dot_bracket3.hpp

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// -----------------------------------------------------------------------------------------------------
// Copyright (c) 2006-2021, Knut Reinert & Freie Universität Berlin
// Copyright (c) 2016-2021, Knut Reinert & MPI für molekulare Genetik
// This file may be used, modified and/or redistributed under the terms of the 3-clause BSD-License
// shipped with this file and also available at: https://github.com/seqan/seqan3/blob/master/LICENSE.md
// -----------------------------------------------------------------------------------------------------
 
#pragma once
 
#include <vector>
 
#include <seqan3/alphabet/alphabet_base.hpp>
#include <seqan3/alphabet/structure/concept.hpp>
#include <seqan3/utility/char_operations/transform.hpp>
 
// ------------------------------------------------------------------
// dot_bracket3
// ------------------------------------------------------------------
 
namespace seqan3
{
 
class dot_bracket3 : public alphabet_base<dot_bracket3, 3>
{
private:
    using base_t = alphabet_base<dot_bracket3, 3>;
 
    friend base_t;
 
public:
    constexpr dot_bracket3()                                 noexcept = default; 
    constexpr dot_bracket3(dot_bracket3 const &)             noexcept = default; 
    constexpr dot_bracket3(dot_bracket3 &&)                  noexcept = default; 
    constexpr dot_bracket3 & operator=(dot_bracket3 const &) noexcept = default; 
    constexpr dot_bracket3 & operator=(dot_bracket3 &&)      noexcept = default; 
    ~dot_bracket3()                                          noexcept = default; 
 
 
 
    constexpr bool is_pair_open() const noexcept
    {
        return to_rank() == 1u;
    }
 
    constexpr bool is_pair_close() const noexcept
    {
        return to_rank() == 2u;
    }
 
    constexpr bool is_unpaired() const noexcept
    {
        return to_rank() == 0u;
    }
 
    static constexpr uint8_t max_pseudoknot_depth{1u};
 
    constexpr std::optional<uint8_t> pseudoknot_id() const noexcept
    {
        if (is_unpaired())
            return std::nullopt;
        else
            return 0;
    }
 
private:
    static constexpr char_type rank_to_char_table[alphabet_size]
    {
        '.',
        '(',
        ')'
    };
 
    static constexpr std::array<rank_type, 256> char_to_rank_table
    {
        [] () constexpr
        {
            std::array<rank_type, 256> rank_table{};
 
            // initialize with unpaired (std::array::fill unfortunately not constexpr)
            for (rank_type & rnk : rank_table)
                rnk = 0u;
 
            // canonical
            rank_table['.'] = 0u;
            rank_table['('] = 1u;
            rank_table[')'] = 2u;
 
            return rank_table;
        } ()
    };
 
    static constexpr char_type rank_to_char(rank_type const rank)
    {
        return rank_to_char_table[rank];
    }
 
    static constexpr rank_type char_to_rank(char_type const chr)
    {
        using index_t = std::make_unsigned_t<char_type>;
        return char_to_rank_table[static_cast<index_t>(chr)];
    }
};
 
inline namespace literals
{
 
constexpr dot_bracket3 operator""_db3(char const ch) noexcept
{
    return dot_bracket3{}.assign_char(ch);
}
 
inline std::vector<dot_bracket3> operator""_db3(const char * str, std::size_t len)
{
    std::vector<dot_bracket3> vec;
    vec.resize(len);
 
    for (size_t idx = 0ul; idx < len; ++idx)
        vec[idx].assign_char(str[idx]);
 
    return vec;
}
 
} // inline namespace literals
 
} // namespace seqan3