In Binärdatei suchen und Teile ausschneiden

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'Datei welche druchsucht wird  
        Const FILEIN = "C:\ordner\binary.exe"  
        'Datei in welche der Ausschnitt geschrieben wird  
        Const FILEOUT = "C:\ordner\binary_cut.exe"  
        'Suchstrings  
        Dim SEARCHBYTES1() As Byte = {&H44, &H4F, &H53}
        Dim SEARCHBYTES2() As Byte = {&H50, &H45}

        Dim offset1 As Long, offset2 As Long
        'Suche ersten Offset des Sucharrays  
        offset1 = FindOffset(FILEIN, SEARCHBYTES1)
        If offset1 > -1 Then
            ' Suche den zweiten Offset des zweiten Sucharrays  
            offset2 = FindOffset(FILEIN, SEARCHBYTES2, offset1 + SEARCHBYTES1.Length)
        Else
            MsgBox("Sucharray 1 wurde nicht gefunden", vbExclamation)  
            Exit Sub
        End If
        Try
            'Wurde String gefunden  
            If offset1 > -1 And offset2 > -1 Then
                Dim blockLength As Long = offset2 - offset1
                'Lösche Ausgabedatei wenn vorhanden  
                If File.Exists(FILEOUT) Then Kill(FILEOUT)

                'Anzahl Bytes in einen FileStream einlesen  
                Dim block(blockLength - 1) As Byte
                Using fIn As FileStream = New FileStream(FILEIN, FileMode.Open)
                    fIn.Seek(offset1, 0)
                    fIn.Read(block, 0, blockLength)
                    fIn.Close()
                End Using

                'Auschnitt Bytes in neue Datei schreiben  
                Using fOut As FileStream = New FileStream(FILEOUT, FileMode.CreateNew)
                    fOut.Write(block, 0, block.Length)
                    fOut.Close()
                End Using
            Else
                MsgBox("Sucharray 2 wurde nicht gefunden", vbExclamation)  
                Exit Sub
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

    Public Function FindOffset(filePath As String, arrPattern() As Byte, Optional startOffset As Long = 0) As Long
        Try
            If Not File.Exists(filePath) Then
                Return -1
            End If
            Dim fb() As Byte = File.ReadAllBytes(filePath)
            For i = startOffset To fb.Length - 1
                Dim found As Boolean = True
                For j = 0 To arrPattern.Length - 1
                    If fb(i + j) <> arrPattern(j) Then
                        found = False
                        Exit For
                    End If
                Next
                If found Then
                    Return i
                End If
            Next
            Return -1
        Catch ex As Exception
            MsgBox(ex.Message)
            Return -1
        End Try
    End Function
End Class