Public Class CircleArchive Private InternalCapacity As Integer Private InternalArray() As Object Private InternalLength As Integer Private InternalStart As Integer Public Sub New(ByVal setCap As UShort) If (setCap = 0) Then InternalCapacity = UShort.MaxValue + 1 Else InternalCapacity = setCap End If InternalStart = 0 InternalLength = 0 InternalArray = New Object(InternalCapacity - 1) {} 'need to specify maxindex, not size as the parameter End Sub Public Sub AddObject(ByVal ObjectToAdd As Object) Dim NewIndex As Integer If IsFull Then 'overwrite the oldest InternalArray(InternalStart) = ObjectToAdd InternalStart = (InternalStart + 1) Mod InternalCapacity Else NewIndex = (InternalStart + InternalLength) Mod InternalCapacity InternalArray(NewIndex) = ObjectToAdd InternalLength += 1 End If End Sub Public Function GetObjectFIFO(ByVal Index As Integer) As Object Dim r As Object = Nothing Dim TrueIndex As Integer If ((Index >= 0) AndAlso (Index < InternalLength)) Then TrueIndex = (InternalStart + Index) Mod InternalCapacity r = InternalArray(TrueIndex) ElseIf (Index < 0) Then Throw New IndexOutOfRangeException("got negative value: " & Index.ToString) Else Throw New IndexOutOfRangeException("got " & Index.ToString & " when " & InternalLength.ToString & " item(s) stored") End If Return r End Function Public Function GetObject(ByVal Index As Integer) As Object 'just an alias for GetObjectFIFO Return GetObjectFIFO(Index) End Function Public Function GetObjectLIFO(ByVal Index As Integer) As Object Dim r As Object = Nothing Dim TrueIndex As Integer If ((Index >= 0) AndAlso (Index < InternalLength)) Then TrueIndex = InternalLength - 1 - Index 'invert TrueIndex = (InternalStart + TrueIndex) Mod InternalCapacity r = InternalArray(TrueIndex) ElseIf (Index < 0) Then Throw New IndexOutOfRangeException("got negative value: " & Index.ToString) Else Throw New IndexOutOfRangeException("got " & Index.ToString & " when " & InternalLength.ToString & " item(s) stored") End If Return r End Function Public Sub Clear() Dim i As Integer Dim TrueIndex As Integer For i = 0 To (InternalLength - 1) 'nullify existing items TrueIndex = (InternalStart + i) Mod InternalCapacity InternalArray(TrueIndex) = Nothing Next InternalLength = 0 End Sub 'Public Sub QuickClear() ' InternalLength = 0 'End Sub Public ReadOnly Property Capacity As Integer Get Return InternalCapacity End Get End Property Public ReadOnly Property Length As Integer Get Return InternalLength End Get End Property Public ReadOnly Property IsFull As Boolean Get Return (InternalLength = InternalCapacity) End Get End Property 'additional features Public Sub RemoveObjects(ByVal Index As Integer, ByVal Count As Integer) Dim r As Object = Nothing Dim TrueIndexSrc As Integer Dim TrueIndexDst As Integer Dim TrueCount As Integer Dim i As Integer If ((Index < 0) OrElse (Index >= InternalLength)) Then Exit Sub End If If (Count <= 0) Then Exit Sub End If If (Count < (InternalLength - Index)) Then TrueCount = Count Else TrueCount = InternalLength - Index End If If (TrueCount = InternalLength) Then 'need to delete all Clear() Else 'need to delete part of the items For i = Index To (Index + TrueCount - 1) TrueIndexSrc = (InternalStart + i) Mod InternalCapacity InternalArray(TrueIndexSrc) = Nothing Next 'nullification loop If (Index = 0) Then 'the beginning has been deleted InternalStart = (InternalStart + TrueCount) Mod InternalCapacity 'just move the start position ElseIf ((Index + TrueCount) < InternalLength) Then 'need array shift 'decide what direction it will be faster to shift If ((InternalLength - Index - TrueCount) <= Index) Then 'shift the end For i = (Index + TrueCount) To (InternalLength - 1) TrueIndexSrc = (InternalStart + i) Mod InternalCapacity TrueIndexDst = (InternalStart + i - TrueCount) Mod InternalCapacity InternalArray(TrueIndexDst) = InternalArray(TrueIndexSrc) InternalArray(TrueIndexSrc) = Nothing Next Else 'shift the beginning i = Index - 1 While (i >= 0) TrueIndexSrc = (InternalStart + i) Mod InternalCapacity TrueIndexDst = (InternalStart + i + TrueCount) Mod InternalCapacity InternalArray(TrueIndexDst) = InternalArray(TrueIndexSrc) InternalArray(TrueIndexSrc) = Nothing i -= 1 End While InternalStart = (InternalStart + TrueCount) Mod InternalCapacity 'move the start position End If 'array shift direction switch End If 'the third case is the end has been deleted: we don't need neither start movement nor array shift InternalLength -= TrueCount End If '(not) TrueCount = InternalLength End Sub 'RemoveObjects Public Sub RemoveFirst(ByVal Count As Integer) RemoveObjects(0, Count) End Sub Public Sub RemoveLast(ByVal Count As Integer) RemoveObjects((InternalLength - Count), Count) End Sub Public Sub InsertObject(ByVal ObjectToInsert As Object, ByVal InsBefore As Integer) Dim TrueIndexSrc As Integer Dim TrueIndexDst As Integer Dim i As Integer Dim FirstElementBuf As Object If ((InsBefore >= 0) AndAlso (InsBefore < InternalLength)) Then If (InsBefore = 0) Then If (Not IsFull) Then 'no need array shift, just move the start position 1 step backward InternalStart = (InternalStart + InternalCapacity - 1) Mod InternalCapacity InternalArray(InternalStart) = ObjectToInsert 'and increase length InternalLength += 1 End If 'Not IsFull Else 'need array shift 'decide what direction it will be faster to shift If (InsBefore > (InternalLength \ 2)) Then 'shift the end i = InternalLength - 1 While (i >= InsBefore) TrueIndexSrc = (InternalStart + i) Mod InternalCapacity TrueIndexDst = (InternalStart + i + 1) Mod InternalCapacity InternalArray(TrueIndexDst) = InternalArray(TrueIndexSrc) i -= 1 End While TrueIndexDst = (InternalStart + InsBefore) Mod InternalCapacity InternalArray(TrueIndexDst) = ObjectToInsert If IsFull Then 'the oldest was overwritten, need to move the start position 1 step forward InternalStart = (InternalStart + 1) Mod InternalCapacity Else InternalLength += 1 End If '(not) IsFull Else 'shift the beginning FirstElementBuf = InternalArray(InternalStart) For i = 1 To (InsBefore - 1) TrueIndexSrc = (InternalStart + i) Mod InternalCapacity TrueIndexDst = (InternalStart + i - 1) Mod InternalCapacity InternalArray(TrueIndexDst) = InternalArray(TrueIndexSrc) Next TrueIndexDst = (InternalStart + InsBefore - 1) Mod InternalCapacity InternalArray(TrueIndexDst) = ObjectToInsert If (Not IsFull) Then 'move the start position InternalStart = (InternalStart + InternalCapacity - 1) Mod InternalCapacity InternalArray(InternalStart) = FirstElementBuf InternalLength += 1 End If 'Not IsFull End If 'array shift direction switch End If '(not) InsBefore = 0 ElseIf (InsBefore < 0) Then Throw New IndexOutOfRangeException("got negative value: " & InsBefore.ToString) Else Throw New IndexOutOfRangeException("got " & InsBefore.ToString & " when " & InternalLength.ToString & " item(s) stored") End If End Sub 'InsertObject Public Sub ReplaceObject(ByVal Index As Integer, ByVal NewObject As Object) Dim TrueIndex As Integer If ((Index >= 0) AndAlso (Index < InternalLength)) Then TrueIndex = (InternalStart + Index) Mod InternalCapacity InternalArray(TrueIndex) = NewObject ElseIf (Index < 0) Then Throw New IndexOutOfRangeException("got negative value: " & Index.ToString) Else Throw New IndexOutOfRangeException("got " & Index.ToString & " when " & InternalLength.ToString & " item(s) stored") End If End Sub 'ReplaceObject End Class 

 Public Class Form1 Private Structure AGCBufferElement Public InputPCMVal As Short ' ,    Public OutputPCMVal As Short ' ,      End Structure Private Sub ButtonAGC_Click(sender As System.Object, e As System.EventArgs) Handles ButtonAGC.Click Dim InputFileName As String = My.Application.Info.DirectoryPath & "\Input.pcm" Dim OutputFileName As String = My.Application.Info.DirectoryPath & "\Output.pcm" Dim InputFileStream As System.IO.FileStream = Nothing Dim OutputFileStream As System.IO.FileStream = Nothing Dim NSamples As Long '    Dim SampleIndex As Long Dim OneSecBufIndex As Integer '       anticlipping Dim kmax As Double = Decimal.ToDouble(NumericUpDownMaxGain.Value) Dim TargetVolume As Double = Decimal.ToDouble(NumericUpDownTargetVol.Value) '     Dim vmin As Double '  Dim AGCLeap As Boolean '  Dim k As Double '  Dim b As Double '  Dim CurrBuf As AGCBufferElement '  PCM Dim PrevBuf As AGCBufferElement Dim u As Double '  Dim v As Double ' ,        Dim OneSecBuf As CircleArchive '       anticlipping Dim NegHalfwave As Boolean '     0 '  Try If (My.Computer.FileSystem.FileExists(InputFileName)) Then InputFileStream = New System.IO.FileStream(InputFileName, IO.FileMode.Open) OutputFileStream = New System.IO.FileStream(OutputFileName, IO.FileMode.Create) End If Catch ex As Exception End Try If ((InputFileStream IsNot Nothing) AndAlso (OutputFileStream IsNot Nothing)) Then ' vmin = TargetVolume / kmax b = 1.0 - Math.Pow(10.0, (-1.0 / Decimal.ToDouble(Decimal.Multiply(NumericUpDownSampleRate.Value, NumericUpDownFalloffTime.Value)))) v = vmin OneSecBuf = New CircleArchive(CUShort(NumericUpDownSampleRate.Value)) InputFileStream.Position = 0 NSamples = InputFileStream.Length \ 2 '2 bytes per sample '! For SampleIndex = 0 To (NSamples - 1) '  PCM   CurrBuf.InputPCMVal = CShort(InputFileStream.ReadByte) 'LSB first (Intel manner) CurrBuf.InputPCMVal = CurrBuf.InputPCMVal Or (CShort(InputFileStream.ReadByte) << 8) 'MSB last (Intel manner) If (CurrBuf.InputPCMVal = Short.MinValue) Then CurrBuf.InputPCMVal += 1 '     -32767 .. 32767 End If '  Double    If (CurrBuf.InputPCMVal < 0) Then u = -CurrBuf.InputPCMVal / Short.MaxValue Else u = CurrBuf.InputPCMVal / Short.MaxValue End If '   ' If (u < vmin) Then u = vmin End If '   '  AGCLeap = (u > v) If AGCLeap Then v = u End If '   ,      k = TargetVolume / v '   '   If (AGCLeap AndAlso CheckBoxAnticlipping.Checked) Then ' anticlipping:            0 NegHalfwave = (CurrBuf.InputPCMVal < 0) '     ? OneSecBufIndex = OneSecBuf.Length - 1 While (OneSecBufIndex >= 0) PrevBuf = CType(OneSecBuf.GetObjectFIFO(OneSecBufIndex), AGCBufferElement) '   0 If (PrevBuf.InputPCMVal = 0) Then Exit While ElseIf (NegHalfwave Xor (PrevBuf.InputPCMVal < 0)) Then Exit While End If '     ,    0   PrevBuf.OutputPCMVal = PrevBuf.InputPCMVal * k '    PCM        (   ,  k  ) OneSecBuf.ReplaceObject(OneSecBufIndex, PrevBuf) '  OneSecBufIndex -= 1 ' ,  ,    End While '   OneSecBuf End If ' anticlipping CurrBuf.OutputPCMVal = CurrBuf.InputPCMVal * k '     If OneSecBuf.IsFull Then '             ,    PrevBuf = CType(OneSecBuf.GetObjectFIFO(0), AGCBufferElement) Try '   OutputFileStream.WriteByte(CByte(PrevBuf.OutputPCMVal And Byte.MaxValue)) 'LSB first (Intel manner) OutputFileStream.WriteByte(CByte((PrevBuf.OutputPCMVal >> 8) And Byte.MaxValue)) 'MSB last (Intel manner) Catch ex As Exception End Try End If 'OneSecBuf.IsFull OneSecBuf.AddObject(CurrBuf) '     OneSecBuf ' ,      If (Not AGCLeap) Then v = v - b * (v - u) '  v      End If Next '     ' OneSecBuf For OneSecBufIndex = 0 To (OneSecBuf.Length - 1) PrevBuf = CType(OneSecBuf.GetObjectFIFO(OneSecBufIndex), AGCBufferElement) Try OutputFileStream.WriteByte(CByte(PrevBuf.OutputPCMVal And Byte.MaxValue)) 'LSB first (Intel manner) OutputFileStream.WriteByte(CByte((PrevBuf.OutputPCMVal >> 8) And Byte.MaxValue)) 'MSB last (Intel manner) Catch ex As Exception End Try Next '   OneSecBuf End If '     If (OutputFileStream IsNot Nothing) Then OutputFileStream.Close() End If If (InputFileStream IsNot Nothing) Then InputFileStream.Close() End If MsgBox("The end.") End Sub End Class