1# Generate the 'leapseconds' file from 'leap-seconds.list'. 2 3# This file is in the public domain. 4 5BEGIN { 6 print "# Allowance for leapseconds added to each timezone file." 7 print "" 8 print "# This file is in the public domain." 9 print "" 10 print "# This file is generated automatically from the data in the public-domain" 11 print "# leap-seconds.list file available from most NIST time servers." 12 print "# If the URL <ftp://time.nist.gov/pub/leap-seconds.list> does not work," 13 print "# you should be able to pick up leap-seconds.list from a secondary NIST server." 14 print "# For more about leap-seconds.list, please see" 15 print "# The NTP Timescale and Leap Seconds" 16 print "# <http://www.eecis.udel.edu/~mills/leap.html>." 17 print "" 18 print "# The International Earth Rotation Service periodically uses leap seconds" 19 print "# to keep UTC to within 0.9 s of UT1" 20 print "# (which measures the true angular orientation of the earth in space); see" 21 print "# Terry J Quinn, The BIPM and the accurate measure of time," 22 print "# Proc IEEE 79, 7 (July 1991), 894-905 <http://dx.doi.org/10.1109/5.84965>." 23 print "# There were no leap seconds before 1972, because the official mechanism" 24 print "# accounting for the discrepancy between atomic time and the earth's rotation" 25 print "# did not exist until the early 1970s." 26 print "" 27 print "# The correction (+ or -) is made at the given time, so lines" 28 print "# will typically look like:" 29 print "# Leap YEAR MON DAY 23:59:60 + R/S" 30 print "# or" 31 print "# Leap YEAR MON DAY 23:59:59 - R/S" 32 print "" 33 print "# If the leapsecond is Rolling (R) the given time is local time." 34 print "# If the leapsecond is Stationary (S) the given time is UTC." 35 print "" 36 print "# Leap YEAR MONTH DAY HH:MM:SS CORR R/S" 37} 38 39/^ *$/ { next } 40/^#/ { next } 41 42{ 43 NTP_timestamp = $1 44 TAI_minus_UTC = $2 45 hash_mark = $3 46 one = $4 47 month = $5 48 year = $6 49 if (old_TAI_minus_UTC) { 50 if (old_TAI_minus_UTC < TAI_minus_UTC) { 51 sign = "23:59:60\t+" 52 } else { 53 sign = "23:59:59\t-" 54 } 55 if (month == "Jan") { 56 year--; 57 month = "Dec"; 58 day = 31 59 } else if (month == "Jul") { 60 month = "Jun"; 61 day = 30 62 } 63 printf "Leap\t%s\t%s\t%s\t%s\tS\n", year, month, day, sign 64 } 65 old_TAI_minus_UTC = TAI_minus_UTC 66} 67