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LibCompress: Port DeflateCompressor to Core::Stream
This commit is contained in:
Tim Schumacher
Andreas Kling
parent
a212bc3052
commit
8cd2cf2b77
7 changed files with 107 additions and 97 deletions
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@ -116,9 +116,10 @@ ErrorOr<u32> CanonicalCode::read_symbol(Core::Stream::LittleEndianInputBitStream
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}
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}
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void CanonicalCode::write_symbol(OutputBitStream& stream, u32 symbol) const
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ErrorOr<void> CanonicalCode::write_symbol(Core::Stream::LittleEndianOutputBitStream& stream, u32 symbol) const
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{
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stream.write_bits(m_bit_codes[symbol], m_bit_code_lengths[symbol]);
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TRY(stream.write_bits(m_bit_codes[symbol], m_bit_code_lengths[symbol]));
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return {};
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}
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DeflateDecompressor::CompressedBlock::CompressedBlock(DeflateDecompressor& decompressor, CanonicalCode literal_codes, Optional<CanonicalCode> distance_codes)
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@ -437,10 +438,10 @@ ErrorOr<void> DeflateDecompressor::decode_codes(CanonicalCode& literal_code, Opt
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return {};
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}
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DeflateCompressor::DeflateCompressor(OutputStream& stream, CompressionLevel compression_level)
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DeflateCompressor::DeflateCompressor(Core::Stream::Handle<Core::Stream::Stream> stream, CompressionLevel compression_level)
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: m_compression_level(compression_level)
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, m_compression_constants(compression_constants[static_cast<int>(m_compression_level)])
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, m_output_stream(stream)
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, m_output_stream(Core::Stream::LittleEndianOutputBitStream::construct(move(stream)).release_value_but_fixme_should_propagate_errors())
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{
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m_symbol_frequencies.fill(0);
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m_distance_frequencies.fill(0);
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@ -451,7 +452,12 @@ DeflateCompressor::~DeflateCompressor()
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VERIFY(m_finished);
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}
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size_t DeflateCompressor::write(ReadonlyBytes bytes)
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ErrorOr<Bytes> DeflateCompressor::read(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> DeflateCompressor::write(ReadonlyBytes bytes)
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{
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VERIFY(!m_finished);
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@ -462,21 +468,25 @@ size_t DeflateCompressor::write(ReadonlyBytes bytes)
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m_pending_block_size += n_written;
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if (m_pending_block_size == block_size)
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flush();
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TRY(flush());
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return n_written + write(bytes.slice(n_written));
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return n_written + TRY(write(bytes.slice(n_written)));
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}
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bool DeflateCompressor::write_or_error(ReadonlyBytes bytes)
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bool DeflateCompressor::is_eof() const
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{
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if (write(bytes) < bytes.size()) {
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set_fatal_error();
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return false;
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}
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return true;
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}
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bool DeflateCompressor::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 DeflateCompressor::close()
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{
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}
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// Knuth's multiplicative hash on 4 bytes
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u16 DeflateCompressor::hash_sequence(u8 const* bytes)
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{
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@ -730,7 +740,7 @@ size_t DeflateCompressor::huffman_block_length(Array<u8, max_huffman_literals> c
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size_t DeflateCompressor::uncompressed_block_length()
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{
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auto padding = 8 - ((m_output_stream.bit_offset() + 3) % 8);
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auto padding = 8 - ((m_output_stream->bit_offset() + 3) % 8);
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// 3 bit block header + align to byte + 2 * 16 bit length fields + block contents
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return 3 + padding + (2 * 16) + m_pending_block_size * 8;
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}
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@ -765,25 +775,26 @@ size_t DeflateCompressor::dynamic_block_length(Array<u8, max_huffman_literals> c
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return length + huffman_block_length(literal_bit_lengths, distance_bit_lengths);
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}
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void DeflateCompressor::write_huffman(CanonicalCode const& literal_code, Optional<CanonicalCode> const& distance_code)
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ErrorOr<void> DeflateCompressor::write_huffman(CanonicalCode const& literal_code, Optional<CanonicalCode> const& distance_code)
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{
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auto has_distances = distance_code.has_value();
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for (size_t i = 0; i < m_pending_symbol_size; i++) {
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if (m_symbol_buffer[i].distance == 0) {
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literal_code.write_symbol(m_output_stream, m_symbol_buffer[i].literal);
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TRY(literal_code.write_symbol(*m_output_stream, m_symbol_buffer[i].literal));
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continue;
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}
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VERIFY(has_distances);
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auto symbol = length_to_symbol[m_symbol_buffer[i].length];
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literal_code.write_symbol(m_output_stream, symbol);
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TRY(literal_code.write_symbol(*m_output_stream, symbol));
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// Emit extra bits if needed
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m_output_stream.write_bits(m_symbol_buffer[i].length - packed_length_symbols[symbol - 257].base_length, packed_length_symbols[symbol - 257].extra_bits);
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TRY(m_output_stream->write_bits<u16>(m_symbol_buffer[i].length - packed_length_symbols[symbol - 257].base_length, packed_length_symbols[symbol - 257].extra_bits));
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auto base_distance = distance_to_base(m_symbol_buffer[i].distance);
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distance_code.value().write_symbol(m_output_stream, base_distance);
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TRY(distance_code.value().write_symbol(*m_output_stream, base_distance));
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// Emit extra bits if needed
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m_output_stream.write_bits(m_symbol_buffer[i].distance - packed_distances[base_distance].base_distance, packed_distances[base_distance].extra_bits);
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TRY(m_output_stream->write_bits<u16>(m_symbol_buffer[i].distance - packed_distances[base_distance].base_distance, packed_distances[base_distance].extra_bits));
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}
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return {};
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}
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size_t DeflateCompressor::encode_huffman_lengths(Array<u8, max_huffman_literals + max_huffman_distances> const& lengths, size_t lengths_count, Array<code_length_symbol, max_huffman_literals + max_huffman_distances>& encoded_lengths)
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@ -854,65 +865,62 @@ size_t DeflateCompressor::encode_block_lengths(Array<u8, max_huffman_literals> c
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return encode_huffman_lengths(all_lengths, lengths_count, encoded_lengths);
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}
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void DeflateCompressor::write_dynamic_huffman(CanonicalCode const& literal_code, size_t literal_code_count, Optional<CanonicalCode> const& distance_code, size_t distance_code_count, Array<u8, 19> const& code_lengths_bit_lengths, size_t code_length_count, Array<code_length_symbol, max_huffman_literals + max_huffman_distances> const& encoded_lengths, size_t encoded_lengths_count)
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ErrorOr<void> DeflateCompressor::write_dynamic_huffman(CanonicalCode const& literal_code, size_t literal_code_count, Optional<CanonicalCode> const& distance_code, size_t distance_code_count, Array<u8, 19> const& code_lengths_bit_lengths, size_t code_length_count, Array<code_length_symbol, max_huffman_literals + max_huffman_distances> const& encoded_lengths, size_t encoded_lengths_count)
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{
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m_output_stream.write_bits(literal_code_count - 257, 5);
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m_output_stream.write_bits(distance_code_count - 1, 5);
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m_output_stream.write_bits(code_length_count - 4, 4);
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TRY(m_output_stream->write_bits(literal_code_count - 257, 5));
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TRY(m_output_stream->write_bits(distance_code_count - 1, 5));
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TRY(m_output_stream->write_bits(code_length_count - 4, 4));
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for (size_t i = 0; i < code_length_count; i++) {
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m_output_stream.write_bits(code_lengths_bit_lengths[code_lengths_code_lengths_order[i]], 3);
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TRY(m_output_stream->write_bits(code_lengths_bit_lengths[code_lengths_code_lengths_order[i]], 3));
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}
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auto code_lengths_code = CanonicalCode::from_bytes(code_lengths_bit_lengths);
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VERIFY(code_lengths_code.has_value());
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for (size_t i = 0; i < encoded_lengths_count; i++) {
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auto encoded_length = encoded_lengths[i];
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code_lengths_code->write_symbol(m_output_stream, encoded_length.symbol);
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TRY(code_lengths_code->write_symbol(*m_output_stream, encoded_length.symbol));
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if (encoded_length.symbol == deflate_special_code_length_copy) {
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m_output_stream.write_bits(encoded_length.count - 3, 2);
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TRY(m_output_stream->write_bits<u8>(encoded_length.count - 3, 2));
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} else if (encoded_length.symbol == deflate_special_code_length_zeros) {
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m_output_stream.write_bits(encoded_length.count - 3, 3);
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TRY(m_output_stream->write_bits<u8>(encoded_length.count - 3, 3));
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} else if (encoded_length.symbol == deflate_special_code_length_long_zeros) {
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m_output_stream.write_bits(encoded_length.count - 11, 7);
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TRY(m_output_stream->write_bits<u8>(encoded_length.count - 11, 7));
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}
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}
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write_huffman(literal_code, distance_code);
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TRY(write_huffman(literal_code, distance_code));
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return {};
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}
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void DeflateCompressor::flush()
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ErrorOr<void> DeflateCompressor::flush()
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{
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if (m_output_stream.handle_any_error()) {
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set_fatal_error();
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return;
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}
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m_output_stream.write_bit(m_finished);
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TRY(m_output_stream->write_bits(m_finished, 1));
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// if this is just an empty block to signify the end of the deflate stream use the smallest block possible (10 bits total)
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if (m_pending_block_size == 0) {
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VERIFY(m_finished); // we shouldn't be writing empty blocks unless this is the final one
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m_output_stream.write_bits(0b01, 2); // fixed huffman codes
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m_output_stream.write_bits(0b0000000, 7); // end of block symbol
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m_output_stream.align_to_byte_boundary();
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return;
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VERIFY(m_finished); // we shouldn't be writing empty blocks unless this is the final one
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TRY(m_output_stream->write_bits(0b01u, 2)); // fixed huffman codes
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TRY(m_output_stream->write_bits(0b0000000u, 7)); // end of block symbol
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TRY(m_output_stream->align_to_byte_boundary());
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return {};
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}
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auto write_uncompressed = [&]() {
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m_output_stream.write_bits(0b00, 2); // no compression
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m_output_stream.align_to_byte_boundary();
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auto write_uncompressed = [&]() -> ErrorOr<void> {
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TRY(m_output_stream->write_bits(0b00u, 2)); // no compression
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TRY(m_output_stream->align_to_byte_boundary());
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LittleEndian<u16> len = m_pending_block_size;
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m_output_stream << len;
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TRY(m_output_stream->write_entire_buffer(len.bytes()));
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LittleEndian<u16> nlen = ~m_pending_block_size;
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m_output_stream << nlen;
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m_output_stream.write_or_error(pending_block().slice(0, m_pending_block_size));
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TRY(m_output_stream->write_entire_buffer(nlen.bytes()));
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TRY(m_output_stream->write_entire_buffer(pending_block().slice(0, m_pending_block_size)));
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return {};
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};
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if (m_compression_level == CompressionLevel::STORE) { // disabled compression fast path
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write_uncompressed();
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TRY(write_uncompressed());
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m_pending_block_size = 0;
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return;
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return {};
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}
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// The following implementation of lz77 compression and huffman encoding is based on the reference implementation by Hans Wennborg https://www.hanshq.net/zip.html
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@ -956,19 +964,21 @@ void DeflateCompressor::flush()
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// If the compression somehow didn't reduce the size enough, just write out the block uncompressed as it allows for much faster decompression
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if (uncompressed_size <= min(fixed_huffman_size, dynamic_huffman_size)) {
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write_uncompressed();
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} else if (fixed_huffman_size <= dynamic_huffman_size) { // If the fixed and dynamic huffman codes come out the same size, prefer the fixed version, as it takes less time to decode
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m_output_stream.write_bits(0b01, 2); // fixed huffman codes
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write_huffman(CanonicalCode::fixed_literal_codes(), CanonicalCode::fixed_distance_codes());
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TRY(write_uncompressed());
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} else if (fixed_huffman_size <= dynamic_huffman_size) {
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// If the fixed and dynamic huffman codes come out the same size, prefer the fixed version, as it takes less time to decode fixed huffman codes.
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TRY(m_output_stream->write_bits(0b01u, 2));
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TRY(write_huffman(CanonicalCode::fixed_literal_codes(), CanonicalCode::fixed_distance_codes()));
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} else {
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m_output_stream.write_bits(0b10, 2); // dynamic huffman codes
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// dynamic huffman codes
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TRY(m_output_stream->write_bits(0b10u, 2));
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auto literal_code = CanonicalCode::from_bytes(dynamic_literal_bit_lengths);
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VERIFY(literal_code.has_value());
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auto distance_code = CanonicalCode::from_bytes(dynamic_distance_bit_lengths);
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write_dynamic_huffman(literal_code.value(), literal_code_count, distance_code, distance_code_count, code_lengths_bit_lengths, code_lengths_count, encoded_lengths, encoded_lengths_count);
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TRY(write_dynamic_huffman(literal_code.value(), literal_code_count, distance_code, distance_code_count, code_lengths_bit_lengths, code_lengths_count, encoded_lengths, encoded_lengths_count));
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}
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if (m_finished)
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m_output_stream.align_to_byte_boundary();
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TRY(m_output_stream->align_to_byte_boundary());
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// reset all block specific members
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m_pending_block_size = 0;
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@ -977,28 +987,30 @@ void DeflateCompressor::flush()
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m_distance_frequencies.fill(0);
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// On the final block this copy will potentially produce an invalid search window, but since its the final block we dont care
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pending_block().copy_trimmed_to({ m_rolling_window, block_size });
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return {};
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}
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void DeflateCompressor::final_flush()
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ErrorOr<void> DeflateCompressor::final_flush()
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{
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VERIFY(!m_finished);
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m_finished = true;
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flush();
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TRY(flush());
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return {};
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}
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Optional<ByteBuffer> DeflateCompressor::compress_all(ReadonlyBytes bytes, CompressionLevel compression_level)
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ErrorOr<ByteBuffer> DeflateCompressor::compress_all(ReadonlyBytes bytes, CompressionLevel compression_level)
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{
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DuplexMemoryStream output_stream;
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DeflateCompressor deflate_stream { output_stream, compression_level };
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auto output_stream = TRY(try_make<Core::Stream::AllocatingMemoryStream>());
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DeflateCompressor deflate_stream { Core::Stream::Handle<Core::Stream::Stream>(*output_stream), compression_level };
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deflate_stream.write_or_error(bytes);
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TRY(deflate_stream.write_entire_buffer(bytes));
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TRY(deflate_stream.final_flush());
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deflate_stream.final_flush();
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auto buffer = TRY(ByteBuffer::create_uninitialized(output_stream->used_buffer_size()));
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TRY(output_stream->read_entire_buffer(buffer));
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if (deflate_stream.handle_any_error())
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return {};
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return output_stream.copy_into_contiguous_buffer();
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return buffer;
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}
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}
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