mirror of
https://github.com/zebrajr/ladybird.git
synced 2025-12-06 00:19:53 +01:00
afd170d16c
This allows you to reinterpret a Span to any given type, maintaining the original data and working out the new size for you. The target type must evenly fit into the Span's original type, ensuring bytes are not dropped.
422 lines
11 KiB
C++
422 lines
11 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() * sizeof(T));
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TypedTransfer<T>::copy(this->data() + offset, static_cast<T const*>(data), data_size / sizeof(T));
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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 bool ends_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(offset_pointer(size() - other.size()), 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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constexpr bool operator==(Span<T const> const& other) const
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requires(!IsConst<T>)
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{
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return Span<T const>(*this) == other;
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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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Optional<size_t> index_of(ReadonlySpan<T> other, size_t start_offset = 0) const
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{
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Checked maximum_offset { start_offset };
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maximum_offset += other.size();
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if (maximum_offset.has_overflow() || maximum_offset.value() > size())
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return {};
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if (other.is_empty())
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return start_offset;
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for (size_t index = start_offset; index <= size() - other.size(); ++index) {
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if (TypedTransfer<T>::compare(data() + index, other.data(), other.size()))
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return index;
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}
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return {};
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}
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template<typename TUnaryPredicate>
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Optional<T&> last_matching(TUnaryPredicate const& predicate)
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{
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for (ssize_t i = size() - 1; i >= 0; --i) {
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if (predicate(at(i))) {
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return at(i);
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}
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}
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return {};
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}
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template<typename TUnaryPredicate>
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Optional<T&> first_matching(TUnaryPredicate const& predicate)
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{
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for (size_t i = 0; i < size(); ++i) {
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if (predicate(at(i))) {
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return at(i);
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}
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}
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return {};
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}
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template<typename TargetType>
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ALWAYS_INLINE constexpr Span<TargetType> reinterpret()
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{
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if constexpr (sizeof(T) % sizeof(TargetType) != 0)
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VERIFY((size() * sizeof(T)) % sizeof(TargetType) == 0);
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return Span<TargetType> { reinterpret_cast<TargetType*>(data()), (size() * sizeof(T)) / sizeof(TargetType) };
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}
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template<typename TargetType>
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ALWAYS_INLINE constexpr Span<TargetType const> reinterpret() const
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{
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if constexpr (sizeof(T) % sizeof(TargetType) != 0)
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VERIFY((size() * sizeof(T)) % sizeof(TargetType) == 0);
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return Span<TargetType const> { reinterpret_cast<TargetType const*>(data()), (size() * sizeof(T)) / sizeof(TargetType) };
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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 span.template reinterpret<u8 const>();
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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 span.template reinterpret<u8>();
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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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