/// <summary>
/// Function to retrieve the timeGetTime time data.
/// </summary>
private void GetWin32Time()
{
if (!_initialized)
{
Reset();
}
long currentTime = WinMultimediaApi.timeGetTime();
long ticks = Environment.TickCount;
// Handle wrap around every ~50 days.
if (currentTime < _startTime)
{
long diff = uint.MaxValue - _startTime;
_startTime = diff;
currentTime += diff;
}
if (ticks < _startTick)
{
long diff = uint.MaxValue - _startTick;
_startTick = diff;
ticks += diff;
}
unchecked
{
_milliseconds = (currentTime - _startTime);
_currentTicks = ticks - _startTick;
}
}
/// <summary>
/// Function to end the timing period for the timer.
/// </summary>
/// <remarks>
/// <para>
/// This will end the current timing period for calls to the Win32 <a href="https://msdn.microsoft.com/en-us/library/dd757629(v=vs.85).aspx" target="_blank">timeGetTime</a> API function.
/// </para>
/// <para>
/// Calls to this method must be paired with the <see cref="BeginTiming"/> static method, otherwise the system will be left in a state where the task scheduler switches tasks more often and the power
/// saving may not trigger properly. If <see cref="BeginTiming"/> was never called, then this method will do nothing.
/// </para>
/// </remarks>
/// <exception cref="Win32Exception">Thrown when the last known period value is out of range.</exception>
public static void EndTiming()
{
if (_lastPeriod == null)
{
return;
}
if (WinMultimediaApi.timeEndPeriod((uint)_lastPeriod.Value) == ErrorNoCanDo)
{
throw new Win32Exception(Resources.GOR_ERR_TIME_CANNOT_END);
}
_lastPeriod = null;
}
/// <summary>
/// Function to reset the timer.
/// </summary>
/// <exception cref="Win32Exception">Thrown when timer information cannot be retrieved from the operating system.</exception>
public void Reset()
{
if (WinMultimediaApi.timeGetDevCaps(ref _timeCaps, Unsafe.SizeOf <TIMECAPS>()) != 0)
{
throw new Win32Exception(Resources.GOR_ERR_TIME_CANNOT_BEGIN);
}
if (_lastPeriod != null)
{
int period = _lastPeriod.Value;
EndTiming();
BeginTiming(period);
}
_startTick = Environment.TickCount;
_startTime = WinMultimediaApi.timeGetTime();
_initialized = true;
}
/// <summary>
/// Function to set the timing period for the timer.
/// </summary>
/// <param name="period">[Optional] Minimum timer resolution, in milliseconds, for the application or device driver. A lower value specifies a higher (more accurate) resolution..</param>
/// <remarks>
/// <para>
/// This will set the timing period for calls to the Win32 <a href="https://msdn.microsoft.com/en-us/library/dd757629(v=vs.85).aspx" target="_blank">timeGetTime</a> API function so that the resolution for the timer
/// can be adjusted for maximum performance.
/// </para>
/// <para>
/// Calls to this method must be paired with the <see cref="EndTiming"/> static method, otherwise the system will be left in a state where the task scheduler switches tasks more often and the power
/// saving may not trigger properly.
/// </para>
/// </remarks>
/// <exception cref="Win32Exception">Thrown when the <paramref name="period"/> value is out of range.</exception>
public static void BeginTiming(int period = 1)
{
if (_lastPeriod != null)
{
EndTiming();
}
if (period < _timeCaps.MinPeriod)
{
period = (int)_timeCaps.MinPeriod;
}
if (WinMultimediaApi.timeBeginPeriod((uint)period) == ErrorNoCanDo)
{
throw new Win32Exception(Resources.GOR_ERR_TIME_CANNOT_BEGIN);
}
_lastPeriod = period;
}
