MicroTimer, Resource Friendly Accurate Timer

[TizzyT]

As suggested here is the source:

Imports System.Runtime.InteropServices
Imports System.Threading

Public Class MicroTimer

    Public Shared Event Elapsed()

#Region "Misc"
    Public Shared Function TicksPerYoctosecond() As Decimal
        Return Stopwatch.Frequency / 1000000000000000000000000D
    End Function

    Public Shared Function TicksPerZeptosecond() As Decimal
        Return Stopwatch.Frequency / 1000000000000000000000D
    End Function

    Public Shared Function TicksPerAttosecond() As Decimal
        Return Stopwatch.Frequency / 1000000000000000000D
    End Function

    Public Shared Function TicksPerFemtosecond() As Decimal
        Return Stopwatch.Frequency / 1000000000000000D
    End Function

    Public Shared Function TicksPerPicosecond() As Decimal
        Return Stopwatch.Frequency / 1000000000000D
    End Function

    Public Shared Function TicksPerNanosecond() As Decimal
        Return Stopwatch.Frequency / 1000000000D
    End Function

    Public Shared Function TicksPerMicrosecond() As Decimal
        Return Stopwatch.Frequency / 1000000D
    End Function

    Private Shared _TicksPerMillisecond As Decimal = Stopwatch.Frequency / 1000D
    Public Shared Function TicksPerMillisecond() As Decimal
        Return _TicksPerMillisecond
    End Function

    Public Shared Function TicksPerSecond() As Decimal
        Return Stopwatch.Frequency
    End Function

    Public Shared Function TicksPerMinute() As Decimal
        Return Stopwatch.Frequency * 60D
    End Function

    Public Shared Function TicksPerHour() As Decimal
        Return Stopwatch.Frequency * 3600D
    End Function

    Public Shared Function TicksPerDay() As Decimal
        Return Stopwatch.Frequency * 86400D
    End Function

    Public Shared Function TicksPerWeek() As Decimal
        Return Stopwatch.Frequency * 604800D
    End Function

    Public Shared Function TicksPerMonth() As Decimal
        Return Stopwatch.Frequency * 2592000D
    End Function

    Public Shared Function TicksPerYear() As Decimal
        Return Stopwatch.Frequency * 31536000D
    End Function
#End Region

    <DllImport("winmm.dll")>
    Private Shared Function timeBeginPeriod(ByVal msec As UInteger) As MMRESULT
    End Function
    <DllImport("winmm.dll")>
    Private Shared Function timeEndPeriod(ByVal msec As UInteger) As MMRESULT
    End Function
    <DllImport("winmm.dll")>
    Private Shared Function timeSetEvent(ByVal delay As UInteger, ByVal resolution As UInteger,
                                         ByVal handler As TimerEventDel, ByVal user As IntPtr,
                                         ByVal eventType As UInteger) As MMRESULT
    End Function
    <DllImport("winmm.dll")>
    Private Shared Function timeKillEvent(ByVal id As UInteger) As MMRESULT
    End Function

    Private Delegate Sub TimerEventDel(ByVal id As UInteger,
                                       ByVal msg As UInteger,
                                       ByVal user As IntPtr,
                                       ByVal dw1 As IntPtr,
                                       ByVal dw2 As IntPtr)

    Private Shared mHandler As New TimerEventDel(Sub(ByVal id As UInteger,
                                                     ByVal msg As UInteger,
                                                     ByVal user As IntPtr,
                                                     ByVal dw1 As IntPtr,
                                                     ByVal dw2 As IntPtr)
                                                     timeKillEvent(id)
                                                     wh.Set()
                                                 End Sub)

    Private Shared wh As New AutoResetEvent(False)
    Private Shared wThread As Thread = Nothing
    Private Shared I As Integer = 0
    Private Shared NextTime As Decimal
    Private Shared Mode As Integer
    Private Shared _TicksPerInterval As Decimal

    Public Enum TimerMode As Integer
        Poll = -1
        Efficient = 0
    End Enum

    Private Enum MMRESULT
        MMSYSERR_NOERROR = 0
        MMSYSERR_ERROR = 1
        MMSYSERR_BADDEVICEID = 2
        MMSYSERR_NOTENABLED = 3
        MMSYSERR_ALLOCATED = 4
        MMSYSERR_INVALHANDLE = 5
        MMSYSERR_NODRIVER = 6
        MMSYSERR_NOMEM = 7
        MMSYSERR_NOTSUPPORTED = 8
        MMSYSERR_BADERRNUM = 9
        MMSYSERR_INVALFLAG = 10
        MMSYSERR_INVALPARAM = 11
        MMSYSERR_HANDLEBUSY = 12
        MMSYSERR_INVALIDALIAS = 13
        MMSYSERR_BADDB = 14
        MMSYSERR_KEYNOTFOUND = 15
        MMSYSERR_READERROR = 16
        MMSYSERR_WRITEERROR = 17
        MMSYSERR_DELETEERROR = 18
        MMSYSERR_VALNOTFOUND = 19
        MMSYSERR_NODRIVERCB = 20
        WAVERR_BADFORMAT = 32
        WAVERR_STILLPLAYING = 33
        WAVERR_UNPREPARED = 34
    End Enum

    Public Shared Sub SetStart(ByVal Ticks As Long, Optional ByVal Mode As TimerMode = TimerMode.Efficient)
        If Ticks > 0 Then
            Interlocked.Exchange(_TicksPerInterval, Ticks)
            Interlocked.Exchange(MicroTimer.Mode, Mode)
            If wThread Is Nothing Then CreateStartThread()
        End If
    End Sub

    Public Shared Sub SetStart(ByVal Ticks As Long, ByVal Precision As Integer)
        If Precision < 0 Then Throw New ArgumentOutOfRangeException(Precision, "Value must be of integer type greater than or equal to 0")
        If Ticks > 0 Then
            Interlocked.Exchange(_TicksPerInterval, Ticks)
            Interlocked.Exchange(Mode, Precision)
            If wThread Is Nothing Then CreateStartThread()
        End If
    End Sub

    Public Shared Sub SetStart(ByVal Rate As Decimal, Optional ByVal Mode As TimerMode = TimerMode.Efficient)
        If Rate > 0 Then
            Interlocked.Exchange(_TicksPerInterval, Stopwatch.Frequency / Rate)
            Interlocked.Exchange(MicroTimer.Mode, Mode)
            If wThread Is Nothing Then CreateStartThread()
        End If
    End Sub

    Public Shared Sub SetStart(ByVal Rate As Decimal, ByVal Precision As Integer)
        If Precision < 0 Then Throw New ArgumentOutOfRangeException(Precision, "Value must be of integer type greater than or equal to 0")
        If Rate > 0 Then
            Interlocked.Exchange(_TicksPerInterval, Stopwatch.Frequency / Rate)
            Interlocked.Exchange(Mode, Precision)
            If wThread Is Nothing Then CreateStartThread()
        End If
    End Sub

    Private Shared Sub CreateStartThread()
        wThread = New Thread(Sub()
                                 NextTime = Stopwatch.GetTimestamp
                                 While True
                                     If Mode > -1 Then
                                         If Mode = TimerMode.Efficient _
                                            Then I = (NextTime - Stopwatch.GetTimestamp) / _TicksPerMillisecond _
                                            Else I = Math.Round(((NextTime - Stopwatch.GetTimestamp) / _TicksPerMillisecond) - Mode)
                                         If I > 1 Then
                                             timeSetEvent(I, 0, mHandler, IntPtr.Zero, 0)
                                             wh.WaitOne()
                                         End If
                                     End If
                                     While Stopwatch.GetTimestamp < NextTime : End While
                                     Do
                                         RaiseEvent Elapsed()
                                         NextTime += GetTicksPerInterval()
                                     Loop While NextTime < Stopwatch.GetTimestamp
                                 End While
                             End Sub) With {.Priority = ThreadPriority.Highest, .IsBackground = True}
        wThread.Start()
    End Sub

    Public Shared Function GetTicksPerInterval() As Decimal
        Return _TicksPerInterval
    End Function
End Class

The reason initially why I didn't paste the source is because I thought that if I ever wanted to make changes I only had to edit from one location but I guess you have a point with the potential reliability of pastebin or lack thereof.