tempo.h

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/*
    Copyright (C) 2000 Paul Davis

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef __ardour_tempo_h__
#define __ardour_tempo_h__

#include <list>
#include <string>
#include <vector>
#include <cmath>
#include <glibmm/threads.h>

#include "pbd/undo.h"
#include "pbd/stateful.h"
#include "pbd/statefuldestructible.h"

#include "evoral/types.hpp"

#include "ardour/ardour.h"

class BBTTest;
class FrameposPlusBeatsTest;
class TempoTest;
class XMLNode;

namespace ARDOUR {

class Meter;
class TempoMap;

class LIBARDOUR_API Tempo {
  public:
        Tempo (double bpm, double type=4.0) // defaulting to quarter note
                : _beats_per_minute (bpm), _note_type(type) {}

        double beats_per_minute () const { return _beats_per_minute;}
        double note_type () const { return _note_type;}
        double frames_per_beat (framecnt_t sr) const {
                return (60.0 * sr) / _beats_per_minute;
        }

  protected:
        double _beats_per_minute;
        double _note_type;
};

class LIBARDOUR_API Meter {
  public:
        Meter (double dpb, double bt)
                : _divisions_per_bar (dpb), _note_type (bt) {}

        double divisions_per_bar () const { return _divisions_per_bar; }
        double note_divisor() const { return _note_type; }

        double frames_per_bar (const Tempo&, framecnt_t sr) const;
        double frames_per_grid (const Tempo&, framecnt_t sr) const;

  protected:
        double _divisions_per_bar;

        double _note_type;
};

class LIBARDOUR_API MetricSection {
  public:
        MetricSection (const Timecode::BBT_Time& start)
                : _start (start), _frame (0), _movable (true) {}
        MetricSection (framepos_t start)
                : _frame (start), _movable (true) {}

        virtual ~MetricSection() {}

        const Timecode::BBT_Time& start() const { return _start; }
        framepos_t                frame() const { return _frame; }

        void set_movable (bool yn) { _movable = yn; }
        bool movable() const { return _movable; }

        virtual void set_frame (framepos_t f) {
                _frame = f;
        }

        virtual void set_start (const Timecode::BBT_Time& w) {
                _start = w;
        }

        /* MeterSections are not stateful in the full sense,
           but we do want them to control their own
           XML state information.
        */
        virtual XMLNode& get_state() const = 0;

  private:
        Timecode::BBT_Time _start;
        framepos_t         _frame;
        bool               _movable;
};

class LIBARDOUR_API MeterSection : public MetricSection, public Meter {
  public:
        MeterSection (const Timecode::BBT_Time& start, double bpb, double note_type)
                : MetricSection (start), Meter (bpb, note_type) {}
        MeterSection (framepos_t start, double bpb, double note_type)
                : MetricSection (start), Meter (bpb, note_type) {}
        MeterSection (const XMLNode&);

        static const std::string xml_state_node_name;

        XMLNode& get_state() const;
};

class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
  public:
        TempoSection (const Timecode::BBT_Time& start, double qpm, double note_type)
                : MetricSection (start), Tempo (qpm, note_type), _bar_offset (-1.0)  {}
        TempoSection (framepos_t start, double qpm, double note_type)
                : MetricSection (start), Tempo (qpm, note_type), _bar_offset (-1.0) {}
        TempoSection (const XMLNode&);

        static const std::string xml_state_node_name;

        XMLNode& get_state() const;

        void update_bar_offset_from_bbt (const Meter&);
        void update_bbt_time_from_bar_offset (const Meter&);
        double bar_offset() const { return _bar_offset; }

  private:
        /* this value provides a fractional offset into the bar in which
           the tempo section is located in. A value of 0.0 indicates that
           it occurs on the first beat of the bar, a value of 0.5 indicates
           that it occurs halfway through the bar and so on.
           
           this enables us to keep the tempo change at the same relative
           position within the bar if/when the meter changes.
        */
        double _bar_offset;
};

typedef std::list<MetricSection*> Metrics;

class LIBARDOUR_API TempoMetric {
  public:
        TempoMetric (const Meter& m, const Tempo& t)
                : _meter (&m), _tempo (&t), _frame (0) {}

        void set_tempo (const Tempo& t)              { _tempo = &t; }
        void set_meter (const Meter& m)              { _meter = &m; }
        void set_frame (framepos_t f)                { _frame = f; }
        void set_start (const Timecode::BBT_Time& t) { _start = t; }

        void set_metric (const MetricSection* section) {
                const MeterSection* meter;
                const TempoSection* tempo;
                if ((meter = dynamic_cast<const MeterSection*>(section))) {
                        set_meter(*meter);
                } else if ((tempo = dynamic_cast<const TempoSection*>(section))) {
                        set_tempo(*tempo);
                }

                set_frame(section->frame());
                set_start(section->start());
        }

        const Meter&              meter() const { return *_meter; }
        const Tempo&              tempo() const { return *_tempo; }
        framepos_t                frame() const { return _frame; }
        const Timecode::BBT_Time& start() const { return _start; }

  private:
        const Meter*       _meter;
        const Tempo*       _tempo;
        framepos_t         _frame;
        Timecode::BBT_Time _start;
};

class LIBARDOUR_API TempoMap : public PBD::StatefulDestructible
{
  public:
        TempoMap (framecnt_t frame_rate);
        ~TempoMap();

        /* measure-based stuff */

        enum BBTPointType {
                Bar,
                Beat,
        };

        struct BBTPoint {
                framepos_t          frame;
                const MeterSection* meter;
                const TempoSection* tempo;
                uint32_t            bar;
                uint32_t            beat;
            
                BBTPoint (const MeterSection& m, const TempoSection& t, framepos_t f,
                          uint32_t b, uint32_t e)
                        : frame (f), meter (&m), tempo (&t), bar (b), beat (e) {}
                
                Timecode::BBT_Time bbt() const { return Timecode::BBT_Time (bar, beat, 0); }
                operator Timecode::BBT_Time() const { return bbt(); }
                operator framepos_t() const { return frame; }
                bool is_bar() const { return beat == 1; }
        };

        typedef std::vector<BBTPoint> BBTPointList;

        template<class T> void apply_with_metrics (T& obj, void (T::*method)(const Metrics&)) {
                Glib::Threads::RWLock::ReaderLock lm (lock);
                (obj.*method)(metrics);
        }

        void get_grid (BBTPointList::const_iterator&, BBTPointList::const_iterator&, 
                       framepos_t start, framepos_t end);
        
        /* TEMPO- AND METER-SENSITIVE FUNCTIONS 

           bbt_time(), bbt_time_rt(), frame_time() and bbt_duration_at()
           are all sensitive to tempo and meter, and will give answers
           that align with the grid formed by tempo and meter sections.
           
           They SHOULD NOT be used to determine the position of events 
           whose location is canonically defined in beats.
        */

        void bbt_time (framepos_t when, Timecode::BBT_Time&);

        /* realtime safe variant of ::bbt_time(), will throw 
           std::logic_error if the map is not large enough
           to provide an answer.
        */
        void       bbt_time_rt (framepos_t when, Timecode::BBT_Time&);
        framepos_t frame_time (const Timecode::BBT_Time&);
        framecnt_t bbt_duration_at (framepos_t, const Timecode::BBT_Time&, int dir);

        /* TEMPO-SENSITIVE FUNCTIONS
           
           These next 4 functions will all take tempo in account and should be
           used to determine position (and in the last case, distance in beats)
           when tempo matters but meter does not.

           They SHOULD be used to determine the position of events 
           whose location is canonically defined in beats.
        */

        framepos_t framepos_plus_bbt (framepos_t pos, Timecode::BBT_Time b) const;
        framepos_t framepos_plus_beats (framepos_t, Evoral::Beats) const;
        framepos_t framepos_minus_beats (framepos_t, Evoral::Beats) const;
        Evoral::Beats framewalk_to_beats (framepos_t pos, framecnt_t distance) const;

        static const Tempo& default_tempo() { return _default_tempo; }
        static const Meter& default_meter() { return _default_meter; }

        const Tempo& tempo_at (framepos_t) const;
        const Meter& meter_at (framepos_t) const;

        const TempoSection& tempo_section_at (framepos_t) const;
        const MeterSection& meter_section_at (framepos_t) const;

        void add_tempo (const Tempo&, Timecode::BBT_Time where);
        void add_meter (const Meter&, Timecode::BBT_Time where);

        void remove_tempo (const TempoSection&, bool send_signal);
        void remove_meter (const MeterSection&, bool send_signal);

        void replace_tempo (const TempoSection&, const Tempo&, const Timecode::BBT_Time& where);
        void replace_meter (const MeterSection&, const Meter&, const Timecode::BBT_Time& where);

        framepos_t round_to_bar  (framepos_t frame, RoundMode dir);
        framepos_t round_to_beat (framepos_t frame, RoundMode dir);
        framepos_t round_to_beat_subdivision (framepos_t fr, int sub_num, RoundMode dir);

        void set_length (framepos_t frames);

        XMLNode& get_state (void);
        int set_state (const XMLNode&, int version);

        void dump (std::ostream&) const;
        void clear ();

        TempoMetric metric_at (Timecode::BBT_Time bbt) const;

        TempoMetric metric_at (framepos_t, Metrics::const_iterator* last=NULL) const;

        Metrics::const_iterator metrics_end() { return metrics.end(); }

        void change_existing_tempo_at (framepos_t, double bpm, double note_type);
        void change_initial_tempo (double bpm, double note_type);

        void insert_time (framepos_t, framecnt_t);
        bool cut_time (framepos_t where, framecnt_t amount);  //returns true if anything was moved
        
        int n_tempos () const;
        int n_meters () const;

        framecnt_t frame_rate () const { return _frame_rate; }

  private:

        friend class ::BBTTest;
        friend class ::FrameposPlusBeatsTest;
        friend class ::TempoTest;
        
        static Tempo    _default_tempo;
        static Meter    _default_meter;

        Metrics                       metrics;
        framecnt_t                    _frame_rate;
        mutable Glib::Threads::RWLock lock;
        BBTPointList                  _map;

        void recompute_map (bool reassign_tempo_bbt, framepos_t end = -1);
        void extend_map (framepos_t end);
        void require_map_to (framepos_t pos);
        void require_map_to (const Timecode::BBT_Time&);
        void _extend_map (TempoSection* tempo, MeterSection* meter, 
                          Metrics::iterator next_metric,
                          Timecode::BBT_Time current, framepos_t current_frame, framepos_t end);

        BBTPointList::const_iterator bbt_before_or_at (framepos_t);
        BBTPointList::const_iterator bbt_before_or_at (const Timecode::BBT_Time&);
        BBTPointList::const_iterator bbt_after_or_at (framepos_t);
        
        framepos_t round_to_type (framepos_t fr, RoundMode dir, BBTPointType);
        void bbt_time (framepos_t, Timecode::BBT_Time&, const BBTPointList::const_iterator&);
        framecnt_t bbt_duration_at_unlocked (const Timecode::BBT_Time& when, const Timecode::BBT_Time& bbt, int dir);
        
        const MeterSection& first_meter() const;
        MeterSection&       first_meter();
        const TempoSection& first_tempo() const;
        TempoSection&       first_tempo();
        
        void do_insert (MetricSection* section);

        void add_tempo_locked (const Tempo&, Timecode::BBT_Time where, bool recompute);
        void add_meter_locked (const Meter&, Timecode::BBT_Time where, bool recompute);

        bool remove_tempo_locked (const TempoSection&);
        bool remove_meter_locked (const MeterSection&);

};

}; /* namespace ARDOUR */

std::ostream& operator<< (std::ostream&, const ARDOUR::Meter&);
std::ostream& operator<< (std::ostream&, const ARDOUR::Tempo&);
std::ostream& operator<< (std::ostream&, const ARDOUR::MetricSection&);

#endif /* __ardour_tempo_h__ */