Vita/third_party/VST_SDK/VST3_SDK/base/source/timer.h

//------------------------------------------------------------------------
// Project     : SDK Base
// Version     : 1.0
// 
// Category    : Helpers
// Filename    : base/source/timer.h
// Created by  : Steinberg, 05/2006
// Description : Timer class for receiving tiggers at regular intervals
// 
//-----------------------------------------------------------------------------
// LICENSE
// (c) 2018, Steinberg Media Technologies GmbH, All Rights Reserved
//-----------------------------------------------------------------------------
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//   * Redistributions of source code must retain the above copyright notice, 
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation 
//     and/or other materials provided with the distribution.
//   * Neither the name of the Steinberg Media Technologies nor the names of its
//     contributors may be used to endorse or promote products derived from this 
//     software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
// IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE  OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
//-----------------------------------------------------------------------------

#pragma once

#include "fobject.h"
#include <limits>

namespace Steinberg {
class Timer;

//------------------------------------------------------------------------
namespace SystemTime {

uint64 getTicks64 ();

inline uint64 getTicksDuration (uint64 old, uint64 now)
{
	if (old > now)
		return (std::numeric_limits<uint64>::max) () - old + now;
	return now - old;
}

int32 getTicks (); ///< deprecated, use getTicks64 ()

//------------------------------------------------------------------------
} // SystemTime

//------------------------------------------------------------------------
/** @class ITimerCallback
    

    Implement this callback interface to receive triggers from a timer.
    Note: This interface is intended as a mix-in class and therefore does not provide refcounting.
    

    @see Timer */
//------------------------------------------------------------------------
class ITimerCallback
{
public:
	virtual ~ITimerCallback () {}
	/** This method is called at the end of each interval.
	    

	    \param timer The timer which calls.
	*/
	virtual void onTimer (Timer* timer) = 0;
};

template <typename Call>
ITimerCallback* newTimerCallback (const Call& call)
{
	struct Callback : public ITimerCallback
	{
		Callback (const Call& call) : call (call) {}
		void onTimer (Timer* timer) SMTG_OVERRIDE { call (timer); }
		Call call;
	};
	return NEW Callback (call);
}

// -----------------------------------------------------------------
/** @class Timer

    Timer is a class that allows you to receive triggers at regular intervals.

    Note: The timer class is an abstract base class with (hidden) platform specific subclasses.



    Usage:
    @code
    class TimerReceiver : public FObject, public ITimerCallback
    {
        ...
        virtual void onTimer (Timer* timer)
        {
            // do stuff
        }
        ...
    };

    TimerReceiver* receiver =  new TimerReceiver ();
    Timer* myTimer = Timer::create (receiver, 100); // interval: every 100ms
    

    ...
    ...

    if (myTimer)
        myTimer->release ();
    if (receiver)
        receiver->release ();
    @endcode

    @see ITimerCallback
    */
// -----------------------------------------------------------------
class Timer : public FObject
{
public:
	/** Create a timer with a given interval
	    \param callback The receiver of the timer calls.
	    \param intervalMilliseconds The timer interval in milliseconds.
	    \return The created timer if any, callers owns the timer. The timer starts immediately.
	*/
	static Timer* create (ITimerCallback* callback, uint32 intervalMilliseconds);

	virtual void stop () = 0; ///< Stop the timer.
};

// -----------------------------------------------------------------
/** @class DisableDispatchingTimers

    Disables dispatching of timers for the live time of this object

    */
// -----------------------------------------------------------------
class DisableDispatchingTimers
{
public:
	DisableDispatchingTimers ();
	~DisableDispatchingTimers ();

private:
	bool oldState;
};

//------------------------------------------------------------------------
} // namespace Steinberg