Commit graph

12 commits

Author SHA1 Message Date
kleines Filmröllchen 9d4c50ca60 AK: Add big endian bit reading to InputBitStream
The existing InputBitStream methods only read in little endian, as this
is what the rest of the system requires. Two new methods allow the input
bitstream to read bits in big endian as well, while using the existing
state infrastructure.

Note that it can lead to issues if little endian and big endian reads
are used out of order without aligning to a byte boundary first.
2021-06-25 20:48:14 +04:30
Idan Horowitz 1c512a702a AK+Userland: Use idan.horowitz@serenityos.org for my copyright headers 2021-04-22 22:42:38 +02:00
Brian Gianforcaro 1682f0b760 Everything: Move to SPDX license identifiers in all files.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.

See: https://spdx.dev/resources/use/#identifiers

This was done with the `ambr` search and replace tool.

 ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 11:22:27 +02:00
Idan Horowitz ea5f83616e LibCompress+AK: Dont short-circuit error handling propagation
In the case that both the stream and the wrapped substream had errors
to be handled only one of the two would be resolved due to boolean
short circuiting. this commit ensures both are handled irregardless
of one another.
2021-03-16 14:56:50 +01:00
Idan Horowitz a955fd4156 LibCompress+AK: Propagate error handling to wrapped streams
This ensures that when a DeflateCompressor stream is cleared of any
errors its underlying wrapped streams (InputBitStream/InputMemoryStream)
will be cleared as well and wont fail a VERIFY on destruction.
2021-03-15 21:35:48 +01:00
Idan Horowitz 1b7b503bae AK: Add fast paths for aligned bit writes in BitOutputStream
If the bit write is aligned (or has been aligned during the write) we can
write in multiples of 32/16/8 bits for increased performance.
2021-03-13 23:50:07 +01:00
Idan Horowitz 0ddc0e45ae AK: Add OutputBitStream class
This will be used in the deflate compressor.
2021-03-13 20:07:25 +01:00
asynts 96edcbc27c AK: Lower the requirements for InputStream::eof and rename it.
Consider the following snippet:

    void foo(InputStream& stream) {
        if(!stream.eof()) {
            u8 byte;
            stream >> byte;
        }
    }

There is a very subtle bug in this snippet, for some input streams eof()
might return false even if no more data can be read. In this case an
error flag would be set on the stream.

Until now I've always ensured that this is not the case, but this made
the implementation of eof() unnecessarily complicated.
InputFileStream::eof had to keep a ByteBuffer around just to make this
possible. That meant a ton of unnecessary copies just to get a reliable
eof().

In most cases it isn't actually necessary to have a reliable eof()
implementation.

In most other cases a reliable eof() is avaliable anyways because in
some cases like InputMemoryStream it is very easy to implement.
2020-09-14 20:58:12 +02:00
Ben Wiederhake 0d3a8d5397 AK: Fix accidentally-recursive call in BitStream 2020-09-12 00:13:29 +02:00
asynts 6de63782c7 Streams: Consistent behaviour when reading from stream with error.
The streaming operator doesn't short-circuit, consider the following
snippet:

    void foo(InputStream& stream) {
        int a, b;
        stream >> a >> b;
    }

If the first read fails, the second is called regardless. It should be
well defined what happens in this case: nothing.
2020-09-06 12:54:45 +02:00
asynts 9ce4475907 Streams: Distinguish recoverable and fatal errors. 2020-09-01 17:25:26 +02:00
asynts 71cbf72e8a AK: Add InputBitStream class. 2020-08-26 21:07:53 +02:00