EventDelay.h

/*
 * EventDelay.h
 *
 * This file is part of Mozzi.
 *
 * Copyright 2012-2024 Tim Barrass and the Mozzi Team
 *
 * Mozzi is licensed under the GNU Lesser General Public Licence (LGPL) Version 2.1 or later.
 *
 */
 
#ifndef EVENTDELAY_H_
#define EVENTDELAY_H_
 
 
/** A non-blocking replacement for Arduino's delay() function. 
EventDelay can be set() to a number of milliseconds, then after calling start(), ready() will return true when the time is up.  
Alternatively, start(milliseconds) will call set() and start() together.
*/
class EventDelay
{
 
public:
 
    /** Constructor.
    Declare an EventDelay object.
    @param delay_milliseconds how long until ready() returns true, after calling start().  Defaults to 0 if no parameter is supplied.
    */
    EventDelay(unsigned int delay_milliseconds = 0): AUDIO_TICKS_PER_MILLISECOND((float)MOZZI_AUDIO_RATE/1000.0f)
    {
        set(delay_milliseconds);
    }
 
 
    /** Set the delay time.  This setting is persistent, until you change it by using set() again.
    @param delay_milliseconds delay time in milliseconds.
    @note timing: 12us
    */
    inline
    void set(unsigned int delay_milliseconds)
    {
        ticks = (unsigned long)(AUDIO_TICKS_PER_MILLISECOND*delay_milliseconds); // 12us
    }
 
 
    /** Start the delay.
    @todo have a parameter to set whether it's single or repeating, so start doesn't have to be called for repeats.  
    Pro: simpler user programming. Con: would require an if..then every time ready() is called.
    */
    inline
    void start()
    {
        deadline=audioTicks()+ticks;
    }
 
 
    /** Set the delay time and start the delay.
    @param delay_milliseconds delay time in milliseconds.
    */
    inline
    void start(unsigned int delay_milliseconds)
    {
        set(delay_milliseconds);
        start();
    }
 
 
    /** Call this in updateControl() or updateAudio() to check if the delay time is up.
    @return true if the time is up.
    @note timing: 1us.
    */
    inline
    bool ready()
    {
        return(audioTicks()>=deadline); // 1us
    }
 
 
protected:
    // Metronome accesses these
    unsigned long deadline;
    unsigned long ticks;
 
private:
    const float AUDIO_TICKS_PER_MILLISECOND;
};
 
/**
@example 02.Control/EventDelay/EventDelay.ino
This example shows how to use the EventDelay class.
*/
 
#endif /* EVENTDELAY_H_ */