Sound.Osc.Time

Osc related timing functions. Osc timestamps are 64-bit Ntp values, http://ntp.org/.

Temporal types

type Ntp64 = Word64

Type for binary (integeral) representation of a 64-bit Ntp timestamp (ie. ntpi). The Ntp epoch is January 1, 1900. Ntp v4 also includes a 128-bit format, which is not used by Osc.

type NtpReal = Double

Ntp time in real-valued (fractional) form.

type PosixReal = Double

Unix/Posix time in real-valued (fractional) form. The Unix/Posix epoch is January 1, 1970.

Time conversion

ntpr_to_ntpi :: NtpReal -> Ntp64

Convert an NtpReal timestamp to an Ntp64 timestamp.

ntpr_to_ntpi 0 == 0
fmap ntpr_to_ntpi time

ntpi_to_ntpr :: Ntp64 -> NtpReal

Convert an Ntp64 timestamp to a real-valued Ntp timestamp.

ntpi_to_ntpr 0 == 0.0

ntp_posix_epoch_diff :: Num n => n

Difference (in seconds) between Ntp and Posix epochs.

ntp_posix_epoch_diff / (24 * 60 * 60) == 25567
25567 `div` 365 == 70

posix_to_ntpi :: PosixReal -> Ntp64

Convert a PosixReal timestamp to an Ntp64 timestamp.

posix_to_ntpr :: Num n => n -> n

Convert Unix/Posix to Ntp.

ntpr_to_posix :: Num n => n -> n

Convert Ntp to Unix/Posix.

ntpi_to_posix :: Ntp64 -> PosixReal

Convert Ntp64 to Unix/Posix.

ntpr_to_posixtime :: NtpReal -> POSIXTime

Convert Time to POSIXTime.

posixtime_to_ntpr :: POSIXTime -> NtpReal

Convert POSIXTime to Time.

Time inter-operation.

posix_epoch :: UTCTime

The time at 1970-01-01:00:00:00 which is the Unix/Posix epoch.

utc_to_posix :: Fractional n => UTCTime -> n

Convert UTCTime to Unix/Posix.

Clock operations

getCurrentTimeAsPosix :: IO PosixReal

utc_to_posix of Clock.getCurrentTime.

getPosixTimeAsPosix :: IO PosixReal

realToFrac of Clock.Posix.getPOSIXTime

get_ct = getCurrentTimeAsPosix
get_pt = getPosixTimeAsPosix
(ct,pt) <- get_ct >>= \t0 -> get_pt >>= \t1 -> return (t0,t1)
print (pt - ct,pt - ct < 1e-5)

currentTime :: IO NtpReal

Read current real-valued Ntp timestamp.