I attached a patch that should reconstruct a long if it's bigendian, although it doesn't give 1000000 for the sequence you provided...

The floating point numbers are more difficult, you need to separate the sign, exponent and mantissa and then put it all together.

Martin

On 2013-03-13 06:08, Petar Jercic wrote:

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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