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LibCompress: Move common LZMA end-of-file checks into helper functions

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Tim Schumacher 2023-03-29 23:37:59 +02:00 committed by Andreas Kling
parent 0016f63547
commit b6f3b2f116
2 changed files with 19 additions and 4 deletions
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21
Userland/Libraries/LibCompress/Lzma.cpp
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@ -140,6 +140,19 @@ LzmaDecompressor::LzmaDecompressor(MaybeOwned<Stream> stream, LzmaDecompressorOp
initialize_to_default_probability(m_is_rep0_long_probabilities);
}
bool LzmaDecompressor::is_range_decoder_in_clean_state() const
{
return m_range_decoder_code == 0;
}
bool LzmaDecompressor::has_reached_expected_data_size() const
{
if (!m_options.uncompressed_size.has_value())
return false;
return m_total_decoded_bytes >= m_options.uncompressed_size.value();
}
ErrorOr<void> LzmaDecompressor::initialize_range_decoder()
{
// "The LZMA Encoder always writes ZERO in initial byte of compressed stream.
@ -451,7 +464,7 @@ ErrorOr<Bytes> LzmaDecompressor::read_some(Bytes bytes)
break;
}
if (m_options.uncompressed_size.has_value() && m_total_decoded_bytes >= m_options.uncompressed_size.value()) {
if (has_reached_expected_data_size()) {
// FIXME: This should validate that either EOF or the 'end of stream' marker follow immediately.
// Both of those cases count as the 'end of stream' marker being found and should check for a clean decoder state.
break;
@ -654,7 +667,7 @@ ErrorOr<Bytes> LzmaDecompressor::read_some(Bytes bytes)
}
if (m_found_end_of_stream_marker) {
if (m_range_decoder_code != 0)
if (!is_range_decoder_in_clean_state())
return Error::from_string_literal("LZMA stream ends in an unclean state");
}
@ -671,8 +684,8 @@ bool LzmaDecompressor::is_eof() const
if (m_dictionary->used_space() > 0)
return false;
if (m_options.uncompressed_size.has_value())
return m_total_decoded_bytes >= m_options.uncompressed_size.value();
if (has_reached_expected_data_size())
return true;
return m_found_end_of_stream_marker;
}

2
Userland/Libraries/LibCompress/Lzma.h
View file

@ -81,6 +81,8 @@ private:
MaybeOwned<CircularBuffer> m_dictionary;
u64 m_total_decoded_bytes { 0 };
bool m_found_end_of_stream_marker { false };
bool is_range_decoder_in_clean_state() const;
bool has_reached_expected_data_size() const;
Optional<u16> m_leftover_match_length;
// Range decoder state (initialized with stream data in LzmaDecompressor::create).