[R] Time conversion from Win32 64bit FILETIME?

[jim holtman]

One way might be to convert the number to POSIXct by scaling it based
that POSIXct is from 1970 and your number is from 1601.  So if you
subtract the difference between 1601 and 1970 then you should have a
compliant number for R:

# read your number
x <- 12345678901234567890  # big number (your 64-bit time)
x.sec <- x / 10^9 # convert to seconds
xBase <- unclass(as.POSIXct('1601-1-1'))  # your time base, relative to 1970
x.sec <- x.sec - abs(xBase)  # scale to 1970
x.time <- structure(x.sec, class=c("POSIXt", "POSIXct"))  # convert to POSIXct


On 10/19/06, Derek Eder <derek.eder at lungall.gu.se> wrote:
> Windows-32 has a time structure called FILETIME, a 64-bit value
> representing the number of 100-nanosecond intervals since January 1,
> 1601 (UTC).   That is not a typo, the year is 1601.
>
> Does anyone have a clue(or algorhithm)for how this is converted to
> something a little more POSIX-like ?
>
> Thank you,
>
> Derek
>
> --
> Derek N. Eder
>
> Gothenburg University
> VINKLA - Vigilance and Neurocognition laboratory
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?