Previously, we did many conversions for Cyrillic and Central European
single-byte encodings by converting to a related MULE_INTERNAL coding
scheme before converting to the destination. This seems unnecessarily
inefficient. Moreover, if the conversion encounters an untranslatable
character, the error message will confusingly complain about failure
to convert to or from MULE_INTERNAL, rather than the user-visible
encodings. Worse still, this approach results in some completely
unnecessary conversion failures; there are cases where the chosen
MULE subset lacks characters that exist in both of the user-visible
encodings, causing a conversion failure that need not occur.
This patch fixes the first two of those deficiencies by introducing
a new local2local() conversion support subroutine for direct conversion
between any two single-byte character sets, and adding new conversion
tables where needed. However, I generated the new conversion tables by
testing PG 9.5's behavior, so that the actual conversion behavior is
bug-compatible with previous releases; the only user-visible behavior
change is that the error messages for conversion failures are saner.
Changes in the conversion behavior will probably ensue after discussion.
Interestingly, although this approach requires more tables, the .so files
actually end up smaller (at least on my x86_64 machine); the tables are
smaller than the management code needed for double conversion.
Per a complaint from Albe Laurenz.
Until now, these functions have only supported encoding conversions using
lookup tables, which is fine as long as there's not too many code points
to convert. However, GB18030 expects all 1.1 million Unicode code points
to be convertible, which would require a ridiculously-sized lookup table.
Fortunately, a large fraction of those conversions can be expressed through
arithmetic, ie the conversions are one-to-one in certain defined ranges.
To support that, provide a callback function that is used after consulting
the lookup tables. (This patch doesn't actually change anything about the
GB18030 conversion behavior, just provide infrastructure for fixing it.)
Since this requires changing the APIs of UtfToLocal/LocalToUtf anyway,
take the opportunity to rearrange their argument lists into what seems
to me a saner order. And beautify the call sites by using lengthof()
instead of error-prone sizeof() arithmetic.
In passing, also mark all the lookup tables used by these calls "const".
This moves an impressive amount of stuff into the text segment, at least
on my machine, and is safer anyhow.
This is mainly to suppress "uninitialized variable" warnings from very
recent versions of gcc. But it seems like a good robustness thing anyway,
not to mention that we might someday decide to support 6-byte UTF8.
Per report from Karol Trzcionka. No back-patch since there's no reason
at the moment to think this is more than cosmetic.
This addresses only those cases that are easy to fix by adding or
moving a const qualifier or removing an unnecessary cast. There are
many more complicated cases remaining.
characters in all cases. Formerly we mostly just threw warnings for invalid
input, and failed to detect it at all if no encoding conversion was required.
The tighter check is needed to defend against SQL-injection attacks as per
CVE-2006-2313 (further details will be published after release). Embedded
zero (null) bytes will be rejected as well. The checks are applied during
input to the backend (receipt from client or COPY IN), so it no longer seems
necessary to check in textin() and related routines; any string arriving at
those functions will already have been validated. Conversion failure
reporting (for characters with no equivalent in the destination encoding)
has been cleaned up and made consistent while at it.
Also, fix a few longstanding errors in little-used encoding conversion
routines: win1251_to_iso, win866_to_iso, euc_tw_to_big5, euc_tw_to_mic,
mic_to_euc_tw were all broken to varying extents.
Patches by Tatsuo Ishii and Tom Lane. Thanks to Akio Ishida and Yasuo Ohgaki
for identifying the security issues.
#define HIGHBIT (0x80)
#define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT)
and removed CSIGNBIT and mapped it uses to HIGHBIT. I have also added
uses for IS_HIGHBIT_SET where appropriate. This change is
purely for code clarity.
Also performed an initial run through of upgrading our Copyright date to
extend to 2005 ... first run here was very simple ... change everything
where: grep 1996-2004 && the word 'Copyright' ... scanned through the
generated list with 'less' first, and after, to make sure that I only
picked up the right entries ...
conversion procs and conversions are added in initdb. Currently
supported conversions are:
UTF-8(UNICODE) <--> SQL_ASCII, ISO-8859-1 to 16, EUC_JP, EUC_KR,
EUC_CN, EUC_TW, SJIS, BIG5, GBK, GB18030, UHC,
JOHAB, TCVN
EUC_JP <--> SJIS
EUC_TW <--> BIG5
MULE_INTERNAL <--> EUC_JP, SJIS, EUC_TW, BIG5
Note that initial contents of pg_conversion system catalog are created
in the initdb process. So doing initdb required is ideal, it's
possible to add them to your databases by hand, however. To accomplish
this:
psql -f your_postgresql_install_path/share/conversion_create.sql your_database
So I did not bump up the version in cataversion.h.
TODO:
Add more conversion procs
Add [CASCADE|RESTRICT] to DROP CONVERSION
Add tuples to pg_depend
Add regression tests
Write docs
Add SQL99 CONVERT command?
--
Tatsuo Ishii
o Change all current CVS messages of NOTICE to WARNING. We were going
to do this just before 7.3 beta but it has to be done now, as you will
see below.
o Change current INFO messages that should be controlled by
client_min_messages to NOTICE.
o Force remaining INFO messages, like from EXPLAIN, VACUUM VERBOSE, etc.
to always go to the client.
o Remove INFO from the client_min_messages options and add NOTICE.
Seems we do need three non-ERROR elog levels to handle the various
behaviors we need for these messages.
Regression passed.
> > > > It was made to cope with encoding such as an Asian bloc in 7.2Beta2.
> > > >
> > > > Added ServerEncoding
> > > > Korean (JOHAB), Thai (WIN874),
> > > > Vietnamese (TCVN), Arabic (WIN1256)
> > > >
> > > > Added ClientEncoding
> > > > Simplified Chinese (GBK), Korean (UHC)
> > > >
> > > >
> > > >
> http://www.sankyo-unyu.co.jp/Pool/postgresql-7.2b2.newencoding.diff.tar.gz
> > > > (608K)
> > >
> > > Looks good. I need some people to review this for me.
> >
> > For me they look good too. The only missing part is a
> > documentation. I will ask him to write it up. If he couldn't, I will
> > do it for him.
> > > The diff is 3mb
> > > but appears to address only additions to multibyte. I have attached a
> > > list of files it modifies. Also, look at the sizes of the mb/
> > > directory. It is getting large:
> > >
> > > 4 ./CVS
> > > 6 ./Unicode/CVS
> > > 3433 ./Unicode
> > > 6197 .
> >
> > Yes. We definitely need the on-the-fly encoding addition capability:
> > i.e. CREATE CHRACTER SET in the future...
> > --
> > Tatsuo Ishii
> >
> >
Address chainge.
http://www.sankyo-unyu.co.jp/Pool/postgresql-7.2.newencoding.diff.gz
Add PsqlODBC and document ...etc patch.
Eiji Tokuya
