chord_provider.h

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/*
 * Copyright (C) 2026 Paul Davis <paul@linuxaudiosystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#pragma once
 
#include <vector>
#include <string>
#include <map>
 
namespace ARDOUR {
 
class ScaleProvider;
 
class ChordProvider
{
  public:
        ChordProvider () {}
        virtual ~ChordProvider() {}
 
        typedef std::vector<int> Intervals;
 
        virtual bool get_midi_chord (int root_pitch, Intervals& pitches) const = 0;
 
        /* maps a hash of Intervals to a name */
        typedef std::map<int64_t, std::string> IntervalsToChordName;
        static IntervalsToChordName tet12_names;
 
        /* maps (potentiall multiple) names to Intervals */
        typedef std::map<std::string,Intervals> ChordNameToIntervals;
        static ChordNameToIntervals tet12_chords;
 
        static void build_12tet_chords ();
        template<typename...Names> static void register_12tet_chord (Intervals const & intervals, std::string const & canonical_name, Names...chord_names);
 
        std::string identify_chord (Intervals const &);
 
        enum TET12Intervals {
                Unison = 0,
                MinorSecond = 1,
                MajorSecond = 2,
                MinorThird = 3,
                MajorThird = 4,
                PerfectFourth = 5,
                Tritone = 6,
                PerfectFifth = 7,
                MinorSixth = 8,
                MajorSixth = 9,
                MinorSeventh = 10,
                MajorSeventh = 11,
                PerfectOctave = 12,
 
                /* aliases set #1 */
 
                P0 = PerfectOctave,
                m2 = MinorSecond,
                M2 = MajorSecond,
                m3 = MinorThird,
                M3 = MajorThird,
                P4 = PerfectFourth,
                A4 = Tritone,
                d5 = Tritone,
                P5 = PerfectFifth,
                m6 = MinorSixth,
                M6 = MajorSixth,
                m7 = MinorSeventh,
                M7 = MajorSeventh,
                P8 = PerfectOctave,
 
                /* aliases set two */
 
                flat2 = MinorSecond,
                fourth = PerfectFourth,
                flat5 = Tritone,
                sharp5 = MinorSixth,
                dom7 = MinorSeventh,
                dblflat7 = MajorSixth,
 
                /* aliases set three */
 
                AugmentedFifth = 8,
                DiminishedFifth = 6,
                DiminishedSeventh = 9,
 
                /* aliases set four */
 
                MajorNinth = 14, // Octave + 2
                M9 = 14,
                PerfectEleventh = 17,
                P11 = 17,
                MajorThirteenth = 21, // Octave + 9
                M13 = 21,
                
        };
};
 
}