transform.h

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/*
 * Copyright (C) 2014-2015 David Robillard <d@drobilla.net>
 * Copyright (C) 2017 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 <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<Temporal::Beats>::NotePtr   NotePtr;
        typedef Evoral::Sequence<Temporal::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);
 
        PBD::Command* operator()(std::shared_ptr<ARDOUR::MidiModel> model,
                                 Temporal::Beats                      position,
                                 std::vector<Notes>&                  seqs);
 
        std::string name() const { return std::string ("transform"); }
 
private:
        const Program _prog;
};
 
} /* namespace */