[Gambas-user] someshort="xy" returns "Wanted short, got string instead"

[tobias]

hi,

> 
> tobias-47 wrote:
>> i forgot the asc() functions, of course:
>>
>> PUBLIC FUNCTION GetShort(sWord AS String) AS Short
>>
>> 	RETURN Asc(Mid$(sWord, 1, 1)) * 256 + Asc(Mid$(sWord, 2, 1))
>>
>> END
>>
>> or alternatively, you can assign the positions in the asc() function, like
>>
>> RETURN Asc(sWord, 1) * 256 + Asc(sWord, 2)
>>
> 
> Thanks Tobi, I'll give that a try if it becomes the only option. Hopefully
> there's something I can do like a variable pointer, so the data can
> basically just be copied from the string directly. This is for a real-time
> game so any inefficiencies can cause it to "hang" for a second and interrupt
> the smoothness of play.
> 
> 
> Benoît Minisini wrote:
>>> I can say, somebyte=ASC("x"), but is it possible to quickly assign a
>>> two-byte string to a typical two-byte short?
>> It's a bad idea. What do you want to do exactly?
>>
> 
> Hi Benoît. Maybe there's a better way for me to have come to this point, but
> here's what's happening:
> 
> A server app retrieves sets of data from five binary files and stores them
> consecutively in a string. The first set is a 48x48 grid of shorts for a
> total of 4608 bytes (48x48x1x2). The last four sets are 48x48 grids of bytes
> for a total of 9216 bytes (48x48x4x1). So in total we have 13824 bytes (2304
> shorts and 9216 bytes), converted to one large string something like this:
> 
> DIM data AS String
> DIM chunk AS String
> 
> READ #somefileofshorts, chunk, 2
> data = data & chunk
> 
> READ #somefileofbytes, chunk, 1
> data = data & chunk
> 
> Normally I might read the shorts into an array of shorts, but in this case
> the final string is sent to a client app as a UDP packet. I also need to
> send all the data as a single packet rather than several. The client app
> receives the packet and parses it, assigning the floats and bytes of the
> payload to five 48x48 element arrays like this:
> 
> DIM somearray AS Short[48, 48]
> 
> somearray[x, y] =  Mid$(payload, position, 2)
> 
> It needs to make that string to short conversion 2304 times (48x48) in as
> little time as possible.
> 
> I can only think of two solutions here. One is to find a way to convert a
> two-character string to a short as quickly as possible (the subject of the
> post), and the other is to change the way I'm collecting the data to be sent
> as a UDP packet so that it can be read more "normally" by the client. The
> UDP_Read procedure is generic however, and has no way of knowing what kind
> of data is contained within the packet, so that may be difficult at best.
> 
> -----
> Kevin Fishburne, Eight Virtues
> www:  http://sales.eightvirtues.com http://sales.eightvirtues.com 
> e-mail:  mailto:sales at ...1887... sales at ...1887... 
> phone: (770) 853-6271

oh, hum, first: why am i "tobi-47"? :D
well, i searched the web and the doc and the only thing i found related 
to this was the function VarPtr() in the language index which should 
return a pointer to the given variable but for the reason that this 
function is declared as a gambas3 function it wasn't possible for me to 
test it and there seems to be a limitation for strings...
the c++ ways to get a memory address don't work, too, with gambas 
strings (&s is stupid in gambas and s[0] returns "not an object")
sorry...

regards,
tobi