**********************************************************************
* Copyright (c) 2003-2004, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
* Author: Alan Liu
* Created: August 18 2003
* Since: ICU 2.8
**********************************************************************
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OVERVIEW
This file describes the tools in icu/source/tools/tzcode
The purpose of these tools is to process the zoneinfo or "Olson" time
zone database into a form usable by ICU4C (release 2.8 and later).
Unlike earlier releases, ICU4C 2.8 supports historical time zone
behavior, as well as the full set of Olson compatibility IDs.
References:
ICU4C: http://icu.sourceforge.net/
Olson: ftp://elsie.nci.nih.gov/pub/
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ICU4C vs. ICU4J
For ICU releases >= 2.8, both ICU4C and ICU4J implement full
historical time zones, based on Olson data. The implementations in C
and Java are somewhat different. The C implementation is a
self-contained implementation, whereas ICU4J uses the underlying JDK
1.3 or 1.4 time zone implementation.
Older versions of ICU (C and Java <= 2.6) implement a "present day
snapshot". This only reflects current time zone behavior, without
historical variation. Furthermore, it lacks the full set of Olson
compatibility IDs.
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BACKGROUND
The zoneinfo or "Olson" time zone package is used by various systems
to describe the behavior of time zones. The package consists of
several parts. E.g.:
Index of ftp://elsie.nci.nih.gov/pub/
classictzcode.tar.gz 65 KB 12/10/1994 12:00:00 AM
classictzdata.tar.gz 67 KB 12/10/1994 12:00:00 AM
e5+57.tar.gz 2909 KB 3/22/1993 12:00:00 AM
iso8601.ps.gz 16 KB 7/27/1996 12:00:00 AM
leastsq.xls 49 KB 4/24/1997 12:00:00 AM
ltroff.tar.gz 36 KB 7/16/1993 12:00:00 AM
pi.shar.gz 4 KB 3/9/1994 12:00:00 AM
tzarchive.gz 3412 KB 8/18/2003 4:00:00 AM
tzcode2003a.tar.gz 98 KB 3/24/2003 2:32:00 PM
tzdata2003a.tar.gz 132 KB 3/24/2003 2:32:00 PM
ICU only uses the tzcodeYYYYV.tar.gz and tzdataYYYYV.tar.gz files,
where YYYY is the year and V is the version letter ('a'...'z').
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HOWTO
1. Obtain the current versions of tzcodeYYYYV.tar.gz (aka `tzcode')
and tzdataYYYYV.tar.gz (aka `tzdata') from the FTP site given
above. Either manually download or use wget:
$ cd {path_to}/icu/source/tools/tzcode
$ wget "ftp://elsie.nci.nih.gov/pub/tz*.tar.gz"
2. Unpack tzcode and tzdata directly into the directory tzcode:
$ tar xzvf tzcode*.tar.gz
$ tar xzvf tzdata*.tar.gz
*** Make sure you only have ONE FILE named tzdata*.tar.gz in the
directory.
*** Do NOT delete the tzdata*.tar.gz file.
The Makefile looks in the current directory to determine the
version of Olson data it is building by looking for tzdata*.tar.gz.
3. Apply the ICU patch to zic.c:
$ patch < patch-icu-tzcode
If patch complains at this point, there is a mismatch that must be
manually addressed. See the CVS log of `patch-icu-tzcode' for
version details.
4. Build:
$ make icu_data
5. Copy the data files to the correct location in the ICU4C/ICU4J
source trees:
$ cp zoneinfo.txt ../../../data/misc/
$ cp ZoneMetaData.java {path_to}/icu4j/src/com/ibm/icu/impl
6. Rebuild ICU:
$ cd ../../../
$ {*make}
7. Don't forget to check in the new zoneinfo.txt (from its location at
{path_to}/icu/source/data/misc/zoneinfo.txt) into CVS.
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HOWTO regenerate patch-icu-tzcode
If you need to edit any of the tzcode* files, you will need to
regenerate the patch file as follows.
1. Follow the above instructions to extract and patch the tzcode*
files in {path_to}/icu/source/tools/tzcode. Modify any of the
tzcode files.
2. Extract a clean set of the tzcode* files into a new directory,
../tzcode.orig/:
$ mkdir ../tzcode.orig
$ cd ../tzcode.orig
$ tar xzf ../tzcode/tzcode*.tar.gz
$ cd ../tzcode
3. Compute diffs, ignoring files that are in only one directory:
$ diff -ur ../tzcode.orig . | grep -vE -e "^Only in " > patch-icu-tzcode
4. Test the patch-icu-tzcode file by regenerating and diffing the
files again in another directory. The expected output from the
final diff command is *nothing*.
$ mkdir ../tzcode.new
$ cd ../tzcode.new
$ tar xzf ../tzcode/tzcode*.tar.gz
$ patch < ../tzcode/patch-icu-tzcode
$ cd ../tzcode
$ diff -ur ../tzcode.new . | grep -vE -e "^Only in "
5. Check in the new patch-icu-tzcode file.
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