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AK: Use hashing to accelerate searching a CircularBuffer

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Tim Schumacher 2023-06-02 13:37:47 +02:00 • committed by Linus Groh
parent 4a10cf1506
commit 60ac254df6
4 changed files with 269 additions and 101 deletions
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8
Userland/Libraries/LibCompress/Lzma.cpp
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@ -1007,17 +1007,17 @@ ErrorOr<void> LzmaCompressor::encode_once()
}
// If we weren't able to find any viable existing offsets, we now have to search the rest of the dictionary for possible new offsets.
auto new_distance_results = TRY(m_dictionary->find_copy_in_seekback(m_dictionary->used_space(), normalized_to_real_match_length_offset));
auto new_distance_result = m_dictionary->find_copy_in_seekback(m_dictionary->used_space(), normalized_to_real_match_length_offset);
if (new_distance_results.size() > 0) {
auto selected_match = new_distance_results[0];
if (new_distance_result.has_value()) {
auto selected_match = new_distance_result.release_value();
TRY(encode_new_match(selected_match.distance, selected_match.length));
return {};
}
// If we weren't able to find any matches, we don't have any other choice than to encode the next byte as a literal.
u8 next_byte { 0 };
m_dictionary->read({ &next_byte, sizeof(next_byte) });
TRY(m_dictionary->read({ &next_byte, sizeof(next_byte) }));
TRY(encode_literal(next_byte));
return {};
}