->m_size);
return this->m_values[index];
}
[[nodiscard]] ALWAYS_INLINE constexpr T& at(size_t index)
{
VERIFY(index < this->m_size);
return this->m_values[index];
}
[[nodiscard]] ALWAYS_INLINE constexpr T const& first() const
{
return this->at(0);
}
[[nodiscard]] ALWAYS_INLINE constexpr T& first()
{
return this->at(0);
}
[[nodiscard]] ALWAYS_INLINE constexpr T const& last() const
{
return this->at(this->size() - 1);
}
[[nodiscard]] ALWAYS_INLINE constexpr T& last()
{
return this->at(this->size() - 1);
}
[[nodiscard]] ALWAYS_INLINE constexpr T const& operator[](size_t index) const
{
return at(index);
}
void reverse()
{
for (size_t i = 0; i < size() / 2; ++i)
AK::swap(at(i), at(size() - i - 1));
}
[[nodiscard]] ALWAYS_INLINE constexpr T& operator[](size_t index)
{
return at(index);
}
constexpr bool operator==(Span const& other) const
{
if (size() != other.size())
return false;
return TypedTransfer<T>::compare(data(), other.data(), size());
}
ALWAYS_INLINE constexpr operator ReadonlySpan<T>() const
{
return { data(), size() };
}
};
template<typename T>
struct Traits<Span<T>> : public DefaultTraits<Span<T>> {
static unsigned hash(Span<T> const& span)
{
unsigned hash = 0;
for (auto const& value : span) {
auto value_hash = Traits<T>::hash(value);
hash = pair_int_hash(hash, value_hash);
}
return hash;
}
constexpr static bool is_trivial() { return true; }
};
template<typename T>
using ReadonlySpan = Span<T const>;
using ReadonlyBytes = ReadonlySpan<u8>;
using Bytes = Span<u8>;
template<typename T>
requires(IsTrivial<T>)
ReadonlyBytes to_readonly_bytes(Span<T> span)
{
return ReadonlyBytes { static_cast<void const*>(span.data()), span.size() * sizeof(T) };
}
template<typename T>
requires(IsTrivial<T> && !IsConst<T>)
Bytes to_bytes(Span<T> span)
{
return Bytes { static_cast<void*>(span.data()), span.size() * sizeof(T) };
}
}
#if USING_AK_GLOBALLY
using AK::Bytes;
using AK::ReadonlyBytes;
using AK::ReadonlySpan;
using AK::Span;
using AK::to_bytes;
using AK::to_readonly_bytes;
#endif