Commit 955405d1 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Theodore Ts'o
Browse files

unicode: introduce UTF-8 character database 

The decomposition and casefolding of UTF-8 characters are described in a
prefix tree in utf8data.h, which is a generate from the Unicode
Character Database (UCD), published by the Unicode Consortium, and
should not be edited by hand.  The structures in utf8data.h are meant to
be used for lookup operations by the unicode subsystem, when decoding a
utf-8 string.

mkutf8data.c is the source for a program that generates utf8data.h. It
was written by Olaf Weber from SGI and originally proposed to be merged
into Linux in 2014.  The original proposal performed the compatibility
decomposition, NFKD, but the current version was modified by me to do
canonical decomposition, NFD, as suggested by the community.  The
changes from the original submission are:

  * Rebase to mainline.
  * Fix out-of-tree-build.
  * Update makefile to build 11.0.0 ucd files.
  * drop references to xfs.
  * Convert NFKD to NFD.
  * Merge back robustness fixes from original patch. Requested by
    Dave Chinner.

The original submission is archived at:

<https://linux-xfs.oss.sgi.narkive.com/Xx10wjVY/rfc-unicode-utf-8-support-for-xfs

>

The utf8data.h file can be regenerated using the instructions in
fs/unicode/README.utf8data.

- Notes on the update from 8.0.0 to 11.0:

The structure of the ucd files and special cases have not experienced
any changes between versions 8.0.0 and 11.0.0.  8.0.0 saw the addition
of Cherokee LC characters, which is an interesting case for
case-folding.  The update is accompanied by new tests on the test_ucd
module to catch specific cases.  No changes to mkutf8data script were
required for the updates.

Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 310a997f

fs/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -317,5 +317,6 @@ endif # NETWORK_FILESYSTEMS 


source "fs/nls/Kconfig"

source "fs/dlm/Kconfig"

source "fs/unicode/Kconfig"



endmenu

fs/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ obj-$(CONFIG_EXPORTFS) += exportfs/ 
obj-$(CONFIG_NFSD)		+= nfsd/

obj-$(CONFIG_LOCKD)		+= lockd/

obj-$(CONFIG_NLS)		+= nls/

obj-$(CONFIG_UNICODE)		+= unicode/

obj-$(CONFIG_SYSV_FS)		+= sysv/

obj-$(CONFIG_CIFS)		+= cifs/

obj-$(CONFIG_HPFS_FS)		+= hpfs/

fs/unicode/Kconfig

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#

# UTF-8 normalization

#

config UNICODE

	bool "UTF-8 normalization and casefolding support"

	help

	  Say Y here to enable UTF-8 NFD normalization and NFD+CF casefolding

	  support.

fs/unicode/Makefile

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# SPDX-License-Identifier: GPL-2.0



# This rule is not invoked during the kernel compilation.  It is used to

# regenerate the utf8data.h header file.

utf8data.h.new: *.txt $(objdir)/scripts/mkutf8data

	$(objdir)/scripts/mkutf8data \

		-a DerivedAge.txt \

		-c DerivedCombiningClass.txt \

		-p DerivedCoreProperties.txt \

		-d UnicodeData.txt \

		-f CaseFolding.txt \

		-n NormalizationCorrections.txt \

		-t NormalizationTest.txt \

		-o $@

fs/unicode/README.utf8data

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The utf8data.h file in this directory is generated from the Unicode

Character Database for version 11.0.0 of the Unicode standard.



The full set of files can be found here:



  http://www.unicode.org/Public/11.0.0/ucd/



Individual source links:



  http://www.unicode.org/Public/11.0.0/ucd/CaseFolding.txt

  http://www.unicode.org/Public/11.0.0/ucd/DerivedAge.txt

  http://www.unicode.org/Public/11.0.0/ucd/extracted/DerivedCombiningClass.txt

  http://www.unicode.org/Public/11.0.0/ucd/DerivedCoreProperties.txt

  http://www.unicode.org/Public/11.0.0/ucd/NormalizationCorrections.txt

  http://www.unicode.org/Public/11.0.0/ucd/NormalizationTest.txt

  http://www.unicode.org/Public/11.0.0/ucd/UnicodeData.txt



md5sums (verify by running "md5sum -c README.utf8data"):



  414436796cf097df55f798e1585448ee  CaseFolding.txt

  6032a595fbb782694456491d86eecfac  DerivedAge.txt

  3240997d671297ac754ab0d27577acf7  DerivedCombiningClass.txt

  2a4fe257d9d8184518e036194d2248ec  DerivedCoreProperties.txt

  4e7d383fa0dd3cd9d49d64e5b7b7c9e0  NormalizationCorrections.txt

  c9500c5b8b88e584469f056023ecc3f2  NormalizationTest.txt

  acc291106c3758d2025f8d7bd5518bee  UnicodeData.txt



sha1sums (verify by running "sha1sum -c README.utf8data"):



  9184727adf7bd20e36312a68581d12ba3ffb9854  CaseFolding.txt

  86c55b3eb89de61704da16af9c3f22854f61b57d  DerivedAge.txt

  b615703f62b1dbc5110e91acc3ff8b3789a067cf  DerivedCombiningClass.txt

  f8b07ef116d7dc21a94f26e70178ed2acf8713e9  DerivedCoreProperties.txt

  a5fafb8998c0b8153a2a58430b8a35c811db0abc  NormalizationCorrections.txt

  070cdcb00cd4f0860e476750e404c59c2ebe9b25  NormalizationTest.txt

  0e060fafb08d6722fbec56d9f9ebe8509f01d0ee  UnicodeData.txt



To update to the newer version of the Unicode standard, the latest

released version of the UCD can be found here:



  http://www.unicode.org/Public/UCD/latest/



To build the utf8data.h file, from a kernel tree that has been built,

cd to this directory (fs/unicode) and run this command:



	make C=../.. objdir=../.. utf8data.h.new



After sanity checking the newly generated utf8data.h.new file (the

version generated from the 11.0.0 UCD should be 13,834 lines long, and

have a total size of 1104k) and/or comparing it with the older version

of utf8data.h, rename it to utf8data.h.



If you are a kernel developer updating to a newer version of the

Unicode Character Database, please update this README.utf8data file

with the version of the UCD that was used, the md5sum and sha1sums of

the *.txt files, before checking in the new versions of the utf8data.h

and README.utf8data files.

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