Spring

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WScript.Echo  utf8to16(Base64Decode("5om55aSE55CG5LmL5a62"))

Function utf8to16(str)
    Dim out, i, len1, c, t
    Dim char2, char3
    out = ""
    len1 = Len(str)
    i = 0
    While (i < len1)
        c = Asc(Mid(str, i + 1, 1))
        i = i + 1
        t = c \ 16
        If t >= 0 And t <= 7 Then
            out = out + Mid(str, i, 1)
        ElseIf t = 12 Or t = 13 Then
            char2 = Asc(Mid(str, i + 1, 1))
            i = i + 1
            out = out + Chr(((c And 31) * 64) Or (char2 And 31))
        ElseIf t = 14 Then
            char2 = Asc(Mid(str, i + 1, 1))
            i = i + 1
            char3 = Asc(Mid(str, i + 1, 1))
            i = i + 1
            out = out + ChrW(((c And 15) * 4096) Or ((char2 And 63) * 64) Or ((char3 And 63)))
        End If
    Wend
    utf8to16 = out
End Function

' Decodes a base-64 encoded string (BSTR type).
' 1999 - 2004 Antonin Foller, http://www.motobit.com
' 1.01 - solves problem with Access And 'Compare Database' (InStr)
Function Base64Decode(ByVal base64String)
  'rfc1521
  '1999 Antonin Foller, Motobit Software, http://Motobit.cz
  Const Base64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
  Dim dataLength, sOut, groupBegin
  
  'remove white spaces, If any
  base64String = Replace(base64String, vbCrLf, "")
  base64String = Replace(base64String, vbTab, "")
  base64String = Replace(base64String, " ", "")
  
  'The source must consists from groups with Len of 4 chars
  dataLength = Len(base64String)
  If dataLength Mod 4 <> 0 Then
    Err.Raise 1, "Base64Decode", "Bad Base64 string."
    Exit Function
  End If

  
  ' Now decode each group:
  For groupBegin = 1 To dataLength Step 4
    Dim numDataBytes, CharCounter, thisChar, thisData, nGroup, pOut
    ' Each data group encodes up To 3 actual bytes.
    numDataBytes = 3
    nGroup = 0

    For CharCounter = 0 To 3
      ' Convert each character into 6 bits of data, And add it To
      ' an integer For temporary storage.  If a character is a '=', there
      ' is one fewer data byte.  (There can only be a maximum of 2 '=' In
      ' the whole string.)

      thisChar = Mid(base64String, groupBegin + CharCounter, 1)

      If thisChar = "=" Then
        numDataBytes = numDataBytes - 1
        thisData = 0
      Else
        thisData = InStr(1, Base64, thisChar, vbBinaryCompare) - 1
      End If
      If thisData = -1 Then
        Err.Raise 2, "Base64Decode", "Bad character In Base64 string."
        Exit Function
      End If

      nGroup = 64 * nGroup + thisData
    Next
    
    'Hex splits the long To 6 groups with 4 bits
    nGroup = Hex(nGroup)
    
    'Add leading zeros
    nGroup = String(6 - Len(nGroup), "0") & nGroup
    
    'Convert the 3 byte hex integer (6 chars) To 3 characters
    pOut = Chr(CByte("&H" & Mid(nGroup, 1, 2))) + _
      Chr(CByte("&H" & Mid(nGroup, 3, 2))) + _
      Chr(CByte("&H" & Mid(nGroup, 5, 2)))
    
    'add numDataBytes characters To out string
    sOut = sOut & Left(pOut, numDataBytes)
  Next

  Base64Decode = sOut
End Function
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