Public Class Main

#Region " Declarations "
    Private Const _PAGE_SIZE As Integer = 16384
#End Region

#Region " Public Methods "
    Public Shared Sub Main(ByVal args() As String)
        Try
            If args.Length > 0 Then
                'Do command line processing
                _ExtractBootImage(args(0), args(1))
            Else
                'Do GUI-based processing
                Dim ofd As New OpenFileDialog

                ofd.DefaultExt = "73V"
                ofd.CheckFileExists = True
                ofd.CheckPathExists = True
                ofd.Filter = "TI-73 Explorer AppVars (*.73v)|*.73v|All Files (*.*)|*.*"
                ofd.FilterIndex = 0
                ofd.Multiselect = False
                ofd.Title = "Select TI-73 Explorer AppVar"

                If ofd.ShowDialog() = DialogResult.OK Then
                    Dim sfd As New SaveFileDialog

                    sfd.Filter = "Binary Image (*.bin)|*.bin|All Files (*.*)|*.*"
                    sfd.FilterIndex = 0
                    sfd.Title = "Enter Location to Save Binary Image"

                    If sfd.ShowDialog() = DialogResult.OK Then
                        _ExtractBootImage(ofd.FileName, sfd.FileName)
                    End If
                End If
            End If
        Catch ex As Exception
            MessageBox.Show(ex.ToString(), "Error!", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub
#End Region

#Region " Private Methods "
    Private Shared Sub _ExtractBootImage(ByVal calcPath As String, ByVal binPath As String)
        Dim calcFile As New IO.FileStream(calcPath, IO.FileMode.Open, IO.FileAccess.Read)
        Dim buffer() As Byte = New Byte(_PAGE_SIZE) {}

        calcFile.Seek(&H37, IO.SeekOrigin.Begin)
        calcFile.Read(buffer, 0, 2)
        calcFile.Seek(BitConverter.ToInt16(buffer, 0) + 4, IO.SeekOrigin.Current)
        calcFile.Read(buffer, 0, _PAGE_SIZE)
        calcFile.Close()

        Dim binFile As New IO.FileStream(binPath, IO.FileMode.Create)
        binFile.Write(buffer, 0, _PAGE_SIZE)
        binFile.Close()
    End Sub
#End Region

End Class