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LibCompress: Switch the deflate seekback buffer to CircularBuffer

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Tim Schumacher 2023-01-01 01:08:53 +01:00 committed by Andrew Kaster
parent 35548cab75
commit 46a53dc6e0
Notes: sideshowbarker 2024-07-17 01:44:33 +09:00 
Author: https://github.com/timschumi
Commit: https://github.com/SerenityOS/serenity/commit/46a53dc6e0
Pull-request: https://github.com/SerenityOS/serenity/pull/16917
Reviewed-by: https://github.com/ADKaster ✅
2 changed files with 20 additions and 18 deletions
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34
Userland/Libraries/LibCompress/Deflate.cpp
View file

@ -139,7 +139,8 @@ ErrorOr<bool> DeflateDecompressor::CompressedBlock::try_read_more()
return Error::from_string_literal("Invalid deflate literal/length symbol");
if (symbol < 256) {
m_decompressor.m_output_stream << static_cast<u8>(symbol);
u8 byte_symbol = symbol;
m_decompressor.m_output_buffer.write({ &byte_symbol, sizeof(byte_symbol) });
return true;
} else if (symbol == 256) {
m_eof = true;
@ -157,12 +158,9 @@ ErrorOr<bool> DeflateDecompressor::CompressedBlock::try_read_more()
for (size_t idx = 0; idx < length; ++idx) {
u8 byte = 0;
m_decompressor.m_output_stream.read({ &byte, sizeof(byte) }, distance);
TRY(m_decompressor.m_output_buffer.read_with_seekback({ &byte, sizeof(byte) }, distance));
if (m_decompressor.m_output_stream.handle_any_error())
return Error::from_string_literal("A back reference was requested that was too far back");
m_decompressor.m_output_stream << byte;
m_decompressor.m_output_buffer.write({ &byte, sizeof(byte) });
}
return true;
@ -180,21 +178,25 @@ ErrorOr<bool> DeflateDecompressor::UncompressedBlock::try_read_more()
if (m_bytes_remaining == 0)
return false;
auto const nread = min(m_bytes_remaining, m_decompressor.m_output_stream.remaining_contiguous_space());
m_bytes_remaining -= nread;
TRY(m_decompressor.m_input_stream->read(m_decompressor.m_output_stream.reserve_contiguous_space(nread)));
Array<u8, 4096> temporary_buffer;
auto readable_bytes = temporary_buffer.span().trim(min(m_bytes_remaining, m_decompressor.m_output_buffer.empty_space()));
auto read_bytes = TRY(m_decompressor.m_input_stream->read(readable_bytes));
auto written_bytes = m_decompressor.m_output_buffer.write(read_bytes);
VERIFY(read_bytes.size() == written_bytes);
m_bytes_remaining -= written_bytes;
return true;
}
ErrorOr<NonnullOwnPtr<DeflateDecompressor>> DeflateDecompressor::construct(Core::Stream::Handle<Core::Stream::Stream> stream)
{
return TRY(adopt_nonnull_own_or_enomem(new (nothrow) DeflateDecompressor(move(stream))));
auto output_buffer = TRY(CircularBuffer::create_empty(32 * KiB));
return TRY(adopt_nonnull_own_or_enomem(new (nothrow) DeflateDecompressor(move(stream), move(output_buffer))));
}
DeflateDecompressor::DeflateDecompressor(Core::Stream::Handle<Core::Stream::Stream> stream)
DeflateDecompressor::DeflateDecompressor(Core::Stream::Handle<Core::Stream::Stream> stream, CircularBuffer output_buffer)
: m_input_stream(make<Core::Stream::LittleEndianInputBitStream>(move(stream)))
, m_output_buffer(move(output_buffer))
{
}
@ -257,10 +259,10 @@ ErrorOr<Bytes> DeflateDecompressor::read(Bytes bytes)
}
if (m_state == State::ReadingCompressedBlock) {
auto nread = m_output_stream.read(slice);
auto nread = m_output_buffer.read(slice).size();
while (nread < slice.size() && TRY(m_compressed_block.try_read_more())) {
nread += m_output_stream.read(slice.slice(nread));
nread += m_output_buffer.read(slice.slice(nread)).size();
}
total_read += nread;
@ -274,10 +276,10 @@ ErrorOr<Bytes> DeflateDecompressor::read(Bytes bytes)
}
if (m_state == State::ReadingUncompressedBlock) {
auto nread = m_output_stream.read(slice);
auto nread = m_output_buffer.read(slice).size();
while (nread < slice.size() && TRY(m_uncompressed_block.try_read_more())) {
nread += m_output_stream.read(slice.slice(nread));
nread += m_output_buffer.read(slice.slice(nread)).size();
}
total_read += nread;

4
Userland/Libraries/LibCompress/Deflate.h
View file

@ -88,7 +88,7 @@ public:
static ErrorOr<ByteBuffer> decompress_all(ReadonlyBytes);
private:
DeflateDecompressor(Core::Stream::Handle<Core::Stream::Stream> stream);
DeflateDecompressor(Core::Stream::Handle<Core::Stream::Stream> stream, CircularBuffer buffer);
ErrorOr<u32> decode_length(u32);
ErrorOr<u32> decode_distance(u32);
@ -103,7 +103,7 @@ private:
};
Core::Stream::Handle<Core::Stream::LittleEndianInputBitStream> m_input_stream;
CircularDuplexStream<32 * KiB> m_output_stream;
CircularBuffer m_output_buffer;
};
class DeflateCompressor final : public Core::Stream::Stream {