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- /*
- * Copyright (c) 2020, the SerenityOS developers.
- * Copyright (c) 2021, Idan Horowitz <idan.horowitz@gmail.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- #include <LibCompress/Gzip.h>
- #include <AK/MemoryStream.h>
- #include <AK/String.h>
- namespace Compress {
- bool GzipDecompressor::is_likely_compressed(ReadonlyBytes bytes)
- {
- return bytes.size() >= 2 && bytes[0] == gzip_magic_1 && bytes[1] == gzip_magic_2;
- }
- bool BlockHeader::valid_magic_number() const
- {
- return identification_1 == gzip_magic_1 && identification_2 == gzip_magic_2;
- }
- bool BlockHeader::supported_by_implementation() const
- {
- if (compression_method != 0x08) {
- // RFC 1952 does not define any compression methods other than deflate.
- return false;
- }
- if (flags > Flags::MAX) {
- // RFC 1952 does not define any more flags.
- return false;
- }
- return true;
- }
- GzipDecompressor::GzipDecompressor(InputStream& stream)
- : m_input_stream(stream)
- {
- }
- GzipDecompressor::~GzipDecompressor()
- {
- m_current_member.clear();
- }
- // FIXME: Again, there are surely a ton of bugs because the code doesn't check for read errors.
- size_t GzipDecompressor::read(Bytes bytes)
- {
- size_t total_read = 0;
- while (total_read < bytes.size()) {
- if (has_any_error() || m_eof)
- break;
- auto slice = bytes.slice(total_read);
- if (m_current_member.has_value()) {
- size_t nread = current_member().m_stream.read(slice);
- current_member().m_checksum.update(slice.trim(nread));
- current_member().m_nread += nread;
- if (current_member().m_stream.handle_any_error()) {
- set_fatal_error();
- break;
- }
- if (nread < slice.size()) {
- LittleEndian<u32> crc32, input_size;
- m_input_stream >> crc32 >> input_size;
- if (crc32 != current_member().m_checksum.digest()) {
- // FIXME: Somehow the checksum is incorrect?
- set_fatal_error();
- break;
- }
- if (input_size != current_member().m_nread) {
- set_fatal_error();
- break;
- }
- m_current_member.clear();
- total_read += nread;
- continue;
- }
- total_read += nread;
- continue;
- } else {
- m_partial_header_offset += m_input_stream.read(Bytes { m_partial_header, sizeof(BlockHeader) }.slice(m_partial_header_offset));
- if (m_input_stream.handle_any_error() || m_input_stream.unreliable_eof()) {
- m_eof = true;
- break;
- }
- if (m_partial_header_offset < sizeof(BlockHeader)) {
- break; // partial header read
- }
- m_partial_header_offset = 0;
- BlockHeader header = *(reinterpret_cast<BlockHeader*>(m_partial_header));
- if (!header.valid_magic_number() || !header.supported_by_implementation()) {
- set_fatal_error();
- break;
- }
- if (header.flags & Flags::FEXTRA) {
- LittleEndian<u16> subfield_id, length;
- m_input_stream >> subfield_id >> length;
- m_input_stream.discard_or_error(length);
- }
- if (header.flags & Flags::FNAME) {
- String original_filename;
- m_input_stream >> original_filename;
- }
- if (header.flags & Flags::FCOMMENT) {
- String comment;
- m_input_stream >> comment;
- }
- if (header.flags & Flags::FHCRC) {
- LittleEndian<u16> crc16;
- m_input_stream >> crc16;
- // FIXME: we should probably verify this instead of just assuming it matches
- }
- m_current_member.emplace(header, m_input_stream);
- continue;
- }
- }
- return total_read;
- }
- bool GzipDecompressor::read_or_error(Bytes bytes)
- {
- if (read(bytes) < bytes.size()) {
- set_fatal_error();
- return false;
- }
- return true;
- }
- bool GzipDecompressor::discard_or_error(size_t count)
- {
- u8 buffer[4096];
- size_t ndiscarded = 0;
- while (ndiscarded < count) {
- if (unreliable_eof()) {
- set_fatal_error();
- return false;
- }
- ndiscarded += read({ buffer, min<size_t>(count - ndiscarded, sizeof(buffer)) });
- }
- return true;
- }
- Optional<ByteBuffer> GzipDecompressor::decompress_all(ReadonlyBytes bytes)
- {
- InputMemoryStream memory_stream { bytes };
- GzipDecompressor gzip_stream { memory_stream };
- DuplexMemoryStream output_stream;
- u8 buffer[4096];
- while (!gzip_stream.has_any_error() && !gzip_stream.unreliable_eof()) {
- const auto nread = gzip_stream.read({ buffer, sizeof(buffer) });
- output_stream.write_or_error({ buffer, nread });
- }
- if (gzip_stream.handle_any_error())
- return {};
- return output_stream.copy_into_contiguous_buffer();
- }
- bool GzipDecompressor::unreliable_eof() const { return m_eof; }
- bool GzipDecompressor::handle_any_error()
- {
- bool handled_errors = m_input_stream.handle_any_error();
- return Stream::handle_any_error() || handled_errors;
- }
- GzipCompressor::GzipCompressor(OutputStream& stream)
- : m_output_stream(stream)
- {
- }
- GzipCompressor::~GzipCompressor()
- {
- }
- size_t GzipCompressor::write(ReadonlyBytes bytes)
- {
- BlockHeader header;
- header.identification_1 = 0x1f;
- header.identification_2 = 0x8b;
- header.compression_method = 0x08;
- header.flags = 0;
- header.modification_time = 0;
- header.extra_flags = 3; // DEFLATE sets 2 for maximum compression and 4 for minimum compression
- header.operating_system = 3; // unix
- m_output_stream << Bytes { &header, sizeof(header) };
- DeflateCompressor compressed_stream { m_output_stream };
- VERIFY(compressed_stream.write_or_error(bytes));
- compressed_stream.final_flush();
- Crypto::Checksum::CRC32 crc32;
- crc32.update(bytes);
- LittleEndian<u32> digest = crc32.digest();
- LittleEndian<u32> size = bytes.size();
- m_output_stream << digest << size;
- return bytes.size();
- }
- bool GzipCompressor::write_or_error(ReadonlyBytes bytes)
- {
- if (write(bytes) < bytes.size()) {
- set_fatal_error();
- return false;
- }
- return true;
- }
- Optional<ByteBuffer> GzipCompressor::compress_all(const ReadonlyBytes& bytes)
- {
- DuplexMemoryStream output_stream;
- GzipCompressor gzip_stream { output_stream };
- gzip_stream.write_or_error(bytes);
- if (gzip_stream.handle_any_error())
- return {};
- return output_stream.copy_into_contiguous_buffer();
- }
- }
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