Function Base64Decode( base64String_o) As String
Const Base64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
Dim dataLength, sOut, groupBegin
Dim numDataBytes, CharCounter, thisChar, thisData, nGroup, pOut
Dim Base64String
Dim i As Long
Dim s As String
Dim eval As Variant
'remove white spaces, If any
' Print "Base64: Removing Whitespaces #13 "
base64String = base64String_o
' Print "Base64: Removing Whitespaces #13 "
base64String = Replace(base64String, Chr$(13), "")
' Print "Base64: Removing Whitespaces #10 "
base64String = Replace(base64String, Chr$(10), "")
' Print "Base64: Removing Whitespaces #9 "
base64String = Replace(base64String, Chr$(9), "")
' Print "Base64: Removing Whitespaces #32 "
base64String = Replace(base64String, " ", "")
'The source must consists from groups with Len of 4 chars
dataLength = Len(base64String)
If dataLength Mod 4 <> 0 Then
Messagebox "Bad string length must be a multiple of 4"
Exit Function
End If
' Now decode each group:
Print "Base64: Converting... "
For groupBegin = 1 To dataLength Step 4
' If groupBegin Mod 25 =0 Then Print "Base64: Converting "+Cstr( groupBegin )
' 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(Base64, thisChar) - 1
End If
If thisData = -1 Then
Messagebox " 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
