transform.h

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/*
    Copyright (C) 2014 Paul Davis
    Author: David Robillard

    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_transform_h__
#define __ardour_transform_h__

#include <stack>
#include <string>

#include "ardour/libardour_visibility.h"
#include "ardour/midi_model.h"
#include "ardour/midi_operator.h"
#include "ardour/types.h"
#include "ardour/variant.h"

namespace ARDOUR {

class LIBARDOUR_API Transform : public MidiOperator {
public:
        typedef Evoral::Sequence<Evoral::Beats>::NotePtr     NotePtr;
        typedef Evoral::Sequence<Evoral::Beats>::Notes       Notes;
        typedef ARDOUR::MidiModel::NoteDiffCommand::Property Property;

        struct Context {
                Context() : index(0) {}

                Variant pop();

                std::stack<Variant> stack;      
                size_t              index;      
                size_t              n_notes;    
                NotePtr             prev_note;  
                NotePtr             this_note;  
        };

        struct Value {
                enum Source {
                        NOWHERE,    
                        THIS_NOTE,  
                        PREV_NOTE,  
                        INDEX,      
                        N_NOTES,    
                        LITERAL,    
                        RANDOM      
                };

                Value()                 : source(NOWHERE) {}
                Value(Source s)         : source(s) {}
                Value(const Variant& v) : source(LITERAL), value(v) {}
                Value(double v)         : source(LITERAL), value(Variant(v)) {}

                Variant eval(const Context& context) const;

                Source   source;  
                Variant  value;   
                Property prop;    
        };

        struct Operation {
                enum Operator {
                        PUSH,  
                        ADD,   
                        SUB,   
                        MULT,  
                        DIV,   
                        MOD    
                };

                Operation(Operator o, const Value& a=Value()) : op(o), arg(a) {}

                void eval(Context& context) const;

                Operator op;
                Value    arg;
        };

        struct Program {
                Property             prop;  
                std::list<Operation> ops;   
        };

        Transform(const Program& prog);

        Command* operator()(boost::shared_ptr<ARDOUR::MidiModel> model,
                            Evoral::Beats                        position,
                            std::vector<Notes>&                  seqs);

        std::string name() const { return std::string ("transform"); }

private:
        const Program _prog;
};

} /* namespace */

#endif /* __ardour_transform_h__ */