small_vector.hpp

// Copyright Take Vos 2019, 2021.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "utility.hpp"
#include <array>
 
namespace hi::inline v1 {
 
template<typename T, std::size_t N>
class small_vector {
    using value_type = T;
    using array_type = std::array<T, N>;
    using iterator = typename array_type::iterator;
    using const_iterator = typename array_type::iterator;
 
    array_type items;
    iterator _end;
 
public:
    constexpr small_vector() noexcept
    {
        _end = items.begin();
    }
 
    constexpr auto begin() noexcept
    {
        return items.begin();
    }
 
    constexpr auto end() noexcept
    {
        return _end;
    }
 
    constexpr std::size_t size() const noexcept
    {
        return static_cast<std::size_t>(_end - items.begin());
    }
 
    constexpr void clear() noexcept
    {
        _end = items.begin();
    }
 
    constexpr bool push_back(value_type &&value) noexcept
    {
        if (_end == items.end()) {
            return false;
        }
        *(_end++) = std::move(value);
        return true;
    }
 
    constexpr bool push_back(value_type const &value) noexcept
    {
        if (_end == items.end()) {
            return false;
        }
        *(_end++) = value;
        return true;
    }
};
 
} // namespace hi::inline v1