Xor ?

[kurtsimons]

I have a unicode string high order first chr(0) & "A"

but my program wants it to be the other way around "A" & chr(0)

I was told XOR could do it but ?????? if I know


where % is really NULL chr(0)


str1 = "A%B%C%"

str1 = xor str1

str1 = "%A%B%C"


????????????

[Nucleus]

Where did the unicode string chr(0) & "A" come from?

How are you storing the data, in a string?
Sounds odd to me.

If you already have the bytes:

"%A%B%C"

then delete the first byte and add that byte to the end to get:

"A%B%C%"

Now you have a normal unicode string for VB to work with.

[kurtsimons]

the data is comming into the winsock control from in an "XML" format.

I don't want the unicode at all. no need. when it comes in I want to convert it to a string

when it goes out I want to convert it back.


the problem is the byte order, why is thing differnet from VB !

[Nucleus]

Well once you have recived all the bytes, I assume into a byte array, all you have to do is remove the first element of the byte array and add a single byte to the end of the byte array.

Like this:

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (dest As Any, source As Any, ByVal numBytes As Long)

Sub DeleteArrayItemByte(arr() As Byte, index As Long)
    If index < UBound(arr) Then
        CopyMemory arr(index), arr(index + 1), (UBound(arr) - index) * LenB(arr(index))
    End If
    arr(UBound(arr)) = Empty
End Sub

Private Sub Command1_Click()
 Dim ba() As Byte: ReDim ba(13)
 Dim i&
 ba(0) = 0
 ba(1) = 78
 ba(2) = 0
 ba(3) = 85
 ba(4) = 0
 ba(5) = 67
 ba(6) = 0
 ba(7) = 76
 ba(8) = 0
 ba(9) = 69
 ba(10) = 0
 ba(11) = 85
 ba(12) = 0
 ba(13) = 83
 
Call DeleteArrayItemByte(ba, 0) ' Get rid of leading Byte FAST using copy memory ;)

For i = 0 To UBound(ba)
    Debug.Print ba(i)
Next

MsgBox ba

End Sub

[parksie]

AFAIK the Xor is to swap the two bytes around, something like:

Dim it(0 to 1) as Byte
 
it(0) = it(0) Xor it(1)
it(1) = it(1) Xor it(0)
it(0) = it(0) Xor it(1)

I dunno, can't really remember

[Nucleus]

You need to convert back again too, well here is code to do that too, enjoy. Should be a fast way of doing it too especially if they are large byte arrays :

Option Explicit

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (dest As Any, source As Any, ByVal numBytes As Long)

Sub InsertArrayItemByte(arr() As Byte, index As Long, newValue As Byte)
    If index < UBound(arr) Then
        ReDim Preserve arr(UBound(arr) + 1)
        CopyMemory arr(index + 1), arr(index), (UBound(arr) - index - 1) * LenB(arr(index))
    End If
    arr(index) = newValue
End Sub
Sub DeleteArrayItemByte(arr() As Byte, index As Long)
    If index < UBound(arr) Then
        CopyMemory arr(index), arr(index + 1), (UBound(arr) - index) * LenB(arr(index))
    End If
    arr(UBound(arr)) = Empty
End Sub

Private Sub Command1_Click()
 Dim ba() As Byte: ReDim ba(13)
 Dim i&
 ba(0) = 0
 ba(1) = 78
 ba(2) = 0
 ba(3) = 85
 ba(4) = 0
 ba(5) = 67
 ba(6) = 0
 ba(7) = 76
 ba(8) = 0
 ba(9) = 69
 ba(10) = 0
 ba(11) = 85
 ba(12) = 0
 ba(13) = 83
 
Call DeleteArrayItemByte(ba, 0) ' Get rid of leading Byte FAST using copy memory ;)

For i = 0 To UBound(ba)
    Debug.Print "convert To vb friendly", ba(i)
Next

MsgBox ba

'now manipulate the String with VB here

Call InsertArrayItemByte(ba, 0, 0) ' convert back To original format

For i = 0 To UBound(ba)
    Debug.Print "convert back To xml", ba(i)
Next

End Sub

[kurtsimons]

OK i'll give it a go...

any idea why everything is opposite, what is the format??

count I just do it like this?

str1 = "%A%B%c"

str1 = mid(str1,2) & "%"

where %A = null