mirror of
https://github.com/RGBCube/serenity
synced 2025-07-06 17:37:35 +00:00
98e18d7339
For now this only contains DEFLATE, and a very simple Zlib Eventually GZip, etc. can go here as well.
98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/CircularQueue.h>
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#include <AK/Span.h>
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#include <AK/Types.h>
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#include <AK/Vector.h>
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#include <cstring>
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namespace Compress {
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// Reads one bit at a time starting with the rightmost bit
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class BitStreamReader {
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public:
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BitStreamReader(ReadonlyBytes data)
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: m_data(data)
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{
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}
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i8 read();
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i8 read_byte();
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u32 read_bits(u8);
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u8 get_bit_byte_offset();
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private:
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ReadonlyBytes m_data;
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size_t m_data_index { 0 };
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i8 m_current_byte { 0 };
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u8 m_remaining_bits { 0 };
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};
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class CanonicalCode {
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public:
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CanonicalCode(Vector<u8>);
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u32 next_symbol(BitStreamReader&);
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private:
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Vector<u32> m_symbol_codes;
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Vector<u32> m_symbol_values;
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};
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class Deflate {
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public:
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Deflate(ReadonlyBytes data)
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: m_reader(data)
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, m_literal_length_codes(generate_literal_length_codes())
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, m_fixed_distance_codes(generate_fixed_distance_codes())
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{
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}
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Vector<u8> decompress();
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private:
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void decompress_uncompressed_block();
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void decompress_static_block();
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void decompress_dynamic_block();
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void decompress_huffman_block(CanonicalCode&, CanonicalCode*);
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Vector<CanonicalCode> decode_huffman_codes();
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void copy_from_history(u32, u32);
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u32 decode_run_length(u32);
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u32 decode_distance(u32);
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Vector<u8> generate_literal_length_codes();
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Vector<u8> generate_fixed_distance_codes();
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BitStreamReader m_reader;
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CircularQueue<u8, 32 * 1024> m_history_buffer;
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Vector<u8, 256> m_output_buffer;
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CanonicalCode m_literal_length_codes;
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CanonicalCode m_fixed_distance_codes;
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};
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}
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