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#pragma once
#include <std/fwd/vector.hpp>
#include <memory>
namespace std {
template <class T, class Allocator>
class vector {
public:
using size_type = size_t;
using value_type = T;
using reference = value_type &;
using const_reference = const value_type &;
private:
Allocator _alloc;
size_type _capacity;
size_type _size;
T *_data;
constexpr void expand_capacity_to(size_type at_least) {
size_type new_capacity = _capacity == 0 ? 1 : _capacity;
while (new_capacity < at_least)
new_capacity *= 2;
if (new_capacity == _capacity)
return;
T *new_data = _alloc.allocate(new_capacity);
for (size_type i = 0; i < _size; ++i) {
std::construct_at(new_data + i, std::move(_data[i]));
std::destroy_at(_data + i);
}
if (_capacity > 0)
_alloc.deallocate(_data, _capacity);
_capacity = new_capacity;
_data = new_data;
}
public:
constexpr vector() noexcept(noexcept(Allocator()))
: _alloc(), _capacity(0), _size(0), _data(0) {}
constexpr vector(const vector &other)
: _alloc(), _capacity(other._size), _size(other._size),
_data(_alloc.allocate(_capacity)) {
for (size_type i = 0; i < _size; ++i)
std::construct_at(_data + i, other._data[i]);
}
constexpr vector(vector &&other) noexcept
: _alloc(std::move(other._alloc)), _capacity(other._capacity),
_size(other._size), _data(other._data) {
other._capacity = 0;
other._size = 0;
}
constexpr vector(
std::initializer_list<T> init, const Allocator &alloc = Allocator())
: _alloc(alloc), _capacity(init.size()),
_size(init.size()), _data(_alloc.allocate(_capacity)) {
for (size_type i = 0; i < _size; ++i)
std::construct_at(_data + i, init.begin()[i]);
}
explicit vector(size_type count)
: _alloc(), _capacity(count), _size(count),
_data(_alloc.allocate(_capacity)) {
for (size_type i = 0; i < _size; ++i)
std::construct_at(_data + i);
}
constexpr ~vector() {
if (_capacity > 0) {
for (size_type i = 0; i < _size; ++i)
std::destroy_at(_data + i);
_alloc.deallocate(_data, _capacity);
}
}
constexpr vector &operator =(const vector &other) {
if (&other == this)
return *this;
expand_capacity_to(other._size);
for (size_type i = 0; i < _size; ++i)
std::destroy_at(_data + i);
for (size_type i = 0; i < other._size; ++i) {
std::construct_at(_data + i, std::move(other._data[i]));
std::destroy_at(other._data + i);
}
_size = other._size;
return *this;
}
constexpr vector &operator =(vector &&other)
noexcept(
std::allocator_traits<Allocator>::
propagate_on_container_move_assignment::value ||
std::allocator_traits<Allocator>::
is_always_equal::value) {
if (&other == this)
return *this;
if (_capacity > 0) {
for (size_type i = 0; i < _size; ++i)
std::destroy_at(_data + i);
_alloc.deallocate(_data, _capacity);
}
_alloc = std::move(other._alloc);
_capacity = other._capacity;
_size = other._size;
_data = other._data;
other._capacity = 0;
other._size = 0;
return *this;
}
constexpr size_type size() const noexcept {
return _size;
}
constexpr T *data() noexcept {
return _data;
}
constexpr const T *data() const noexcept {
return _data;
}
constexpr reference operator[](size_type pos) {
return _data[pos];
}
constexpr const_reference operator[](size_type pos) const {
return _data[pos];
}
constexpr reference back() {
return _data[_size - 1];
}
constexpr const_reference back() const {
return _data[_size - 1];
}
constexpr void resize(size_type count) {
if (count < _size) {
for (size_type i = count; i < _size; ++i)
std::destroy_at(_data + i);
_size = count;
}
else if (count > _size) {
expand_capacity_to(count);
for (size_type i = _size; i < count; ++i)
std::construct_at(_data + i);
_size = count;
}
}
constexpr void push_back(const T &value) {
expand_capacity_to(_size + 1);
std::construct_at(_data + _size, value);
++_size;
}
constexpr void push_back(T &&value) {
expand_capacity_to(_size + 1);
std::construct_at(_data + _size, std::move(value));
++_size;
}
};
}
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