Unlike iterator_at_byte_offset(), this function assumes the provided
byte offset is a valid offset into the UTF-8 character stream.
This avoids walking the stream from the start.
There was a subtle mismatch between the obviously expected behavior
of BumpAllocator::for_each_chunk() and its actual implementation.
You'd think it would invoke the callback with the address of each chunk,
but actually it also took the liberty of adding sizeof(ChunkHeader) to
this address. UniformBumpAllocator::destroy_all() relied on this to
get the right address for objects to delete.
The bug happened in BumpAllocator::deallocate_all(), where we use
for_each_chunk() to walk the list of chunks and munmap() them.
To avoid memory mapping churn, we keep a global cache of 1 chunk around.
Since we were being called with the offset chunk address, it meant that
the cached chunk shifted 16 bytes away from its real address every time
we re-added it to the cache.
Eventually the cached chunk address would leave its memory region
entirely, and at that point, any attempt to allocate from it would yield
an address outside the region, causing memory corruption.
Even if the pointer value is const, the value they point to is not
necessarily const, so these functions should not add the qualifier.
This also removes the redundant non-const implementations of these
operators.
This means that rather than this:
```
AK_TYPEDEF_DISTINCT_NUMERIC_GENERAL(u64, true, true, false, false,
false, true, FunctionAddress);
```
We now have this:
```
AK_TYPEDEF_DISTINCT_NUMERIC_GENERAL(u64, FunctionAddress, Arithmetic,
Comparison, Increment);
```
Which is a lot more readable. :^)
Co-authored-by: Ali Mohammad Pur <mpfard@serenityos.org>
When calling clear_with_capacity on an empty HashTable/HashMap, a null
deref would occur when trying to memset() m_buckets. Checking that it
has capacity before clearing fixes the issue.
C++20 can automatically synthesize `operator!=` from `operator==`, so
there is no point in writing such functions by hand if all they do is
call through to `operator==`.
This fixes a compile error with compilers that implement P2468 (Clang
16 currently). This paper restores the C++17 behavior that if both
`T::operator==(U)` and `T::operator!=(U)` exist, `U == T` won't be
rewritten in reverse to call `T::operator==(U)`. Removing `!=` operators
makes the rewriting possible again.
See https://reviews.llvm.org/D134529#3853062
Currently, the floating point to string conversion is implemented
several times across the codebase. This commit provides a pretty
low-level function to unify all of such conversions. It converts the
given double to a fixed point decimal satisfying a few correctness
criteria.
This adds try_* methods to AK::SinglyLinkedList and
AK::SinglyLinkedListWithCount and updates the network stack to use
those to gracefully handle allocation failures.
Refs #6369.
Previously we'd VERIFY() that the user had called finish(). This makes
the following code incorrect though:
auto json = TRY(JsonObjectSerializer<>::try_create(builder));
TRY(json.add("total_time"sv, total_time_scheduled.total));
TRY(json.finish());
return ...;
If the second TRY() returns early we'd fail at the VERIFY() call in the
destructor.
Calling finish() in the destructor - like we had done earlier - is also
not helpful because we have no idea whether the builder is still valid.
Plus we wouldn't be able to handle any errors for that call.
Verifying that either finish() was called or an error occurred doesn't
work either because the caller might have multiple Json*Serializer
objects, e.g. when inserting a JSON array into a JSON object. Forcing
the user to call finish() on their "main" object when a sub-object
caused an error seems unnecessarily tedious.
This file will be the basis for abstracting away the out-of-thread or
later out-of-process decoding from applications displaying videos. For
now, the demuxer is hardcoded to be MatroskaParser, since that is all
we support so far. The demuxer should later be selected based on the
file header.
The playback and decoding are currently all done on one thread using
timers. The design of the code is such that adding threading should
be trivial, at least based on an earlier version of the code. For now,
though, it's better that this runs in one thread, as the multithreaded
approach causes the Video Player to lock up permanently after a few
frames are decoded.
Because we still support u64 and i64 (on top of i32 and u32) we do still
have to parse the number ourself first. Then if we determine that the
number is a floating point or is outside of the range of i64 and u64 we
fallback and parse it as a double.
Before JsonParser had ifdefs guarding the double computation, but it
just build when we error on ifdef KERNEL so JsonParser is no longer
usable in the Kernel. This can be remedied fairly easily but since
it is not needed we #error on that for now.
These are guarded with #ifndef KERNEL, since doubles (and floats) are
not allowed in KERNEL mode.
In StringUtils there is convert_to_floating_point which does have a
template parameter incase you have a templated type.
Similar to decimal floating point parsing the current strtod hex float
parsing gives a lot of incorrect results. We can use a similar technique
as with decimal parsing however hex floats are much simpler as we don't
need to scale with a power of 5.
For hex floats we just provide the parse_first_hexfloat API as there is
currently no need for a parse_hexfloat_completely API.
Again the accepted input for parse_first_hexfloat is very lenient and
any validation should be done before calling this method.
This is based on the paper by Daniel Lemire called
"Number parsing at a Gigabyte per second", currently available at
https://arxiv.org/abs/2101.11408
An implementation can be found at
https://github.com/fastfloat/fast_float
To support both strtod like methods and String::to_double we have two
different APIs. The parse_first_floating_point gives back both the
result, next character to read and the error/out of range status.
Out of range here means we rounded to infinity 0.
The other API, parse_floating_point_completely, will return a floating
point only if the given character range contains just the floating point
and nothing else. This can be much faster as we can skip actually
computing the value if we notice we did not parse the whole range.
Both of these APIs support a very lenient format to be usable in as many
places as possible. Also it does not check for "named" values like
"nan", "inf", "NAN" etc. Because this can be different for every usage.
For integers and small values this new method is not faster and often
even a tiny bit slower than the current strtod implementation. However
the strtod implementation is wrong for a lot of values and has a much
less predictable running time.
For correctness this method was tested against known string -> double
datasets from https://github.com/nigeltao/parse-number-fxx-test-data
This method gives 100% accuracy.
The old strtod gave an incorrect value in over 50% of the numbers
tested.
By appending individual bytes as code points, we were "breaking apart"
multi-byte UTF-8 code points. This now behaves the same way as the
invert_case() helper in StringUtils.
I'm not sure there's a material improvement from this patch. However,
I've been reading the error handling code from multiple projects and
was excited to see Serenity being able to handle assignment
(`auto x = TRY(make_x())`) the same way as actions (`TRY(do_x())`).
I think it's worth documenting that this is only possible due to
non-standard extensions.
This lets us remove a glob pattern from LibC, the DynamicLoader, and,
later, Lagom. The Kernel already has its own separate list of AK files
that it wants, which is only a subset of all AK files.
This prevents an ICE with GCC trying to declare e.g. Variant<String&>.
Using a concept is a bit overkill here, but clang otherwise trips over
the friendship declaration to other Variant types:
template<typename... NewTs>
friend struct Variant;
Without using a concept, clang believes this is re-declaring the Variant
type with differing requirements ("error: requires clause differs in
template redeclaration").
Even though this almost certainly wouldn't run properly even if we had
a working kernel for AARCH64 this at least lets us build all the
userland binaries.
WebDriver aims to implement the WebDriver specification found at
https://w3c.github.io/webdriver/webdriver-spec.html . It's an HTTP
server that can create Browser sessions and control them.
Co-authored-by: Florent Castelli <florent.castelli@gmail.com>
If the entire string you want to right-trim consists of characters you
want to remove, we previously would incorrectly leave the first
character there.
For example: `trim("aaaaa", "a")` would return "a" instead of "".
We can't use `i >= 0` in the loop since that would fail to detect
underflow, so instead we keep `i` in the range `size .. 1` and then
subtract 1 from it when reading the character.
Added some trim() tests while I was at it. (And to confirm that this was
the issue.)
Instead of doing anything reasonable, Utf8CodePointIterator returned
invalid code points, for example U+123456. However, many callers of this
iterator assume that a code point is always at most 0x10FFFF.
In fact, this is one of two reasons for the following OSS Fuzz issue:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49184
This is probably a very old bug.
In the particular case of URLParser, AK::is_url_code_point got confused:
return /* ... */ || code_point >= 0xA0;
If code_point is a "code point" beyond 0x10FFFF, this violates the
condition given in the preceding comment, but satisfies the given
condition, which eventually causes URLParser to crash.
This commit fixes *only* the erroneous UTF-8 decoding, and does not
fully resolve OSS-Fuzz#49184.
In particular, StringView::contains(char) is often used with a u32
code point. When this is done, the compiler will for some reason allow
data corruption to occur silently.
In fact, this is one of two reasons for the following OSS Fuzz issue:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49184
This is probably a very old bug.
In the particular case of URLParser, AK::is_url_code_point got confused:
return /* ... */ || "!$&'()*+,-./:;=?@_~"sv.contains(code_point);
If code_point is a large code point that happens to have the correct
lower bytes, AK::is_url_code_point is then convinced that the given
code point is okay, even if it is actually problematic.
This commit fixes *only* the silent data corruption due to the erroneous
conversion, and does not fully resolve OSS-Fuzz#49184.
GCC seems to get tripped up over this inheritance when converting from
an ErrorOr<StringView> to the partially specialized ErrorOr<void>. See
the following snippet:
NEVER_INLINE ErrorOr<StringView> foo()
{
auto string = "abc"sv;
outln("{:p}", string.characters_without_null_termination());
return string;
}
NEVER_INLINE ErrorOr<void> bar()
{
auto string = TRY(foo());
outln("{:p}", string.characters_without_null_termination());
VERIFY(!string.starts_with('#'));
return {};
}
int main()
{
MUST(bar());
}
On some machines, bar() will contain a StringView whose pointer has had
its upper bits set to 0:
0x000000010cafd6f8
0x000000000cafd6f8
I'm not 100% clear on what's happening in the default-generated Variant
destructor that causes this. Probably worth investigating further.
The error would also be alleviated by making the Variant destructor
virtual, but rather than that, let's make ErrorOr simply contain a
Variant rather than inherit from it.
Fixes#15449.
Until now, VERIFY() failures would just cause a __builtin_trap() in
release builds, which made them a bit too harsh. This commit adds an
out-of-line helper function that prints the error before trapping.
Doesn't use them in libc headers so that those don't have to pull in
AK/Platform.h.
AK_COMPILER_GCC is set _only_ for gcc, not for clang too. (__GNUC__ is
defined in clang builds as well.) Using AK_COMPILER_GCC simplifies
things some.
AK_COMPILER_CLANG isn't as much of a win, other than that it's
consistent with AK_COMPILER_GCC.
Clang patch D116203 added various builtin functions for type traits,
`__decay` being one of them. This name conflicts with our
`AK::Detail::__decay`, leading to compiler warnings with Clang 16.
This is the initial port of Lagom to win32. This will enable developers
to use Lagom as an alternative to vanilla STL/StandardC++Library - which
gives a much richer environment (think QtCore - but modern).
My main incentive - is to have a native Windows Ladybird working.
I am starting with AK, which does not yet fully compile (on mingw). When
AK is compiling (currently fails building StringBuffer.cpp) - I will
continue to LibCore and then the rest of the user space libraries
(excluding the GUI, which will be another different effort).
Most of the code is happily stollen from Andrew Kaster's fork - he
deserves the credit.
Co-authored-by: Andrew Kaster <akaster@serenityos.org>
URL had properly named replacements for protocol(), set_protocol() and
create_with_file_protocol() already. This patch removes these function
and updates all call sites to use the functions named according to the
specification.
See https://url.spec.whatwg.org/#concept-url-scheme
This code generator no longer creates JS wrappers for platform objects
in the old sense, instead they're JS objects internally themselves.
Most of what we generate now are prototypes - which can be seen as
bindings for the internal C++ methods implementing getters, setters, and
methods - as well as object constructors, i.e. bindings for the internal
create_with_global_object() method.
Also tweak the naming of various CMake glue code existing around this.
JS::Value stores 48 bit pointers to separately allocated objects in its
payload. On x86-64, canonical addresses have their top 16 bits set to
the same value as bit 47, effectively meaning that the value has to be
sign-extended to get the pointer. AArch64, however, expects the topmost
bits to be all zeros.
This commit gates sign extension behind `#if ARCH(X86_64)`, and adds an
`#error` for unsupported architectures, so that we do not forget to
think about pointer handling when porting to a new architecture.
Fixes#15290FixesSerenityOS/ladybird#56
We were dropping the base URL path components in the resulting URL due
to mistakenly determining the input URL to start with a Windows drive
letter. Fix this, add a spec link, and a test.
A StringView is sufficient here. This also removes the declaration of
fuzzy_match_recursive from the header, as it's only needed from within
the implementation file.
LLVM 15 switched around what it's basing its `nullptr_t` definitions on,
it's now defining `std::nullptr_t` using `::nullptr_t` instead of the
other way around.
Work around any errors that result from that by just defining it both in
the global namespace as well as in `std` ourselves.
I was very confused why I was getting "no key named `foo`" errors, so
hopefully this will save someone that confusion in the future. :^)
(It'll probably be me again...)
This was present in Vector already. Clang-format fixed some const
positions automatically too.
Also removed a now-ambiguous and unnecessary constructor from Shell.
This is a set of functions that allow you to convert between arbitrary
IEEE 754 floating point types, as long as they can be represented
within 64 bits. Conversion methods between floats and doubles are
provided, as well as a generic `float_to_float()`.
Example usage:
#include <AK/FloatingPoint.h>
double val = 1.234;
auto weird_f16 =
convert_from_native_double<FloatingPointBits<0, 6, 10>>(val);
Signed and unsigned floats are supported, and both NaN and +/-Inf are
handled correctly. Values that do not fit in the target floating point
type are clamped.
Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:
- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable
This patch renames the Kernel classes so that they can coexist with
the original AK classes:
- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable
The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.
Instead of having two separate implementations of AK::RefCounted, one
for userspace and one for kernelspace, there is now RefCounted and
AtomicRefCounted.
The commit that introduced BuiltinWrappers (548529a) accidentally used
`val` instead of `value` in the non `__GNUC__` and `__clang__` versions
of the functions.
That this did not already happen took me by surprise, as for
most other similar containers/types in AK (e.g. Span) the index
will be checked. This check not happening could easily let
off-by-one indexing errors slip through the cracks.
This can almost be identical to the Linux version, except that the
`pthread_attr_t` object is populated using a call to
`pthread_attr_get_np` instead of `pthread_getattr_np`.
FreeBSD also needs `pthread_atttr_t` to be initialized using
`pthread_attr_init` instead of zero-initialization, but it's the
technically correct thing to do on Linux as well.
This constructor relied on running strlen implicitly on its argument,
thereby potentially causing out-of-bound reads (some of which were
caught a few days ago). The removal of this constructor ensures that the
caller must explicitly pass the size of the string by either:
1) Using operator""sv on literal strings; or
2) Calling strlen explicitly, making it clear that the size of the view
is being calculated at runtime.
During the removal of StringView(char const*), all users of these
functions were removed, and they are of dubious value (relying on
implicit StringView conversion).
This prevents us from needing a sv suffix, and potentially reduces the
need to run generic code for a single character (as contains,
starts_with, ends_with etc. for a char will be just a length and
equality check).
No functional changes.
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.
Error::from_string_literal now takes direct char const*s, while
Error::from_string_view does what Error::from_string_literal used to do:
taking StringViews. This change will remove the need to insert `sv`
after error strings when returning string literal errors once
StringView(char const*) is removed.
No functional changes.
This commit moves the length calculations out to be directly on the
StringView users. This is an important step towards the goal of removing
StringView(char const*), as it moves the responsibility of calculating
the size of the string to the user of the StringView (which will prevent
naive uses causing OOB access).
This makes the assumption that we never pass a stack-allocated char
array to CheckedFormatString arguments (dbgln, outln, warnln). This
assumption seems to hold true for the current state of Serenity code, at
least. :^)
Previously we would treat the empty string as `null`. This caused
JavaScript like this to fail:
```js
var object = {};
try {
object = JSON.parse("");
} catch {}
var array = object.array || [];
```
Since `JSON.parse("")` returned null instead of throwing, it would set
`object` to null and then try and use it instead of using the default
backup value.
Is it another great upgrade to our PNG encoder like in 9aafaec259?
Well, not really - it's not a 2x or 55x improvement like you saw there,
but still it saves something:
- a screenshot of a blank Serenity desktop dropped from about 45 KiB
to 40 KiB.
- re-encoding NASA photo of the Earth to PNG again saves about 25%
(16.5 MiB -> 12.3 MiB), compared to not using filters.
[1]: https://commons.wikimedia.org/wiki/File:The_Blue_Marble_(remastered).jpg
This commit has no behavior changes.
In particular, this does not fix any of the wrong uses of the previous
default parameter (which used to be 'false', meaning "only replace the
first occurence in the string"). It simply replaces the default uses by
String::replace(..., ReplaceMode::FirstOnly), leaving them incorrect.
ByteBuffer::get_bytes_for_writing() was only ensuring capacity before
this patch. The method needs to call resize to register the appended
data, otherwise it will be overwritten with next data addition.
Usually the values of the previous and next pointers of deleted buckets
are never used, as they're not part of the main ordered bucket chain,
but if an in-place rehashing is done, which results in the bucket being
turned into a free bucket, the stale pointers will remain, at which
point any item that is inserted into said free-bucket will have either
a stale previous pointer if the HashTable was empty on insertion, or a
stale next pointer, resulting in undefined behaviour.
This commit also includes a new HashMap test that reproduces this issue
This reverts commit 50c88e5e3a.
The intention was to add them to NonnullRefPtr, not NonnullOwnPtr. That
is also what was advertised in the PR, but not actually done in the
reverted commit.
It was mostly implemented based on a spec note, that described only
allowed characters, but instead of allowing some special characters not
to be escaped, we escaped every special character except those 'new in
this encode set' disallowed characters from the spec definition.
This is an issue on systems that don't have the empty base class
optimisation (such as windows), and we normally don't need to care -
however static_cast is technically the right thing to use, so let's use
that instead.
Co-Authored-By: Daniel Bertalan <dani@danielbertalan.dev>
The compiler would complain about `__builtin_memcpy` in ByteBuffer::copy
writing out of bounds, as it isn't able to deduce the invariant that the
inline buffer is only used when the requested size is smaller than the
inline capacity.
The other change is more bizarre. If the destructor's declaration
exists, gcc complains about a `delete` operation causing an
out-of-bounds array access.
error: array subscript 'DHCPv4Client::__as_base [0]' is partly outside
array bounds of 'unsigned char [8]' [-Werror=array-bounds]
14 | ~DHCPv4Client() = default;
| ^
This looks like a compiler bug, and I'll report it if I find a suitable
reduced reproducer.
This allows direct inlining and hides away some assembly and
bit-fiddling when manipulating the floating point environment.
This only implements the x87/SSE versions, as of now.
This uses the `fistp` and `cvts[sd]2si` respectively, to potentially
round floating point values with just one instruction.
This falls back to `llrint[fl]?` on aarch64 for now.
This new class with an admittedly long OOP-y name provides a circular
queue in shared memory. The queue is a lock-free synchronous queue
implemented with atomics, and its implementation is significantly
simplified by only accounting for one producer (and multiple consumers).
It is intended to be used as a producer-consumer communication
datastructure across processes. The original motivation behind this
class is efficient short-period transfer of audio data in userspace.
This class includes formal proofs of several correctness properties of
the main queue operations `enqueue` and `dequeue`. These proofs are not
100% complete in their existing form as the invariants they depend on
are "handwaved". This seems fine to me right now, as any proof is better
than no proof :^). Anyways, the proofs should build confidence that the
implemented algorithms, which are only roughly based on existing work,
operate correctly in even the worst-case concurrency scenarios.
This allows for calling this function with any argument type for which
the appropriate traits and operators have been implemented so it can be
compared to the Vector's item type
This patch adds a header containing the fuzzy match algorithm
previously used in Assistant. The algorithm was moved to AK
since there are many places where a search may benefit from fuzzyness.
Some functions want to ignore cv-qualifiers, and it's much easier to
constrain the type through a concept than a separate requires clause on
the function.
Both calls essentially only differ in one boolean, which dictates
whether to print the value in uppercase or lowercase.
Move the long function call into a new function and pass in the
"uppercase" boolean seperately to avoid having to write everything
twice.
Those functions only differ by the input type of `number`. No other
wrapper does this, as they rely on adjusting the type of the argument on
the caller side instead.
Avoid specializing too much by just doing the same for signed numbers.
We were decoding and then re-encoding the query string in URLs.
This round-trip caused us to lose information about plus ('+')
ASCII characters encoded as "%2B".
A change was made prior to percent encode plus signs in order to fix an
issue with the Google cookie consent page.
Unforunately, this was treating a symptom of a problem and not the root
cause and is incorrect behavior.
When we want to use the find_first_index that base Vector provides, we
need to provide an element of the real contained type. That's impossible
for OwnPtr, however, and even with RefPtr there might be instances where
we have a raw reference to the object we want to find, but no smart
pointer. Therefore, overloading this function (with an identical body,
the magic is done by the find_index templatization) with `T const&` as a
parameter allows there use cases.
On oss-fuzz, the LibJS REPL is provided a file encoded with Windows-1252
with the following contents:
/ô¡°½/
The REPL assumes the input file is UTF-8. So in Windows-1252, the above
is represented as [0x2f 0xf4 0xa1 0xb0 0xbd 0x2f]. The inner 4 bytes are
actually a valid UTF-8 encoding if we only look at the most significant
bits to parse leading/continuation bytes. However, it decodes to the
code point U+121c3d, which is not a valid code point.
This commit adds additional validation to ensure the decoded code point
itself is also valid.
These functions are _very_ misleading, as `first()` and `last()` return
references, but `{first,last}_matching()` return copies of the values.
This commit makes it so that they now return Optional<T&>, eliminating
the copy and the confusion.
This implements Optional<T&> as a T*, whose presence has been missing
since the early days of Optional.
As a lot of find_foo() APIs return an Optional<T> which imposes a
pointless copy on the underlying value, and can sometimes be very
misleading, with this change, those APIs can return Optional<T&>.
This method exploits the fact that the values themselves hold the tree
pointers, and as a result this let's us skip the O(logn) traversal down
to the matching Node for a Key-Value pair.
Adds a new optional parameter 'reserved_chars' to
AK::URL::percent_encode. This new optional parameter allows the caller
to specify custom characters to be percent encoded. This is then used
to percent encode plus signs by HttpRequest::to_raw_request.
As seen on TV, HashTable can get "thrashed", i.e. it has a bunch of
deleted buckets that count towards the load factor. This means that hash
tables which are large enough for their contents need to be resized.
This was fixed in 9d8da16 with a workaround that shrinks the HashTable
back down in these cases, as after the resize and re-hash the load
factor is very low again. However, that's not a good solution. If you
insert and remove repeatedly around a size boundary, you might get
frequent resizes, which involve frequent re-allocations.
The new solution is an in-place rehashing algorithm that I came up with.
(Do complain to me, I'm at fault.) Basically, it iterates the buckets
and re-hashes the used buckets while marking the deleted slots empty.
The issue arises with collisions in the re-hash. For this reason, there
are two kinds of used buckets during the re-hashing: the normal "used"
buckets, which are old and are treated as free space, and the
"re-hashed" buckets, which are new and treated as used space, i.e. they
trigger probing. Therefore, the procedure for relocating a bucket's
contents is as follows:
- Locate the "real" bucket of the contents with the hash. That bucket is
the starting point for the target bucket, and the current (old) bucket
is the bucket we want to move.
- While we still need to move the bucket:
- If we're the target, something strange happened last iteration or we
just re-hashed to the same location. We're done.
- If the target is empty or deleted, just move the bucket. We're done.
- If the target is a re-hashed full bucket, we probe by double-hashing
our hash as usual. Henceforth, we move our target for the next
iteration.
- If the target is an old full bucket, we swap the target and to-move
buckets. Therefore, the bucket to move is a the correct location and the
former target, which still needs to find a new place, is now in the
bucket to move. So we can just continue with the loop; the target is
re-obtained from the bucket to move. This happens for each and every
bucket, though some buckets are "coincidentally" moved before their
point of iteration is reached. Either way, this guarantees full in-place
movement (even without stack storage) and therefore space complexity of
O(1). Time complexity is amortized O(2n) asssuming a good hashing
function.
This leads to a performance improvement of ~30% on the benchmark
introduced with the last commit.
Co-authored-by: Hendiadyoin1 <leon.a@serenityos.org>
The hash table buckets had three different state booleans that are in
fact exclusive. In preparation for further states, this commit
consolidates them into one enum. This has the added benefit on not
relying on the compiler's boolean packing anymore; we definitely now
only need one byte for the bucket state.
Currently this can parse XML and resolve external resources/references,
and read a DTD (but not apply or verify its rules).
That's good enough for _most_ XHTML documents as the HTML 5 spec
enforces its own rules about document well-formedness, and does not make
use of XML DTDs (aside from a list of predefined entities).
An accompanying `xml` utility is provided that can read and dump XML
documents, and can also run the XML conformance test suite.
This is an enum-like type that works with arbitrary sized storage > u64,
which is the limit for a regular enum class - which limits it to 64
members when needing bit field behavior.
Co-authored-by: Ali Mohammad Pur <mpfard@serenityos.org>
Previously, case-insensitively searching the haystack "Go Go Back" for
the needle "Go Back" would return false:
1. Match the first three characters. "Go ".
2. Notice that 'G' and 'B' don't match.
3. Skip ahead 3 characters, plus 1 for the outer for-loop.
4. Now, the haystack is effectively "o Back", so the match fails.
Reducing the skip by 1 fixes this issue. I'm not 100% convinced this
fixes all cases, but I haven't been able to find any cases where it
doesn't work now. :^)
Day and month name constants are defined in numerous places. This
pulls them together into a single place and eliminates the
duplication. It also ensures they are `constexpr`.
Even though the StringView(char*, size_t) constructor only runs its
overflow check when evaluated in a runtime context, the code generated
here could prevent the compiler from optimizing invocations from the
StringView user-defined literal (verified on Compiler Explorer).
This changes the user-defined literal declaration to be consteval to
ensure it is evaluated at compile time.
C++20 provides the `requires` clause which simplifies the ability to
limit overload resolution. Prefer it over `EnableIf`
With all uses of `EnableIf` being removed, also remove the
implementation so future devs are not tempted.
Since the allocated memory is going to be zeroed immediately anyway,
let's avoid redundantly scrubbing it with MALLOC_SCRUB_BYTE just before
that.
The latest versions of gcc and Clang can automatically do this malloc +
memset -> calloc optimization, but I've seen a couple of places where it
failed to be done.
This commit also adds a naive kcalloc function to the kernel that
doesn't (yet) eliminate the redundancy like the userland does.
Previously, if you forgot to set a key on a SourceGenerator, you would
get this less-than-helpful error message:
> Generate_CSS_MediaFeatureID_cpp:
/home/sam/serenity/Meta/Lagom/../../AK/Optional.h:174: T
AK::Optional<T>::release_value() [with T = AK::String]: Assertion
`m_has_value' failed.
Now, it instead looks like this:
> No key named `name:titlecase` set on SourceGenerator
Generate_CSS_MediaFeatureID_cpp:
/home/sam/serenity/Meta/Lagom/../../AK/SourceGenerator.h:44:
AK::String AK::SourceGenerator::get(AK::StringView) const: Assertion
`false' failed.
This is the IPv6 counter part to the IPv4Address class and implements
parsing strings into a in6_addr and formatting one as a string. It
supports the address compression scheme as well as IPv4 mapped
addresses.
If the utilization of a HashTable (size vs capacity) goes below 20%,
we'll now shrink the table down to capacity = (size * 2).
This fixes an issue where tables would grow infinitely when inserting
and removing keys repeatedly. Basically, we would accumulate deleted
buckets with nothing reclaiming them, and eventually deciding that we
needed to grow the table (because we grow if used+deleted > limit!)
I found this because HashTable iteration was taking a suspicious amount
of time in Core::EventLoop::get_next_timer_expiration(). Turns out the
timer table kept growing in capacity over time. That made iteration
slower and slower since HashTable iterators visit every bucket.
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