mirror of
https://github.com/LadybirdBrowser/ladybird.git
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267 lines
8.5 KiB
C++
267 lines
8.5 KiB
C++
/*
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* Copyright (c) 2020-2022, the SerenityOS developers.
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* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibCompress/Gzip.h>
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#include <AK/BitStream.h>
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#include <AK/MemoryStream.h>
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#include <AK/String.h>
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#include <LibCore/DateTime.h>
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namespace Compress {
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bool GzipDecompressor::is_likely_compressed(ReadonlyBytes bytes)
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{
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return bytes.size() >= 2 && bytes[0] == gzip_magic_1 && bytes[1] == gzip_magic_2;
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}
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bool BlockHeader::valid_magic_number() const
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{
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return identification_1 == gzip_magic_1 && identification_2 == gzip_magic_2;
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}
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bool BlockHeader::supported_by_implementation() const
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{
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if (compression_method != 0x08) {
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// RFC 1952 does not define any compression methods other than deflate.
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return false;
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}
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if (flags > Flags::MAX) {
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// RFC 1952 does not define any more flags.
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return false;
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}
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return true;
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}
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ErrorOr<NonnullOwnPtr<GzipDecompressor::Member>> GzipDecompressor::Member::construct(BlockHeader header, LittleEndianInputBitStream& stream)
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{
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auto deflate_stream = TRY(DeflateDecompressor::construct(MaybeOwned<LittleEndianInputBitStream>(stream)));
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return TRY(adopt_nonnull_own_or_enomem(new (nothrow) Member(header, move(deflate_stream))));
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}
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GzipDecompressor::Member::Member(BlockHeader header, NonnullOwnPtr<DeflateDecompressor> stream)
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: m_header(header)
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, m_stream(move(stream))
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{
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}
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GzipDecompressor::GzipDecompressor(MaybeOwned<Stream> stream)
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: m_input_stream(make<LittleEndianInputBitStream>(move(stream)))
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{
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}
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GzipDecompressor::~GzipDecompressor()
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{
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m_current_member.clear();
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}
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ErrorOr<Bytes> GzipDecompressor::read_some(Bytes bytes)
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{
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size_t total_read = 0;
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while (total_read < bytes.size()) {
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if (is_eof())
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break;
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auto slice = bytes.slice(total_read);
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if (m_current_member) {
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auto current_slice = TRY(current_member().m_stream->read_some(slice));
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current_member().m_checksum.update(current_slice);
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current_member().m_nread += current_slice.size();
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if (current_slice.size() < slice.size()) {
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u32 crc32 = TRY(m_input_stream->read_value<LittleEndian<u32>>());
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u32 input_size = TRY(m_input_stream->read_value<LittleEndian<u32>>());
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if (crc32 != current_member().m_checksum.digest())
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return Error::from_string_literal("Stored CRC32 does not match the calculated CRC32 of the current member");
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if (input_size != current_member().m_nread)
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return Error::from_string_literal("Input size does not match the number of read bytes");
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m_current_member.clear();
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total_read += current_slice.size();
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continue;
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}
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total_read += current_slice.size();
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continue;
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} else {
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auto current_partial_header_slice = Bytes { m_partial_header, sizeof(BlockHeader) }.slice(m_partial_header_offset);
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auto current_partial_header_data = TRY(m_input_stream->read_some(current_partial_header_slice));
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m_partial_header_offset += current_partial_header_data.size();
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if (is_eof())
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break;
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if (m_partial_header_offset < sizeof(BlockHeader)) {
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break; // partial header read
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}
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m_partial_header_offset = 0;
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BlockHeader header = *(reinterpret_cast<BlockHeader*>(m_partial_header));
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if (!header.valid_magic_number())
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return Error::from_string_literal("Header does not have a valid magic number");
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if (!header.supported_by_implementation())
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return Error::from_string_literal("Header is not supported by implementation");
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if (header.flags & Flags::FEXTRA) {
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u16 subfield_id = TRY(m_input_stream->read_value<LittleEndian<u16>>());
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u16 length = TRY(m_input_stream->read_value<LittleEndian<u16>>());
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TRY(m_input_stream->discard(length));
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(void)subfield_id;
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}
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auto discard_string = [&]() -> ErrorOr<void> {
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char next_char;
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do {
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next_char = TRY(m_input_stream->read_value<char>());
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} while (next_char);
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return {};
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};
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if (header.flags & Flags::FNAME)
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TRY(discard_string());
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if (header.flags & Flags::FCOMMENT)
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TRY(discard_string());
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if (header.flags & Flags::FHCRC) {
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u16 crc = TRY(m_input_stream->read_value<LittleEndian<u16>>());
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// FIXME: we should probably verify this instead of just assuming it matches
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(void)crc;
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}
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m_current_member = TRY(Member::construct(header, *m_input_stream));
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continue;
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}
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}
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return bytes.slice(0, total_read);
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}
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ErrorOr<Optional<String>> GzipDecompressor::describe_header(ReadonlyBytes bytes)
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{
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if (bytes.size() < sizeof(BlockHeader))
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return OptionalNone {};
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auto& header = *(reinterpret_cast<BlockHeader const*>(bytes.data()));
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if (!header.valid_magic_number() || !header.supported_by_implementation())
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return OptionalNone {};
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LittleEndian<u32> original_size = *reinterpret_cast<u32 const*>(bytes.offset(bytes.size() - sizeof(u32)));
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return TRY(String::formatted("last modified: {}, original size {}", Core::DateTime::from_timestamp(header.modification_time), (u32)original_size));
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}
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ErrorOr<ByteBuffer> GzipDecompressor::decompress_all(ReadonlyBytes bytes)
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{
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auto memory_stream = TRY(try_make<FixedMemoryStream>(bytes));
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auto gzip_stream = make<GzipDecompressor>(move(memory_stream));
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AllocatingMemoryStream output_stream;
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auto buffer = TRY(ByteBuffer::create_uninitialized(4096));
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while (!gzip_stream->is_eof()) {
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auto const data = TRY(gzip_stream->read_some(buffer));
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TRY(output_stream.write_until_depleted(data));
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}
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auto output_buffer = TRY(ByteBuffer::create_uninitialized(output_stream.used_buffer_size()));
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TRY(output_stream.read_until_filled(output_buffer));
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return output_buffer;
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}
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bool GzipDecompressor::is_eof() const { return m_input_stream->is_eof(); }
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ErrorOr<size_t> GzipDecompressor::write_some(ReadonlyBytes)
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{
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return Error::from_errno(EBADF);
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}
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ErrorOr<NonnullOwnPtr<GzipCompressor>> GzipCompressor::create(MaybeOwned<Stream> output_stream)
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{
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BlockHeader header;
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header.identification_1 = 0x1f;
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header.identification_2 = 0x8b;
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header.compression_method = 0x08;
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header.flags = 0;
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header.modification_time = 0;
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header.extra_flags = 3; // DEFLATE sets 2 for maximum compression and 4 for minimum compression
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header.operating_system = 3; // unix
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TRY(output_stream->write_until_depleted({ &header, sizeof(header) }));
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auto deflate_compressor = TRY(DeflateCompressor::construct(MaybeOwned(*output_stream)));
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return adopt_own(*new GzipCompressor { move(output_stream), move(deflate_compressor) });
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}
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GzipCompressor::GzipCompressor(MaybeOwned<Stream> output_stream, NonnullOwnPtr<DeflateCompressor> deflate_compressor)
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: m_output_stream(move(output_stream))
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, m_deflate_compressor(move(deflate_compressor))
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{
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}
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ErrorOr<Bytes> GzipCompressor::read_some(Bytes)
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{
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return Error::from_errno(EBADF);
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}
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ErrorOr<size_t> GzipCompressor::write_some(ReadonlyBytes bytes)
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{
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VERIFY(!m_finished);
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TRY(m_deflate_compressor->write_until_depleted(bytes));
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m_total_bytes += bytes.size();
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m_crc32.update(bytes);
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return bytes.size();
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}
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ErrorOr<void> GzipCompressor::finish()
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{
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VERIFY(!m_finished);
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m_finished = true;
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TRY(m_deflate_compressor->final_flush());
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TRY(m_output_stream->write_value<LittleEndian<u32>>(m_crc32.digest()));
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TRY(m_output_stream->write_value<LittleEndian<u32>>(m_total_bytes));
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return {};
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}
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bool GzipCompressor::is_eof() const
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{
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return true;
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}
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bool GzipCompressor::is_open() const
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{
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return m_output_stream->is_open();
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}
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void GzipCompressor::close()
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{
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}
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ErrorOr<ByteBuffer> GzipCompressor::compress_all(ReadonlyBytes bytes)
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{
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auto output_stream = TRY(try_make<AllocatingMemoryStream>());
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auto gzip_stream = TRY(GzipCompressor::create(MaybeOwned { *output_stream }));
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TRY(gzip_stream->write_until_depleted(bytes));
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TRY(gzip_stream->finish());
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auto buffer = TRY(ByteBuffer::create_uninitialized(output_stream->used_buffer_size()));
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TRY(output_stream->read_until_filled(buffer.bytes()));
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return buffer;
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}
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}
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