CommonULong64 OverflowException

I think I finally have it!

Here is the final version, uncompressed and compressed:

UnCompressed:

Public Shared Function Build64(ByVal value As Object) As UInt64
        Dim ui64High As UInt64 = (value.high << 32)
        Dim ui64Low As UInt64 = CLng("&H" & (Hex("&H" & Hex(value.low))))
        Return Convert.ToUInt64(ui64High Or ui64Low)
    End Function

Compressed:

Public Shared Function Build64(ByVal value As Object) As UInt64
        Return Convert.ToUInt64((value.high << 32) Or CLng("&H" & (Hex("&H" & Hex(value.low)))))
End Function

I double checked my numbers whith what is being reported on the F5 and they are correct. Unless someone sees a problem with what I am doing, I am going with it.

Thanks for all the help so far!

Yeah, Yeah, bang on the VB developer :'( Yes, I know. I do need to drop the VB and move to C at some point, but this app was written in VB so that is what I am going with and what I know (for now). Here are the definitions of the two functions:

 

 

CLng http://msdn2.microsoft.com/en-us/library/ck4c5842.aspx

 

Hex http://msdn2.microsoft.com/en-us/library/8t2d9cx5.aspx

 

 

As for efficiency, you are probably correct. However, if there is any slow down the result is trivial in my case.

 

 

Basically you are correct. The Hex function returns the number as a hex string, then CLng turns it back in to a Long integer (which is a positive number).

 

 

I will keep messing with the code to "optimize" the calculations. If I come up with something better, I will post it. Thanks to both of you for your help..

I converted your code to VB (yes, VB) and it does work. Considering speed, do you think your method is faster:

 

 

    Public Shared Function Build64(ByVal value As Object) As UInt64
        Dim High As Int32 = value.high
        Dim Low As Int32 = value.low
        Dim lowLow As Int32 = value.low And &HFFFF
        Dim lowHigh As Int32 = (value.low >> 16) And &HFFFF
        Dim high64 As UInt64 = Convert.ToUInt64(High)
        Dim lowLow64 As UInt64 = Convert.ToUInt64(lowLow)
        Dim lowHigh64 As UInt64 = Convert.ToUInt64(lowHigh)
        Dim final As UInt64 = (high64 << 32) Or (lowHigh64 << 16) Or lowLow64
        Return myfinal
    End Function

 

 

Mike

All "bashing" aside, your help has been invaluable and I cannot thank you enough! Below is the final function that resolved the issue:

Public Shared Function Build64(ByVal value As Object) As UInt64
        Return (Convert.ToUInt64(value.high) << 32) Or (Convert.ToUInt64((value.low >> 16) And &HFFFF) << 16) Or Convert.ToUInt64(value.low And &HFFFF)
End Function

Hopefully this will help others in the VB world with the same problem...

You all absolutely ROCK! This is what community is all about and what makes our little slice of the net so rewarding to us here at DC.

 

 

When I get done with Gnomedex (Click here), I'll play around with this and toss something up on my blog highlighting you all - look for it in the podcast next week as well.

 

 

-Joe

Posted By bikemike on 08/10/2007 9:26 AM

All "bashing" aside, your help has been invaluable and I cannot thank you enough! Below is the final function that resolved the issue:

Public Shared Function Build64(ByVal value As Object) As UInt64
        Return (Convert.ToUInt64(value.high) << 32) Or (Convert.ToUInt64((value.low >> 16) And &HFFFF) << 16) Or Convert.ToUInt64(value.low And &HFFFF)
End Function

Hopefully this will help others in the VB world with the same problem...

Mike, looks basically good, but you have one problem... You're word-swapping the low DWORD and not the high DWORD. They both need it because of the way the CPU stores DWORDS. Just do the top in 16 bit chunks just like you did the bottom, and this should be good for any value.

Don.

So, you are saying I should be doing something like this:

    Public Shared Function Build64(ByVal value As Object) As String
        Return FormatNumber((Convert.ToUInt64((value.high >> 16) And &HFFFF) << 16) Or _
                             Convert.ToUInt64(value.high And &HFFFF) Or _
                            (Convert.ToUInt64((value.low >> 16) And &HFFFF) << 16) Or _
                             Convert.ToUInt64(value.low And &HFFFF), 0)
    End Function

Thanks....

I really need to take a moment to review this function and figure out the inner workings. To some extent I understand what is going on, but not fully. That is why I had to keep coming back to you guys for verification of my changes.

 

 

In any case, I think we have finally concluded on an acceptable solution and I cannot thank you guys enough! Hopefully this is the last you will hear from me on this one :')

Doing it in Java should be trivial. The High and Low values are both longs, which are already 64 bits in Java, so no casting is needed. I believe just doing this will work:

long value = (high << 32) | low;

It's been done in Java for a while, this conversation just made me want to check it over again.

 

 

The class for Java is here: http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=78

 

 

Don.