Re: Stream device - parsing array of pairs of floats

[Dirk Zimoch via Tech-talk <tech-talk@aps.anl.gov>]

The | in the regexp needs to be escaped:

in "%#/[.0-9]+\|//%f";

in "%#/\|[.0-9E+-]+//%f";

Without the escape it means "a number or an empty string". The empty 
string matches always and is replaced by an empty string, not changing 
the string at all and advancing by 0 bytes. Looking for the next match 
starts the endless loop.

Need to fix that.

But otherwise it works. I got the two arrays.

If you want to do further processing on the arrays, be aware that the 
"I/O Intr" record gets the value before the active one. So by the time 
the active record processes its FLNK or triggers any monitors, the "I/O 
Intr" record has already the corresponding value.

Dirk

On 15.02.19 10:58, Dirk Zimoch via Tech-talk wrote:
> I tested it and it hung up my ioc. Seems I have a bug in regsub.
>
> On 15.02.19 09:55, Dirk Zimoch via Tech-talk wrote:
> > Unfortunately StreamDevice cannot easily parse such interlaced arrays 
> > at the moment.
> >
> > Maybe the following works:
> >
> > For the values:
> > Separator=",";
> > in "%#/[.0-9]+|//%f";
> >
> > For the Timestamps:
> > Separator=",";
> > in "%#/|[.0-9E+-]+//%f";
> >
> > %#/regexp/subs/ is the regular expression pre-processor, here removing 
> > the "other" array from the input. Performance may be not so good and 
> > scales like O(n²) with the array length because of all the copying 
> > involved.
> >
> > One of the records should be active having the 'out' command that 
> > produces the reply. The other should be "I/O Intr" reading the time 
> > stamps passively.
> >
> > Not tested. Hope it works.
> > Dirk
> >
> >
> > On 14.02.19 18:35, Joao Afonso via Tech-talk wrote:
> > > Hello,
> > >
> > > I have a string returned by a device, representing an array where 
> > > each element is a pair <time, value>:
> > >
> > > - each pair is separated by "|": <timestamp>|<value>
> > > - each element of the array separated by ","
> > > - all values are floats
> > > - the timestamp increment may not be linear (that is why it needs to 
> > > be recorded)
> > >
> > > Example
> > > 0.1000|0.1230000E+00,0.2000|0.4560000E+00,0.3000|0.7890000E+00, [...]
> > >
> > > Is it possible to parse this using stream device (into two waveform 
> > > records)?
> > > Or do I have to use something more powerful such as asynDriver?
> > > I have seen several examples, but only with using simple type 
> > > elements, not like this.
> > >
> > > As a followup, is it possible to do the inverse, merging two waveform 
> > > records into a string?
> > >
> > > Thank you in advance,
> > > Joao
> > > CERN TE-EPC-CCS