RE: [PATCH] SMPP validity

> -----Original Message-----
> From: Vibhu Mohindra [mailto:[email protected]]

> > Why would I want to handle years and days when I only need the hour
> > difference ?
> 
> OK, here's why looking only at hours and minutes isn't 
> enough. A country
> which is +12 GMT will be identified at 11am as being -12 GMT. 
> Past noon
> it will be correctly identified as +12 GMT. Our normalising version
> which adds/subtracts 24 hours doesn't work for such a place.

Ahmm... GMT+12 and GMT-12 is the same timezone. it's just a matter of
how you look at it. both are valid. it's like saying GMT+0 and GMT-0 are
different time zones.

> I believe that it is not a matter of correcting the 
> normalising algorithm
> proposed. In fact, this cannot be corrected only by looking at hours
> and minutes. So you get into the process of comparing days of the year
> as well. That leads to having to compare years as well to account for
> wrap arounds on New Year's. That leads to accounting for leap years...

No - it's not. you can account only for hours and minutes and then
handle a few special cases (one or two).

for the sake of portability, minimize your use of library calls - use
the only the most necessary and implement the algorithms yourself - the
library call doesn't do much more then what we are doing.

For setting SMPP validity we do not need to have a 100% correct
implementation - most SMSCs that I used don't handle time stamps very
well anyway - you just need an implementation that works in a
predictable way.

the following code seems to me to be good enough :
<snip>
gmtime = gw_gmtime(time(NULL));
localtime = gw_localtime(time(NULL));
gwqdiff = ((localtime.tm_hour - gmtime.tm_hour) * 4)
                  + ((localtime.tm_min - gmtime.tm_min) / 15);
gwqdiff = (gwqdiff>48?gwqdiff-96):(gwqdiff<=-48?gwqdiff+96:gwqdiff)
<snip>

This will normalize anything to the range GMT-11 - GMT+12, or you can
have it normalize to GMT-12 - GMT+11 by changing '<=' to '<' and '>' to
'>='.

--
Oded Arbel
m-Wise mobile solutions
[email protected]

+972-9-9581711 (116)
+972-67-340014

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