query string decoding?

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February 9th, 2003, 03:37 PM

irm_lexx

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query string decoding?

Does anyone know how to decode a HL server query string?
Here is a query code

Code:

Private Sub send_Click()
    winsock.RemoteHost = ip 'server ip
    winsock.RemotePort = CInt(Port) 'server port
    winsock.SendData Char(255) & Char(255) & Char(255) & Char(255) & "players"
End Sub


Private Sub winsock_DataArrival(ByVal bytesTotal As Long)
     Dim Data As String
     winsock.GetData Data, , bytesTotal 'returned packet
End Sub

It returns some crazy string that needs to be decoded or something?

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Thank you for any help.

February 10th, 2003, 06:15 PM

Scorpions4ever

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Don't think anyone can help you unless you tell us what the encoding method from the server is first (or provide us a sample string possibly)

February 22nd, 2003, 10:14 AM

irm_lexx

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the return data is inthe following format

(int32) -1
(byte) ASCII 'D' (players response, S2A_PLAYER)
(byte) active client count
for each active client
(byte) client number / index
(string) player name
(int32) client's frag total
(float32) client's total time in-game

sample data returned , I recieved the data as string:

Quote:

ÿÿÿÿD
Cygnus )ŒBLee KUM Kee Êã’Cwildchild )ÿÙBMeMp|-|IS i2AiNeS ó6_DMr.Deagle
ùYE[needclan] CsMaster ótäD

Most of the time asc() works to turn the strings into numbers but negative numbers dont work with asc()?

February 22nd, 2003, 01:14 PM

epl

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have you tried defining the data variable as a user defined type / structure in the same format as the data?
or as a byte array while you debug...

February 22nd, 2003, 05:55 PM

irm_lexx

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byte array is okay, but is it correct that say -1 ( negative one)
is 255 as a byte because thats what i get, and so on -2 = 254, -3 = 243 is that right?

February 22nd, 2003, 06:04 PM

epl

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i would have thought that a 32 bit int would be spread over 4 bytes - and for -1 you'll get four 255's in each of the bytes ... but you're right that the negatives are 255 = 2^8-1 = -1, 254 = -2 etc. for 8 bit. 65535 = 2^16-1 = -1, 65534 = -2 for 16bit and so on, if you follow

if you read the first value into a long it should just come out as -1
ie (i guess)

Code:

Private Sub winsock_DataArrival(ByVal bytesTotal As Long)
     Dim Data As String, MinusOne as Long
     winsock.GetData MinusOne, , 4
     winsock.GetData Data, , bytesTotal-4
End Sub

What do you think?

February 22nd, 2003, 06:11 PM

epl

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i think the tidiest way might be to read into user defined structures like this (from the top of my head)

Code:

Private Type Header
  MinusOne as Long
  Response as Byte
  PlayerCount as Byte
End Type

Private Type Player
  Index as Byte
  Name as String
  FragTotal as Long
  TimeTotal as Double
End Type

Private Sub winsock_DataArrival(ByVal bytesTotal As Long)
  Dim Header as Header, Player as Player, i as Byte
  call winsock.GetData(Header, , Len(Header))
  For i=1 to Header.PlayerCount
    call winsock.GetData(Player, , Len(Player))
  Next i
End Sub

Does that make sense? Like I say, it's off the top of my head so I don't necessarily expect to to work straight off - just to illustrate what i mean

February 22nd, 2003, 06:41 PM

irm_lexx

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it sounds good

I get error " only user-defined types defined in public objects modules can be coerced to or from a variant or passed to late-bound functions" and it points to "Call Winsock.GetData(Header, , Len(Header))" and hilights Header

February 22nd, 2003, 06:55 PM

epl

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Try playing around a bit with where you declare the type (at the top of which module) and also try changing Private Type to Public Type etc. and see what the compiler accepts

#10

February 22nd, 2003, 07:02 PM

irm_lexx

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ya, i tried placing it everywhere and changed to public and stuff, still gives me that error....

#11

March 19th, 2003, 07:51 PM

irm_lexx

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I have problem with getting data from a winsock packet....
in the udp it returns int32 along with strings and float32
so the first int32

i go

dim num as long
winsock.getdata num,vblong,4

But i get an error saying that the "datagram is too large to fit into the buffer and is trucated", what does that mean? isnt Long 4 bytes?

Also if I just do the bytes array like

dim bytes() as byte
winsock.getdata bytes

the float32 is spread in 4 slots, like bytes(1), bytes(2), bytes(3), and bytes(4), so how can they be turn it into a single number?

#12

March 20th, 2003, 04:43 AM

epl

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yes, a long is 4 bytes (you can use LenB to check)
I think you can possibly load the float the same way (into a single?) ... otherwise you could experiment with some different numbers and see what you get in your byte array for different float values.

#13

March 20th, 2003, 12:17 PM

irm_lexx

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like turn those 4 bytes into one number, I tried

clng(bytes(1)&bytes(2)&bytes(3)&bytes(4))

but it doesnt work, it gives over flow error.

#14

March 20th, 2003, 12:39 PM

epl

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no, i mean find out (search the net, i guess) how vb stores floats and reconstruct the relevant value from the byte array. what happens if you read directly into a single?

#15

March 20th, 2003, 01:42 PM

epl

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some links...

an explanation of converting from single number to underlying bytes
http://www.cis.udel.edu/~sullivan/c...nternalRep.html

a microsoft description:
http://msdn.microsoft.com/library/d...tm/decla_36.asp

and a description of the byte representation:
http://msdn.microsoft.com/library/d...t_Languages.asp
(I think there's an error in that the sign bit is missing from the real * 4 definition and the mantissa has nine bits ... i guess that the first mantissa bit should, in fact, be the sign bit

here's a conversion function from the top of my head:

Code:

Option Base 0

Public Function bytesToSingle(ByRef bytes() As Byte) As Single
Dim sign As Integer, exponent As Byte, mantissa As Long
  Let sign = IIf(bytes(0) \ 128, -1, 1)
  Let exponent = (2 * (bytes(0) And 127) + bytes(1) \ 128)
  Let mantissa = (bytes(1) Or 128) * 65536& _
                + bytes(2) * 256& _
                + bytes(3)
  Let bytesToSingle = sign * mantissa * 2 ^ (exponent - 150)
End Function

Last edited by epl : March 21st, 2003 at 04:13 AM.

query string decoding?

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