[erlang-questions] Working with dates.

[Ben Hood]

> >-define(UnixEpoch, 62167219200).
>
> (I.e. the value returned by
> calendar:datetime_to_gregorian_seconds({{1970,1,1},{0,0,0}}).)
>
> >encode_timestamp({MegaSecs, Secs, MicroSecs}) ->
> >    MegaSecs * ?MegaSeconds + Secs * ?Seconds + MicroSecs / ?MicroSeconds.
>
> Well, this turns what is apparently an erlang:now() value into
> milliseconds as a floating-point number - I don't know of any Unix
> timestamps that are expressed as milliseconds, whether floating-point or
> integer... To get a time() timestamp, it would just be
>
> encode_timestamp({MegaSecs, Secs, _MicroSecs}) ->
>     MegaSecs * 1000000 + Secs.
>
> (And if you want integer milliseconds, use 'div' instead of '/'.)
>
> >encode_localtime(DateTime={{Year,Month,Day},{Hour,Min,Sec}}) ->
> >    [Universal] = calendar:local_time_to_universal_time_dst(DateTime),
> >    Seconds = calendar:datetime_to_gregorian_seconds(Universal),
> >    (Seconds - ?UnixEpoch) * 1000.
>
> This will be integer milliseconds - to get time() stamp, just drop the
> '* 1000'.

Fair point. It is rather conveluted. But at least I got some code
reviewed.....;-)

Thanks for your input,

Ben