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/*
* Copyright (c) 2020, the SerenityOS developers.
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibCompress/Deflate.h>
#include <LibCrypto/Checksum/CRC32.h>
namespace Compress {
constexpr u8 gzip_magic_1 = 0x1f;
constexpr u8 gzip_magic_2 = 0x8b;
struct [[gnu::packed]] BlockHeader {
u8 identification_1;
u8 identification_2;
u8 compression_method;
u8 flags;
LittleEndian<u32> modification_time;
u8 extra_flags;
u8 operating_system;
bool valid_magic_number() const;
bool supported_by_implementation() const;
};
struct Flags {
static constexpr u8 FTEXT = 1 << 0;
static constexpr u8 FHCRC = 1 << 1;
static constexpr u8 FEXTRA = 1 << 2;
static constexpr u8 FNAME = 1 << 3;
static constexpr u8 FCOMMENT = 1 << 4;
static constexpr u8 MAX = FTEXT | FHCRC | FEXTRA | FNAME | FCOMMENT;
};
class GzipDecompressor final : public InputStream {
public:
GzipDecompressor(InputStream&);
~GzipDecompressor();
size_t read(Bytes) override;
bool read_or_error(Bytes) override;
bool discard_or_error(size_t) override;
bool unreliable_eof() const override;
bool handle_any_error() override;
static Optional<ByteBuffer> decompress_all(ReadonlyBytes);
static Optional<String> describe_header(ReadonlyBytes);
static bool is_likely_compressed(ReadonlyBytes bytes);
private:
class Member {
public:
Member(BlockHeader header, InputStream& stream)
: m_header(header)
, m_stream(stream)
{
}
BlockHeader m_header;
DeflateDecompressor m_stream;
Crypto::Checksum::CRC32 m_checksum;
size_t m_nread { 0 };
};
const Member& current_member() const { return m_current_member.value(); }
Member& current_member() { return m_current_member.value(); }
InputStream& m_input_stream;
u8 m_partial_header[sizeof(BlockHeader)];
size_t m_partial_header_offset { 0 };
Optional<Member> m_current_member;
bool m_eof { false };
};
class GzipCompressor final : public OutputStream {
public:
GzipCompressor(OutputStream&);
~GzipCompressor();
size_t write(ReadonlyBytes) override;
bool write_or_error(ReadonlyBytes) override;
static Optional<ByteBuffer> compress_all(const ReadonlyBytes& bytes);
private:
OutputStream& m_output_stream;
};
}
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