Mirror keys for multiboxing MMORPG games like WOW/LOTRO

Public Class UdpKeyBufferFILO
    Private Const m_buffer_length_default As Integer = 4
    Private m_buffer(m_buffer_length_default) As UdpKeyInfo
    Public Sub New(Optional ByVal _length As Integer = m_buffer_length_default)
        If _length <> m_buffer_length_default Then
            If _length > 1 Then
                ReDim m_buffer(_length - 1)
            Else
                _length = m_buffer_length_default
            End If
        End If
        For i As Integer = 0 To _length - 1
            m_buffer(i) = Nothing
        Next
    End Sub
    Public Sub Push(ByVal KeyInfo As UdpKeyInfo)
        If ((KeyInfo.Message And CUInt(1)) = 0) Then 'keydown - valid for pushes
            Dim found As Boolean = False
            For i As Integer = 0 To m_buffer.Length - 1
                If ((Not m_buffer(i) Is Nothing) AndAlso (m_buffer(i).VKey = KeyInfo.VKey) AndAlso (m_buffer(i).Device = KeyInfo.Device)) Then
                    found = True
                End If
            Next
            If Not found Then
                For i As Integer = m_buffer.Length - 1 To 1 Step -1
                    m_buffer(i) = m_buffer(i - 1)
                Next
                m_buffer(0) = KeyInfo
            End If
        End If
    End Sub
    Public Function Pop(ByVal KeyInfo As UdpKeyInfo) As UdpKeyInfo
        Dim result As UdpKeyInfo = Nothing
        If ((KeyInfo.Message And CUInt(1)) = 1) Then 'keyup - valid for pops
            For i As Integer = m_buffer.Length - 1 To 0 Step -1
                If ((Not m_buffer(i) Is Nothing) AndAlso (m_buffer(i).VKey = KeyInfo.VKey) AndAlso (m_buffer(i).Device = KeyInfo.Device)) Then
                    result = m_buffer(i)
                    m_buffer(i) = Nothing
                End If
            Next
        End If
        Return result
    End Function
End Class