icuSources/tools/tzcode/readme.txt

   1 **********************************************************************
   2 * Copyright (c) 2003-2014, International Business Machines
   3 * Corporation and others.  All Rights Reserved.
   4 **********************************************************************
   5 * Author: Alan Liu
   6 * Created: August 18 2003
   7 * Since: ICU 2.8
   8 **********************************************************************
   9
  10 Note:  this directory currently contains tzcode as of tzcode2014b.tar.gz
  11    with localtime.c  patches from tzcode2014b.tar.gz
  12
  13
  14 ----------------------------------------------------------------------
  15 OVERVIEW
  16
  17 This file describes the tools in icu/source/tools/tzcode
  18
  19 The purpose of these tools is to process the zoneinfo or "Olson" time
  20 zone database into a form usable by ICU4C (release 2.8 and later).
  21 Unlike earlier releases, ICU4C 2.8 supports historical time zone
  22 behavior, as well as the full set of Olson compatibility IDs.
  23
  24 References:
  25
  26 ICU4C:  http://www.icu-project.org/
  27 Olson:  ftp://ftp.iana.org/tz/releases/
  28
  29 ----------------------------------------------------------------------
  30 ICU4C vs. ICU4J
  31
  32 For ICU releases >= 2.8, both ICU4C and ICU4J implement full
  33 historical time zones, based on Olson data.  The implementations in C
  34 and Java are somewhat different.  The C implementation is a
  35 self-contained implementation, whereas ICU4J uses the underlying JDK
  36 1.3 or 1.4 time zone implementation.
  37
  38 Older versions of ICU (C and Java <= 2.6) implement a "present day
  39 snapshot".  This only reflects current time zone behavior, without
  40 historical variation.  Furthermore, it lacks the full set of Olson
  41 compatibility IDs.
  42
  43 ----------------------------------------------------------------------
  44 BACKGROUND
  45
  46 The zoneinfo or "Olson" time zone package is used by various systems
  47 to describe the behavior of time zones.  The package consists of
  48 several parts.  E.g.:
  49
  50   Index of ftp://ftp.iana.org/tz/releases/
  51
  52   tzcode2014b.tar.gz      172 KB       3/25/2014     05:11:00 AM
  53   tzdata2014b.tar.gz      216 KB       3/25/2014     05:11:00 AM
  54
  55 ICU only uses the tzdataYYYYV.tar.gz files,
  56 where YYYY is the year and V is the version letter ('a'...'z').
  57
  58 This directory has partial contents of tzcode checked into ICU
  59
  60 ----------------------------------------------------------------------
  61 HOWTO
  62
  63 0. Note, these instructions will only work on POSIX type systems.
  64
  65 1. Obtain the current versions of tzdataYYYYV.tar.gz (aka `tzdata') from
  66    the FTP site given above.  Either manually download or use wget:
  67
  68    $ cd {path_to}/icu/source/tools/tzcode
  69    $ wget "ftp://ftp.iana.org/tz/releases/tzdata*.tar.gz"
  70
  71 2. Copy only one tzdata*.tar.gz file into the icu/source/tools/tzcode/
  72    directory (this directory).
  73
  74    *** Make sure you only have ONE FILE named tzdata*.tar.gz in the
  75        directory.
  76
  77 3. Build ICU normally. You will see a notice "updating zoneinfo.txt..."
  78
  79 ### Following instructions for ICU maintainers only ###
  80
  81 4. Obtain the current version of tzcodeYYYY.tar.gz from the FTP site to
  82    this directory.
  83
  84 5. Run make target "check-dump".  This target extract makes the original
  85    tzcode and compile the original tzdata with icu supplemental data
  86    (icuzones).  Then it makes zdump / icuzdump and dump all time
  87    transitions for all ICU timezone to files under zdumpout / icuzdumpout
  88    directory.  When they produce different results, the target returns
  89    the error.
  90
  91 6. Don't forget to check in the new zoneinfo64.txt (from its location at
  92    {path_to}/icu/source/data/misc/zoneinfo64.txt) into SVN.
  93