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").
