out_file_iterator.hpp

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// SPDX-FileCopyrightText: 2006-2025 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2025 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: BSD-3-Clause

 
#pragma once
 
#include <cassert>
#include <ranges>
 
#include <seqan3/core/platform.hpp>
 
namespace seqan3::detail
{

template <typename file_type>
class out_file_iterator
{
    static_assert(!std::is_const_v<file_type>,
                  "You cannot iterate over const files, because the iterator changes the file.");
 
public:

    using value_type = void;
    using reference = void;
    using const_reference = void;
    using size_type = void;
    using difference_type = std::ptrdiff_t;
    using pointer = void *;
    using iterator_category = std::output_iterator_tag;

    constexpr out_file_iterator() = default;
    constexpr out_file_iterator(out_file_iterator const &) = default;
    constexpr out_file_iterator & operator=(out_file_iterator const &) = default;
    constexpr out_file_iterator(out_file_iterator &&) = default;
    constexpr out_file_iterator & operator=(out_file_iterator &&) = default;
    ~out_file_iterator() = default;

    constexpr out_file_iterator(file_type & _host) noexcept : host{&_host}
    {}

    out_file_iterator & operator++()
    {
        return *this;
    }

    out_file_iterator operator++(int)
    {
        return *this;
    }

 
    out_file_iterator & operator*() noexcept
    {
        return *this;
    }

    template <typename arg_t>
    out_file_iterator & operator=(arg_t && arg)
    {
        assert(host != nullptr);
        host->push_back(std::forward<arg_t>(arg));
        return *this;
    }


    constexpr bool operator==(std::default_sentinel_t const &) const noexcept
    {
        return false;
    }

    constexpr bool operator!=(std::default_sentinel_t const &) const noexcept
    {
        return true;
    }

    constexpr friend bool operator==(std::default_sentinel_t const &, out_file_iterator const & it) noexcept
    {
        return (it == std::default_sentinel);
    }

    constexpr friend bool operator!=(std::default_sentinel_t const &, out_file_iterator const & it) noexcept
    {
        return (it != std::default_sentinel);
    }
 
private:
    file_type * host{};
};
 
} // namespace seqan3::detail