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LibCore: Add Stream::discard()

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This commit is contained in:
Tim Schumacher 2022-11-28 18:54:14 +01:00 • committed by Andreas Kling
parent 7a065513cd
commit 6e29619dcb
2 changed files with 38 additions and 0 deletions
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30
Userland/Libraries/LibCore/Stream.cpp
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@ -73,6 +73,22 @@ ErrorOr<ByteBuffer> Stream::read_all_impl(size_t block_size, size_t expected_fil
return data;
}
ErrorOr<void> Stream::discard(size_t discarded_bytes)
{
// Note: This was chosen arbitrarily.
// Note: This can't be PAGE_SIZE because it is defined to sysconf() on Lagom.
constexpr size_t continuous_read_size = 4096;
Array<u8, continuous_read_size> buffer;
while (discarded_bytes > 0) {
auto slice = TRY(read(buffer.span().slice(0, min(discarded_bytes, continuous_read_size))));
discarded_bytes -= slice.size();
}
return {};
}
bool Stream::write_or_error(ReadonlyBytes buffer)
{
VERIFY(buffer.size());
@ -120,6 +136,12 @@ ErrorOr<off_t> SeekableStream::size()
return seek_result.value();
}
ErrorOr<void> SeekableStream::discard(size_t discarded_bytes)
{
TRY(seek(discarded_bytes, SeekMode::FromCurrentPosition));
return {};
}
ErrorOr<NonnullOwnPtr<File>> File::open(StringView filename, OpenMode mode, mode_t permissions)
{
auto file = TRY(adopt_nonnull_own_or_enomem(new (nothrow) File(mode)));
@ -729,6 +751,14 @@ ErrorOr<Bytes> WrappedAKInputStream::read(Bytes bytes)
return bytes.slice(0, bytes_read);
}
ErrorOr<void> WrappedAKInputStream::discard(size_t discarded_bytes)
{
if (!m_stream->discard_or_error(discarded_bytes))
return Error::from_string_literal("Underlying InputStream indicated an error");
return {};
}
ErrorOr<size_t> WrappedAKInputStream::write(ReadonlyBytes)
{
VERIFY_NOT_REACHED();