[PD] TCP/IP communication from the unix server to the Pure Data

[Petar Jercic]

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*
>>>> *
>>>>
>>>>
>>>> _______________________________________________
>>>> Pd-list at iem.at mailing list
>>>> UNSUBSCRIBE and account-management ->
>>>> http://lists.puredata.info/listinfo/pd-list
>>>>
>>>
>>
>>
>>
>

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#N canvas 854 72 607 550 10;
#X declare -lib maxlib -lib oscx -lib mrpeach;
#X declare -lib mrpeach -lib moocow;
#X msg 85 75 disconnect;
#X text 168 74 <-- disconnect when you are done to free the port;
#X msg 64 48 connect comj3426.com.bth.se 9035;
#X obj 82 186 unpack 0 0 0 0;
#X floatatom 82 209 3 0 0 0 - - -;
#X floatatom 113 209 3 0 0 0 - - -;
#X floatatom 145 209 3 0 0 0 - - -;
#X floatatom 177 209 3 0 0 0 - - -;
#X text 42 208 from;
#X obj 102 160 tgl 15 0 empty empty connected 18 7 0 8 -24198 -13381
-1 0 1;
#X text 113 260 Received messages are output as a list of bytes;
#X obj 62 261 spigot;
#X obj 101 238 tgl 15 0 empty empty enable_print 18 7 0 8 -24198 -13381
-1 0 1;
#X obj 62 290 print >>>;
#X obj 62 134 tcpclient;
#X obj 62 466 import maxlib oscx mrpeach;
#X obj 63 425 import mrpeach moocow;
#X text 278 47 <-- first connect to the server;
#X text 134 290 data is: typedef struct int var_code \; int sample_time
\; int hr \; float hs \; phy_data \;;
#X text 221 206 First number 2 [fixed] in bytes;
#X connect 0 0 14 0;
#X connect 2 0 14 0;
#X connect 3 0 4 0;
#X connect 3 1 5 0;
#X connect 3 2 6 0;
#X connect 3 3 7 0;
#X connect 11 0 13 0;
#X connect 12 0 11 1;
#X connect 14 0 11 0;
#X connect 14 0 3 0;
#X connect 14 2 9 0;