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Name: icu
Version: 63.1
License: MIT
Security Critical: yes
This directory contains the source code of ICU 63.1 for C/C++.
A. How to update ICU
1. Run "scripts/ <version>" (e.g. 60-1).
This will download ICU from the upstream svn repository.
It does preserve Chrome-specific build files (* and
converter files. (see section C) and icu.gyp* files are automatically updated, too.
2. Review and apply patches/changes in "D. Local Modifications" if
necessary/applicable. Update patch files in patches/.
3. Follow the instructions in section B on building ICU data files
B. How to build ICU data files
Pre-built data files are generated and checked in with the following steps
1. icu data files for Chrome OS, Linux, Mac and Windows
a. Make a icu data build directory outside the Chromium source tree
and cd to that directory (say, $ICUBUILDIR).
b. Run
${CHROME_ICU_TREE_TOP}/source/runConfigureICU Linux --disable-layout --disable-tests
c. Run make
'make' will fail when pkgdata looks for root_subset.res. This
is expected. See
d. Run
This script takes the following steps:
i) scripts/
The full locale data for Chrome's UI languages and their select variants
and the bare minimum locale data for other locales will be kept.
ii) scripts/
This makes icudt${version}l.dat.
iii) scripts/ common
This copies the ICU data files for non-Android platforms
(both Little and Big Endian) to the following locations:
iv) cast/
On top of (step d), further cuts the data entries for
v) Repeat ii) and iii) for cast to get cast/icudtl.dat
vi) android/
On top of (step d), further cuts the data entries for
vii) Repeat ii) and iii) for Android to get android/icudtl.dat
viii) ios/
Further cuts the data size for iOS.
ix) Repeat ii) and iii) for iOS to get ios/icudtl.dat
x) Repeat ii) and iii) for Flutter to get flutter/icudtl.dat
xi) scripts/
This reverts the result of and and
make the tree ready for committing updated ICU data files for
non-Android and Android platforms.
e. Whenever data is updated (e.g timezone update), take step d as long
as the ICU build directory used in a ~ c is kept.
2. Note on the locale data customization
- scripts/
a. Trim the locale data for Chrome's UI langauges :
locales, lang, region, currency, zone
b. Trim the locale data for non-UI languages to the bare minimum :
ExemplarCharacters, LocaleScript, layout, and the name of the
language for a locale in its native language.
c. Remove the legacy Chinese character set-based collation
(big5han/gb2312han) that don't make any sense and nobdoy uses.
- android/
a. Make changes to source/data/{region,lang} to exclude these data
except the language and script names of zh_Hans and zh_Hant.
b. Remove exemplar cities in timezone data (data/zone).
c. Keep only the minimal calendar data in data/locales.
d. Include currency display names for a smaller subset of currencies.
e. Minimize the locale data for 9 locales to which Chrome on Android
is not localized.
f. Also apply android/brkitr.patch
- android/brkitr.patch
Do not use the C+J dictionary for Chinese/Japanese segmentation
to reduce the data size. Adjust word.txt and a few other files.
C. Chromium-specific data build files and converters
They're preserved in step A.1 above. In general, there's no need to touch
them when updating ICU.
1. source/data/mappings
- convrtrs.txt : Lists encodings and aliases required by the WHATWG
Encoding spec plus a few extra (see the file as to why).
- ucmlocal.txt : to list only converters we need.
- *html.ucm: Mapping files per WHATWG encoding standards for EUC-JP,
Shift_JIS, Big5 (Big5+Big5HKSCS), EUC-KR and all the single byte encodings.
They're generated with scripts/{eucjp,sjis,big5,euckr,single_byte}
- gb18030.ucm and windows-936.ucm
gb_table.patch was applied for the following changes. No need
to apply it again. The patch is kept for the record.
a. Map \xA3\xA0 to U+3000 instead of U+E5E5 in gb18030 and windows-936 per
the encoding spec (one-way mapping in toUnicode direction).
b. Map \xA8\xBF to U+01F9 instead of U+E7C8. Add one-way map
from U+1E3F to \xA8\xBC (windows-936/GBK).
2. source/data/*/*
- List locales of interest to Chromium
a. Chrome's UI languages
b. Variants of UI languages
c. Other locales in Accept-Language list : will only have bare minimum
locale data
- drops some line*brk files to save space for now.
3. source/data/brkitr
- dictionaries/khmerdict.txt: Abridged Khmer dictionary. See
- rules/word_ja.txt (used only on Android)
Added for Japanese-specific word-breaking without the C+J dictionary.
- rules/{root,zh,zh_Hant}.txt
a. Use line_normal by default.
b. Drop local patches we used to have for the following issues. They'll
be dealt with in the upstream (Unicode/CLDR). (
4. source/data/trnslit/root_subset.txt
Subset of transliteration data to keep for:
5. Add {an,ku,tg,wa}.txt to source/data/{locale,lang}
with the minimal locale data necessary for spellchecker and
and language menus.
D. Local Modifications
1. Applied locale data patches from Google obtained by diff'ing
the upstream copy and Google's internal copy for source/data
- patches/locale_google.patch:
* Google's internal ICU locale changes
* Simpler region names for Hong Kong and Macau in all locales
* Currency signs in ru and uk locales (do not include 'tr' locale changes)
* AM/PM, midnight, noon formatting for a few Indian locales
* Timezone name changes in Korean and Chinese locales
* Default digit for Arabic locale is European digits.
- patches/locale1.patch: Minor fixes for Korean
2. Breakiterator patches
- patches/wordbrk.patch for word.txt
a. Move full stops (U+002E, U+FF0E) from MidNumLet to MidNum so that
FQDN labels can be split at '.'
b. Move fullwidth digits (U+FF10 - U+FF19) from Ideographic to Numeric.
- patches/khmer-dictbe.patch
Adjust parameters to use a smaller Khmer dictionary (khmerdict.txt).
- Add several common Chinese words that were dropped previously to
patch: patches/cjdict.patch
upstream bug:
3. Timezone data update
Run scripts/ to grab the latest version of the
following timezone data files and put them in source/data/misc
As of Dec 31, 2018, the latest version is 2018i and the above files
are available at the ICU github repos.
4. Build-related changes
- patches/wpo.patch (only needed when icudata dll is used).
upstream bugs :
- patches/vscomp.patch for building with Visual Studio on Windows:
do not use WINDOWS_LOCALE_API in locmap.c
- patches/ :
Remove unnecessary resources : unames, collator rule source
- patches/ :
Windows-only data build patch.
- patches/data_symb.patch :
Put ICU_DATA_ENTRY_POINT(icudtXX_dat) in common when we use
the icu data file or icudt.dll
5. Fix -Wsign-compare warning in EnumSet::isValidEnum()
- patches/isvalidenum.patch
upstream bug:
6. Double conversion library build failure
- patches/double_conversion.patch
- upstream bugs:
7. Fix std::atomic related compilation issue
- patches/atomic_win.patch
- upstream bugs:
- Fix:
8. Fix an integer overflow in the number parsing
- patches/numparse_overflow.patch
- upstream bug:
- Fix:
9. ISO-2022-JP encoding (fromUnicode) change per WHATWG encoding spec.
- patches/iso2022jp.patch
- upstream bug:
10. UnicodeSet creation performance enhancement
- patches/uniset_perf.patch
- upstream bug:
- Fix:
11. Locale parsing with tz unicode extension.
- patches/locale_id_tz_parsing.patch
- upstream bug:
- Fix:
12. Windows 7 timezone detection fix
- patches/win7_tz.patch
- upstream bug:
- Fix: