The current algorithm is currently O(N^2) because we forward-search an
ever-increasing substring of the haystack. This implementation reduces
the search time of a 500,000-length string (where the desired needle is
at index 0) from 72 seconds to 2-3 milliseconds.
Caught by clang-format-17. Note that clang-format-16 is fine with this
as well (it leaves the const placement alone), it just doesn't perform
the formatting to east-const itself.
Using a vector to represent a list of painting commands results in many
reallocations, especially on pages with a lot of content.
This change addresses it by introducing a SegmentedVector, which allows
fast appending by representing a list as a sequence of fixed-size
vectors. Currently, this new data structure supports only the
operations used in RecordingPainter, which are appending and iterating.
Much of the UTF-8 data that we'll iterate over will be ASCII only,
and we can get a significant speed-up by simply having a fast path
when the iterator points at a byte that is obviously an ASCII character
(<= 0x7F).
Since we're already building up a percent-encoded ASCII-only string
in the internal parser buffer, there's no need to do a second UTF-8
validation pass before assigning each part of the parsed URL.
This makes URL parsing signficantly faster.
Instead of do a wrappy MUST(try_append_code_point()), we now inline
the UTF-8 encoding logic. This allows us to grow the buffer by the
right increment up front, and also removes a bunch of ErrorOr ceremony
that we don't care about.
Once we know that a code point must be a valid ASCII character,
we now cast it to `char` and avoid the expensive generic
StringView::contains(u32 code_point) checks.
This dramatically speeds up URL parsing.
UTF8Decoder was already converting invalid data into replacement
characters while converting, so we know for sure we have valid UTF-8
by the time conversion is finished.
This patch adds a new StringBuilder::to_string_without_validation()
and uses it to make UTF8Decoder avoid half the work it was doing.
Instead of using a StringBuilder, add a String::repeated(String, N)
overload that takes advantage of knowing it's already all UTF-8.
This makes the following microbenchmark go 4x faster:
"foo".repeat(100_000_000)
And for single character strings, we can even go 10x faster:
"x".repeat(100_000_000)
In a bunch of cases, this actually ends up simplifying the code as
to_number will handle something such as:
```
Optional<I> opt;
if constexpr (IsSigned<I>)
opt = view.to_int<I>();
else
opt = view.to_uint<I>();
```
For us.
The main goal here however is to have a single generic number conversion
API between all of the String classes.
Half the functions used are not readily available on windows, instead of
creating more ifdef soup, this commit simply disables the rich debug
stuff on windows.
If we don't have __builtin_add_overflow_p(), we can also try using
__builtin_add_overflow(). This makes debug builds with Clang
significantly faster since they no longer need to use the generic
implementation. Same for multiplication.
Previously, `replace` used `find_all` to find all of the positions to
replace. But `find_all` finds all the *overlapping* instances of the
needle, while `replace` assumed that the next position was always at
least `needle.length()` away from the last one. This led to crashes like
https://github.com/SerenityOS/jakt/issues/1159.
This commit un-deprecates DeprecatedString, and repurposes it as a byte
string.
As the null state has already been removed, there are no other
particularly hairy blockers in repurposing this type as a byte string
(what it _really_ is).
This commit is auto-generated:
$ xs=$(ack -l \bDeprecatedString\b\|deprecated_string AK Userland \
Meta Ports Ladybird Tests Kernel)
$ perl -pie 's/\bDeprecatedString\b/ByteString/g;
s/deprecated_string/byte_string/g' $xs
$ clang-format --style=file -i \
$(git diff --name-only | grep \.cpp\|\.h)
$ gn format $(git ls-files '*.gn' '*.gni')
This requires duplicating some logic from Core::Process::get_name()
into AK, which seems unfortunate. But for now, this greatly improves the
log messages for testing Ladybird on Linux.
The feature is hidden behind a runtime flag with a global setter in the
same way that totally enabling/disabling dbgln is.
This tries to optimize the refill code by making it easier to digest for
the branch predictor. This includes not looping as much across function
calls and marking our EOF case to be unlikely.
Co-Authored-By: Lucas Chollet <lucas.chollet@free.fr>
This is an extension of cc0b970d but for the reference-handling
specialization of Optional.
This basically allow us to write code like:
```cpp
Optional<u8&> opt;
opt = OptionalNone{};
```
Previously, we were returning an empty optional if key contained a
numerical value which was not stored as double. Stop doing that and
rename the method to signify the change in the behavior.
Apparently, this fixes bug in an InspectorWidget in Ladybird on
Serenity: it showed 0 for element's boxes with integer sizes.
ASAN was crying way too much when running the LibJS JIT since the old
OFFSET_OF implementation was too wild for its liking.
By turning off the invalid-offsetof warnings, we can use the offsetof
builtin instead. However, I'm leaving this as a wrapper macro, since
we may still want to do something different for other compilers.
The streams and other common APIs require byte spans to operate on
arbitrary data. This is less than helpful when wanting to serialize
spans of other data types, such as from an Array or Vector of u32s.
There were two issues:
1) the C+=R and C-=R operators expected arithmetic types to have .real()
2) the R+C, R-C, R*C and R/C operators applied the operation in wrong
order (did C+R, C-R, C*R and C/R instead). This wouldn't matter for
+ and * which are commutative, but is incorrect for - and /.
This is a bit spammy now that we are performing some overload resolution
at build time. The fallback to an interface has generally worked fine on
the types it warns about (BufferSource, Module, etc.) so let's not warn
about it for every build.
