RosettaCodeData/Task/Vigen-re-cipher/VBA/vigen-re-cipher.vba
2023-07-01 13:44:08 -04:00

65 lines
2.2 KiB
Text

Option Explicit
Sub test()
Dim Encryp As String
Encryp = Vigenere("Beware the Jabberwock, my son! The jaws that bite, the claws that catch!", "vigenerecipher", True)
Debug.Print "Encrypt:= """ & Encryp & """"
Debug.Print "Decrypt:= """ & Vigenere(Encryp, "vigenerecipher", False) & """"
End Sub
Private Function Vigenere(sWord As String, sKey As String, Enc As Boolean) As String
Dim bw() As Byte, bk() As Byte, i As Long, c As Long
Const sW As String = "ÁÂÃÄÅÇÈÉÊËÌÍÎÏÑÒÓÔÕÖÙÚÛÜÝ"
Const sWo As String = "AAAAACEEEEIIIINOOOOOUUUUY"
Const A As Long = 65
Const N As Long = 26
c = Len(sKey)
i = Len(sWord)
sKey = Left(IIf(c < i, StrRept(sKey, (i / c) + 1), sKey), i)
sKey = StrConv(sKey, vbUpperCase) 'Upper case
sWord = StrConv(sWord, vbUpperCase)
sKey = StrReplace(sKey, sW, sWo) 'Replace accented characters
sWord = StrReplace(sWord, sW, sWo)
sKey = RemoveChars(sKey) 'Remove characters (numerics, spaces, comas, ...)
sWord = RemoveChars(sWord)
bk = CharToAscii(sKey) 'To work with Bytes instead of String
bw = CharToAscii(sWord)
For i = LBound(bw) To UBound(bw)
Vigenere = Vigenere & Chr((IIf(Enc, ((bw(i) - A) + (bk(i) - A)), ((bw(i) - A) - (bk(i) - A)) + N) Mod N) + A)
Next i
End Function
Private Function StrRept(s As String, N As Long) As String
Dim j As Long, c As String
For j = 1 To N
c = c & s
Next
StrRept = c
End Function
Private Function StrReplace(s As String, What As String, By As String) As String
Dim t() As String, u() As String, i As Long
t = SplitString(What)
u = SplitString(By)
StrReplace = s
For i = LBound(t) To UBound(t)
StrReplace = Replace(StrReplace, t(i), u(i))
Next i
End Function
Private Function SplitString(s As String) As String()
SplitString = Split(StrConv(s, vbUnicode), Chr(0))
End Function
Private Function RemoveChars(str As String) As String
Dim b() As Byte, i As Long
b = CharToAscii(str)
For i = LBound(b) To UBound(b)
If b(i) >= 65 And b(i) <= 90 Then RemoveChars = RemoveChars & Chr(b(i))
Next i
End Function
Private Function CharToAscii(s As String) As Byte()
CharToAscii = StrConv(s, vbFromUnicode)
End Function