RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-27 04:07:45 +00:00
Code Issues Activity Actions

LibCompress: Handle literal only lz77 streams in DeflateCompressor

Browse source 
Very incompressible data could sometimes produce no backreferences
which would result in no distance huffman code being created (as it
was not needed), so VERIFY the code exists only if it is actually
needed for writing the stream.
This commit is contained in:
Idan Horowitz 2021-03-14 11:43:18 +02:00 • committed by Andreas Kling
parent 1db943e146
commit 7e587a615e
3 changed files with 16 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

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

@ -190,10 +190,10 @@ private:
template<size_t Size>
static void generate_huffman_lengths(Array<u8, Size>& lengths, const Array<u16, Size>& frequencies, size_t max_bit_length, u16 frequency_cap = UINT16_MAX);
size_t huffman_block_length(const Array<u8, max_huffman_literals>& literal_bit_lengths, const Array<u8, max_huffman_distances>& distance_bit_lengths);
void write_huffman(const CanonicalCode& literal_code, const CanonicalCode& distance_code);
void write_huffman(const CanonicalCode& literal_code, const Optional<CanonicalCode>& distance_code);
static size_t encode_huffman_lengths(const Array<u8, max_huffman_literals + max_huffman_distances>& lengths, size_t lengths_count, Array<code_length_symbol, max_huffman_literals + max_huffman_distances>& encoded_lengths);
size_t encode_block_lengths(const Array<u8, max_huffman_literals>& literal_bit_lengths, const Array<u8, max_huffman_distances>& distance_bit_lengths, Array<code_length_symbol, max_huffman_literals + max_huffman_distances>& encoded_lengths, size_t& literal_code_count, size_t& distance_code_count);
void write_dynamic_huffman(const CanonicalCode& literal_code, size_t literal_code_count, const CanonicalCode& distance_code, size_t distance_code_count, const Array<u8, 19>& code_lengths_bit_lengths, size_t code_length_count, const Array<code_length_symbol, max_huffman_literals + max_huffman_distances>& encoded_lengths, size_t encoded_lengths_count);
void write_dynamic_huffman(const CanonicalCode& literal_code, size_t literal_code_count, const Optional<CanonicalCode>& distance_code, size_t distance_code_count, const Array<u8, 19>& code_lengths_bit_lengths, size_t code_length_count, const Array<code_length_symbol, max_huffman_literals + max_huffman_distances>& encoded_lengths, size_t encoded_lengths_count);
size_t uncompressed_block_length();
size_t fixed_block_length();