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LibCompress: Implement DEFLATE properly.
Now we have an actual stream implementation that can read arbitrary (dynamic codes aren't supported yet) deflate encoded data. Even if the blocks are really large. And all of that happens with a single buffer of 32KiB. DEFLATE is amazing!
This commit is contained in:
asynts
Andreas Kling
parent
71cbf72e8a
commit
7c53f14bbc
Notes:
sideshowbarker
2024-07-19 03:06:59 +09:00
Author: https://github.com/asynts Commit: https://github.com/SerenityOS/serenity/commit/7c53f14bbcb Pull-request: https://github.com/SerenityOS/serenity/pull/3309 Reviewed-by: https://github.com/awesomekling Reviewed-by: https://github.com/stelar7
5 changed files with 417 additions and 504 deletions
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@ -25,352 +25,34 @@
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*/
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#include <AK/Assertions.h>
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#include <AK/BinarySearch.h>
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#include <AK/FixedArray.h>
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#include <AK/LogStream.h>
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#include <AK/Span.h>
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#include <AK/Types.h>
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#include <AK/Vector.h>
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#include <LibCompress/Deflate.h>
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namespace Compress {
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bool DeflateStream::read_next_block() const
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// FIXME: This logic needs to go into the deflate decoder somehow, we don't want
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// to assert that the input is valid. Instead we need to set m_error on the
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// stream.
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DeflateDecompressor::CanonicalCode::CanonicalCode(ReadonlyBytes codes)
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{
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if (m_read_last_block)
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return false;
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// FIXME: I can't quite follow the algorithm here, but it seems to work.
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m_read_last_block = m_reader.read_bits(1);
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auto block_type = m_reader.read_bits(2);
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switch (block_type) {
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case 0:
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decompress_uncompressed_block();
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break;
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case 1:
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decompress_static_block();
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break;
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case 2:
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decompress_dynamic_block();
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break;
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case 3:
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dbg() << "Block contains reserved block type...";
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ASSERT_NOT_REACHED();
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break;
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default:
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dbg() << "Invalid block type was read...";
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ASSERT_NOT_REACHED();
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break;
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}
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return true;
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}
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void DeflateStream::decompress_uncompressed_block() const
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{
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// Align to the next byte boundary.
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while (m_reader.get_bit_byte_offset() != 0) {
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m_reader.read();
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}
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auto length = m_reader.read_bits(16) & 0xFFFF;
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auto negated_length = m_reader.read_bits(16) & 0xFFFF;
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if ((length ^ 0xFFFF) != negated_length) {
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dbg() << "Block length is invalid...";
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ASSERT_NOT_REACHED();
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}
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for (size_t i = 0; i < length; i++) {
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auto byte = m_reader.read_byte();
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if (byte < 0) {
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dbg() << "Ran out of bytes while reading uncompressed block...";
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ASSERT_NOT_REACHED();
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}
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m_intermediate_stream << byte;
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}
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}
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void DeflateStream::decompress_static_block() const
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{
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decompress_huffman_block(m_literal_length_codes, &m_fixed_distance_codes);
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}
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void DeflateStream::decompress_dynamic_block() const
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{
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auto codes = decode_huffman_codes();
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if (codes.size() == 2) {
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decompress_huffman_block(codes[0], &codes[1]);
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} else {
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decompress_huffman_block(codes[0], nullptr);
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}
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}
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void DeflateStream::decompress_huffman_block(CanonicalCode& length_codes, CanonicalCode* distance_codes) const
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{
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for (;;) {
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u32 symbol = length_codes.next_symbol(m_reader);
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// End of block.
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if (symbol == 256) {
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break;
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}
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// literal byte.
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if (symbol < 256) {
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m_intermediate_stream << static_cast<u8>(symbol);
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continue;
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}
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// Length and distance for copying.
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ASSERT(distance_codes);
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auto run = decode_run_length(symbol);
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if (run < 3 || run > 258) {
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dbg() << "Invalid run length";
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ASSERT_NOT_REACHED();
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}
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auto distance_symbol = distance_codes->next_symbol(m_reader);
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auto distance = decode_distance(distance_symbol);
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if (distance < 1 || distance > 32768) {
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dbg() << "Invalid distance";
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ASSERT_NOT_REACHED();
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}
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copy_from_history(distance, run);
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}
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}
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Vector<CanonicalCode> DeflateStream::decode_huffman_codes() const
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{
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// FIXME: This path is not tested.
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Vector<CanonicalCode> result;
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auto length_code_count = m_reader.read_bits(5) + 257;
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auto distance_code_count = m_reader.read_bits(5) + 1;
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size_t length_code_code_length = m_reader.read_bits(4) + 4;
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Vector<u8> code_length_code_length;
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code_length_code_length.resize(19);
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code_length_code_length[16] = m_reader.read_bits(3);
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code_length_code_length[17] = m_reader.read_bits(3);
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code_length_code_length[18] = m_reader.read_bits(3);
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code_length_code_length[0] = m_reader.read_bits(3);
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for (size_t i = 0; i < length_code_code_length; i++) {
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auto index = (i % 2 == 0) ? (8 + (i / 2)) : (7 - (i / 2));
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code_length_code_length[index] = m_reader.read_bits(3);
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}
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auto code_length_code = CanonicalCode(code_length_code_length);
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Vector<u32> code_lens;
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code_lens.resize(length_code_count + distance_code_count);
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for (size_t index = 0; index < code_lens.capacity();) {
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auto symbol = code_length_code.next_symbol(m_reader);
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if (symbol <= 15) {
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code_lens[index] = symbol;
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index++;
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continue;
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}
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u32 run_length;
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u32 run_value = 0;
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if (symbol == 16) {
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if (index == 0) {
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dbg() << "No code length value avaliable";
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ASSERT_NOT_REACHED();
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}
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run_length = m_reader.read_bits(2) + 3;
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run_value = code_lens[index - 1];
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} else if (symbol == 17) {
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run_length = m_reader.read_bits(3) + 3;
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} else if (symbol == 18) {
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run_length = m_reader.read_bits(7) + 11;
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} else {
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dbg() << "Code symbol is out of range!";
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ASSERT_NOT_REACHED();
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}
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u32 end = index + run_length;
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if (end > code_lens.capacity()) {
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dbg() << "Code run is out of range!";
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ASSERT_NOT_REACHED();
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}
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memset(code_lens.data() + index, run_value, run_length);
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index = end;
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}
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Vector<u8> literal_codes;
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literal_codes.resize(length_code_count);
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memcpy(literal_codes.data(), code_lens.data(), literal_codes.capacity());
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result.append(CanonicalCode(literal_codes));
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Vector<u8> distance_codes;
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distance_codes.resize(distance_code_count);
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memcpy(distance_codes.data(), code_lens.data() + length_code_count, distance_codes.capacity());
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if (distance_code_count == 1 && distance_codes[0] == 0) {
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return result;
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}
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u8 one_count = 0;
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u8 other_count = 0;
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for (size_t i = 0; i < distance_codes.capacity(); i++) {
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u8 value = distance_codes.at(i);
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if (value == 1) {
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one_count++;
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} else if (value > 1) {
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other_count++;
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}
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}
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if (one_count == 1 && other_count == 0) {
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distance_codes.resize(32);
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distance_codes[31] = 1;
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}
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result.append(CanonicalCode(distance_codes));
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return result;
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}
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u32 DeflateStream::decode_run_length(u32 symbol) const
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{
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if (symbol <= 264) {
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return symbol - 254;
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}
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if (symbol <= 284) {
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auto extra_bits = (symbol - 261) / 4;
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return ((((symbol - 265) % 4) + 4) << extra_bits) + 3 + m_reader.read_bits(extra_bits);
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}
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if (symbol == 285) {
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return 258;
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}
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dbg() << "Found invalid symbol in run length " << symbol;
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ASSERT_NOT_REACHED();
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}
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u32 DeflateStream::decode_distance(u32 symbol) const
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{
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if (symbol <= 3) {
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return symbol + 1;
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}
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if (symbol <= 29) {
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auto extra_bits = (symbol / 2) - 1;
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return (((symbol % 2) + 2) << extra_bits) + 1 + m_reader.read_bits(extra_bits);
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}
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dbg() << "Found invalid symbol in distance" << symbol;
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ASSERT_NOT_REACHED();
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}
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void DeflateStream::copy_from_history(u32 distance, u32 run) const
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{
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for (size_t i = 0; i < run; i++) {
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u8 byte;
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// FIXME: In many cases we can read more than one byte at a time, this should
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// be refactored into a while loop. Beware, edge case:
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//
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// // The first four bytes are on the stream already, the other four
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// // are written by copy_from_history() itself.
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// copy_from_history(4, 8);
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m_intermediate_stream.read({ &byte, sizeof(byte) }, m_intermediate_stream.woffset() - distance);
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m_intermediate_stream << byte;
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}
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}
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i8 BitStreamReader::read()
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{
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if (m_current_byte == -1) {
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return -1;
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}
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if (m_remaining_bits == 0) {
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if (m_data_index + 1 > m_data.size())
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return -1;
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m_current_byte = m_data.at(m_data_index++);
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m_remaining_bits = 8;
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}
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m_remaining_bits--;
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return (m_current_byte >> (7 - m_remaining_bits)) & 1;
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}
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i8 BitStreamReader::read_byte()
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{
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m_current_byte = 0;
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m_remaining_bits = 0;
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if (m_data_index + 1 > m_data.size())
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return -1;
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return m_data.at(m_data_index++);
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}
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u8 BitStreamReader::get_bit_byte_offset()
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{
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return (8 - m_remaining_bits) % 8;
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}
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u32 BitStreamReader::read_bits(u8 count)
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{
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ASSERT(count > 0 && count < 32);
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u32 result = 0;
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for (size_t i = 0; i < count; i++) {
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result |= read() << i;
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}
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return result;
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}
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Vector<u8> DeflateStream::generate_literal_length_codes() const
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{
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Vector<u8> ll_codes;
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ll_codes.resize(288);
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memset(ll_codes.data() + 0, 8, 144 - 0);
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memset(ll_codes.data() + 144, 9, 256 - 144);
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memset(ll_codes.data() + 256, 7, 280 - 256);
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memset(ll_codes.data() + 280, 8, 288 - 280);
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return ll_codes;
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}
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Vector<u8> DeflateStream::generate_fixed_distance_codes() const
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{
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Vector<u8> fd_codes;
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fd_codes.resize(32);
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memset(fd_codes.data(), 5, 32);
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return fd_codes;
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}
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CanonicalCode::CanonicalCode(Vector<u8> codes)
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{
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m_symbol_codes.resize(codes.size());
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m_symbol_values.resize(codes.size());
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auto allocated_symbols_count = 0;
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auto next_code = 0;
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for (size_t code_length = 1; code_length <= 15; code_length++) {
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for (size_t code_length = 1; code_length <= 15; ++code_length) {
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next_code <<= 1;
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auto start_bit = 1 << code_length;
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for (size_t symbol = 0; symbol < codes.size(); symbol++) {
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if (codes.at(symbol) != code_length) {
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for (size_t symbol = 0; symbol < codes.size(); ++symbol) {
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if (codes[symbol] != code_length)
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continue;
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}
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if (next_code > start_bit) {
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dbg() << "Canonical code overflows the huffman tree";
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@ -391,38 +73,284 @@ CanonicalCode::CanonicalCode(Vector<u8> codes)
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}
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}
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static i32 binary_search(Vector<u32>& heystack, u32 needle)
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const DeflateDecompressor::CanonicalCode& DeflateDecompressor::CanonicalCode::fixed_literal_codes()
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{
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i32 low = 0;
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i32 high = heystack.size();
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static CanonicalCode* code = nullptr;
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while (low <= high) {
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u32 mid = (low + high) >> 1;
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u32 value = heystack.at(mid);
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if (code)
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return *code;
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if (value < needle) {
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low = mid + 1;
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} else if (value > needle) {
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high = mid - 1;
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} else {
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return mid;
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}
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}
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FixedArray<u8> data { 288 };
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data.bytes().slice(0, 144 - 0).fill(8);
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data.bytes().slice(144, 256 - 144).fill(9);
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data.bytes().slice(256, 280 - 256).fill(7);
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data.bytes().slice(280, 288 - 280).fill(8);
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return -1;
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code = new CanonicalCode(data);
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return *code;
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}
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u32 CanonicalCode::next_symbol(BitStreamReader& reader)
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const DeflateDecompressor::CanonicalCode& DeflateDecompressor::CanonicalCode::fixed_distance_codes()
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{
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auto code_bits = 1;
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static CanonicalCode* code = nullptr;
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if (code)
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return *code;
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FixedArray<u8> data { 32 };
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data.bytes().fill(5);
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code = new CanonicalCode(data);
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return *code;
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}
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u32 DeflateDecompressor::CanonicalCode::read_symbol(InputBitStream& stream) const
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{
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u32 code_bits = 1;
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for (;;) {
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code_bits = code_bits << 1 | reader.read();
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i32 index = binary_search(m_symbol_codes, code_bits);
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if (index >= 0) {
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return m_symbol_values.at(index);
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}
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code_bits = code_bits << 1 | stream.read_bits(1);
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size_t index;
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if (AK::binary_search(m_symbol_codes.span(), code_bits, AK::integral_compare<u32>, &index))
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return m_symbol_values[index];
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}
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}
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DeflateDecompressor::CompressedBlock::CompressedBlock(DeflateDecompressor& decompressor, CanonicalCode literal_codes, Optional<CanonicalCode> distance_codes)
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: m_decompressor(decompressor)
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, m_literal_codes(literal_codes)
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, m_distance_codes(distance_codes)
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{
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}
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bool DeflateDecompressor::CompressedBlock::try_read_more()
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{
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if (m_eof == true)
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return false;
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const auto symbol = m_literal_codes.read_symbol(m_decompressor.m_input_stream);
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if (symbol < 256) {
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m_decompressor.m_output_stream << static_cast<u8>(symbol);
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return true;
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} else if (symbol == 256) {
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m_eof = true;
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return false;
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} else {
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ASSERT(m_distance_codes.has_value());
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const auto run_length = m_decompressor.decode_run_length(symbol);
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const auto distance = m_decompressor.decode_distance(m_distance_codes.value().read_symbol(m_decompressor.m_input_stream));
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auto bytes = m_decompressor.m_output_stream.reserve_contigous_space(run_length);
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m_decompressor.m_output_stream.read(bytes, distance + bytes.size());
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return true;
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}
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}
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DeflateDecompressor::UncompressedBlock::UncompressedBlock(DeflateDecompressor& decompressor, size_t length)
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: m_decompressor(decompressor)
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, m_bytes_remaining(length)
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{
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}
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bool DeflateDecompressor::UncompressedBlock::try_read_more()
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{
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if (m_bytes_remaining == 0)
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return false;
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const auto nread = min(m_bytes_remaining, m_decompressor.m_output_stream.remaining_contigous_space());
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m_bytes_remaining -= nread;
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m_decompressor.m_input_stream >> m_decompressor.m_output_stream.reserve_contigous_space(nread);
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||||
|
||||
return true;
|
||||
}
|
||||
|
||||
DeflateDecompressor::DeflateDecompressor(InputStream& stream)
|
||||
: m_input_stream(stream)
|
||||
{
|
||||
}
|
||||
|
||||
DeflateDecompressor::~DeflateDecompressor()
|
||||
{
|
||||
if (m_state == State::ReadingCompressedBlock)
|
||||
m_compressed_block.~CompressedBlock();
|
||||
if (m_state == State::ReadingUncompressedBlock)
|
||||
m_uncompressed_block.~UncompressedBlock();
|
||||
}
|
||||
|
||||
size_t DeflateDecompressor::read(Bytes bytes)
|
||||
{
|
||||
// FIXME: There are surely a ton of bugs because we don't check for read errors
|
||||
// very often.
|
||||
|
||||
if (m_state == State::Idle) {
|
||||
if (m_read_final_bock)
|
||||
return 0;
|
||||
|
||||
m_read_final_bock = m_input_stream.read_bit();
|
||||
const auto block_type = m_input_stream.read_bits(2);
|
||||
|
||||
if (block_type == 0b00) {
|
||||
m_input_stream.align_to_byte_boundary();
|
||||
|
||||
LittleEndian<u16> length, negated_length;
|
||||
m_input_stream >> length >> negated_length;
|
||||
|
||||
if ((length ^ 0xffff) != negated_length) {
|
||||
m_error = true;
|
||||
return 0;
|
||||
}
|
||||
|
||||
m_state = State::ReadingUncompressedBlock;
|
||||
new (&m_uncompressed_block) UncompressedBlock(*this, length);
|
||||
|
||||
return read(bytes);
|
||||
}
|
||||
|
||||
if (block_type == 0b01) {
|
||||
m_state = State::ReadingCompressedBlock;
|
||||
new (&m_compressed_block) CompressedBlock(*this, CanonicalCode::fixed_literal_codes(), CanonicalCode::fixed_distance_codes());
|
||||
|
||||
return read(bytes);
|
||||
}
|
||||
|
||||
if (block_type == 0b10) {
|
||||
CanonicalCode literal_codes, distance_codes;
|
||||
decode_codes(literal_codes, distance_codes);
|
||||
new (&m_compressed_block) CompressedBlock(*this, literal_codes, distance_codes);
|
||||
|
||||
return read(bytes);
|
||||
}
|
||||
|
||||
ASSERT_NOT_REACHED();
|
||||
}
|
||||
|
||||
if (m_state == State::ReadingCompressedBlock) {
|
||||
auto nread = m_output_stream.read(bytes);
|
||||
|
||||
while (nread < bytes.size() && m_compressed_block.try_read_more()) {
|
||||
nread += m_output_stream.read(bytes.slice(nread));
|
||||
}
|
||||
|
||||
if (nread == bytes.size())
|
||||
return nread;
|
||||
|
||||
m_compressed_block.~CompressedBlock();
|
||||
m_state = State::Idle;
|
||||
|
||||
return nread + read(bytes.slice(nread));
|
||||
}
|
||||
|
||||
if (m_state == State::ReadingUncompressedBlock) {
|
||||
auto nread = m_output_stream.read(bytes);
|
||||
|
||||
while (nread < bytes.size() && m_uncompressed_block.try_read_more()) {
|
||||
nread += m_output_stream.read(bytes.slice(nread));
|
||||
}
|
||||
|
||||
if (nread == bytes.size())
|
||||
return nread;
|
||||
|
||||
m_uncompressed_block.~UncompressedBlock();
|
||||
m_state = State::Idle;
|
||||
|
||||
return nread + read(bytes.slice(nread));
|
||||
}
|
||||
|
||||
ASSERT_NOT_REACHED();
|
||||
}
|
||||
|
||||
bool DeflateDecompressor::read_or_error(Bytes bytes)
|
||||
{
|
||||
if (read(bytes) < bytes.size()) {
|
||||
m_error = true;
|
||||
return false;
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
bool DeflateDecompressor::discard_or_error(size_t count)
|
||||
{
|
||||
u8 buffer[4096];
|
||||
|
||||
size_t ndiscarded = 0;
|
||||
while (ndiscarded < count) {
|
||||
if (eof()) {
|
||||
m_error = true;
|
||||
return false;
|
||||
}
|
||||
|
||||
ndiscarded += read({ buffer, min<size_t>(count - ndiscarded, 4096) });
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
bool DeflateDecompressor::eof() const { return m_state == State::Idle && m_read_final_bock; }
|
||||
|
||||
ByteBuffer DeflateDecompressor::decompress_all(ReadonlyBytes bytes)
|
||||
{
|
||||
InputMemoryStream memory_stream { bytes };
|
||||
InputBitStream bit_stream { memory_stream };
|
||||
DeflateDecompressor deflate_stream { bit_stream };
|
||||
|
||||
auto buffer = ByteBuffer::create_uninitialized(4096);
|
||||
|
||||
size_t nread = 0;
|
||||
while (!deflate_stream.eof()) {
|
||||
nread += deflate_stream.read(buffer.bytes().slice(nread));
|
||||
if (buffer.size() - nread < 4096)
|
||||
buffer.grow(buffer.size() + 4096);
|
||||
}
|
||||
|
||||
buffer.trim(nread);
|
||||
return buffer;
|
||||
}
|
||||
|
||||
u32 DeflateDecompressor::decode_run_length(u32 symbol)
|
||||
{
|
||||
// FIXME: I can't quite follow the algorithm here, but it seems to work.
|
||||
|
||||
if (symbol <= 264)
|
||||
return symbol - 254;
|
||||
|
||||
if (symbol <= 284) {
|
||||
auto extra_bits = (symbol - 261) / 4;
|
||||
return (((symbol - 265) % 4 + 4) << extra_bits) + 3 + m_input_stream.read_bits(extra_bits);
|
||||
}
|
||||
|
||||
if (symbol == 285)
|
||||
return 258;
|
||||
|
||||
ASSERT_NOT_REACHED();
|
||||
}
|
||||
|
||||
u32 DeflateDecompressor::decode_distance(u32 symbol)
|
||||
{
|
||||
// FIXME: I can't quite follow the algorithm here, but it seems to work.
|
||||
|
||||
if (symbol <= 3)
|
||||
return symbol + 1;
|
||||
|
||||
if (symbol <= 29) {
|
||||
auto extra_bits = (symbol / 2) - 1;
|
||||
return ((symbol % 2 + 2) << extra_bits) + 1 + m_input_stream.read_bits(extra_bits);
|
||||
}
|
||||
|
||||
ASSERT_NOT_REACHED();
|
||||
}
|
||||
|
||||
void DeflateDecompressor::decode_codes(CanonicalCode&, CanonicalCode&)
|
||||
{
|
||||
// FIXME: This was already implemented but I removed it because it was quite chaotic and untested.
|
||||
// I am planning to come back to this. @asynts
|
||||
// https://github.com/SerenityOS/serenity/blob/208cb995babb13e0af07bb9d3219f0a9fe7bca7d/Libraries/LibCompress/Deflate.cpp#L144-L242
|
||||
TODO();
|
||||
}
|
||||
|
||||
}
|
||||
|
|
|
|||
|
|
@ -26,160 +26,90 @@
|
|||
|
||||
#pragma once
|
||||
|
||||
#include <AK/CircularQueue.h>
|
||||
#include <AK/Span.h>
|
||||
#include <AK/Stream.h>
|
||||
#include <AK/Types.h>
|
||||
#include <AK/BitStream.h>
|
||||
#include <AK/ByteBuffer.h>
|
||||
#include <AK/CircularDuplexStream.h>
|
||||
#include <AK/Endian.h>
|
||||
#include <AK/Vector.h>
|
||||
#include <cstring>
|
||||
|
||||
namespace Compress {
|
||||
|
||||
// Reads one bit at a time starting with the rightmost bit
|
||||
class BitStreamReader {
|
||||
public:
|
||||
BitStreamReader(ReadonlyBytes data)
|
||||
: m_data(data)
|
||||
{
|
||||
}
|
||||
class DeflateDecompressor final : public InputStream {
|
||||
private:
|
||||
class CanonicalCode {
|
||||
public:
|
||||
CanonicalCode() = default;
|
||||
CanonicalCode(ReadonlyBytes);
|
||||
u32 read_symbol(InputBitStream&) const;
|
||||
|
||||
i8 read();
|
||||
i8 read_byte();
|
||||
u32 read_bits(u8);
|
||||
u8 get_bit_byte_offset();
|
||||
static const CanonicalCode& fixed_literal_codes();
|
||||
static const CanonicalCode& fixed_distance_codes();
|
||||
|
||||
private:
|
||||
Vector<u32> m_symbol_codes;
|
||||
Vector<u32> m_symbol_values;
|
||||
};
|
||||
|
||||
class CompressedBlock {
|
||||
public:
|
||||
CompressedBlock(DeflateDecompressor&, CanonicalCode literal_codes, Optional<CanonicalCode> distance_codes);
|
||||
|
||||
bool try_read_more();
|
||||
|
||||
private:
|
||||
bool m_eof { false };
|
||||
|
||||
DeflateDecompressor& m_decompressor;
|
||||
CanonicalCode m_literal_codes;
|
||||
Optional<CanonicalCode> m_distance_codes;
|
||||
};
|
||||
|
||||
class UncompressedBlock {
|
||||
public:
|
||||
UncompressedBlock(DeflateDecompressor&, size_t);
|
||||
|
||||
bool try_read_more();
|
||||
|
||||
private:
|
||||
DeflateDecompressor& m_decompressor;
|
||||
size_t m_bytes_remaining;
|
||||
};
|
||||
|
||||
enum class State {
|
||||
Idle,
|
||||
ReadingCompressedBlock,
|
||||
ReadingUncompressedBlock
|
||||
};
|
||||
|
||||
public:
|
||||
friend CompressedBlock;
|
||||
friend UncompressedBlock;
|
||||
|
||||
DeflateDecompressor(InputStream&);
|
||||
~DeflateDecompressor();
|
||||
|
||||
size_t read(Bytes) override;
|
||||
bool read_or_error(Bytes) override;
|
||||
bool discard_or_error(size_t) override;
|
||||
bool eof() const override;
|
||||
|
||||
static ByteBuffer decompress_all(ReadonlyBytes);
|
||||
|
||||
private:
|
||||
ReadonlyBytes m_data;
|
||||
size_t m_data_index { 0 };
|
||||
u32 decode_run_length(u32);
|
||||
u32 decode_distance(u32);
|
||||
void decode_codes(CanonicalCode&, CanonicalCode&);
|
||||
|
||||
i8 m_current_byte { 0 };
|
||||
u8 m_remaining_bits { 0 };
|
||||
};
|
||||
bool m_read_final_bock { false };
|
||||
|
||||
class CanonicalCode {
|
||||
public:
|
||||
CanonicalCode(Vector<u8>);
|
||||
u32 next_symbol(BitStreamReader&);
|
||||
State m_state { State::Idle };
|
||||
union {
|
||||
CompressedBlock m_compressed_block;
|
||||
UncompressedBlock m_uncompressed_block;
|
||||
};
|
||||
|
||||
private:
|
||||
Vector<u32> m_symbol_codes;
|
||||
Vector<u32> m_symbol_values;
|
||||
};
|
||||
|
||||
// Implements a DEFLATE decompressor according to RFC 1951.
|
||||
class DeflateStream final : public InputStream {
|
||||
public:
|
||||
// FIXME: This should really return a ByteBuffer.
|
||||
static Vector<u8> decompress_all(ReadonlyBytes bytes)
|
||||
{
|
||||
DeflateStream stream { bytes };
|
||||
while (stream.read_next_block()) {
|
||||
}
|
||||
|
||||
Vector<u8> vector;
|
||||
vector.resize(stream.m_intermediate_stream.remaining());
|
||||
stream >> vector;
|
||||
|
||||
return vector;
|
||||
}
|
||||
|
||||
DeflateStream(ReadonlyBytes data)
|
||||
: m_reader(data)
|
||||
, m_literal_length_codes(generate_literal_length_codes())
|
||||
, m_fixed_distance_codes(generate_fixed_distance_codes())
|
||||
{
|
||||
}
|
||||
|
||||
// FIXME: Accept an InputStream.
|
||||
|
||||
size_t read(Bytes bytes) override
|
||||
{
|
||||
if (m_intermediate_stream.remaining() >= bytes.size())
|
||||
return m_intermediate_stream.read_or_error(bytes);
|
||||
|
||||
while (read_next_block()) {
|
||||
if (m_intermediate_stream.remaining() >= bytes.size())
|
||||
return m_intermediate_stream.read_or_error(bytes);
|
||||
}
|
||||
|
||||
return m_intermediate_stream.read(bytes);
|
||||
}
|
||||
|
||||
bool read_or_error(Bytes bytes) override
|
||||
{
|
||||
if (m_intermediate_stream.remaining() >= bytes.size()) {
|
||||
m_intermediate_stream.read_or_error(bytes);
|
||||
return true;
|
||||
}
|
||||
|
||||
while (read_next_block()) {
|
||||
if (m_intermediate_stream.remaining() >= bytes.size()) {
|
||||
m_intermediate_stream.read_or_error(bytes);
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
m_error = true;
|
||||
return false;
|
||||
}
|
||||
|
||||
bool eof() const override
|
||||
{
|
||||
if (!m_intermediate_stream.eof())
|
||||
return false;
|
||||
|
||||
while (read_next_block()) {
|
||||
if (!m_intermediate_stream.eof())
|
||||
return false;
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
bool discard_or_error(size_t count) override
|
||||
{
|
||||
if (m_intermediate_stream.remaining() >= count) {
|
||||
m_intermediate_stream.discard_or_error(count);
|
||||
return true;
|
||||
}
|
||||
|
||||
while (read_next_block()) {
|
||||
if (m_intermediate_stream.remaining() >= count) {
|
||||
m_intermediate_stream.discard_or_error(count);
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
m_error = true;
|
||||
return false;
|
||||
}
|
||||
|
||||
private:
|
||||
void decompress_uncompressed_block() const;
|
||||
void decompress_static_block() const;
|
||||
void decompress_dynamic_block() const;
|
||||
void decompress_huffman_block(CanonicalCode&, CanonicalCode*) const;
|
||||
|
||||
Vector<CanonicalCode> decode_huffman_codes() const;
|
||||
u32 decode_run_length(u32) const;
|
||||
u32 decode_distance(u32) const;
|
||||
|
||||
void copy_from_history(u32, u32) const;
|
||||
|
||||
Vector<u8> generate_literal_length_codes() const;
|
||||
Vector<u8> generate_fixed_distance_codes() const;
|
||||
|
||||
mutable BitStreamReader m_reader;
|
||||
|
||||
mutable CanonicalCode m_literal_length_codes;
|
||||
mutable CanonicalCode m_fixed_distance_codes;
|
||||
|
||||
// FIXME: Theoretically, blocks can be extremly large, reading a single block could
|
||||
// exhaust memory. Maybe wait for C++20 coroutines?
|
||||
bool read_next_block() const;
|
||||
|
||||
mutable bool m_read_last_block { false };
|
||||
mutable DuplexMemoryStream m_intermediate_stream;
|
||||
InputBitStream m_input_stream;
|
||||
CircularDuplexStream<32 * 1024> m_output_stream;
|
||||
};
|
||||
|
||||
}
|
||||
|
|
|
|||
|
|
@ -55,9 +55,9 @@ Zlib::Zlib(ReadonlyBytes data)
|
|||
m_data_bytes = data.slice(2, data.size() - 2 - 4);
|
||||
}
|
||||
|
||||
Vector<u8> Zlib::decompress()
|
||||
ByteBuffer Zlib::decompress()
|
||||
{
|
||||
return DeflateStream::decompress_all(m_data_bytes);
|
||||
return DeflateDecompressor::decompress_all(m_data_bytes);
|
||||
}
|
||||
|
||||
u32 Zlib::checksum()
|
||||
|
|
|
|||
|
|
@ -26,18 +26,25 @@
|
|||
|
||||
#pragma once
|
||||
|
||||
#include <AK/ByteBuffer.h>
|
||||
#include <AK/Span.h>
|
||||
#include <AK/Types.h>
|
||||
#include <AK/Vector.h>
|
||||
|
||||
namespace Compress {
|
||||
|
||||
class Zlib {
|
||||
public:
|
||||
Zlib(ReadonlyBytes data);
|
||||
|
||||
Vector<u8> decompress();
|
||||
ByteBuffer decompress();
|
||||
u32 checksum();
|
||||
|
||||
static ByteBuffer decompress_all(ReadonlyBytes bytes)
|
||||
{
|
||||
Zlib zlib { bytes };
|
||||
return zlib.decompress();
|
||||
}
|
||||
|
||||
private:
|
||||
u8 m_compression_method;
|
||||
u8 m_compression_info;
|
||||
|
|
|
|||
|
|
@ -52,11 +52,59 @@ TEST_CASE(deflate_decompress_compressed_block)
|
|||
|
||||
const u8 uncompressed[] = "This is a simple text file :)";
|
||||
|
||||
const auto decompressed = Compress::DeflateStream::decompress_all({ compressed, sizeof(compressed) });
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) - 1 }, decompressed.span()));
|
||||
const auto decompressed = Compress::DeflateDecompressor::decompress_all({ compressed, sizeof(compressed) });
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) - 1 }, decompressed.bytes()));
|
||||
}
|
||||
|
||||
TEST_CASE(zlib_simple_decompress)
|
||||
TEST_CASE(deflate_decompress_uncompressed_block)
|
||||
{
|
||||
const u8 compressed[] = {
|
||||
0x01, 0x0d, 0x00, 0xf2, 0xff, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20,
|
||||
0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21
|
||||
};
|
||||
|
||||
const u8 uncompressed[] = "Hello, World!";
|
||||
|
||||
const auto decompressed = Compress::DeflateDecompressor::decompress_all({ compressed, sizeof(compressed) });
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) - 1 }, decompressed.bytes()));
|
||||
}
|
||||
|
||||
TEST_CASE(deflate_decompress_multiple_blocks)
|
||||
{
|
||||
const u8 compressed[] = {
|
||||
0x00, 0x1f, 0x00, 0xe0, 0xff, 0x54, 0x68, 0x65, 0x20, 0x66, 0x69, 0x72,
|
||||
0x73, 0x74, 0x20, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x20, 0x69, 0x73, 0x20,
|
||||
0x75, 0x6e, 0x63, 0x6f, 0x6d, 0x70, 0x72, 0x65, 0x73, 0x73, 0x65, 0x64,
|
||||
0x53, 0x48, 0xcc, 0x4b, 0x51, 0x28, 0xc9, 0x48, 0x55, 0x28, 0x4e, 0x4d,
|
||||
0xce, 0x07, 0x32, 0x93, 0x72, 0xf2, 0x93, 0xb3, 0x15, 0x32, 0x8b, 0x15,
|
||||
0x92, 0xf3, 0x73, 0x0b, 0x8a, 0x52, 0x8b, 0x8b, 0x53, 0x53, 0xf4, 0x00
|
||||
};
|
||||
|
||||
const u8 uncompressed[] = "The first block is uncompressed and the second block is compressed.";
|
||||
|
||||
const auto decompressed = Compress::DeflateDecompressor::decompress_all({ compressed, sizeof(compressed) });
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) - 1 }, decompressed.bytes()));
|
||||
}
|
||||
|
||||
// FIXME: The following test uses a dynamic encoding which isn't supported by DeflateDecompressor yet.
|
||||
|
||||
/*
|
||||
TEST_CASE(deflate_decompress_zeroes)
|
||||
{
|
||||
const u8 compressed[] = {
|
||||
0xed, 0xc1, 0x01, 0x0d, 0x00, 0x00, 0x00, 0xc2, 0xa0, 0xf7, 0x4f, 0x6d,
|
||||
0x0f, 0x07, 0x14, 0x00, 0x00, 0x00, 0xf0, 0x6e
|
||||
};
|
||||
|
||||
u8 uncompressed[4096];
|
||||
Bytes { uncompressed, sizeof(uncompressed) }.fill(0);
|
||||
|
||||
const auto decompressed = Compress::DeflateDecompressor::decompress_all({ compressed, sizeof(compressed) });
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) }, decompressed.bytes()));
|
||||
}
|
||||
*/
|
||||
|
||||
TEST_CASE(zlib_decompress_simple)
|
||||
{
|
||||
const u8 compressed[] = {
|
||||
0x78, 0x01, 0x01, 0x1D, 0x00, 0xE2, 0xFF, 0x54, 0x68, 0x69, 0x73, 0x20,
|
||||
|
|
@ -67,8 +115,8 @@ TEST_CASE(zlib_simple_decompress)
|
|||
|
||||
const u8 uncompressed[] = "This is a simple text file :)";
|
||||
|
||||
const auto decompressed = Compress::Zlib { { compressed, sizeof(compressed) } }.decompress();
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) - 1 }, decompressed.span()));
|
||||
const auto decompressed = Compress::Zlib::decompress_all({ compressed, sizeof(compressed) });
|
||||
EXPECT(compare({ uncompressed, sizeof(uncompressed) - 1 }, decompressed.bytes()));
|
||||
}
|
||||
|
||||
TEST_MAIN(Compress)
|
||||
|
|
|
|||
Loading…
Reference in a new issue