[PD] bi-directional OSC over TCP from liblo

[Martin Peach]

On 2012-11-10 05:24, Roman Haefeli wrote:
> On Fre, 2012-11-09 at 17:19 +0100, IOhannes m zmölnig wrote:
>> On 11/09/2012 02:51 PM, Jamie Bullock wrote:
>>>
>>> So, it seems like [packOSCstream] and [unpackOSCstream] are (un)packing message in a format that can't be used with external clients/servers. Is that correct?
>>
>>
>> from your experience with liblo, you seem to conclude that:
>> a) all "external clients/servers" are build on top of liblo.
>> b) liblo handles OSC over TCP/IP correctly
>> c) [(un)packOSCstream] handles it wrongly.
>>
>>
>> anyhow:
>> originally OSC did not define how to transmit OSC-packets over a
>> stream-based protocol like TCP/IP (that has no notion of ending packets).
>> implementations that wanted to transmit OSC over stream-based protocols
>> had to find solutions for themselves.
>>
>> a few years ago, the OSC specs have been extended, to explicitely
>> mention "SLIP" encoding as the means to packetize streams of OSC-data.
>
> This was added to OSC 1.1, iirc.
>
> OSC 1.0 proposed to prepend to each OSC packet a 4 byte header that
> contains the byte count of following OSC packet. Old versions of
> [packOSCstream]/[unpackOSCstream] implemented this proposal.
>

The latest version of liblo does exactly this. See liblo-0.26/src/send.c 
at line 411. It actually sends a packet containing only the length of 
the OSC message that is sent next.

Martin