- tz - lists.iana.org

[PATCH] Document some longstanding unwritten guidelines.
by Paul Eggert Sept. 3, 2013

Sept. 3, 2013

These come from POSIX or similar platforms, or from the standard 'zic' implementation, but never got written down anywhere. * Theory: Document other POSIX-inspired restrictions on names. * zic.8 (DESCRIPTION): Document that zic's behavior is unspecified if some names are duplicates. Sometimes it complains, sometimes not. --- Theory | 10 ++++++++-- zic.8 | 3 +++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/Theory b/Theory index bd62c5c..b11cbc8 100644 --- a/Theory +++ b/Theory @@ -299,15 +299,21 @@ Here are the general rules used for choosing location names, in decreasing order of importance: Use only valid POSIX file name components (i.e., the parts of - names other than '/'). Within a file name component, + names other than '/'). Do not use the file name + components '.' and '..'. Within a file name component, use only ASCII letters, '.', '-' and '_'. Do not use digits, as that might create an ambiguity with POSIX TZ strings. A file name component must not exceed 14 characters or start with '-'. E.g., prefer 'Brunei' to 'Bandar_Seri_Begawan'. + A name must not be empty, or contain '//', or start or end with '/'. Do not use names that differ only in case. Although the reference - implementation is case-sensitive, some other implementations + implementation is case-sensitive, some other implementations are not, and they would mishandle names differing only in case. + If one name A is an initial prefix of another name AB (ignoring case), + then B must not start with '/', as a regular file cannot have + the same name as a directory in POSIX. For example, + 'America/New_York' precludes 'America/New_York/Bronx'. Uninhabited regions like the North Pole and Bouvet Island do not need locations, since local time is not defined there. If all the clocks in a region have agreed since 1970, diff --git a/zic.8 b/zic.8 index d61555e..d0d34ce 100644 --- a/zic.8 +++ b/zic.8 @@ -362,6 +362,9 @@ field is used as an alternate name for that zone. .PP Except for continuation lines, lines may appear in any order in the input. +However, the behavior is unspecified if multiple zone or link lines +define the same name, or if the source of one link line is the target +of another. .PP Lines in the file that describes leap seconds have the following form: .nf -- 1.8.1.2

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[PATCH 2/3] Replace some zones with links when that doesn't lose non-LMT info.
by Meno Hochschild Sept. 3, 2013

Sept. 3, 2013

*Paul Eggert* eggert at cs.ucla.edu <mailto:tz%40iana.org?Subject=Re:%20Re%3A%20%5Btz%5D%20%5BPATCH%202/3%5D%20Replace%20some%20zones%20with%20links%20when%20that%0A%20doesn%27t%20lose%20non-LMT%20info.&In-Reply-To=%3C522616ED.6060902%40cs.ucla.edu%3E> /Tue Sep 3 17:05:49 UTC 2013/ Lester Caine wrote: >/can we at least agree that the quality of the material is heading in the right direction? / Yes, that's the idea. While I personally have no problem with tidy-up of obviously wrong data and also agree that correction of mistakes is more important than stability (which has never been absolutely pretended), I think end-users of tzdb should get a better opportunity to estimate how reliable the data are and how much trust they can put in their time zone calculations. Offsets in LMT-lines can easily be qualified as UNKNOWN. For the proposed date of 1970 as general separation point between UNSAFE and (apparently) RELIABLE I am not so sure. Would it not be helpful for end-users if there is an additional year-type attribute per zone which tells the users since when the data can be confirmed with high probability of correctness? Would require about 400+ attributes (ok, 1970 as default). I am sure for example in UK or in Germany the data are correct even a pretty while before 1970. Flexibility would be a good thing, isn't it? External APIs could support the users with this extra quality information per offset and make them better aware that historical tz data are not set in stone. Just giving a thought...

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Dealing with Pre-1970 Data
by David Patte ₯ Sept. 3, 2013

Sept. 3, 2013

Though it has been handy to have some pre-1970 data within the tz database, I don't see that it is the best solution for historical tz data in the long run. It is clear that that going back far enough in time there is a different LMT for every 15 seconds of latitude. My own preference would be that historical (and perhaps all tz data) be given a numberic identifier, not a 'America/Someplace' name, for the populated areas in question. A good source of geographic identifiers already available is the geonames database. The tz data for Montreal could be identified by the geonames number for Montreal, and the tz data for Toronto associated with the geoname number for Toronto. Then, to build regions, since all geonames records already have a field for the tz region, these could reflect the numeric identifier of the tz recommended region for each location. For example, Ottawa, in the geonames database would refer to the numeric identifier of Toronto instead of 'America/Toronto', until sometime decides to add historical data for Ottawa's own tz history, at which point it would adopt the identifier for Ottawa.

10 69

Value of data ...
by Lester Caine Sept. 3, 2013

Sept. 3, 2013

Norbert supplied a link to a ecma document which makes interesting reading ... From the section on 'Time Zone Names' > All registered Zone and Link names are allowed. Implementations must recognize all such names, and use > best available current and historical information about their offsets from UTC and their daylight saving time > rules in calculations. Note the use of 'and historical information' here. One has to bare in mind the target data set when deciding what data is useful and what can be thrown away, and for much day to day work a TZ database that only provides future 'estimated' data is probably more than adequate. Banks may be able to get away with 'it's ten years old so we can throw it away' and take control of dormant funds, but for some of us the history is as important as the present day. In fifty years time a large proportion of the data we are creating today will still be available. I dug out material going back 200+ years last night which has now been scanned and archived ... material on 'time' in the Isle of Man for the record ... which helps to clarify calculations for UTC time offsets for material in the early 1900's, which if now stored as UTC normalised data need to be 'corrected' using an historic version of the TZ data. If someone tries to use that data with a 'winnowed' data set, then the wrong times will be returned? Who is to say what an end user is going to be doing with their machine? All right you can reduce 440 zones down to 300 or so, but all of the original 440 names still need to be available, and in these days does saving a few bytes really matter? 'Simplification' of access is more to do with showing the appropriate subset of options by the application and historical ones may actually be the correct answer. So the data should be as complete a record of the 'best available current and historical information' that we have! Providing a version of the data that will be WRONG for some users is not an option? -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

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[PATCH] Revert recent pre-1970 changes.
by Paul Eggert Sept. 3, 2013

Sept. 3, 2013

Other tz file readers had problems with the new pre1970 file, so remove it and related changes. To recover the pre-1970 data, instead change pre-1970 Zone entries in other files back to what they were. Perhaps we'll try to find a better way someday. * .gitignore: Remove back-pre1970. * Makefile (BACKWARD): Remove. All uses changed back to 'backward'. (AWK_SCRIPTS): Remove back-pre1970.awk. (back-pre1970): Remove. (clean_misc): Don't rm back-pre1970. (check_public): Remove special case for pre1970. * back-pre1970.awk, pre1970: Remove. * backward (America/Anguilla, America/Antigua, America/Aruba) (America/Atikokan, America/Blanc-Sablon, America/Cayman) (America/Creston, America/Curacao, America/Dominica, America/Grenada) (America/Guadeloupe, America/Montreal, America/Montserrat) (America/Nassau, America/Port_of_Spain, America/St_Kitts) (America/St_Lucia, America/St_Thomas, America/St_Vincent) (America/Tortola): Remove, as these are zones again. (America/Coral_Harbour, America/Kralendijk, America/Lower_Princes) (America/Marigot, America/St_Barthelemy, America/Virgin): Revert to previous links. * northamerica (Mont, America/Blanc-Sablon, America/Montreal) (America/Atikokan, America/Creston, America/Anguilla, America/Antigua) (Bahamas, America/Nassau, America/Cayman, America/Dominica) (America/Grenada, America/Guadeloupe, America/Montserrat) (America/St_Kitts, America/St_Lucia, America/St_Vincent) (America/Tortola, America/St_Thomas): * southamerica (America/Aruba, America/Curacao, America/Port_of_Spain): Restore these rules and zones. * .gitignore: Add back-pre1970. --- .gitignore | 1 - Makefile | 34 ++----- back-pre1970.awk | 18 ---- backward | 32 ++---- northamerica | 140 ++++++++++++++++++++------ pre1970 | 291 ------------------------------------------------------- southamerica | 20 +++- 7 files changed, 140 insertions(+), 396 deletions(-) delete mode 100644 back-pre1970.awk delete mode 100644 pre1970 diff --git a/.gitignore b/.gitignore index 28b1bc9..18dbbcc 100644 --- a/.gitignore +++ b/.gitignore @@ -4,7 +4,6 @@ *.txt *~ ChangeLog -back-pre1970 date leapseconds time.tab diff --git a/Makefile b/Makefile index ffddb08..e439055 100644 --- a/Makefile +++ b/Makefile @@ -49,22 +49,6 @@ POSIXRULES= America/New_York ZONETABTYPE= zone -# How to support obsolescent time zones in a backward-compatible way. -# This variable affects only pre-1970 time stamps, on hosts that support them. -# It has two possible values, 'backward' and 'pre1970 back-pre1970'. -# -# 'backward' is the traditional approach, and is simpler and more efficient; -# it is designed to generate one zone for each region where clocks have agreed -# since 1970. -# -# 'pre1970 back-pre1970' can generate more than one zone in that situation, -# which means it can preserve a bit of pre-1970 data that 'backward' does not; -# almost all pre-1970 data is missing, though, so don't get your hopes up. -# -# Sometimes 'backward' is more-compatible with earlier versions of this database, -# and sometimes 'pre1970 back-pre1970' is; it depends on the situation. -BACKWARD= backward - # Also see TZDEFRULESTRING below, which takes effect only # if the time zone files cannot be accessed. @@ -338,7 +322,7 @@ COMMON= Makefile DOCS= README Theory $(MANS) date.1 PRIMARY_YDATA= africa antarctica asia australasia \ europe northamerica southamerica -YDATA= $(PRIMARY_YDATA) pacificnew etcetera $(BACKWARD) +YDATA= $(PRIMARY_YDATA) pacificnew etcetera backward NDATA= systemv factory SDATA= solar87 solar88 solar89 TDATA= $(YDATA) $(NDATA) $(SDATA) @@ -346,10 +330,10 @@ TABDATA= iso3166.tab time.tab zone.tab DATA= $(YDATA) $(NDATA) $(SDATA) $(TABDATA) \ leap-seconds.list yearistype.sh WEB_PAGES= tz-art.htm tz-link.htm -AWK_SCRIPTS= back-pre1970.awk checktab.awk leapseconds.awk zone-time.awk +AWK_SCRIPTS= checktab.awk leapseconds.awk zone-time.awk MISC= usno1988 usno1989 usno1989a usno1995 usno1997 usno1998 \ - $(WEB_PAGES) $(AWK_SCRIPTS) \ - workman.sh zoneinfo2tdf.pl + $(WEB_PAGES) $(AWK_SCRIPTS) workman.sh \ + zoneinfo2tdf.pl ENCHILADA= $(COMMON) $(DOCS) $(SOURCES) $(DATA) $(MISC) # And for the benefit of csh users on systems that assume the user @@ -440,9 +424,6 @@ zones: $(REDO) time.tab: $(YDATA) zone.tab zone-time.awk $(AWK) -f zone-time.awk $(YDATA) >$@ -back-pre1970: pre1970 backward - $(AWK) -v pre1970=pre1970 -f $@.awk backward >$@ - $(TZLIB): $(LIBOBJS) -mkdir $(TOPDIR) $(LIBDIR) ar ru $@ $(LIBOBJS) @@ -477,7 +458,7 @@ check_web: $(WEB_PAGES) clean_misc: rm -f core *.o *.out \ - back-pre1970 time.tab \ + time.tab \ date leapseconds tzselect version.h zdump zic yearistype clean: clean_misc rm -f -r tzpublic @@ -509,7 +490,7 @@ set-timestamps: $$cmd || exit; \ done -# The zics below ensure that each non-pre1970 data file can stand on its own. +# The zics below ensure that each data file can stand on its own. # We also do an all-files run to catch links to links. check_public: $(ENCHILADA) @@ -517,8 +498,7 @@ check_public: $(ENCHILADA) make "CFLAGS=$(GCC_DEBUG_FLAGS)" mkdir tzpublic for i in $(TDATA) ; do \ - test $$i = pre1970 || $(zic) -v -d tzpublic $$i 2>&1 \ - || exit; \ + $(zic) -v -d tzpublic $$i 2>&1 || exit; \ done $(zic) -v -d tzpublic $(TDATA) rm -f -r tzpublic diff --git a/back-pre1970.awk b/back-pre1970.awk deleted file mode 100644 index f7c54fc..0000000 --- a/back-pre1970.awk +++ /dev/null @@ -1,18 +0,0 @@ -# Generate 'back-pre1970' from the two input files 'pre1970' and 'backward'. -# The output consists of all lines in 'backward' that are not links to -# files mentioned in 'pre1970'. Think of it as 'backward' minus 'pre1970'. - -# The 'backward' file is the input. -# The awk variable 'pre1970' contains the name of the pre1970 file. - -# This file is in the public domain. - -# Contributed by Paul Eggert. - -BEGIN { - while ((getline <pre1970) == 1) - if ($1 == "Zone") - pre1970_zone[$2] = 1 -} - -! (/^Link/ && pre1970_zone[$3]) { print } diff --git a/backward b/backward index efb5353..561e2ff 100644 --- a/backward +++ b/backward @@ -7,47 +7,27 @@ Link Africa/Asmara Africa/Asmera Link Africa/Bamako Africa/Timbuktu -Link America/Puerto_Rico America/Anguilla -Link America/Puerto_Rico America/Antigua Link America/Argentina/Catamarca America/Argentina/ComodRivadavia -Link America/Puerto_Rico America/Aruba -Link America/Panama America/Atikokan Link America/Adak America/Atka -Link America/Puerto_Rico America/Blanc-Sablon Link America/Argentina/Buenos_Aires America/Buenos_Aires Link America/Argentina/Catamarca America/Catamarca -Link America/Panama America/Cayman -Link America/Panama America/Coral_Harbour +Link America/Atikokan America/Coral_Harbour Link America/Argentina/Cordoba America/Cordoba -Link America/Phoenix America/Creston -Link America/Puerto_Rico America/Curacao -Link America/Puerto_Rico America/Dominica Link America/Tijuana America/Ensenada Link America/Indiana/Indianapolis America/Fort_Wayne -Link America/Puerto_Rico America/Grenada -Link America/Puerto_Rico America/Guadeloupe Link America/Indiana/Indianapolis America/Indianapolis Link America/Argentina/Jujuy America/Jujuy Link America/Indiana/Knox America/Knox_IN -Link America/Puerto_Rico America/Kralendijk +Link America/Curacao America/Kralendijk Link America/Kentucky/Louisville America/Louisville -Link America/Puerto_Rico America/Lower_Princes -Link America/Puerto_Rico America/Marigot +Link America/Curacao America/Lower_Princes +Link America/Guadeloupe America/Marigot Link America/Argentina/Mendoza America/Mendoza -Link America/Toronto America/Montreal -Link America/Puerto_Rico America/Montserrat -Link America/Toronto America/Nassau -Link America/Puerto_Rico America/Port_of_Spain Link America/Rio_Branco America/Porto_Acre Link America/Argentina/Cordoba America/Rosario Link America/Denver America/Shiprock -Link America/Puerto_Rico America/St_Barthelemy -Link America/Puerto_Rico America/St_Kitts -Link America/Puerto_Rico America/St_Lucia -Link America/Puerto_Rico America/St_Thomas -Link America/Puerto_Rico America/St_Vincent -Link America/Puerto_Rico America/Tortola -Link America/Puerto_Rico America/Virgin +Link America/Guadeloupe America/St_Barthelemy +Link America/St_Thomas America/Virgin Link Pacific/Auckland Antarctica/McMurdo Link Pacific/Auckland Antarctica/South_Pole Link Europe/Oslo Arctic/Longyearbyen diff --git a/northamerica b/northamerica index 6210318..418261f 100644 --- a/northamerica +++ b/northamerica @@ -1341,9 +1341,13 @@ Zone America/Moncton -4:19:08 - LMT 1883 Dec 9 # Quebec -# From Paul Eggert (2013-08-26): +# From Paul Eggert (2013-08-30): # Since 1970 most of Quebec has been like Toronto. -# See America/Toronto. +# However, because earlier versions of the tz database mistakenly relied on data +# from Shanks & Pottenger saying that Quebec differed from Ontario after 1970, +# a separate entry was created for most of Quebec. We're loath to lose +# its pre-1970 info, even though the tz database is normally limited to +# zones that differ after 1970, so keep this otherwise out-of-scope entry. # Matthews and Vincent (1998) also write that Quebec east of the -63 # meridian is supposed to observe AST, but residents as far east as @@ -1357,7 +1361,50 @@ Zone America/Moncton -4:19:08 - LMT 1883 Dec 9 # says this common practice was codified into law as of 2007. # For lack of better info, guess this practice began around 1970, contra to # Shanks & Pottenger who have this region observing AST/ADT. -# See America/Puerto_Rico. +# for post-1970 data America/Puerto_Rico. + +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S +Rule Mont 1917 only - Mar 25 2:00 1:00 D +Rule Mont 1917 only - Apr 24 0:00 0 S +Rule Mont 1919 only - Mar 31 2:30 1:00 D +Rule Mont 1919 only - Oct 25 2:30 0 S +Rule Mont 1920 only - May 2 2:30 1:00 D +Rule Mont 1920 1922 - Oct Sun>=1 2:30 0 S +Rule Mont 1921 only - May 1 2:00 1:00 D +Rule Mont 1922 only - Apr 30 2:00 1:00 D +Rule Mont 1924 only - May 17 2:00 1:00 D +Rule Mont 1924 1926 - Sep lastSun 2:30 0 S +Rule Mont 1925 1926 - May Sun>=1 2:00 1:00 D +# The 1927-to-1937 rules can be expressed more simply as +# Rule Mont 1927 1937 - Apr lastSat 24:00 1:00 D +# Rule Mont 1927 1937 - Sep lastSat 24:00 0 S +# The rules below avoid use of 24:00 +# (which pre-1998 versions of zic cannot handle). +Rule Mont 1927 only - May 1 0:00 1:00 D +Rule Mont 1927 1932 - Sep lastSun 0:00 0 S +Rule Mont 1928 1931 - Apr lastSun 0:00 1:00 D +Rule Mont 1932 only - May 1 0:00 1:00 D +Rule Mont 1933 1940 - Apr lastSun 0:00 1:00 D +Rule Mont 1933 only - Oct 1 0:00 0 S +Rule Mont 1934 1939 - Sep lastSun 0:00 0 S +Rule Mont 1946 1973 - Apr lastSun 2:00 1:00 D +Rule Mont 1945 1948 - Sep lastSun 2:00 0 S +Rule Mont 1949 1950 - Oct lastSun 2:00 0 S +Rule Mont 1951 1956 - Sep lastSun 2:00 0 S +Rule Mont 1957 1973 - Oct lastSun 2:00 0 S + +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Blanc-Sablon -3:48:28 - LMT 1884 + -4:00 Canada A%sT 1970 + -4:00 - AST +Zone America/Montreal -4:54:16 - LMT 1884 + -5:00 Mont E%sT 1918 + -5:00 Canada E%sT 1919 + -5:00 Mont E%sT 1942 Feb 9 2:00s + -5:00 Canada E%sT 1946 + -5:00 Mont E%sT 1974 + -5:00 Canada E%sT + # Ontario @@ -1423,16 +1470,14 @@ Zone America/Moncton -4:19:08 - LMT 1883 Dec 9 # can say for certain that Atikokan has been practicing the current # time keeping since 1952, at least. -# From Paul Eggert (2013-08-26): +# From Paul Eggert (2006-07-17): # Shanks & Pottenger say that Atikokan has agreed with Rainy River # ever since standard time was introduced, but the information from # McKinnon sounds more authoritative. For now, assume that Atikokan # switched to EST immediately after WWII era daylight saving time # ended. This matches the old (less-populous) America/Coral_Harbour # entry since our cutoff date of 1970, so we can move -# America/Coral_Harbour to the 'backward' file. And Atikokan itself -# is the same as America/Panama since 1970, so we can move -# America/Atikokan to the 'backward' file as well. +# America/Coral_Harbour to the 'backward' file. # From Mark Brader (2010-03-06): # @@ -1590,6 +1635,11 @@ Zone America/Rainy_River -6:18:16 - LMT 1895 -6:00 Canada C%sT 1940 Sep 29 -6:00 1:00 CDT 1942 Feb 9 2:00s -6:00 Canada C%sT +Zone America/Atikokan -6:06:28 - LMT 1895 + -6:00 Canada C%sT 1940 Sep 29 + -6:00 1:00 CDT 1942 Feb 9 2:00s + -6:00 Canada C%sT 1945 Sep 30 2:00 + -5:00 - EST # Manitoba @@ -1824,8 +1874,7 @@ Zone America/Edmonton -7:33:52 - LMT 1906 Sep # period should be PDT rather than MST, but that doesn't seem important enough # (to anyone) to further complicate the rules. -# From Paul Eggert (2013-08-26): -# See America/Phoenix, since Creston has agreed with Phoenix since 1970. +# The transition dates (and times) are guesses. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Vanc 1918 only - Apr 14 2:00 1:00 D @@ -1845,6 +1894,10 @@ Zone America/Dawson_Creek -8:00:56 - LMT 1884 -8:00 Canada P%sT 1947 -8:00 Vanc P%sT 1972 Aug 30 2:00 -7:00 - MST +Zone America/Creston -7:46:04 - LMT 1884 + -7:00 - MST 1916 Oct 1 + -8:00 - PST 1918 Jun 2 + -7:00 - MST # Northwest Territories, Nunavut, Yukon @@ -2495,10 +2548,15 @@ Zone America/Santa_Isabel -7:39:28 - LMT 1922 Jan 1 0:20:32 ############################################################################### # Anguilla -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Anguilla -4:12:16 - LMT 1912 Mar 2 + -4:00 - AST # Antigua and Barbuda -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Antigua -4:07:12 - LMT 1912 Mar 2 + -5:00 - EST 1951 + -4:00 - AST # Bahamas # @@ -2508,8 +2566,14 @@ Zone America/Santa_Isabel -7:39:28 - LMT 1922 Jan 1 0:20:32 # The Bahamas announced about a month ago that they plan to change their DST # rules to sync with the U.S. starting in 2007.... # http://www.jonesbahamas.com/?c=45&a=10412 -# -# See America/Toronto. + +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S +Rule Bahamas 1964 1975 - Oct lastSun 2:00 0 S +Rule Bahamas 1964 1975 - Apr lastSun 2:00 1:00 D +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Nassau -5:09:30 - LMT 1912 Mar 2 + -5:00 Bahamas E%sT 1976 + -5:00 US E%sT # Barbados @@ -2559,7 +2623,10 @@ Zone Atlantic/Bermuda -4:19:18 - LMT 1930 Jan 1 2:00 # Hamilton -4:00 US A%sT # Cayman Is -# See America/Panama. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Cayman -5:25:32 - LMT 1890 # Georgetown + -5:07:12 - KMT 1912 Feb # Kingston Mean Time + -5:00 - EST # Costa Rica @@ -2805,7 +2872,9 @@ Zone America/Havana -5:29:28 - LMT 1890 -5:00 Cuba C%sT # Dominica -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Dominica -4:05:36 - LMT 1911 Jul 1 0:01 # Roseau + -4:00 - AST # Dominican Republic @@ -2854,10 +2923,15 @@ Zone America/El_Salvador -5:56:48 - LMT 1921 # San Salvador -6:00 Salv C%sT # Grenada -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Grenada -4:07:00 - LMT 1911 Jul # St George's + -4:00 - AST # Guadeloupe -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Guadeloupe -4:06:08 - LMT 1911 Jun 8 # Pointe a Pitre + -4:00 - AST +# Use America/Guadeloupe also for St Barthelemy and for St Martin (French part). # Guatemala # @@ -3027,7 +3101,9 @@ Zone America/Martinique -4:04:20 - LMT 1890 # Fort-de-France # From Paul Eggert (2006-03-22): # In 1995 volcanic eruptions forced evacuation of Plymouth, the capital. # world.gazetteer.com says Cork Hill is the most populous location now. -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Montserrat -4:08:52 - LMT 1911 Jul 1 0:01 # Cork Hill + -4:00 - AST # Nicaragua # @@ -3108,17 +3184,16 @@ Zone America/Puerto_Rico -4:24:25 - LMT 1899 Mar 28 12:00 # San Juan -4:00 US A%sT 1946 -4:00 - AST -# St Barthelemy -# See America/Puerto_Rico. - # St Kitts-Nevis -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/St_Kitts -4:10:52 - LMT 1912 Mar 2 # Basseterre + -4:00 - AST # St Lucia -# See America/Puerto_Rico. - -# St Martin (French part) -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/St_Lucia -4:04:00 - LMT 1890 # Castries + -4:04:00 - CMT 1912 # Castries Mean Time + -4:00 - AST # St Pierre and Miquelon # There are too many St Pierres elsewhere, so we'll use `Miquelon'. @@ -3129,7 +3204,10 @@ Zone America/Miquelon -3:44:40 - LMT 1911 May 15 # St Pierre -3:00 Canada PM%sT # St Vincent and the Grenadines -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/St_Vincent -4:04:56 - LMT 1890 # Kingstown + -4:04:56 - KMT 1912 # Kingstown Mean Time + -4:00 - AST # Turks and Caicos # @@ -3163,7 +3241,11 @@ Zone America/Grand_Turk -4:44:32 - LMT 1890 -5:00 TC E%sT # British Virgin Is -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Tortola -4:18:28 - LMT 1911 Jul # Road Town + -4:00 - AST # Virgin Is -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/St_Thomas -4:19:44 - LMT 1911 Jul # Charlotte Amalie + -4:00 - AST diff --git a/pre1970 b/pre1970 deleted file mode 100644 index d8b8f34..0000000 --- a/pre1970 +++ /dev/null @@ -1,291 +0,0 @@ -# Pre-1970 data - -# This file is in the public domain. - -# This file contains zones that were formerly in other source files, -# but were later removed or replaced by backward-compatibility links -# as they differ from other zones only in pre-1970 time stamps. - -# Although the tz database focuses on post-1970 time stamps, these -# entries are retained here as they may be of some use to people -# interested in pre-1970 time stamps, even though they cover only a -# tiny sliver of pre-1970 data and are unreliable for that data. -# Also, these entries can help with backward compatibility with some -# old versions of the tz database. They are incompatible with other -# old versions of the database, though; it depends on which old -# version you're interested in. - -# Entries are sorted by Zone name. Each entry is preceded by the name -# of the country that the entry is in, along with any other commentary -# and rules associated with the entry. Some rules, e.g., 'Canada', -# are defined by other source files; this file is not intended to be -# used without those other files. - -# Zone NAME GMTOFF RULES FORMAT [UNTIL] - -# Mali -# no longer different from Bamako, but too famous to omit -Zone Africa/Timbuktu -0:12:04 - LMT 1912 - 0:00 - GMT - -# Anguilla -Zone America/Anguilla -4:12:16 - LMT 1912 Mar 2 - -4:00 - AST - -# Antigua and Barbuda -Zone America/Antigua -4:07:12 - LMT 1912 Mar 2 - -5:00 - EST 1951 - -4:00 - AST - -# Argentina -# Chubut (CH) -# The name "Comodoro Rivadavia" exceeds the 14-byte POSIX limit. -Zone America/Argentina/ComodRivadavia -4:30:00 - LMT 1894 Oct 31 - -4:16:48 - CMT 1920 May - -4:00 - ART 1930 Dec - -4:00 Arg AR%sT 1969 Oct 5 - -3:00 Arg AR%sT 1991 Mar 3 - -4:00 - WART 1991 Oct 20 - -3:00 Arg AR%sT 1999 Oct 3 - -4:00 Arg AR%sT 2000 Mar 3 - -3:00 - ART 2004 Jun 1 - -4:00 - WART 2004 Jun 20 - -3:00 - ART - -# Aruba -Zone America/Aruba -4:40:24 - LMT 1912 Feb 12 # Oranjestad - -4:30 - ANT 1965 # Netherlands Antilles Time - -4:00 - AST - -# Canada - -Zone America/Atikokan -6:06:28 - LMT 1895 - -6:00 Canada C%sT 1940 Sep 29 - -6:00 1:00 CDT 1942 Feb 9 2:00s - -6:00 Canada C%sT 1945 Sep 30 2:00 - -5:00 - EST - -Zone America/Blanc-Sablon -3:48:28 - LMT 1884 - -4:00 Canada A%sT 1970 - -4:00 - AST - -# Cayman Is -Zone America/Cayman -5:25:32 - LMT 1890 # Georgetown - -5:07:12 - KMT 1912 Feb # Kingston Mean Time - -5:00 - EST - -# Canada -Zone America/Coral_Harbour -5:32:40 - LMT 1884 - -5:00 NT_YK E%sT 1946 - -5:00 - EST - -# Curacao -Zone America/Curacao -4:35:47 - LMT 1912 Feb 12 # Willemstad - -4:30 - ANT 1965 # Netherlands Antilles Time - -4:00 - AST - -# Dominica -Zone America/Dominica -4:05:36 - LMT 1911 Jul 1 0:01 # Roseau - -4:00 - AST - -# Mexico -Zone America/Ensenada -7:46:28 - LMT 1922 Jan 1 0:13:32 - -8:00 - PST 1927 Jun 10 23:00 - -7:00 - MST 1930 Nov 16 - -8:00 - PST 1942 Apr - -7:00 - MST 1949 Jan 14 - -8:00 - PST 1996 - -8:00 Mexico P%sT - -# US -Zone America/Fort_Wayne -5:00 US E%sT 1946 - -5:00 - EST # Always EST as of 1986 - -# Grenada -Zone America/Grenada -4:07:00 - LMT 1911 Jul # St George's - -4:00 - AST - -# Guadeloupe -Zone America/Guadeloupe -4:06:08 - LMT 1911 Jun 8 # Pointe a Pitre - -4:00 - AST - -# Canada -# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S -Rule Mont 1917 only - Mar 25 2:00 1:00 D -Rule Mont 1917 only - Apr 24 0:00 0 S -Rule Mont 1919 only - Mar 31 2:30 1:00 D -Rule Mont 1919 only - Oct 25 2:30 0 S -Rule Mont 1920 only - May 2 2:30 1:00 D -Rule Mont 1920 1922 - Oct Sun>=1 2:30 0 S -Rule Mont 1921 only - May 1 2:00 1:00 D -Rule Mont 1922 only - Apr 30 2:00 1:00 D -Rule Mont 1924 only - May 17 2:00 1:00 D -Rule Mont 1924 1926 - Sep lastSun 2:30 0 S -Rule Mont 1925 1926 - May Sun>=1 2:00 1:00 D -# The 1927-to-1937 rules can be expressed more simply as -# Rule Mont 1927 1937 - Apr lastSat 24:00 1:00 D -# Rule Mont 1927 1937 - Sep lastSat 24:00 0 S -# The rules below avoid use of 24:00 -# (which pre-1998 versions of zic cannot handle). -Rule Mont 1927 only - May 1 0:00 1:00 D -Rule Mont 1927 1932 - Sep lastSun 0:00 0 S -Rule Mont 1928 1931 - Apr lastSun 0:00 1:00 D -Rule Mont 1932 only - May 1 0:00 1:00 D -Rule Mont 1933 1940 - Apr lastSun 0:00 1:00 D -Rule Mont 1933 only - Oct 1 0:00 0 S -Rule Mont 1934 1939 - Sep lastSun 0:00 0 S -Rule Mont 1946 1973 - Apr lastSun 2:00 1:00 D -Rule Mont 1945 1948 - Sep lastSun 2:00 0 S -Rule Mont 1949 1950 - Oct lastSun 2:00 0 S -Rule Mont 1951 1956 - Sep lastSun 2:00 0 S -Rule Mont 1957 1973 - Oct lastSun 2:00 0 S -# Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone America/Montreal -4:54:16 - LMT 1884 - -5:00 Mont E%sT 1918 - -5:00 Canada E%sT 1919 - -5:00 Mont E%sT 1942 Feb 9 2:00s - -5:00 Canada E%sT 1946 - -5:00 Mont E%sT 1974 - -5:00 Canada E%sT - -# Montserrat -Zone America/Montserrat -4:08:52 - LMT 1911 Jul 1 0:01 # Cork Hill - -4:00 - AST - -# Bahamas -# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S -Rule Bahamas 1964 1975 - Oct lastSun 2:00 0 S -Rule Bahamas 1964 1975 - Apr lastSun 2:00 1:00 D -# Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone America/Nassau -5:09:30 - LMT 1912 Mar 2 - -5:00 Bahamas E%sT 1976 - -5:00 US E%sT - -# Trinidad and Tobago -Zone America/Port_of_Spain -4:06:04 - LMT 1912 Mar 2 - -4:00 - AST - -# Brazil -# Rio_Branco is too ambiguous, since there's a Rio Branco in Uruguay too. -Zone America/Porto_Acre -4:31:12 - LMT 1914 - -5:00 Brazil AC%sT 1988 Sep 12 - -5:00 - ACT - -# Argentina -# Santa Fe (SF), Entre Rios (ER), Corrientes (CN), Misiones (MN), Chaco (CC), -# Formosa (FM), La Pampa (LP), Chubut (CH) -Zone America/Rosario -4:02:40 - LMT 1894 Nov - -4:16:44 - CMT 1920 May - -4:00 - ART 1930 Dec - -4:00 Arg AR%sT 1969 Oct 5 - -3:00 Arg AR%sT 1991 Jul - -3:00 - ART 1999 Oct 3 0:00 - -4:00 Arg AR%sT 2000 Mar 3 0:00 - -3:00 - ART - -# St Kitts-Nevis -Zone America/St_Kitts -4:10:52 - LMT 1912 Mar 2 # Basseterre - -4:00 - AST - -# St Lucia -Zone America/St_Lucia -4:04:00 - LMT 1890 # Castries - -4:04:00 - CMT 1912 # Castries Mean Time - -4:00 - AST - -# Virgin Is -Zone America/St_Thomas -4:19:44 - LMT 1911 Jul # Charlotte Amalie - -4:00 - AST - -# St Vincent and the Grenadines -Zone America/St_Vincent -4:04:56 - LMT 1890 # Kingstown - -4:04:56 - KMT 1912 # Kingstown Mean Time - -4:00 - AST - -# British Virgin Is -Zone America/Tortola -4:18:28 - LMT 1911 Jul # Road Town - -4:00 - AST - -# McMurdo, Ross Island, since 1955-12 -Zone Antarctica/McMurdo 0 - zzz 1956 - 12:00 NZAQ NZ%sT - -# Japan -Zone Asia/Ishigaki 8:16:36 - LMT 1896 - 8:00 - CST - -# Israel -Zone Asia/Tel_Aviv 2:19:04 - LMT 1880 - 2:21 - JMT 1918 - 2:00 Zion I%sT - -# Russia -Zone Asia/Tomsk 5:39:52 - LMT 1924 May 2 - 6:00 - TSK 1957 Mar - 7:00 Russia TS%s 1991 Mar 31 2:00s - 6:00 1:00 TSD 1991 Sep 29 2:00s - 6:00 - TSK 1992 Jan 19 2:00s - 7:00 Russia TS%s - -# Svalbard & Jan Mayen -Zone Atlantic/Jan_Mayen -1:00 - EGT - -# Australia -Zone Australia/Canberra 9:56:32 - LMT 1895 Feb - 10:00 - EST 1917 Jan 1 0:01 - 10:00 Aus EST 1971 Oct 31 2:00 - 10:00 AN EST 1981 Oct 25 2:00 - 10:00 1:00 EST 1982 Apr 4 3:00 - 10:00 AN EST - -# UK -Zone Europe/Belfast -0:23:40 - LMT 1880 Aug 2 - -0:25:21 - DMT 1916 May 21 2:00 # Dublin/Dunsink MT - -0:25:21 1:00 IST 1916 Oct 1 2:00s # Irish Summer Time - 0:00 GB-Eire %s 1968 Oct 27 - 1:00 - BST 1971 Oct 31 2:00u - 0:00 GB-Eire %s 1996 - 0:00 EU GMT/BST - -# Slovenia -Zone Europe/Ljubljana 0:58:04 - LMT 1884 - 1:00 - CET 1941 Apr 18 23:00 - 1:00 C-Eur CE%sT 1945 May 8 2:00s - 1:00 1:00 CEST 1945 Sep 16 2:00s - 1:00 - CET 1982 Nov 27 - 1:00 EU CE%sT - -# Bosnia and Herzegovina -Zone Europe/Sarajevo 1:13:40 - LMT 1884 - 1:00 - CET 1941 Apr 18 23:00 - 1:00 C-Eur CE%sT 1945 May 8 2:00s - 1:00 1:00 CEST 1945 Sep 16 2:00s - 1:00 - CET 1982 Nov 27 - 1:00 EU CE%sT - -# Macedonia -Zone Europe/Skopje 1:25:44 - LMT 1884 - 1:00 - CET 1941 Apr 18 23:00 - 1:00 C-Eur CE%sT 1945 May 8 2:00s - 1:00 1:00 CEST 1945 Sep 16 2:00s - 1:00 - CET 1982 Nov 27 - 1:00 EU CE%sT - -# Moldova -Zone Europe/Tiraspol 1:58:32 - LMT 1880 - 1:55 - CMT 1918 Feb 15 # Chisinau MT - 1:44:24 - BMT 1931 Jul 24 # Bucharest MT - 2:00 Romania EE%sT 1940 Aug 15 - 2:00 1:00 EEST 1941 Jul 17 - 1:00 C-Eur CE%sT 1944 Aug 24 - 3:00 Russia MSK/MSD 1991 Mar 31 2:00 - 2:00 Russia EE%sT 1992 Jan 19 2:00 - 3:00 Russia MSK/MSD - -# Croatia -# Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Europe/Zagreb 1:03:52 - LMT 1884 - 1:00 - CET 1941 Apr 18 23:00 - 1:00 C-Eur CE%sT 1945 May 8 2:00s - 1:00 1:00 CEST 1945 Sep 16 2:00s - 1:00 - CET 1982 Nov 27 - 1:00 EU CE%sT diff --git a/southamerica b/southamerica index 59f5fe7..ff47cef 100644 --- a/southamerica +++ b/southamerica @@ -631,7 +631,10 @@ Zone America/Argentina/Ushuaia -4:33:12 - LMT 1894 Oct 31 -3:00 - ART # Aruba -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Aruba -4:40:24 - LMT 1912 Feb 12 # Oranjestad + -4:30 - ANT 1965 # Netherlands Antilles Time + -4:00 - AST # Bolivia # Zone NAME GMTOFF RULES FORMAT [UNTIL] @@ -1325,7 +1328,7 @@ Zone America/Bogota -4:56:16 - LMT 1884 Mar 13 # Curacao -# Milne gives 4:35:46.9 for Curacao mean time. +# Milne gives 4:35:46.9 for Curacao mean time; round to nearest. # # From Paul Eggert (2006-03-22): # Shanks & Pottenger say that The Bottom and Philipsburg have been at @@ -1341,7 +1344,14 @@ Zone America/Bogota -4:56:16 - LMT 1884 Mar 13 # Netherlands as Kingdom Islands. This won't affect their time zones # though, as far as we know. # -# For all these regions, see America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Curacao -4:35:47 - LMT 1912 Feb 12 # Willemstad + -4:30 - ANT 1965 # Netherlands Antilles Time + -4:00 - AST + +# Sint Maarten +# Caribbean Netherlands +# Use America/Curacao. # Ecuador # @@ -1615,7 +1625,9 @@ Zone America/Paramaribo -3:40:40 - LMT 1911 -3:00 - SRT # Trinidad and Tobago -# See America/Puerto_Rico. +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone America/Port_of_Spain -4:06:04 - LMT 1912 Mar 2 + -4:00 - AST # Uruguay # From Paul Eggert (1993-11-18): -- 1.8.1.2

7 38

winnowing stats
by Zefram Sept. 3, 2013

Sept. 3, 2013

Here are some stats on how much difference winnowing makes to the dataset. Baseline: the source files define 441 distinct zones. Winnowing then reduces the number of distinct zones thus: YEAR COUNT 0000 440 1880 440 1890 439 1900 439 1910 437 1920 435 1930 435 1940 434 1950 425 1960 423 1970 417 1980 391 1990 365 2000 339 2010 313 2020 305 The reduction by one zone for a threshold year of 0000 comes from Pacific/Johnston, a US minor outlying island, which is defined with data identical to the "HST" zone. (Contrary to the usual practice of using LMT for the first segment of geographical zones.) As the two tzfiles are byte-for-byte identical, tzwinnow will merge them regardless of date thresholds. The results for a threshold in the future set a lower limit on the size to which the database can be reduced by this mechanism. Relative to the present full database of 441 zones, it's only a modest gain. Using a threshold later than 1970 for installation purposes will probably only be attractive in a few more decades' time, when there have been many more zone splits arising from contemporary activity. A threshold later than 1970 is currently much more valuable for tzselect purposes. Here it's saving human cognitive load rather than storage space. The reduction in the number of zones is concentrated disproportionately in the countries that have the greatest complexity. This is particularly noticeable with the US zones, the list of which is quite unwieldy in unwinnowed form. Over the period where we attempt complete coverage (1970 to today), the rate at which the number of distinct zones changes is amazingly consistent at 26 per decade. A similar pattern emerges when winnowing with a varying upper date limit, showing that there's a long-term roughly constant rate of zone churn. The number of zones distinct within a single decade is also roughly constant, around 330. The number distinct within a single year hovers around 300, possibly showing a slight rising trend, but I suspect that's an artifact of incomplete data. This suggests that a strategy of winnowing with a moving threshold that remains N years ago will produce a roughly constant zone count. By contrast, the number of zones differing at any time post-1970 (currently 417), or from any other fixed threshold, can grow without bound, and it looks like it will. -zefram

2 1

scope of tz database, scholarship
by Steve Allen Sept. 2, 2013

Sept. 2, 2013

For the sake of the scholarship I would like to see a modification of the current text that reads As for leap seconds, we don't know the history of earth's rotation accurately enough to map SI seconds to historical solar time to more than about one-hour accuracy; see Stephenson FR (2003), Historical eclipses and Earth's rotation, A&G 44: 2.22-2.27 <http://dx.doi.org/10.1046/j.1468-4004.2003.44222.x>. A more complete reference to the accuracy of historical Delta T is in Historical values of the Earth's clock error Delta T and the calculation of eclipses Morrison, L. V. & Stephenson, F. R. Journal for the History of Astronomy (ISSN 0021-8286), Vol. 35, Part 3, No. 120, p. 327 - 336 (2004) as can be seen at http://articles.adsabs.harvard.edu/full/2004JHA....35..327M where, in particular, Table 1 gives uncertainty estimates back nearly 3000 years. For the oldest data there is an addendum Addendum: Historical values of the Earth's clock error Morrison, L. V. & Stephenson, F. R. Journal for the History of Astronomy (ISSN 0021-8286), Vol. 36, Part 3, No. 124, p. 339 (2005) http://adsabs.harvard.edu/full/2005JHA....36..339M In addition to that, for all practical purposes, civil time prior to 1972 did not use SI seconds, but rather mean solar seconds, and for dates prior to 1955 there cannot even be an argument. Therefore in the extended range of the tz database there is an arguably unspecified point when the kind of seconds counted changes from mean solar (UT) to atomic (SI). -- Steve Allen <sla(a)ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m

3 2

Unacceptable recent changes [wasRe: [PATCH 2/4] Move obsolescent Americas entries to 'backward'.]
by Stephen Colebourne Aug. 31, 2013

Aug. 31, 2013

On 26 August 2013 18:16, Paul Eggert <eggert(a)cs.ucla.edu> wrote: > # Shanks & Pottenger say that Atikokan has agreed with Rainy River > # ever since standard time was introduced, but the information from > # McKinnon sounds more authoritative. For now, assume that Atikokan > # switched to EST immediately after WWII era daylight saving time > # ended. This matches the old (less-populous) America/Coral_Harbour > # entry since our cutoff date of 1970, so we can move > -# America/Coral_Harbour to the 'backward' file. > +# America/Coral_Harbour to the 'backward' file. And Atikokan itself > +# is the same as America/Panama since 1970, so we can move > +# America/Atikokan to the 'backward' file as well. > -Zone America/Atikokan -6:06:28 - LMT 1895 > - -6:00 Canada C%sT 1940 Sep 29 > - -6:00 1:00 CDT 1942 Feb 9 2:00s > - -6:00 Canada C%sT 1945 Sep 30 2:00 > - -5:00 - EST So if I understand correctly, all changes to Atikokan before 1970 have just been lost? And they are supposed to use Panama from now on? Here is what JSR-310 can tell us about the two sets of rules: America/Atikokan Transition[Gap at 1895-01-01T00:00-06:06:28 to -06:00] Transition[Gap at 1918-04-14T02:00-06:00 to -05:00] Transition[Overlap at 1918-10-27T02:00-05:00 to -06:00] Transition[Gap at 1940-09-29T00:00-06:00 to -05:00] America/Panama Transition[Overlap at 1890-01-01T00:00-05:18:08 to -05:19:36] Transition[Gap at 1908-04-22T00:00-05:19:36 to -05:00] Merging these is clearly utterly RIDICULOUS. They contain completely different data, and the 1970 argument simply won't wash. Many users will have stored data in databases or other long term storage that refers to these time-zones being made obsolete. When they read the data back, they will get completely different times for historic events - utterly unacceptable. More broadly, no one can pretend that the IDs we use are meaningless. Whether they should or should not have been created this way is not relevent - what matters is that these IDs are meningful and getting rid of them would be a disaster. The IDs are clearly localized, and they have a huge and longstanding usage globally. Panama is nowhere near Atikokan, nor would any reasonable user connect the two. Paul, you need to STOP NOW. You need to reverse the vast majority of your recent changes. Focus on actual changes happening in 2013. Keep the rest of the database totally and utterly stable. And just accept that there is a measure of politics incumbent in time-zones. NONE of these changes should be happening. STABILITY is vital. Stephen

20 53

Proposal for new rules
by Stephen Colebourne Aug. 30, 2013

Aug. 30, 2013

A simple proposal to move forward from where we are with reliable new rules: 1) Each inhabited ISO-3166 region must have at least one fully defined zone (LMT, pre and post 1970) 2) Links must not cross ISO-3166 region bouindaries Some of the rules that would require reworking (not a complete list): Europe/Busingen America/Atikotan America/Aruba America/Anguilla America/Port_of_Spain Europe/Zagreb Europe/Vatican Note that America/Montreal does not require reworking as a result of the first two new rules, although since it looks to have detailed historical information it would be unwise to lose that. Therefore I would add a third rule: 3) Existing pre-1970 data shall be respected If accepted, then these rules would be encoded in the theory file. Stephen

13 27

Acre, Brazil will attempt to re-introduce its previous timezone
by Alexander Krivenyshev Aug. 30, 2013

Aug. 30, 2013

According to the news from Brazil, Acre, Brazil will attempt to re-introduce its previous timezone, excluding Amazonas. http://www.worldtimezone.com/dst_news/dst_news_brazil11.html Alexander Krivenyshev, http://www.WorldTimeZone.com

1 0

Introducing myself
by Stephen Colebourne Aug. 29, 2013

Aug. 29, 2013

On 29 August 2013 20:39, Kevin Lyda <kevin(a)ie.suberic.net> wrote: > No solution will avoid politics. And someone starting a number of threads on > this topic clearly has their own political agenda. I should introduce myself, as not everyone will know who I am, or what I represent. I am Stephen Colebourne - a Java developer of 15+ years - recognised as a Java Champion, a leader in the Java community - author of Joda-Time, the most widely adopted 3rd party API for date and time in Java - co-spec lead of JSR-310, the effort to write a better API for the Java JDK - have written APIs to parse the tzdb - have designed APIs to expose that data to developers - work very closely with Oracle, and have had conversations with CLDR in the past My "political agenda" is to avoid the effort I've put in over the last 12 years on date and time in Java being damaged. Recent changes give the appearance of a lack of understanding of the importance of pre-1970 data and of cross-border localization. I'm sorry that I've had to write so much and object so strongly. I want to find a solution we can all agree on. It seems harder than it should be. Stephen

3 2

Problematic/dubious commits in 2013
by Stephen Colebourne Aug. 29, 2013

Aug. 29, 2013

I have reviewed every commit since the end of 2012. Here are the ones I consider to be problematic. I suggest that others have another review of these, as it may be that not everyone has taken the time to do this. - One zone for each inhabited ISO-3166 region should not have been removed: https://github.com/eggert/tz/commit/d3b025adb25554ee10b986850371e573df92733… - Ensuing changes were wrong: https://github.com/eggert/tz/commit/df99923bde035a263493f3435db63db15df14d53 - Reversion did not revert everything, specifically the reverted links are still in the backward file, not the main file, indicating that they are deprecated which should not be the case (eg for Europe/Zagreb): https://github.com/eggert/tz/commit/ee40570d7d937de749fe89676dec2ff1526ee68b - Pre-1970 damage: https://github.com/eggert/tz/commit/5903db75e5974fbdede1fa05bcef53ff645ac13d https://github.com/eggert/tz/commit/9432f1d23d3c5bbcc14c26f781185c01679edeef - Montreal removal (looks like it changes pre-1970 history) https://github.com/eggert/tz/commit/45dcf69b45087cff50282d4da64b86a7d705ddf3 - Navajo - America/ShipRock removal https://github.com/eggert/tz/commit/d58b59dd8a1e4c10abdbab8857ae521f6c2d2536 https://github.com/eggert/tz/commit/81be53c16b97ce0bc561ce3891ce2503227e3369 - Other possibly dubious commits tzselect changes https://github.com/eggert/tz/commit/cc3f93886bcfe36dfedc8f340827fded6e43539c https://github.com/eggert/tz/commit/ebdf0c5d0ce06b20dcd7e984b7370548f74dc210 Not all of these cause damage, but some clearly do. I'm unhappy with most of them, as they break the principles I value. Stephen

1 0

Principles
by Stephen Colebourne Aug. 29, 2013

Aug. 29, 2013

It seems like there are conflicts in the principles behind the tzdb. Here are my thoughts: What is the tzdb? Generally accepted: - widely used - ubiquitous - reliable - accurate post-1970 - handles changes occurring now More controversial: - IDs used in GUIs (they are whether we like it or not) - IDs have meaning (they do whether we like it or not) - pre-1970 is in-scope (data is there whether we like it or not) - pre-1970 data may not be accurate (users like data, care less about its accuracy) - pre-1970 LMT is accurate for the location in the tzdb ID What do end users expect? (developers and non-developers) - users often pick zones based on raw tzdb ID - users don't know the history of zone rules in their location - users do know that they live in an area that might have special zone rules, eg. Busingen/Navajo - users want minimal cognitive effort, pick it and it works - users don't understand the nuances of a cross-border zone, they just associate with their region What do I expect? - Stability - No deletions of data, except where _proven_ wrong - Additions focussed on today and the future - Historical changes only following research - No new time-zones in the main files unless they differ post-1970 - At least one time-zone ID for each ISO-3166 region - Using all files except backward should meet goals above - Backward file is for deprecations only I don't think that any of this is unreasonable, or different from how the tzdb has previously worked. Stephen

1 0

Namibia Time Change
by Hank W. Aug. 26, 2013

Aug. 26, 2013

Reminder: The annual switch from West Africa Time (UTC+1) to West Africa Summer Time (UTC+2) in Namibia only is scheduled for this coming Sunday, 1 September, at 2 AM WAT (1 AM UTC).

2 2

Unable to get the tz database
by Peddi, Radhika (Radhika) Aug. 24, 2013

Aug. 24, 2013

Hi, This is Radhika from Avaya. When I am trying to get tz database from the link http://www.twinsun.com/tz/tz-link.htm, by using FTP distribution, I am getting Host Not Found error. Please find the attached screen shot for the same. When I am using below shell command on my linux setup wget 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz', I am getting below error --2013-08-20 03:14:03-- ftp://elsie.nci.nih.gov/pub/tz*.tar.gz => `.listing' Resolving elsie.nci.nih.gov... failed: Name or service not known. wget: unable to resolve host address `elsie.nci.nih.gov' Could you please help me how to get rid of this problem. Thanks & Regards, Radhika Peddi|Avaya India Pvt. Ltd.| Wing 'A', Level -5, Tower-11, Cybercity, Magarpatta City, Hadapsar | Pune, 411028|India Voice +91 20 4101 8311| Email: rpeddi<mailto:rpeddi@avaya.com>@avaya.com [ Please consider the environment before printing this email ]

2 3

infinite loop in time2sub
by enh Aug. 22, 2013

Aug. 22, 2013

i recently upgraded Android's copy of tzcode to be closer to tzcode2013d. with Android's signed 32-bit time_t i'm seeing a change in behavior for out-of-range dates. previously given something like this, mktime would return an error, but now it hangs in the binary search in time2sub. struct tm t; memset(&t, 0, sizeof(tm)); t.tm_year = 200; t.tm_mon = 2; t.tm_mday = 10; changing the if (t == lo) { ++t; if (t <= lo) return WRONG; ++lo; } else if (t == hi) { --t; if (t >= hi) return WRONG; --hi; } back to if (t == lo) { if (t == TIME_T_MAX) return WRONG; ++t; ++lo; } else if (t == hi) { if (t == TIME_T_MIN) return WRONG; --t; --hi; } fixes things. looking at the git history in https://github.com/eggert/tz.gitit looks like the old code, found in Android up to and including jb-mr2 (but no longer in AOSP ToT), was never in upstream tzcode. here's where the upstream tzcode's overflow checks were introduced: commit 46fa7e98177cae664f673c6034c9ac74d0ccd0ec Author: Arthur David Olson <olsona@elsie> Date: Tue Aug 9 09:55:06 2005 -0400 overflow work SCCS-file: localtime.c SCCS-SID: 7.96 diff --git a/localtime.c b/localtime.c index 1c3e9b0..d3edb5a 100644 --- a/localtime.c +++ b/localtime.c @@ -1616,9 +1616,13 @@ const int do_norm_secs; if (dir != 0) { if (t == lo) { ++t; + if (t <= lo) + return WRONG; ++lo; } else if (t == hi) { --t; + if (t >= hi) + return WRONG; --hi; } if (lo > hi) looking at the Android AOSP git history, it looks like we found and fixed this bug years ago but never talked to upstream about it: commit 2093d350be21ff086f9e145404877941b9a42c5c Author: David 'Digit' Turner <digit(a)google.com> Date: Wed Sep 9 17:41:59 2009 -0700 Fix an infinite loop in time2sub. The problem is that time_t is signed, and the original code relied on the fact that (X + c < X) in case of overflow for c >= 0. Unfortunately, this condition is only guaranteed by the standard for unsigned arithmetic, and the gcc 4.4.0 optimizer did completely remove the corresponding test from the code. This resulted in a missing boundary check, and an infinite loop. The problem is solved by testing explicitely for TIME_T_MIN and TIME_T_MAX in the loop that uses this. Also fix increment_overflow and long_increment_overflow which were buggy for exactly the same reasons. Note: a similar fix is needed for system/core/libcutils diff --git a/libc/tzcode/localtime.c b/libc/tzcode/localtime.c index 9c5f218..83c1011 100644 --- a/libc/tzcode/localtime.c +++ b/libc/tzcode/localtime.c @@ -75,6 +75,31 @@ static __inline__ void _tzUnlock(void) pthread_mutex_unlock(&_tzMutex); } +/* Complex computations to determine the min/max of time_t depending + * on TYPE_BIT / TYPE_SIGNED / TYPE_INTEGRAL. + * These macros cannot be used in pre-processor directives, so we + * let the C compiler do the work, which makes things a bit funky. + */ +static const time_t TIME_T_MAX = + TYPE_INTEGRAL(time_t) ? + ( TYPE_SIGNED(time_t) ? + ~((time_t)1 << (TYPE_BIT(time_t)-1)) + : + ~(time_t)0 + ) + : /* if time_t is a floating point number */ + ( sizeof(time_t) > sizeof(float) ? (time_t)DBL_MAX : (time_t)FLT_MAX ); + +static const time_t TIME_T_MIN = + TYPE_INTEGRAL(time_t) ? + ( TYPE_SIGNED(time_t) ? + ((time_t)1 << (TYPE_BIT(time_t)-1)) + : + 0 + ) + : + ( sizeof(time_t) > sizeof(float) ? (time_t)DBL_MIN : (time_t)FLT_MIN ); + #ifndef WILDABBR /* ** Someone might make incorrect use of a time zone abbreviation: @@ -1683,11 +1708,16 @@ increment_overflow(number, delta) int * number; int delta; { - int number0; + unsigned number0 = (unsigned)*number; + unsigned number1 = (unsigned)(number0 + delta); + + *number = (int)number1; - number0 = *number; - *number += delta; - return (*number < number0) != (delta < 0); + if (delta >= 0) { + return ((int)number1 < (int)number0); + } else { + return ((int)number1 > (int)number0); + } } static int @@ -1695,11 +1725,16 @@ long_increment_overflow(number, delta) long * number; int delta; { - long number0; + unsigned long number0 = (unsigned long)*number; + unsigned long number1 = (unsigned long)(number0 + delta); + + *number = (long)number1; - number0 = *number; - *number += delta; - return (*number < number0) != (delta < 0); + if (delta >= 0) { + return ((long)number1 < (long)number0); + } else { + return ((long)number1 > (long)number0); + } } static int @@ -1868,14 +1903,14 @@ const int do_norm_secs; } else dir = tmcomp(&mytm, &yourtm); if (dir != 0) { if (t == lo) { - ++t; - if (t <= lo) + if (t == TIME_T_MAX) return WRONG; + ++t; ++lo; } else if (t == hi) { - --t; - if (t >= hi) + if (t == TIME_T_MIN) return WRONG; + --t; --hi; } if (lo > hi) right now i'm going to work around this by building the tzcode part of the C library with -fno-strict-overflow (because i don't know how many other places are relying on this unspecified behavior), but i'll apply whatever patch goes into upstream as soon as it's available. --elliott

2 2

[PATCH] * .gitignore: Add 'date'.
by Paul Eggert Aug. 22, 2013

Aug. 22, 2013

--- .gitignore | 1 + 1 file changed, 1 insertion(+) diff --git a/.gitignore b/.gitignore index 5759d2a..18dbbcc 100644 --- a/.gitignore +++ b/.gitignore @@ -4,6 +4,7 @@ *.txt *~ ChangeLog +date leapseconds time.tab tzselect -- 1.7.11.7

1 0

[PATCH] tzselect: new options -c COORD and -n LIMIT
by Paul Eggert Aug. 22, 2013

Aug. 22, 2013

These let the user select TZ based on geographical coordinates. Combining '-c COORD' with '-t time' better insulates the user from issues of nationality. * tzselect.8 (SYNOPSIS, OPTIONS): Document the new options. * tzselect.ksh: Implement them, using the great-circle special case of the Vicenty formula for distances on ellipsoids. (LC_ALL): Set to C, since tzselect is English only. That way, we treat decimal-points in -c option operands the same in all environments. (usage): Document new options. Document existing ones better. (output_distances): New variable. --- tzselect.8 | 26 ++++++++++ tzselect.ksh | 162 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 177 insertions(+), 11 deletions(-) diff --git a/tzselect.8 b/tzselect.8 index b5e2c88..884af36 100644 --- a/tzselect.8 +++ b/tzselect.8 @@ -4,6 +4,12 @@ tzselect \- select a time zone .SH SYNOPSIS .B tzselect [ +.B \-c +.I coord +] [ +.B \-n +.I limit +] [ .B \-t .I zonetabtype ] [ @@ -21,6 +27,26 @@ The output is suitable as a value for the TZ environment variable. All interaction with the user is done via standard input and standard error. .SH OPTIONS .TP +.BI "\-c " coord +Instead of asking for continent and then country and then city, +ask for selection from time zones whose largest cities +are closest to the location with geographical coordinates +.IR coord . +Use ISO 6709 notation for +.IR coord , +for example, +.B "\-c\ \+42.391415\-071.570419" +for 42.391415\(de\|N, 71.570419\(de\|W, and +.B "\-c\ +404226\-0740319" +for 48\(de\|42\(fm\|26\(sd\|N, 74\(de\|3\(fm\|19\(sd\|W. +.TP +.BI "\-n " limit +When +.B \-c +is used, display the closest +.I limit +locations (default 10). +.TP .BI "\-t " zonetabtype Make selections from the time zone table of type .IR zonetabtype . diff --git a/tzselect.ksh b/tzselect.ksh index dc9f256..da6adb2 100644 --- a/tzselect.ksh +++ b/tzselect.ksh @@ -1,5 +1,7 @@ #!/bin/bash +export LC_ALL=C + PKGVERSION='(tzcode) ' TZVERSION=see_Makefile REPORT_BUGS_TO=tz(a)iana.org @@ -41,15 +43,43 @@ ZONETABTYPE=zone exit 1 } -usage="Usage: tzselect [--version] [--help] [-t ZONETABTYPE] +coord= +location_limit=10 + +usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT] [-t ZONETABTYPE] Select a time zone interactively. -ZONETABTYPE should be one of 'time' or 'zone'. + +Options: + + -c COORD + Instead of asking for continent and then country and then city, + ask for selection from time zones whose largest cities + are closest to the location with geographical coordinates COORD. + COORD should use ISO 6709 notation, for example, '-c +4852+00220' + for Paris. + + -n LIMIT + Display at most LIMIT locations when -c is used (default $location_limit). + + -t ZONETABTYPE + Use time zone table ZONETABTYPE. ZONETABTYPE should be one of + 'time' or 'zone'. + + --version + Output version information. + + --help + Output this help. Report bugs to $REPORT_BUGS_TO." -while getopts t:-: opt +while getopts c:n:t:-: opt do case $opt$OPTARG in + c*) + coord=$OPTARG ;; + n*) + location_limit=$OPTARG ;; t*) ZONETABTYPE=$OPTARG ;; -help) @@ -90,6 +120,66 @@ case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in ?*) PS3= esac +# Awk script to read a time zone table and output the same table, +# with each column preceded by its distance from 'here'. +output_distances=' + BEGIN { + FS = "\t" + while (getline <TZ_COUNTRY_TABLE) + if ($0 ~ /^[^#]/) + country[$1] = $2 + country["US"] = "US" # Otherwise the strings get too long. + } + function cvt1(coord, deg, min, ilen, sign, sec) { + ilen = length(coord) + sign = substr(coord, 1, 1) + if (coord ~ /\./) { + deg = coord + 0 + } else { + if (ilen <= 6) { + sec = 0 + } else { + sec = sign substr(coord, ilen - 1) + ilen -= 2 + } + min = sign substr(coord, ilen - 1, 2) + deg = substr(coord, 1, ilen - 2) + deg = (deg * 3600.0 + min * 60.0 + sec) / 3600.0 + } + return deg * 0.017453292519943295 + } + function convert_latitude(coord) { + match(coord, /..*[-+]/) + return cvt1(substr(coord, 1, RLENGTH - 1)) + } + function convert_longitude(coord) { + match(coord, /..*[-+]/) + return cvt1(substr(coord, RLENGTH)) + } + # Great-circle distance between points with given latitude and longitude. + # Inputs and output are in radians. This uses the great-circle special + # case of the Vicenty formula for distances on ellipsoids. + function dist(lat1, long1, lat2, long2, dlong, x, y, num, denom) { + dlong = long2 - long1 + x = cos (lat2) * sin (dlong) + y = cos (lat1) * sin (lat2) - sin (lat1) * cos (lat2) * cos (dlong) + num = sqrt (x * x + y * y) + denom = sin (lat1) * sin (lat2) + cos (lat1) * cos (lat2) * cos (dlong) + return atan2(num, denom) + } + BEGIN { + coord_lat = convert_latitude(coord) + coord_long = convert_longitude(coord) + } + /^[^#]/ { + here_lat = convert_latitude($2) + here_long = convert_longitude($2) + line = $1 "\t" $2 "\t" $3 "\t" country[$1] + if (NF == 4) + line = line " - " $4 + printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), line + } +' # Begin the main loop. We come back here if the user wants to retry. while @@ -101,10 +191,14 @@ while country= region= + case $coord in + ?*) + continent=coord;; + '') # Ask the user for continent or ocean. - echo >&2 'Please select a continent or ocean.' + echo >&2 'Please select a continent, ocean, "coord", or "TZ".' select continent in \ Africa \ @@ -117,7 +211,8 @@ while Europe \ 'Indian Ocean' \ 'Pacific Ocean' \ - 'none - I want to specify the time zone using the Posix TZ format.' + 'coord - I want to use geographical coordinates.' \ + 'TZ - I want to specify the time zone using the Posix TZ format.' do case $continent in '') @@ -130,10 +225,12 @@ while break esac done + esac + case $continent in '') exit 1;; - none) + TZ) # Ask the user for a Posix TZ string. Check that it conforms. while echo >&2 'Please enter the desired value' \ @@ -158,6 +255,45 @@ while done TZ_for_date=$TZ;; *) + case $continent in + coord) + case $coord in + '') + echo >&2 'Please enter coordinates' \ + 'in ISO 6709 notation.' + echo >&2 'For example, +4042-07403 stands for' + echo >&2 '40 degrees 42 minutes north,' \ + '74 degrees 3 minutes west.' + read coord;; + esac + distance_table=$($AWK \ + -v coord="$coord" \ + -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ + "$output_distances" <$TZ_ZONE_TABLE | + sort -n | + sed "${location_limit}q" + ) + regions=$(echo "$distance_table" | $AWK ' + BEGIN { FS = "\t" } + { print $NF } + ') + echo >&2 'Please select one of the following' \ + 'time zone regions,' + echo >&2 'listed roughly in increasing order' \ + "of distance from $coord". + select region in $regions + do + case $region in + '') echo >&2 'Please enter a number in range.';; + ?*) break;; + esac + done + TZ=$(echo "$distance_table" | $AWK -v region="$region" ' + BEGIN { FS="\t" } + $NF == region { print $4 } + ') + ;; + *) # Get list of names of countries in the continent or ocean. countries=$($AWK -F'\t' \ -v continent="$continent" \ @@ -185,7 +321,8 @@ while # If there's more than one country, ask the user which one. case $countries in *"$newline"*) - echo >&2 'Please select a country.' + echo >&2 'Please select a country' \ + 'whose clocks agree with yours.' select country in $countries do case $country in @@ -256,6 +393,7 @@ while } $1 == cc && $4 == region { print $3 } ' <$TZ_ZONE_TABLE) + esac # Make sure the corresponding zoneinfo file exists. TZ_for_date=$TZDIR/$TZ @@ -292,9 +430,11 @@ Universal Time is now: $UTdate." echo >&2 "" echo >&2 "The following information has been given:" echo >&2 "" - case $country+$region in - ?*+?*) echo >&2 " $country$newline $region";; - ?*+) echo >&2 " $country";; + case $country%$region%$coord in + ?*%?*%) echo >&2 " $country$newline $region";; + ?*%%) echo >&2 " $country";; + %?*%?*) echo >&2 " coord $coord$newline $region";; + %%?*) echo >&2 " coord $coord";; +) echo >&2 " TZ='$TZ'" esac echo >&2 "" @@ -313,7 +453,7 @@ Universal Time is now: $UTdate." '') exit 1;; Yes) break esac -do : +do coord= done case $SHELL in -- 1.8.1.2

3 7

[PATCH 1/3] Further removal of attempt to support floating-point time_t.
by Paul Eggert Aug. 19, 2013

Aug. 19, 2013

* localtime.c (timesub): * zdump.c (my_localtime): Don't worry about time_t being floating-point. * localtime.c (timesub): Avoid undefined behavior on integer overflow when assigning time_t to int. --- localtime.c | 5 +++-- zdump.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/localtime.c b/localtime.c index 5312ad9..f58b20a 100644 --- a/localtime.c +++ b/localtime.c @@ -1489,9 +1489,10 @@ timesub(const time_t *const timep, const int_fast32_t offset, register int leapdays; tdelta = tdays / DAYSPERLYEAR; - idelta = tdelta; - if (tdelta - idelta >= 1 || idelta - tdelta >= 1) + if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta) + && tdelta <= INT_MAX)) return NULL; + idelta = tdelta; if (idelta == 0) idelta = (tdays < 0) ? -1 : 1; newy = y; diff --git a/zdump.c b/zdump.c index 36c1838..fa5f8d8 100644 --- a/zdump.c +++ b/zdump.c @@ -244,7 +244,7 @@ my_localtime(time_t *tp) tm = *tmp; t = mktime(&tm); - if (t - *tp >= 1 || *tp - t >= 1) { + if (t != *tp) { (void) fflush(stdout); (void) fprintf(stderr, "\n%s: ", progname); (void) fprintf(stderr, tformat(), *tp); -- 1.8.1.2

3 7

Re: [tz] Problem with Busingen
by Paul Eggert Aug. 19, 2013

Aug. 19, 2013

Luca Marzolla wrote: > It is possible to fix this minor inconvenience in the next release? Yes. The problem should already be fixed in the experimental version, which you can get from Github, here: https://github.com/eggert/tz It's fixed in a different way, by the way: the Busingen link got moved to a different file. See: https://github.com/eggert/tz/commit/df99923bde035a263493f3435db63db15df14d53

1 0

Mushroom clowds are forming…
by Steffen Daode Nurpmeso Aug. 17, 2013

Aug. 17, 2013

So if there is a button, someone surely is going to press it. --steffen

1 0

[PATCH] * date.c (nondigit): Add ATTRIBUTE_PURE, to pacify GCC 4.8.1.
by Paul Eggert Aug. 17, 2013

Aug. 17, 2013

--- date.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/date.c b/date.c index 4355a7b..d8ff50e 100644 --- a/date.c +++ b/date.c @@ -497,7 +497,7 @@ errensure(void) retval = EXIT_FAILURE; } -static const char * +static const char * ATTRIBUTE_PURE nondigit(register const char *cp) { while (is_digit(*cp)) -- 1.7.11.7

1 0

[PATCH] * zdump.c: Minor integer-size porting fixes.
by Paul Eggert Aug. 17, 2013

Aug. 17, 2013

(main): Don't assume SECSPERDAY <= INT_MAX here, since we try not to assume that sort of thing elsewhere in this file. Don't rely on undefined behavior in the weird case where cuthitime < absolute_min_time + SECSPERDAY / 2. --- zdump.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/zdump.c b/zdump.c index fa5f8d8..3d5ec64 100644 --- a/zdump.c +++ b/zdump.c @@ -452,7 +452,7 @@ main(int argc, char *argv[]) t = absolute_min_time; if (!Vflag) { show(argv[i], t, TRUE); - t += SECSPERHOUR * HOURSPERDAY; + t += SECSPERDAY; show(argv[i], t, TRUE); } if (t < cutlotime) @@ -463,9 +463,11 @@ main(int argc, char *argv[]) (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1); } for ( ; ; ) { - if (t >= cuthitime || t >= cuthitime - SECSPERHOUR * 12) + newt = (t < absolute_max_time - SECSPERDAY / 2 + ? t + SECSPERDAY / 2 + : absolute_max_time); + if (cuthitime <= newt) break; - newt = t + SECSPERHOUR * 12; newtmp = localtime(&newt); if (newtmp != NULL) newtm = *newtmp; @@ -488,9 +490,9 @@ main(int argc, char *argv[]) } if (!Vflag) { t = absolute_max_time; - t -= SECSPERHOUR * HOURSPERDAY; + t -= SECSPERDAY; show(argv[i], t, TRUE); - t += SECSPERHOUR * HOURSPERDAY; + t += SECSPERDAY; show(argv[i], t, TRUE); } } -- 1.7.11.7

1 0

[PATCH] * zdump.c: Tune performance of -c with large numbers on 64-bit hosts.
by Paul Eggert Aug. 15, 2013

Aug. 15, 2013

On my platform (Ubuntu 13.04 x86-64, Xeon E3-1225 V2), this sped up 'zdump -V -c 2147483647,2147483648 America/Los_Angeles' from 13.880 to 0.000 seconds user+system time. (INTMAX_MAX): Define if the system doesn't. (SECSPER400YEARS): New macro. (SECSPER400YEARS_FITS): New constant. (yeartot): Speed up by using division instead of repeated subtraction. --- zdump.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 46 insertions(+), 17 deletions(-) diff --git a/zdump.c b/zdump.c index 788020a..36c1838 100644 --- a/zdump.c +++ b/zdump.c @@ -60,9 +60,15 @@ typedef int int_fast32_t; # if defined LLONG_MAX || defined __LONG_LONG_MAX__ typedef long long intmax_t; # define PRIdMAX "lld" +# ifdef LLONG_MAX +# define INTMAX_MAX LLONG_MAX +# else +# define INTMAX_MAX __LONG_LONG_MAX__ +# endif # else typedef long intmax_t; # define PRIdMAX "ld" +# define INTMAX_MAX LONG_MAX # endif #endif #ifndef SCNdMAX @@ -140,6 +146,17 @@ typedef long intmax_t; #define SECSPERDAY ((int_fast32_t) SECSPERHOUR * HOURSPERDAY) #define SECSPERNYEAR (SECSPERDAY * DAYSPERNYEAR) #define SECSPERLYEAR (SECSPERNYEAR + SECSPERDAY) +#define SECSPER400YEARS (SECSPERNYEAR * (intmax_t) (300 + 3) \ + + SECSPERLYEAR * (intmax_t) (100 - 3)) + +/* +** True if SECSPER400YEARS is known to be representable as an +** intmax_t. It's OK that SECSPER400YEARS_FITS can in theory be false +** even if SECSPER400YEARS is representable, because when that happens +** the code merely runs a bit more slowly, and this slowness doesn't +** occur on any practical platform. +*/ +enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 }; #ifndef HAVE_GETTEXT #define HAVE_GETTEXT 0 @@ -490,30 +507,42 @@ main(int argc, char *argv[]) static time_t yeartot(const intmax_t y) { - register intmax_t myy; - register int_fast32_t seconds; + register intmax_t myy, seconds, years; register time_t t; myy = EPOCH_YEAR; t = 0; - while (myy != y) { - if (myy < y) { + while (myy < y) { + if (SECSPER400YEARS_FITS && 400 <= y - myy) { + intmax_t diff400 = (y - myy) / 400; + if (INTMAX_MAX / SECSPER400YEARS < diff400) + return absolute_max_time; + seconds = diff400 * SECSPER400YEARS; + years = diff400 * 400; + } else { seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR; - ++myy; - if (t > absolute_max_time - seconds) { - t = absolute_max_time; - break; - } - t += seconds; + years = 1; + } + myy += years; + if (t > absolute_max_time - seconds) + return absolute_max_time; + t += seconds; + } + while (y < myy) { + if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) { + intmax_t diff400 = (myy - y) / 400; + if (INTMAX_MAX / SECSPER400YEARS < diff400) + return absolute_min_time; + seconds = diff400 * SECSPER400YEARS; + years = diff400 * 400; } else { - --myy; - seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR; - if (t < absolute_min_time + seconds) { - t = absolute_min_time; - break; - } - t -= seconds; + seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR; + years = 1; } + myy -= years; + if (t < absolute_min_time + seconds) + return absolute_min_time; + t -= seconds; } return t; } -- 1.8.1.2

2 2

[PATCH 1/4] * date.c: Pacify GCC 4.7.3.
by Paul Eggert Aug. 15, 2013

Aug. 15, 2013

(atof, getlogin, mktime, strchr, time, strftime): Remove old-style declarations. GCC 4.7.3 warns about them, and they aren't needed nowadays anyway. (main) [HAVE_SETTIMEOFDAY != 2]: "Use" dsttime and minuteswest to pacify GCC 4.7.3. --- date.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/date.c b/date.c index 047969f..bae90f3 100644 --- a/date.c +++ b/date.c @@ -54,14 +54,9 @@ static char sccsid[] = "@(#)date.c 4.23 (Berkeley) 9/20/88"; #define SECSPERMIN 60 #endif /* !defined SECSPERMIN */ -extern double atof(); extern char ** environ; -extern char * getlogin(); -extern time_t mktime(); extern char * optarg; extern int optind; -extern char * strchr(); -extern time_t time(); extern char * tzname[2]; static int retval = EXIT_SUCCESS; @@ -270,6 +265,8 @@ _("date: error: multiple values in command line\n")); oops("settimeofday"); #endif /* HAVE_SETTIMEOFDAY == 2 */ #if HAVE_SETTIMEOFDAY != 2 + (void) dsttime; + (void) minuteswest; (void) fprintf(stderr, _("date: warning: kernel doesn't keep -d/-t information, option ignored\n")); #endif /* HAVE_SETTIMEOFDAY != 2 */ @@ -543,8 +540,6 @@ display(const char *const format) exit(retval); } -extern size_t strftime(); - #define INCR 1024 static void -- 1.8.1.2

15 32