#region License
/* Copyright (c) 2005 Leslie Sanford
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#endregion
#region Contact
/*
* Leslie Sanford
* Email: jabberdabber@hotmail.com
*/
#endregion
using System;
namespace Sanford.Multimedia.Midi
{
/// <summary>
/// Provides basic functionality for generating tick events with pulses per
/// quarter note resolution.
/// </summary>
public abstract class PpqnClock : IClock
{
#region PpqnClock Members
#region Fields
/// <summary>
/// The default tempo in microseconds: 120bpm.
/// </summary>
public const int DefaultTempo = 500000;
/// <summary>
/// The minimum pulses per quarter note value.
/// </summary>
public const int PpqnMinValue = 24;
// The number of microseconds per millisecond.
private const int MicrosecondsPerMillisecond = 1000;
// The pulses per quarter note value.
private int ppqn = PpqnMinValue;
// The tempo in microseconds.
private int tempo = DefaultTempo;
// The product of the timer period, the pulses per quarter note, and
// the number of microseconds per millisecond.
private int periodResolution;
// The number of ticks per MIDI clock.
private int ticksPerClock;
// The running fractional tick count.
private int fractionalTicks = 0;
// The timer period.
private readonly int timerPeriod;
// Indicates whether the clock is running.
protected bool running = false;
#endregion
#region Construction
protected PpqnClock(int timerPeriod)
{
#region Require
if(timerPeriod < 1)
{
throw new ArgumentOutOfRangeException("timerPeriod", timerPeriod,
"Timer period cannot be less than one.");
}
#endregion
this.timerPeriod = timerPeriod;
CalculatePeriodResolution();
CalculateTicksPerClock();
}
#endregion
#region Methods
protected int GetTempo()
{
return tempo;
}
protected void SetTempo(int tempo)
{
#region Require
if(tempo < 1)
{
throw new ArgumentOutOfRangeException(
"Tempo out of range.");
}
#endregion
this.tempo = tempo;
}
protected void Reset()
{
fractionalTicks = 0;
}
protected int GenerateTicks()
{
int ticks = (fractionalTicks + periodResolution) / tempo;
fractionalTicks += periodResolution - ticks * tempo;
return ticks;
}
private void CalculatePeriodResolution()
{
periodResolution = ppqn * timerPeriod * MicrosecondsPerMillisecond;
}
private void CalculateTicksPerClock()
{
ticksPerClock = ppqn / PpqnMinValue;
}
protected virtual void OnTick(EventArgs e)
{
EventHandler handler = Tick;
if(handler != null)
{
handler(this, EventArgs.Empty);
}
}
protected virtual void OnStarted(EventArgs e)
{
EventHandler handler = Started;
if(handler != null)
{
handler(this, e);
}
}
protected virtual void OnStopped(EventArgs e)
{
EventHandler handler = Stopped;
if(handler != null)
{
handler(this, e);
}
}
protected virtual void OnContinued(EventArgs e)
{
EventHandler handler = Continued;
if(handler != null)
{
handler(this, e);
}
}
#endregion
#region Properties
public int Ppqn
{
get
{
return ppqn;
}
set
{
#region Require
if(value < PpqnMinValue)
{
throw new ArgumentOutOfRangeException("Ppqn", value,
"Pulses per quarter note out of range.");
}
else if(value % PpqnMinValue != 0)
{
throw new ArgumentException(
"Pulses per quarter note is not a multiple of 24.");
}
#endregion
ppqn = value;
CalculatePeriodResolution();
CalculateTicksPerClock();
}
}
public abstract int Ticks
{
get;
}
public int TicksPerClock
{
get
{
return ticksPerClock;
}
}
#endregion
#endregion
#region IClock Members
public event System.EventHandler Tick;
public event System.EventHandler Started;
public event System.EventHandler Continued;
public event System.EventHandler Stopped;
public bool IsRunning
{
get
{
return running;
}
}
#endregion
}
}