array.hpp

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//
// immer: immutable data structures for C++
// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
//
// This software is distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
//

#pragma once

#include <immer/memory_policy.hpp>
#include <immer/detail/arrays/with_capacity.hpp>

namespace immer {

template <typename T, typename MemoryPolicy>
class array_transient;

template <typename T, typename MemoryPolicy = default_memory_policy>
class array
{
    using impl_t = std::conditional_t<
        MemoryPolicy::use_transient_rvalues,
        detail::arrays::with_capacity<T, MemoryPolicy>,
        detail::arrays::no_capacity<T, MemoryPolicy>>;

    using move_t =
        std::integral_constant<bool, MemoryPolicy::use_transient_rvalues>;

public:
    using value_type = T;
    using reference = const T&;
    using size_type = std::size_t;
    using difference_type = std::ptrdiff_t;
    using const_reference = const T&;

    using iterator         = const T*;
    using const_iterator   = iterator;
    using reverse_iterator = std::reverse_iterator<iterator>;

    using memory_policy  = MemoryPolicy;
    using transient_type = array_transient<T, MemoryPolicy>;

    array() = default;

    array(std::initializer_list<T> values)
        : impl_{impl_t::from_initializer_list(values)}
    {}

    template <typename Iter, typename Sent,
              std::enable_if_t
              <detail::compatible_sentinel_v<Iter, Sent>
               && detail::is_forward_iterator_v<Iter>, bool> = true>
    array(Iter first, Sent last)
        : impl_{impl_t::from_range(first, last)}
    {}

    array(size_type n, T v = {})
        : impl_{impl_t::from_fill(n, v)}
    {}

    iterator begin() const { return impl_.data(); }

    iterator end()   const { return impl_.data() + impl_.size; }

    reverse_iterator rbegin() const { return reverse_iterator{end()}; }

    reverse_iterator rend()   const { return reverse_iterator{begin()}; }

    std::size_t size() const { return impl_.size; }

    bool empty() const { return impl_.d->empty(); }

    const T* data() const { return impl_.data(); }

    const T& back() const { return data()[size() - 1]; }

    const T& front() const { return data()[0]; }

    reference operator[] (size_type index) const
    { return impl_.get(index); }

    reference at(size_type index) const
    { return impl_.get_check(index); }

    bool operator==(const array& other) const
    { return impl_.equals(other.impl_); }
    bool operator!=(const array& other) const
    { return !(*this == other); }

    array push_back(value_type value) const&
    { return impl_.push_back(std::move(value)); }

    decltype(auto) push_back(value_type value) &&
    { return push_back_move(move_t{}, std::move(value)); }

    array set(std::size_t index, value_type value) const&
    { return impl_.assoc(index, std::move(value)); }

    decltype(auto) set(size_type index, value_type value) &&
    { return set_move(move_t{}, index, std::move(value)); }

    template <typename FnT>
    array update(std::size_t index, FnT&& fn) const&
    { return impl_.update(index, std::forward<FnT>(fn)); }

    template <typename FnT>
    decltype(auto) update(size_type index, FnT&& fn) &&
    { return update_move(move_t{}, index, std::forward<FnT>(fn)); }

    array take(size_type elems) const&
    { return impl_.take(elems); }

    decltype(auto) take(size_type elems) &&
    { return take_move(move_t{}, elems); }

    transient_type transient() const&
    { return transient_type{ impl_ }; }
    transient_type transient() &&
    { return transient_type{ std::move(impl_) }; }

    // Semi-private
    const impl_t& impl() const { return impl_; }

private:
    friend transient_type;

    array(impl_t impl) : impl_(std::move(impl)) {}

    array&& push_back_move(std::true_type, value_type value)
    { impl_.push_back_mut({}, std::move(value)); return std::move(*this); }
    array push_back_move(std::false_type, value_type value)
    { return impl_.push_back(std::move(value)); }

    array&& set_move(std::true_type, size_type index, value_type value)
    { impl_.assoc_mut({}, index, std::move(value)); return std::move(*this); }
    array set_move(std::false_type, size_type index, value_type value)
    { return impl_.assoc(index, std::move(value)); }

    template <typename Fn>
    array&& update_move(std::true_type, size_type index, Fn&& fn)
    { impl_.update_mut({}, index, std::forward<Fn>(fn)); return std::move(*this); }
    template <typename Fn>
    array update_move(std::false_type, size_type index, Fn&& fn)
    { return impl_.update(index, std::forward<Fn>(fn)); }

    array&& take_move(std::true_type, size_type elems)
    { impl_.take_mut({}, elems); return std::move(*this); }
    array take_move(std::false_type, size_type elems)
    { return impl_.take(elems); }

    impl_t impl_ = impl_t::empty();
};

} /* namespace immer */