ladybird/AK/FixedArray.h
Andreas Kling 5096eaa845 AK: Add a FixedArray<T> container
This is a simple array wrapper that knows its size. It has begin/end
so you can use range-for. It also has a resize() that reallocates.
2019-08-07 20:05:36 +02:00

84 lines
2.2 KiB
C++

#pragma once
#include <AK/Vector.h>
namespace AK {
template<typename T>
class FixedArray {
public:
FixedArray() {}
explicit FixedArray(size_t size)
: m_size(size)
{
m_elements = (T*)kmalloc(sizeof(T) * m_size);
for (size_t i = 0; i < m_size; ++i)
new (&m_elements[i]) T();
}
~FixedArray()
{
clear();
}
FixedArray(const FixedArray& other)
: m_size(other.m_size)
{
m_elements = (T*)kmalloc(sizeof(T) * m_size);
for (size_t i = 0; i < m_size; ++i)
new (&m_elements[i]) T(other[i]);
}
FixedArray& operator=(const FixedArray&) = delete;
FixedArray(FixedArray&&) = delete;
FixedArray& operator=(FixedArray&&) = delete;
void clear()
{
if (!m_elements)
return;
for (size_t i = 0; i < m_size; ++i)
m_elements[i].~T();
kfree(m_elements);
m_elements = nullptr;
m_size = 0;
}
size_t size() const { return m_size; }
T& operator[](size_t index) { return m_elements[index]; }
const T& operator[](size_t index) const { return m_elements[index]; }
void resize(size_t new_size)
{
if (new_size == m_size)
return;
auto* new_elements = (T*)kmalloc(new_size * sizeof(T));
for (size_t i = 0; i < min(new_size, m_size); ++i)
new (&new_elements[i]) T(move(m_elements[i]));
for (size_t i = min(new_size, m_size); i < new_size; ++i)
new (&new_elements[i]) T();
for (size_t i = 0; i < m_size; ++i)
m_elements[i].~T();
if (m_elements)
kfree(m_elements);
m_elements = new_elements;
m_size = new_size;
}
using Iterator = VectorIterator<FixedArray, T>;
Iterator begin() { return Iterator(*this, 0); }
Iterator end() { return Iterator(*this, size()); }
using ConstIterator = VectorIterator<const FixedArray, const T>;
ConstIterator begin() const { return ConstIterator(*this, 0); }
ConstIterator end() const { return ConstIterator(*this, size()); }
private:
size_t m_size { 0 };
T* m_elements { nullptr };
};
}
using AK::FixedArray;