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UUencode UUDecode

When you want to email a binary file without sending it as an attatchment UUencode translates non-printable characters into printable characters so that email programs can handle them to be sent. It does this by taking 3 chars 8 bit each total 24 bits and stretching them out to 4 chars 6 bits each total 24 bits. 6 bits for each character means a total of 64 possible characters all of which can be used from the printable character set. Does this sound familiar to anyone? Does anyone have an algorithm for this?

Also any procedures for getting/setting specific bits in a byte, integer, word or bit array would be helpfull.

Brendt Hess

Try this ActiveX control

http://www.coolstf.com/activex.html

and select the UUencode/uudecode control for download. You'll have to register, but the control is free.

Also, check out:

http://www.vbip.com/winsock/winsock_uucode_01.asp

This is a tutorial on UUEncode/Decode with VB code examples

plasmatek

Public Function UUDecode(ByVal B64String) As String

Dim TableByte(255) As Integer
Dim SexTet(4) As Integer
Dim SexTetNUM As Integer
Dim n As Integer
Dim i As Integer
Dim T1 As Integer
Dim T2 As Integer
Dim NumBits As Integer
Dim OutStream As String
Dim CharTable As String * 64
Dim LiStream As Long
Dim InStreamIndex As Long
Dim c As Long
CharTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

For n = 0 To 255
TableByte(n) = -1
Next

For n = 0 To 63
i = Asc(Mid(CharTable, n + 1, 1))
TableByte(i) = n
Next

InStreamIndex = 1
LiStream = Len(B64String)
OutStream = Space(Int(72 * Int(LiStream / 74) * 3 / 4) + Int((LiStream Mod 74) * 3 / 4))

While InStreamIndex <= LiStream
SexTetNUM = 1
NumBits = 0

While (SexTetNUM <= 4 And InStreamIndex <= LiStream)
i = Asc(Mid(B64String, InStreamIndex, 1))
InStreamIndex = InStreamIndex + 1
T1 = TableByte(i)

If T1 >= 0 Then
SexTet(SexTetNUM) = T1
NumBits = NumBits + 6
SexTetNUM = SexTetNUM + 1
End If

Wend

If NumBits >= 8 Then
T1 = SexTet(1)
T2 = SexTet(2)
c = c + 1
Mid(OutStream, c, 1) = Chr((4 * T1) + (T2 \ 16))
NumBits = NumBits - 8
End If

If NumBits >= 8 Then
T1 = SexTet(3)
c = c + 1
Mid(OutStream, c, 1) = Chr(16 * (T2 Mod 16) + (T1 \ 4))
NumBits = NumBits - 8
End If

If NumBits >= 8 Then
T2 = SexTet(4)
c = c + 1
Mid(OutStream, c, 1) = Chr(64 * (T1 Mod 4) + T2)
End If

Wend

UUDecode = Left(OutStream, c)
End Function

Public Function UUEncode(ByVal text) As String

Dim a1 As Integer
Dim a2 As Integer
Dim a3 As Integer
Dim LineChars As Integer
Dim OutStream As String
Dim CharTable As String
Dim i As Long
Dim c As Long
CharTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
c = 1
i = Int(4 * Len(text) / 3)
OutStream = Space(i + 2 * (i \ 72 + 1))
LineChars = 0

For i = 1 To Len(text) - 2 Step 3
' 'Get 24 bits
a1 = Asc(Mid(text, i, 1))
a2 = Asc(Mid(text, i + 1, 1))
a3 = Asc(Mid(text, i + 2, 1))

' 'Encode each 6 bits
Mid(OutStream, c, 4) = Mid(CharTable, (a1 And &HFC) \ 4 + 1, 1) _
& Mid(CharTable, (16 * (a1 And &H3) + (a2 And &HF0) \ 16) + 1, 1) _
& Mid(CharTable, (4 * (a2 And &HF) + (a3 And &HC0) \ 64) + 1, 1) _
& Mid(CharTable, (a3 And &H3F) + 1, 1)
c = c + 4

' 'Break line
LineChars = LineChars + 4

If LineChars >= 72 Then
LineChars = 0
Mid(OutStream, c, 2) = vbCrLf
c = c + 2
End If

Next

' 'Add last 24 bits
Select Case Len(text) Mod 3
Case 1
a1 = Asc(Mid(text, i, 1))
a2 = 0
a3 = 0
Mid(OutStream, c, 4) = Mid(CharTable, (a1 And &HFC) \ 4 + 1, 1) _
& Mid(CharTable, (16 * (a1 And &H3) + (a2 And &HF0) \ 16) + 1, 1) _
& "==" & vbCrLf
c = c + 6
Case 2
a1 = Asc(Mid(text, i, 1))
a2 = Asc(Mid(text, i + 1, 1))
a3 = 0
Mid(OutStream, c, 4) = Mid(CharTable, (a1 And &HFC) \ 4 + 1, 1) _
& Mid(CharTable, (16 * (a1 And &H3) + (a2 And &HF0) \ 16) + 1, 1) _
& Mid(CharTable, (4 * (a2 And &HF) + (a3 And &HC0) \ 64) + 1, 1) _
& "=" & vbCrLf
c = c + 6
End Select

UUEncode = Left(OutStream, c - 1)
End Function

there we go :)

Brendt Hess

Whoops - that's base64 Encoding, not uuEncoding in the above example. uuEncoding starts at Space and goes to underscore (ascii 32 to ascii 95), with space normally replaced by ascii 96 (` - a grave accent).

uuEncode does not use lower case letters.

Jsan

ASKER

Yes I would rather uuEncoding. The reason being that I ran plasmatek's but the over head for converting a string was 73% normal uencoding would have an overhead closer to 25%.

I looked at the example bhess1 gave me but the code doesn't run. It blows up on the uuDecode function.

plasmatek's could you provide a normal uuEncoding example please? Or someone point me to a sample UU Encode/Decode code set that works.

Jsan

Brendt Hess

What version of VB are you using?

Where did it blow up in the decode?

Jsan

ASKER

Jsan

ASKER

Im using VB 6. Were you able to run the code successfully? I tried to UU encode and then decode a small 9k gif file.

ASKER CERTIFIED SOLUTION

mcrider

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mcrider