Wow, these methods you proposed made me realize that I was using the wrong endian method on my UNIX server, it has to be ntohl(). Now I got it correct, and I am receiving data (bytes) in the correct order.
*>>>: 0 0 0 2 0 10 114 26 0 0 0 51 0 16 242 78
Sample data might be 2 1000000 51 2000.56, which could be read in the data ... somewhat :)*
**Now my question is, how do I get four compact numbers to work with?* Now I have a series of bytes, but at least in the correct order.
I haven't been able to extract the data using [bytes2any] and [route], so I prepared a small patch to demonstrate the problem, maybe you can show me by modifying it?
//Petar
On 11/3/13 2:31 PM, Martin Peach wrote:
On 2013-03-10 17:58, Petar Jercic wrote:
Sorry, I can't use ASCII text as communication method, since I plan to send large quantities of data at high speed rates, I need to optimize it as much as possible. Compared to streaming bytes, ASCII is inefficient up to a several orders of magnitude.
Is there a method for correct endianness in Pure Data, like these C functions:
ntohs()--"Network to Host Short" ntohl()--"Network to Host Long"
You can do that with Pd like this (ntohs):
[unpack 0 0] | | [* 256] | | | [+ ] | [ \
or
[unpack 0 0] | | | [* 256] | | [+ ] | [ \
for littleendian.
Floats are harder but still possible. The main difficulty is in splitting the incoming stream in the right places. (I think ASCII is not orders of magnitude slower, and it is also less ambiguous).
Martin
On 09/3/13 5:15 PM, Martin Peach wrote:
It's probably safer to get the server to send the numbers as ASCII text, to avoid disagreements about endianness and floating-point representation. Then, to extract the numbers, you could use [moocow/bytes2any] or make a custom parser using [pdlua].
Martin
On 2013-03-09 10:55, Petar Jercic wrote:
Apparently [netclient] on the Pure Data side cannot receive nothing else than ; delimited messages. So the solution for the problem: *My question is, is there a way to send something other than string message to Pure Data, like byte-stream or serialized number stream? Can Pure Data receive such messages?*
The solution is to use [tcpclient], it can receive byte-stream data.
Now I have another problem regarding the data read, on how to convert it back to usable numbers.
From my UNIX server I am sending a structure
typedef struct { int var_code; int sample_time; int hr; float hs; } phy_data;
Sample data might be 2 1000000 51 2000.56
When received and printed in Pure Data I get output like this:
>: 2 0 0 0 104 34 9 0 51 0 0 0 235 50 48 69
You can notice number 2 and number 51 clearly, I guess the others are correct as well. Might be some network inversion of LSB/MSB.
*How can I get these numbers back to a usable format and get them in separate variables?
*//Petar*
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