Implements Unicode simple case mapping, in which all code points map
to exactly one other code point unconditionally.
These tables are generated from UnicodeData.txt, which is already
being used by other infrastructure in src/common/unicode. The tables
are checked into the source tree, so they only need to be regenerated
when we update the Unicode version.
In preparation for the builtin collation provider, and possibly useful
for other callers.
Discussion: https://postgr.es/m/ff4c2f2f9c8fc7ca27c1c24ae37ecaeaeaff6b53.camel%40j-davis.com
Reviewed-by: Peter Eisentraut, Daniel Verite, Jeremy Schneider
This updates the following lookup arrays to use C99-designated
initializer syntax, indexed based on the enum pg_enc:
pg_enc2icu_tbl[]
pg_enc2name_tbl[]
pg_wchar_table[]
This is more readable, and removes problems with ordering mistakes as
this removes dependencies between the arrays and their lookup index in
the enum pg_enc. So, adding new encodings becomes easier, even if this
does not happen often.
Author: Jelte Fennema-Nio
Reviewed-by: Jian He, Japin Li
Discussion: https://postgr.es/m/CAGECzQT3caUbcCcszNewCCmMbCuyP7XNAm60J3ybd6PN5kH2Dw@mail.gmail.com
This function requires simd.h, which is a rather large dependency
for a widely-used header file like pg_wchar.h. Furthermore, there
is a report of a third-party tool that is struggling to use
pg_wchar.h due to its dependence on simd.h (presumably because
simd.h uses several intrinsics). Moving the function to the much
less popular ascii.h resolves these issues for now.
This commit is back-patched for the benefit of the aforementioned
third-party tool. The simd.h dependency was only added in v16,
but we've opted to back-patch to v15 so that is_valid_ascii() lives
in the same file for all versions where it exists. This could
break existing third-party code that uses the function, but we
couldn't find any examples of such code. It should be possible to
fix any code that this commit breaks by including ascii.h in the
file that uses is_valid_ascii().
Author: Jubilee Young
Reviewed-by: Tom Lane, John Naylor, Andres Freund, Eric Ridge
Discussion: https://postgr.es/m/CAPNHn3oKJJxMsYq%2BqLYzVJOFrUcOr4OF1EC-KtFT-qh8nOOOtQ%40mail.gmail.com
Backpatch-through: 15
Commit d8594d123 updated the list of non-spacing codepoints used
for calculating display width, but in doing so inadvertently removed
some, since the script used for that commit only considered combining
characters.
For complete coverage for zero-width characters, include codepoints in
the category Cf (Format). To reflect the wider purpose, also rename files
and update comments that referred specifically to combining characters.
Some of these ranges have been missing since v12, but due to lack of
field complaints it was determined not important enough to justify adding
special-case logic the backbranches.
Kyotaro Horiguchi
Report by Pavel Stehule
Discussion: https://www.postgresql.org/message-id/flat/CAFj8pRBE8yvpQ0FSkPCoe0Ny1jAAsAQ6j3qMgVwWvkqAoaaNmQ%40mail.gmail.com
Per flame graph from Jelte Fennema, COPY FROM ... USING BINARY shows
input validation taking at least 5% of the profile, so it's worth trying
to be more efficient here. With this change, validation of pure ASCII is
nearly 40% faster on contemporary Intel hardware. To make this change
legible and easier to adopt to additional architectures, use helper
functions to abstract the platform details away.
Reviewed by Nathan Bossart
Discussion: https://www.postgresql.org/message-id/CAFBsxsG%3Dk8t%3DC457FXnoBXb%3D8iA4OaZkbFogFMachWif7mNnww%40mail.gmail.com
The previous coding was correct, but the style and commentary were a bit
vague about which operations had to happen, in what circumstances, and
in what order. Rearrange so that the epilogue does nothing in the DFA END
state. That allows turning some conditional statements in the backtracking
logic into asserts. With that, we can be more explicit about needing
to backtrack at least one byte in non-END states to ensure checking the
current byte sequence in the slow path. No change to the regression tests,
since they should be able catch deficiencies here already.
In passing, improve the comments around DFA states where the first
continuation byte has a restricted range.
Our previous validator used a traditional algorithm that performed
comparison and branching one byte at a time. It's useful in that
we always know exactly how many bytes we have validated, but that
precision comes at a cost. Input validation can show up prominently
in profiles of COPY FROM, and future improvements to COPY FROM such
as parallelism or faster line parsing will put more pressure on input
validation. Hence, add fast paths for both ASCII and multibyte UTF-8:
Use bitwise operations to check 16 bytes at a time for ASCII. If
that fails, use a "shift-based" DFA on those bytes to handle the
general case, including multibyte. These paths are relatively free
of branches and thus robust against all kinds of byte patterns. With
these algorithms, UTF-8 validation is several times faster, depending
on platform and the input byte distribution.
The previous coding in pg_utf8_verifystr() is retained for short
strings and for when the fast path returns an error.
Review, performance testing, and additional hacking by: Heikki
Linakangas, Vladimir Sitnikov, Amit Khandekar, Thomas Munro, and
Greg Stark
Discussion:
https://www.postgresql.org/message-id/CAFBsxsEV_SzH%2BOLyCiyon%3DiwggSyMh_eF6A3LU2tiWf3Cy2ZQg%40mail.gmail.com
The hardcoded "wide character" set in ucs_wcwidth() was last updated
around the Unicode 5.0 era. This led to misalignment when printing
emojis and other codepoints that have since been designated
wide or full-width.
To fix and keep up to date, extend update-unicode to download the list
of wide and full-width codepoints from the offical sources.
In passing, remove some comments about non-spacing characters that
haven't been accurate since we removed the former hardcoded logic.
Jacob Champion
Reported and reviewed by Pavel Stehule
Discussion: https://www.postgresql.org/message-id/flat/CAFj8pRCeX21O69YHxmykYySYyprZAqrKWWg0KoGKdjgqcGyygg@mail.gmail.com
An incorrectly-encoded multibyte character near the end of a string
could cause various processing loops to run past the string's
terminating NUL, with results ranging from no detectable issue to
a program crash, depending on what happens to be in the following
memory.
This isn't an issue in the server, because we take care to verify
the encoding of strings before doing any interesting processing
on them. However, that lack of care leaked into client-side code
which shouldn't assume that anyone has validated the encoding of
its input.
Although this is certainly a bug worth fixing, the PG security team
elected not to regard it as a security issue, primarily because
any untrusted text should be sanitized by PQescapeLiteral or
the like before being incorporated into a SQL or psql command.
(If an app fails to do so, the same technique can be used to
cause SQL injection, with probably much more dire consequences
than a mere client-program crash.) Those functions were already
made proof against this class of problem, cf CVE-2006-2313.
To fix, invent PQmblenBounded() which is like PQmblen() except it
won't return more than the number of bytes remaining in the string.
In HEAD we can make this a new libpq function, as PQmblen() is.
It seems imprudent to change libpq's API in stable branches though,
so in the back branches define PQmblenBounded as a macro in the files
that need it. (Note that just changing PQmblen's behavior would not
be a good idea; notably, it would completely break the escaping
functions' defense against this exact problem. So we just want a
version for those callers that don't have any better way of handling
this issue.)
Per private report from houjingyi. Back-patch to all supported branches.
This makes pg_verify_mbstr() function faster, by allowing more efficient
encoding-specific implementations. All the implementations included in
this commit are pretty naive, they just call the same encoding-specific
verifychar functions that were used previously, but that already gives a
performance boost because the tight character-at-a-time loop is simpler.
Reviewed-by: John Naylor
Discussion: https://www.postgresql.org/message-id/e7861509-3960-538a-9025-b75a61188e01@iki.fi
The additional pain from level 4 is excessive for the gain.
Also revert all the source annotation changes to their original
wordings, to avoid back-patching pain.
Discussion: https://postgr.es/m/31166.1589378554@sss.pgh.pa.us
Use it at level 4, a bit more restrictive than the default level, and
tweak our commanding comments to FALLTHROUGH.
(However, leave zic.c alone, since it's external code; to avoid the
warnings that would appear there, change CFLAGS for that file in the
Makefile.)
Author: Julien Rouhaud <rjuju123@gmail.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20200412081825.qyo5vwwco3fv4gdo@nol
Discussion: https://postgr.es/m/flat/E1fDenm-0000C8-IJ@gemulon.postgresql.org
Move all the backend-only code that'd crept into wchar.c and encnames.c
into mbutils.c.
To remove the last few #ifdef dependencies from wchar.c and encnames.c,
also make the following changes:
* Adjust get_encoding_name_for_icu to return NULL, not throw an error,
for unsupported encodings. Its sole caller can perfectly well throw an
error instead. (While at it, I also made this function and its sibling
is_encoding_supported_by_icu proof against out-of-range encoding IDs.)
* Remove the overlength-name error condition from pg_char_to_encoding.
It's completely silly not to treat that just like any other
the-name-is-not-in-the-table case.
Also, get rid of pg_mic_mblen --- there's no obvious reason why
conv.c shouldn't call pg_mule_mblen instead.
Other than that, this is just code movement and comment-polishing with
no functional changes. Notably, I reordered declarations in pg_wchar.h
to show which functions are frontend-accessible and which are not.
Discussion: https://postgr.es/m/CA+TgmoYO8oq-iy8E02rD8eX25T-9SmyxKWqqks5OMHxKvGXpXQ@mail.gmail.com
Formerly, various frontend directories symlinked these two sources
and then built them locally. That's an ancient, ugly hack, and
we now have a much better way: put them into libpgcommon.
So do that. (The immediate motivation for this is the prospect
of having to introduce still more symlinking if we don't.)
This commit moves these two files absolutely verbatim, for ease of
reviewing the git history. There's some follow-on work to be done
that will modify them a bit.
Robert Haas, Tom Lane
Discussion: https://postgr.es/m/CA+TgmoYO8oq-iy8E02rD8eX25T-9SmyxKWqqks5OMHxKvGXpXQ@mail.gmail.com
Jeff Davis
Michael Paquier
Nathan Bossart
Bruce Momjian
John Naylor
Tom Lane
Heikki Linnakangas
Alvaro Herrera