Программа распознавания кодировки - DOS или WIN

Option Explicit
 
Sub Form_Load()
    CheckLang App.Path & "\" & "DOS.txt"
    CheckLang App.Path & "\" & "WIN.txt"
    CheckLang App.Path & "\" & "UTF-8.txt"
    CheckLang App.Path & "\" & "UTF-8-BOM.txt"
    CheckLang App.Path & "\" & "UTF-16.txt"
    CheckLang App.Path & "\" & "UTF-16-BOM.txt"
End Sub
 
Sub CheckLang(file As String)
    Dim buf As String
    Dim ff As Integer
  
    ff = FreeFile()
  
    Open file For Binary As #ff
    buf = Space$(LOF(ff))
    Get #ff, , buf
    Close #ff
    
    Debug.Print file
 
    If HasBOM_UTF16(buf) Then
        Debug.Print "UTF-16"
    ElseIf HasBOM_UTF8(buf) Then
        Debug.Print "UTF-8"
    ElseIf isOEM(buf) Then
        Debug.Print "DOS"
    Else
        Debug.Print "WIN"
    End If
End Sub
 
Public Function isOEM(Source As String) As Boolean
    Dim Ident As String
    Dim i As Long
    
    Ident = "*ќЎўЈ¤Ґ¦§«¬*®ЂЃѓ„…†‡€‰Љ‹ЊЌЋЏђ‘’“”•–—?™њ›љћџ"
    
    For i = 1 To Len(Ident)
        If InStr(Source, Mid(Ident, i, 1)) <> 0 Then isOEM = True: Exit Function
    Next
End Function
 
 
Public Function Convert_OEM_to_Win(Source$, isReverse As Boolean) As String
    Dim OEM$, WIN$, pos&, St$, L$, n&
    
    ' В конце этой строки невидимый символ - не трогать !!!
    OEM = "нќ*ЎўЈ¤Ґс¦§Ё©Є«¬*®ЇабвгдежзиймлкопЂЃ‚ѓ„…р†‡€‰Љ‹ЊЌЋЏђ‘’“”•–—?™њ›љћџртфсух"
    WIN = "эЭабвгдеёжзийклмнопрстуфхцчшщьыъюяАБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЬЫЪЮЯЁЄЇёєї"
 
    For n = 1 To Len(Source)
        L = Mid$(Source, n, 1)
        pos = IIf(isReverse, InStr(WIN, L), InStr(OEM, L))
        If pos <> 0 Then
            St = St & IIf(isReverse, Mid$(OEM, pos, 1), Mid$(WIN, pos, 1))
          Else
            St = St & L
        End If
    Next
    Convert_OEM_to_Win = St
End Function
 
Public Function HasBOM_UTF16(sText As String) As Boolean
    If Left$(sText, 2) = Chr$(&HFF) & Chr$(&HFE) Then HasBOM_UTF16 = True
End Function
 
Public Function HasBOM_UTF8(sText As String) As Boolean
    If Left$(sText, 3) = Chr$(&HEF) & Chr$(&HBB) & Chr$(&HBF) Then HasBOM_UTF8 = True
End Function