deco code rewrite

Jef Driesen jefdriesen at telenet.be
Thu Dec 6 04:42:15 PST 2012


On 2012-12-05 23:20, Jan Schubert wrote:
> I already proceeded with the Shearwater Predator, see attached 
> screenshot.
> Not mentioning the "known issues" there is some other "interessting" 
> things:
>
> - seems there are a lot (!) of events reported
> - seems there are at least some events taken false, there has been 
> for
> sure no gaschange in this dive

That's my fault. The predator stores the active gas on each sample, and 
generating the GASCHANGE2 event on each sample was the quick and easy 
solution for the first version. But later on, I completely forgot about 
that (or I was too concentrated on the new design, where the gaschange 
event will be dropped in favor of an active gas sample) :-)

I'll fix this and only generate an event when the gas actually changes.

> - also pO2, pN2 and pHe are wrong

Currently only the OC gases are reported by libdivecomputer. I didn't 
really know how to deal with this. At first, I just wanted to pick 
either the OC or CC gas mixes, depending on the dive mode. But there is 
no such setting in the header, only in the samples. Apparently the user 
can switch from CC to OC during the dive (confirmed by Shearwater), so 
this is going to be a bit more tricky. Maybe the easiest is to just 
report both sets, until we have some better solution?

The percentages in the GASCHANGE2 event will always be correct, because 
the percentages are directly stored in the sample data. The OC/CC gases 
defined in the header are not used for the events.

PS: As I'm not a rebreather (or technical) diver, I can definitely use 
some help in that area, to make sure libdivecomputer will also supports 
those features that technical divers need.

Jef


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