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https://github.com/LadybirdBrowser/ladybird.git
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135751c3a2
This commit implements a stream compressor for the gzip specification (RFC 1952), which is essentially a thin wrapper around the DEFLATE compression format.
112 lines
3.5 KiB
C++
112 lines
3.5 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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* Copyright (c) 2021, Idan Horowitz <idan.horowitz@gmail.com>
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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 <LibCompress/Deflate.h>
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#include <LibCrypto/Checksum/CRC32.h>
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namespace Compress {
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constexpr u8 gzip_magic_1 = 0x1f;
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constexpr u8 gzip_magic_2 = 0x8b;
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struct [[gnu::packed]] BlockHeader {
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u8 identification_1;
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u8 identification_2;
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u8 compression_method;
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u8 flags;
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LittleEndian<u32> modification_time;
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u8 extra_flags;
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u8 operating_system;
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bool valid_magic_number() const;
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bool supported_by_implementation() const;
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};
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struct Flags {
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static constexpr u8 FTEXT = 1 << 0;
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static constexpr u8 FHCRC = 1 << 1;
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static constexpr u8 FEXTRA = 1 << 2;
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static constexpr u8 FNAME = 1 << 3;
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static constexpr u8 FCOMMENT = 1 << 4;
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static constexpr u8 MAX = FTEXT | FHCRC | FEXTRA | FNAME | FCOMMENT;
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};
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class GzipDecompressor final : public InputStream {
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public:
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GzipDecompressor(InputStream&);
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~GzipDecompressor();
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size_t read(Bytes) override;
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bool read_or_error(Bytes) override;
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bool discard_or_error(size_t) override;
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bool unreliable_eof() const override;
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static Optional<ByteBuffer> decompress_all(ReadonlyBytes);
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static bool is_likely_compressed(ReadonlyBytes bytes);
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private:
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class Member {
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public:
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Member(BlockHeader header, InputStream& stream)
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: m_header(header)
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, m_stream(stream)
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{
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}
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BlockHeader m_header;
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DeflateDecompressor m_stream;
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Crypto::Checksum::CRC32 m_checksum;
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size_t m_nread { 0 };
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};
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const Member& current_member() const { return m_current_member.value(); }
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Member& current_member() { return m_current_member.value(); }
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InputStream& m_input_stream;
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Optional<Member> m_current_member;
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bool m_eof { false };
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};
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class GzipCompressor final : public OutputStream {
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public:
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GzipCompressor(OutputStream&);
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~GzipCompressor();
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size_t write(ReadonlyBytes) override;
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bool write_or_error(ReadonlyBytes) override;
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static Optional<ByteBuffer> compress_all(const ReadonlyBytes& bytes);
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private:
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OutputStream& m_output_stream;
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};
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}
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