mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-11-07 20:31:04 +03:00
e4213f5767
This allows, for example, checking if a Span<String> contains a value without having to allocate a String.
350 lines
8.8 KiB
C++
350 lines
8.8 KiB
C++
/*
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* Copyright (c) 2020-2021, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Array.h>
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#include <AK/Assertions.h>
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#include <AK/Iterator.h>
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#include <AK/TypedTransfer.h>
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#include <AK/Types.h>
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namespace AK {
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namespace Detail {
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template<typename T>
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class Span {
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public:
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ALWAYS_INLINE constexpr Span() = default;
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ALWAYS_INLINE constexpr Span(T* values, size_t size)
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: m_values(values)
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, m_size(size)
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{
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}
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template<size_t size>
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ALWAYS_INLINE constexpr Span(T (&values)[size])
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: m_values(values)
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, m_size(size)
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{
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}
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template<size_t size>
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ALWAYS_INLINE constexpr Span(Array<T, size>& array)
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: m_values(array.data())
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, m_size(size)
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{
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}
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template<size_t size>
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requires(IsConst<T>)
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ALWAYS_INLINE constexpr Span(Array<T, size> const& array)
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: m_values(array.data())
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, m_size(size)
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{
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}
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protected:
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T* m_values { nullptr };
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size_t m_size { 0 };
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};
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template<>
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class Span<u8> {
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public:
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ALWAYS_INLINE constexpr Span() = default;
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ALWAYS_INLINE constexpr Span(u8* values, size_t size)
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: m_values(values)
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, m_size(size)
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{
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}
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ALWAYS_INLINE Span(void* values, size_t size)
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: m_values(reinterpret_cast<u8*>(values))
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, m_size(size)
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{
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}
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template<size_t size>
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ALWAYS_INLINE constexpr Span(u8 (&values)[size])
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: m_values(values)
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, m_size(size)
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{
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}
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protected:
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u8* m_values { nullptr };
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size_t m_size { 0 };
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};
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template<>
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class Span<u8 const> {
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public:
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ALWAYS_INLINE constexpr Span() = default;
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ALWAYS_INLINE constexpr Span(u8 const* values, size_t size)
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: m_values(values)
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, m_size(size)
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{
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}
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ALWAYS_INLINE Span(void const* values, size_t size)
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: m_values(reinterpret_cast<u8 const*>(values))
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, m_size(size)
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{
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}
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ALWAYS_INLINE Span(char const* values, size_t size)
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: m_values(reinterpret_cast<u8 const*>(values))
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, m_size(size)
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{
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}
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template<size_t size>
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ALWAYS_INLINE constexpr Span(u8 const (&values)[size])
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: m_values(values)
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, m_size(size)
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{
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}
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protected:
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u8 const* m_values { nullptr };
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size_t m_size { 0 };
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};
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}
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template<typename T>
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class Span : public Detail::Span<T> {
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public:
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using Detail::Span<T>::Span;
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constexpr Span() = default;
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[[nodiscard]] ALWAYS_INLINE constexpr T const* data() const { return this->m_values; }
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[[nodiscard]] ALWAYS_INLINE constexpr T* data() { return this->m_values; }
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[[nodiscard]] ALWAYS_INLINE constexpr T const* offset_pointer(size_t offset) const { return this->m_values + offset; }
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[[nodiscard]] ALWAYS_INLINE constexpr T* offset_pointer(size_t offset) { return this->m_values + offset; }
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using ConstIterator = SimpleIterator<Span const, T const>;
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using Iterator = SimpleIterator<Span, T>;
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constexpr ConstIterator begin() const { return ConstIterator::begin(*this); }
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constexpr Iterator begin() { return Iterator::begin(*this); }
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constexpr ConstIterator end() const { return ConstIterator::end(*this); }
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constexpr Iterator end() { return Iterator::end(*this); }
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[[nodiscard]] ALWAYS_INLINE constexpr size_t size() const { return this->m_size; }
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[[nodiscard]] ALWAYS_INLINE constexpr bool is_null() const { return this->m_values == nullptr; }
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[[nodiscard]] ALWAYS_INLINE constexpr bool is_empty() const { return this->m_size == 0; }
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[[nodiscard]] ALWAYS_INLINE constexpr Span slice(size_t start, size_t length) const
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{
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VERIFY(start + length <= size());
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return { this->m_values + start, length };
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}
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[[nodiscard]] ALWAYS_INLINE constexpr Span slice(size_t start) const
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{
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VERIFY(start <= size());
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return { this->m_values + start, size() - start };
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}
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[[nodiscard]] ALWAYS_INLINE constexpr Span slice_from_end(size_t count) const
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{
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VERIFY(count <= size());
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return { this->m_values + size() - count, count };
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}
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[[nodiscard]] ALWAYS_INLINE constexpr Span trim(size_t length) const
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{
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return { this->m_values, min(size(), length) };
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}
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[[nodiscard]] Span align_to(size_t alignment) const
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{
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auto* start = reinterpret_cast<T*>(align_up_to((FlatPtr)data(), alignment));
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auto* end = reinterpret_cast<T*>(align_down_to((FlatPtr)(data() + size()), alignment));
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if (end < start)
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return {};
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size_t length = end - start;
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return { start, length };
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T* offset(size_t start) const
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{
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VERIFY(start < this->m_size);
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return this->m_values + start;
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}
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ALWAYS_INLINE constexpr void overwrite(size_t offset, void const* data, size_t data_size)
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{
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// make sure we're not told to write past the end
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VERIFY(offset + data_size <= size());
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__builtin_memmove(this->data() + offset, data, data_size);
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}
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ALWAYS_INLINE constexpr size_t copy_to(Span<RemoveConst<T>> other) const
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{
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VERIFY(other.size() >= size());
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return TypedTransfer<RemoveConst<T>>::copy(other.data(), data(), size());
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}
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ALWAYS_INLINE constexpr size_t copy_trimmed_to(Span<RemoveConst<T>> other) const
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{
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auto const count = min(size(), other.size());
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return TypedTransfer<RemoveConst<T>>::copy(other.data(), data(), count);
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}
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ALWAYS_INLINE constexpr size_t fill(T const& value)
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{
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for (size_t idx = 0; idx < size(); ++idx)
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data()[idx] = value;
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return size();
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}
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template<typename V>
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[[nodiscard]] constexpr bool contains_slow(V const& value) const
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{
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for (size_t i = 0; i < size(); ++i) {
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if (Traits<RemoveReference<T>>::equals(at(i), value))
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return true;
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}
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return false;
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}
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[[nodiscard]] constexpr bool starts_with(ReadonlySpan<T> other) const
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{
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if (size() < other.size())
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return false;
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return TypedTransfer<T>::compare(data(), other.data(), other.size());
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}
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[[nodiscard]] constexpr size_t matching_prefix_length(ReadonlySpan<T> other) const
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{
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auto maximum_length = min(size(), other.size());
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for (size_t i = 0; i < maximum_length; i++) {
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if (data()[i] != other.data()[i])
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return i;
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}
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return maximum_length;
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T const& at(size_t index) const
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{
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VERIFY(index < this->m_size);
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return this->m_values[index];
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T& at(size_t index)
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{
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VERIFY(index < this->m_size);
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return this->m_values[index];
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T const& first() const
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{
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return this->at(0);
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T& first()
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{
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return this->at(0);
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T const& last() const
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{
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return this->at(this->size() - 1);
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T& last()
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{
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return this->at(this->size() - 1);
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T const& operator[](size_t index) const
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{
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return at(index);
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}
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void reverse()
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{
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for (size_t i = 0; i < size() / 2; ++i)
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AK::swap(at(i), at(size() - i - 1));
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}
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[[nodiscard]] ALWAYS_INLINE constexpr T& operator[](size_t index)
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{
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return at(index);
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}
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constexpr bool operator==(Span const& other) const
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{
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if (size() != other.size())
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return false;
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return TypedTransfer<T>::compare(data(), other.data(), size());
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}
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ALWAYS_INLINE constexpr operator ReadonlySpan<T>() const
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{
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return { data(), size() };
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}
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};
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template<typename T>
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struct Traits<Span<T>> : public DefaultTraits<Span<T>> {
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static unsigned hash(Span<T> const& span)
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{
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unsigned hash = 0;
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for (auto const& value : span) {
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auto value_hash = Traits<T>::hash(value);
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hash = pair_int_hash(hash, value_hash);
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}
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return hash;
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}
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constexpr static bool is_trivial() { return true; }
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};
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template<typename T>
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using ReadonlySpan = Span<T const>;
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using ReadonlyBytes = ReadonlySpan<u8>;
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using Bytes = Span<u8>;
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template<typename T>
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requires(IsTrivial<T>)
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ReadonlyBytes to_readonly_bytes(Span<T> span)
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{
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return ReadonlyBytes { static_cast<void const*>(span.data()), span.size() * sizeof(T) };
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}
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template<typename T>
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requires(IsTrivial<T> && !IsConst<T>)
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Bytes to_bytes(Span<T> span)
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{
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return Bytes { static_cast<void*>(span.data()), span.size() * sizeof(T) };
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}
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}
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#if USING_AK_GLOBALLY
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using AK::Bytes;
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using AK::ReadonlyBytes;
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using AK::ReadonlySpan;
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using AK::Span;
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using AK::to_bytes;
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using AK::to_readonly_bytes;
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#endif
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