It's expensive to determine the system time zone from disk each time it
is requested. This makes LibUnicode cache the result, and provides an
API to clear that cache. This will let us set up a monitor to watch for
system time zone changes in platform-dependent ways.
The changes to tests are due to LibTimeZone incorrectly interpreting
time stamps in the TZDB. The TZDB will list zone transitions in either
UTC or the zone's local time (which is then subject to DST offsets).
LibTimeZone did not handle the latter at all.
For example:
The following rule is in effect until November 18, 6PM UTC.
America/Chicago -5:50:36 - LMT 1883 Nov 18 18:00u
The following rule is in effect until March 1, 2AM in Chicago time. But
at that time, a DST transition occurs, so the local time is actually
3AM.
America/Chicago -6:00 Chicago C%sT 1936 Mar 1 2:00
This required updating some LibJS spec steps to their latest versions,
as the data expected by the old steps does not quite match the APIs that
are available with the ICU. The new spec steps are much more aligned.
LibLocale was split off from LibUnicode a couple years ago to reduce the
number of applications on SerenityOS that depend on CLDR data. Now that
we use ICU, both LibUnicode and LibLocale are actually linking in this
data. And since vcpkg gives us static libraries, both libraries are over
30MB in size.
This patch reverts the separation and merges LibLocale into LibUnicode
again. We now have just one library that includes the ICU data.
Further, this will let LibUnicode share the locale cache that previously
would only exist in LibLocale.
There are a couple of differences here due to using ICU:
1. Titlecasing behaves slightly differently. We previously transformed
"123dollars" to "123Dollars", as we would use word segmentation to
split a string into words, then transform the first cased character
to titlecase. ICU doesn't go quite that far, and leaves the string
as "123dollars". While this is a behavior change, the only user of
this API is the `text-transform: capitalize;` CSS rule, and we now
match the behavior of other browsers.
2. There isn't an API to compare strings with case insensitivity without
allocating case-folded strings for both the left- and right-hand-side
strings. Our implementation was previously allocation-free; however,
in a benchmark, ICU is still ~1.4x faster.
https://unicode.org/versions/Unicode15.1.0/
This update includes a new set of code point properties, Indic Conjunct
Break. These may have the values Consonant, Linker, or Extend. These are
used in text segmentation to prevent breaking on some extended grapheme
cluster sequences.
Similar to commit 0652cc4, we now generate 2-stage lookup tables for
case conversion information. Only about 1500 code points are actually
cased. This means that case information is rather highly compressible,
as the blocks we break the code points into will generally all have no
casing information at all.
In total, this change:
* Does not change the size of libunicode.so (which is nice because,
generally, the 2-stage lookup tables are expected to trade a bit
of size for performance).
* Reduces the runtime of the new benchmark test case added here from
1.383s to 1.127s (about an 18.5% improvement).
We currently produce a single table for all categories of code point
properties (GeneralCategory, Script, etc.). Each row contains a field
indicating the range of code points to which that property applies. At
runtime, we then do a binary search through that table to decide if a
code point has a property.
This changes our approach to generate a 2-stage lookup table for each of
those categories. There is an in-depth explanation of these tables above
the new `create_code_point_tables` method. The end effect is that code
point property lookup is reduced from a binary search to constant-time
array lookups.
In total, this change:
* Increases the size of libunicode.so from 2.7 MB to 2.9 MB.
* Reduces the runtime of the new benchmark test case added here from
3.576s to 1.020s (a 3.5x speedup).
* In a profile of resizing a TextEditor window with a 3MB file open,
the runtime of checking if a code point has a word break property
reduces from ~81% to ~56%.
We started generating this data in commit 0505e03, but it was unused.
It's still not used, so let's remove it, rather than bloating the size
of libunicode.so with unused data. If we need it in the future, it's
trivial to add back.
Note we *have* always used the block name data from that commit, and
that is still present here.
This was preventing some unqualified emoji sequences from rendering
properly, such as the custom SerenityOS flag. We rendered the flag
correctly when given the fully qualified sequence:
U+1F3F3 U+FEOF U+200D U+1F41E
But were not detecting the unqualified sequence as an emoji when also
filtering for emoji-presentation sequences:
U+1F3F3 U+200D U+1F41E
For example the words "can't" and "32.3" should not have boundaries
detected on the "'" and "." code points, respectively.
The String test cases fixed here are because "b'ar" is now considered
one word.
Case folding rules have a similar mapping style as special casing rules,
where one code point may map to zero or more case folding rules. These
will be used for case-insensitive string comparisons. To see how case
folding can differ from other casing rules, consider "ß" (U+00DF):
>>> "ß".lower()
'ß'
>>> "ß".upper()
'SS'
>>> "ß".title()
'Ss'
>>> "ß".casefold()
'ss'
Unicode declares that to titlecase a string, the first cased code point
after each word boundary should be transformed to its titlecase mapping.
All other codepoints are transformed to their lowercase mapping.
This fixes `combine_hangul_code_points` which would try to combine
a LVT syllable with a trailing consonant, resulting in a wrong
character.
Also added a test for this specific case.
Currently, LibUnicodeData contains the generated UCD and CLDR data. Move
the UCD data to the main LibUnicode library, and rename LibUnicodeData
to LibLocaleData. This is another prepatory change to migrate to
LibLocale.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
Our generator is currently preferring the DST variant of the time zone
display names over the non-DST variant. LibTimeZone currently does not
have DST support, and operates in a mode that basically assumes DST does
not exist. Swap the display names for now just to be consistent until we
have DST support.
Note we will need to generate both of these variants and select the
appropriate one at runtime once we have DST support.
The following table in TR-35 includes a web of fall back rules when the
requested time zone style is unavailable:
https://unicode.org/reports/tr35/tr35-dates.html#dfst-zone
Conveniently, the subset of styles supported by ECMA-402 (and therefore
LibUnicode) all either fall back to GMT offset or to a style that is
unsupported but itself falls back to GMT offset.
This adds an API to use LibTimeZone to convert a time zone such as
"America/New_York" to a GMT offset string like "GMT-5" (short form) or
"GMT-05:00" (long form).
The generator parses metaZones.json to form a mapping of meta zones to
time zones (AKA "golden zone" in TR-35). This parser errantly assumed
this was a 1-to-1 mapping.
