The proper abstract operations on Navigable and TraversableNavigable are
not quite ready to call from Navigation. With this commit all of the
user-facing APIs of Navigation are in place, and the stage should be set
to implement the parts of the navigation and traversal AOs that need to
interact with the Navigation object.
Instead of grabbing `uname -vr` on non-Serenity platforms, let's just
hardcode a version. This prevents Lagom builds of applications like
Shell or Ladybird from reporting their version as that of the host OS.
Following the removal of the `drand48` patch to the configure script,
we can now remove this patch as it is no longer needed to prevent an
interpreter hang.
These functions are required for the `perl5` port's random function to
operate correctly. As a bonus, this allows us to remove a nasty patch
that replaces `drand48` with `random`.
This is an initial implementation, about as basic as intended by the
RFC, and not configurable from userspace at the moment. It should reduce
the amount of low-sized packets sent, reducing overhead and thereby
network traffic.
Just like on Linux, we can easily print the process creation time. The
format of a printed time is either "hour:minute" if the process started
today, or "short_month_name:day_of_the_month" (for example, "Aug26").
The name for this directory is a bit awkward. Also, the distinction of
constant information is not really valuable as I thought it would be, so
let's bring that information back into the /sys/kernel directory.
The name "variables" is a bit awkward and what the directory entries are
really about is kernel configuration so let's make it clear with the new
name.
When the grid layout gets to
`resolve_items_box_metrics(GridDimension::Column)`, we've already
determined the width of each column. However, the widths of the
individual grid items themselves haven't been set. Rather than using
`get_available_space_for_item()`, which returns an indefinite size if
an item's width/height hasn't been set, we should use the already
known track width as the available size to calculate the fit-content
width.
We can just create a `BigEndianInputBitStream` where it is needed
instead of storing one in the class. After making `read_header()`
static, the only other user of the field was `read_size_information()`,
so let's do that there and then remove the field.
This makes the checks for a frame header more consistent, so if the
conditions for allowed frame headers change, there are less scattered
lines that will need to be changed.
`synchronize()` will now also properly scan the second byte of the hex
sequence `FF FF F0` as a sync code, where previously it would see
`FF F` and skip on to `F0`, ignoring its preceding `FF` that would
indicate that it is a sync code.
`synchronize()` can be simplified greatly by checking whole bytes with
bitwise operations, and doing so also avoids the overhead of reading
individual bits from a bitstream.
Making `read_frame()` also take a `SeekableStream` will allow it to be
used inside `synchronize()` in the next commit.
Prevously, the header size was used to calculate the `slot_count` field
of `MP3::Header`, but `build_seek_table()` just used the maximum size
of the header instead, causing it not to seek far enough, and in cases
where a possible sync code occurred two bytes before the next frame, it
would read that possible sync code as if it was a real frame. It would
then either reject it due to bad field values, or could possibly skip
over the next real frame due to a larger calculated frame size in the
bogus frame.
By fixing this issue, we now properly calculate the duration of MP3
files where these fake sync codes occur. In the case of the raw file
for this podcast:
https://changelog.com/podcast/554
the duration goes from 1:21:57 to 1:22:47, which is the real duration
according to the player user interface.
The seek table must locate the first MP3 frame in the file, so it makes
sense to locate the samples for the sample table first, then that
information to seek to the first frame.
Previously, we would just start from byte 0 and check individual bytes
of the file until we find two bytes starting with `FF F`, and then
assume that that was the MP3 frame sync code. However, some ID3v2 tags
do not have to be what is referred to as "unsynchronized", meaning that
they can contain that `FF F` sequence and cause our decoder to think it
has found a frame.
To avoid this happening, we can read a minimal amount of the ID3 header
to determine how many bytes to skip before attempting to find the MP3
frames.
This allows the recent podcast with Andreas to play here:
https://changelog.com/podcast/554
Seek points were being created after adding to the sample count in
`build_seek_table()`, meaning that they would be offset forward by
`MP3::frame_size` samples.
This also allows us to remove the hardcoded sample 0 seek point that
was previously added, since a seek point at sample 0 will now be added
by the loop.
