1308265Sgjb# Generate the 'leapseconds' file from 'leap-seconds.list'. 2308265Sgjb 3308265Sgjb# This file is in the public domain. 4308265Sgjb 5308265SgjbBEGIN { 6308265Sgjb print "# Allowance for leap seconds added to each time zone file." 7308265Sgjb print "" 8308265Sgjb print "# This file is in the public domain." 9308265Sgjb print "" 10308265Sgjb print "# This file is generated automatically from the data in the public-domain" 11339631Sphilip print "# leap-seconds.list file, which can be copied from" 12339631Sphilip print "# <ftp://ftp.nist.gov/pub/time/leap-seconds.list>" 13339631Sphilip print "# or <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>" 14339631Sphilip print "# or <ftp://tycho.usno.navy.mil/pub/ntp/leap-seconds.list>." 15308265Sgjb print "# For more about leap-seconds.list, please see" 16308265Sgjb print "# The NTP Timescale and Leap Seconds" 17339631Sphilip print "# <https://www.eecis.udel.edu/~mills/leap.html>." 18308265Sgjb print "" 19308265Sgjb print "# The International Earth Rotation and Reference Systems Service" 20308265Sgjb print "# periodically uses leap seconds to keep UTC to within 0.9 s of UT1" 21339631Sphilip print "# (which measures the true angular orientation of the earth in space)" 22339631Sphilip print "# and publishes leap second data in a copyrighted file" 23339631Sphilip print "# <https://hpiers.obspm.fr/iers/bul/bulc/Leap_Second.dat>." 24339631Sphilip print "# See: Levine J. Coordinated Universal Time and the leap second." 25325160Sphilip print "# URSI Radio Sci Bull. 2016;89(4):30-6. doi:10.23919/URSIRSB.2016.7909995" 26339631Sphilip print "# <https://ieeexplore.ieee.org/document/7909995>." 27342669Sphilip print "" 28308265Sgjb print "# There were no leap seconds before 1972, because the official mechanism" 29308265Sgjb print "# accounting for the discrepancy between atomic time and the earth's rotation" 30342669Sphilip print "# did not exist. The first (\"1 Jan 1972\") data line in leap-seconds.list" 31342669Sphilip print "# does not denote a leap second; it denotes the start of the current definition" 32342669Sphilip print"# of UTC." 33308265Sgjb print "" 34308265Sgjb print "# The correction (+ or -) is made at the given time, so lines" 35308265Sgjb print "# will typically look like:" 36308265Sgjb print "# Leap YEAR MON DAY 23:59:60 + R/S" 37308265Sgjb print "# or" 38308265Sgjb print "# Leap YEAR MON DAY 23:59:59 - R/S" 39308265Sgjb print "" 40339631Sphilip print "# If the leap second is Rolling (R) the given time is local time (unused here)." 41339631Sphilip 42339631Sphilip monthabbr[ 1] = "Jan" 43339631Sphilip monthabbr[ 2] = "Feb" 44339631Sphilip monthabbr[ 3] = "Mar" 45339631Sphilip monthabbr[ 4] = "Apr" 46339631Sphilip monthabbr[ 5] = "May" 47339631Sphilip monthabbr[ 6] = "Jun" 48339631Sphilip monthabbr[ 7] = "Jul" 49339631Sphilip monthabbr[ 8] = "Aug" 50339631Sphilip monthabbr[ 9] = "Sep" 51339631Sphilip monthabbr[10] = "Oct" 52339631Sphilip monthabbr[11] = "Nov" 53339631Sphilip monthabbr[12] = "Dec" 54339631Sphilip for (i in monthabbr) { 55339631Sphilip monthnum[monthabbr[i]] = i 56339631Sphilip monthlen[i] = 31 57339631Sphilip } 58339631Sphilip monthlen[2] = 28 59339631Sphilip monthlen[4] = monthlen[6] = monthlen[9] = monthlen[11] = 30 60308265Sgjb} 61308265Sgjb 62308265Sgjb/^#\tUpdated through/ || /^#\tFile expires on:/ { 63308265Sgjb last_lines = last_lines $0 "\n" 64308265Sgjb} 65308265Sgjb 66339631Sphilip/^#[$][ \t]/ { updated = $2 } 67339631Sphilip/^#[@][ \t]/ { expires = $2 } 68339631Sphilip 69308265Sgjb/^#/ { next } 70308265Sgjb 71308265Sgjb{ 72308265Sgjb NTP_timestamp = $1 73308265Sgjb TAI_minus_UTC = $2 74308265Sgjb hash_mark = $3 75308265Sgjb one = $4 76308265Sgjb month = $5 77308265Sgjb year = $6 78308265Sgjb if (old_TAI_minus_UTC) { 79308265Sgjb if (old_TAI_minus_UTC < TAI_minus_UTC) { 80308265Sgjb sign = "23:59:60\t+" 81308265Sgjb } else { 82308265Sgjb sign = "23:59:59\t-" 83308265Sgjb } 84339631Sphilip m = monthnum[month] - 1 85339631Sphilip if (m == 0) { 86308265Sgjb year--; 87339631Sphilip m = 12 88308265Sgjb } 89339631Sphilip month = monthabbr[m] 90339631Sphilip day = monthlen[m] 91339631Sphilip day += m == 2 && year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) 92308265Sgjb printf "Leap\t%s\t%s\t%s\t%s\tS\n", year, month, day, sign 93308265Sgjb } 94308265Sgjb old_TAI_minus_UTC = TAI_minus_UTC 95308265Sgjb} 96308265Sgjb 97308265SgjbEND { 98339631Sphilip # The difference between the NTP and POSIX epochs is 70 years 99339631Sphilip # (including 17 leap days), each 24 hours of 60 minutes of 60 100339631Sphilip # seconds each. 101339631Sphilip epoch_minus_NTP = ((1970 - 1900) * 365 + 17) * 24 * 60 * 60 102339631Sphilip 103339631Sphilip print "" 104339631Sphilip print "# POSIX timestamps for the data in this file:" 105339631Sphilip printf "#updated %s\n", updated - epoch_minus_NTP 106339631Sphilip printf "#expires %s\n", expires - epoch_minus_NTP 107308265Sgjb printf "\n%s", last_lines 108308265Sgjb} 109