diff --git a/AK/FixedArray.h b/AK/FixedArray.h index 55ca1554b92..ed1f426e396 100644 --- a/AK/FixedArray.h +++ b/AK/FixedArray.h @@ -37,13 +37,12 @@ public: { if (size == 0) return FixedArray(); - auto* new_storage = static_cast(kmalloc(storage_allocation_size(size))); - if (!new_storage) + auto* elements = reinterpret_cast(kmalloc(storage_allocation_size(size))); + if (!elements) return Error::from_errno(ENOMEM); - new_storage->size = size; for (size_t i = 0; i < size; ++i) - new (&new_storage->elements[i]) T(); - return FixedArray(new_storage); + new (&elements[i]) T(); + return FixedArray(size, elements); } static FixedArray must_create_but_fixme_should_propagate_errors(size_t size) @@ -62,13 +61,12 @@ public: { if (span.size() == 0) return FixedArray(); - auto* new_storage = static_cast(kmalloc(storage_allocation_size(span.size()))); - if (!new_storage) + auto* elements = reinterpret_cast(kmalloc(storage_allocation_size(span.size()))); + if (!elements) return Error::from_errno(ENOMEM); - new_storage->size = span.size(); for (size_t i = 0; i < span.size(); ++i) - new (&new_storage->elements[i]) T(span[i]); - return FixedArray(new_storage); + new (&elements[i]) T(span[i]); + return FixedArray(span.size(), elements); } ErrorOr> clone() const @@ -76,57 +74,55 @@ public: return create(span()); } - static size_t storage_allocation_size(size_t size) - { - return sizeof(Storage) + size * sizeof(T); - } - // Nobody can ever use these functions, since it would be impossible to make them OOM-safe due to their signatures. We just explicitly delete them. FixedArray(FixedArray const&) = delete; FixedArray& operator=(FixedArray const&) = delete; FixedArray(FixedArray&& other) - : m_storage(exchange(other.m_storage, nullptr)) + : m_size(exchange(other.m_size, 0)) + , m_elements(exchange(other.m_elements, nullptr)) { } FixedArray& operator=(FixedArray&& other) { - m_storage = other.m_storage; - other.m_storage = nullptr; + if (this != &other) { + this->~FixedArray(); + new (this) FixedArray(move(other)); + } return *this; } ~FixedArray() { - if (!m_storage) + if (!m_elements) return; - for (size_t i = 0; i < m_storage->size; ++i) - m_storage->elements[i].~T(); - kfree_sized(m_storage, storage_allocation_size(m_storage->size)); - m_storage = nullptr; + for (size_t i = 0; i < m_size; ++i) + m_elements[i].~T(); + kfree_sized(m_elements, storage_allocation_size(m_size)); + m_elements = nullptr; } - size_t size() const { return m_storage ? m_storage->size : 0; } + size_t size() const { return m_size; } bool is_empty() const { return size() == 0; } - T* data() { return m_storage ? m_storage->elements : nullptr; } - T const* data() const { return m_storage ? m_storage->elements : nullptr; } + T* data() { return m_elements; } + T const* data() const { return m_elements; } T& at(size_t index) { - VERIFY(index < m_storage->size); - return m_storage->elements[index]; + VERIFY(index < m_size); + return m_elements[index]; } T& unchecked_at(size_t index) { - return m_storage->elements[index]; + return m_elements[index]; } T const& at(size_t index) const { - VERIFY(index < m_storage->size); - return m_storage->elements[index]; + VERIFY(index < m_size); + return m_elements[index]; } T& operator[](size_t index) @@ -141,10 +137,10 @@ public: bool contains_slow(T const& value) const { - if (!m_storage) + if (!m_elements) return false; - for (size_t i = 0; i < m_storage->size; ++i) { - if (m_storage->elements[i] == value) + for (size_t i = 0; i < m_size; ++i) { + if (m_elements[i] == value) return true; } return false; @@ -152,15 +148,16 @@ public: void swap(FixedArray& other) { - AK::swap(m_storage, other.m_storage); + AK::swap(m_size, other.m_size); + AK::swap(m_elements, other.m_elements); } void fill_with(T const& value) { - if (!m_storage) + if (!m_elements) return; - for (size_t i = 0; i < m_storage->size; ++i) - m_storage->elements[i] = value; + for (size_t i = 0; i < m_size; ++i) + m_elements[i] = value; } using Iterator = SimpleIterator; @@ -176,17 +173,19 @@ public: ReadonlySpan span() const { return { data(), size() }; } private: - struct Storage { - size_t size { 0 }; - T elements[0]; - }; + static size_t storage_allocation_size(size_t size) + { + return size * sizeof(T); + } - FixedArray(Storage* storage) - : m_storage(storage) + FixedArray(size_t size, T* elements) + : m_size(size) + , m_elements(elements) { } - Storage* m_storage { nullptr }; + size_t m_size { 0 }; + T* m_elements { nullptr }; }; }