diff options
| -rw-r--r-- | Tests/LibCompress/TestXz.cpp | 58 | ||||
| -rw-r--r-- | Userland/Libraries/LibCompress/Lzma.cpp | 2 |
2 files changed, 59 insertions, 1 deletions
diff --git a/Tests/LibCompress/TestXz.cpp b/Tests/LibCompress/TestXz.cpp index 73db7532cb..b5f092a1fa 100644 --- a/Tests/LibCompress/TestXz.cpp +++ b/Tests/LibCompress/TestXz.cpp @@ -120,6 +120,64 @@ TEST_CASE(lzma2_uncompressed_size_overflow) EXPECT(buffer_or_error.is_error()); } +TEST_CASE(lzma2_literal_context_bits_after_state_reset) +{ + Array<u8, 72> const compressed { + // Stream Header + 0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00, // Magic + 0x00, 0x00, // Stream Flags (Check: None) + 0xFF, 0x12, 0xD9, 0x41, // CRC32 + + // Block Header + 0x02, // Block Header Size [(0x02 + 1) * 4, i.e. 12 bytes] + 0x00, // Block Flags (one filter, no compressed or uncompressed size present) + // Filter 0 Flags + 0x21, // Filter ID (0x21 for LZMA2, encoded as a multibyte integer) + 0x01, // Size of Properties (0x01, encoded as a multibyte integer) + 0x00, // Filter Properties (LZMA2 encoded dictionary size byte; 0x00 = 4 KiB) + 0x00, 0x00, 0x00, // Header Padding + 0x37, 0x27, 0x97, 0xD6, // CRC32 + + // Compressed Data (LZMA2) + // LZMA chunk with dictionary reset + 0xE0, // Control Byte + 0x00, 0x00, // Low 16 bits of uncompressed size minus one (big-endian) + 0x00, 0x05, // Compressed size minus one (big-endian) + 0x01, // LZMA properties byte (lc = 1; lp = 0; pb = 0) + 0x00, 0x3F, 0xFF, 0xFC, 0x00, 0x00, + // LZMA chunk with state reset + 0xA0, // Control Byte + 0x00, 0x01, // Low 16 bits of uncompressed size minus one (big-endian) + 0x00, 0x06, // Compressed size minus one (big-endian) + 0x00, 0x40, 0x1F, 0xF4, 0x00, 0x00, 0x00, + // End of LZMA2 stream + 0x00, + + // Block Padding + 0x00, 0x00, 0x00, + + // Index + 0x00, // Index Indicator + 0x01, // Number of Records (multibyte integer) + // Record 0 + 0x25, // Unpadded Size (multibyte integer) + 0x03, // Uncompressed Size (multibyte integer) + // CRC32 + 0x76, 0x34, 0x7C, 0x51, + + // Stream Footer + 0x06, 0x72, 0x9E, 0x7A, // CRC32 + 0x01, 0x00, 0x00, 0x00, // Backward Size + 0x00, 0x00, // Stream Flags + 0x59, 0x5A, // Footer Magic Bytes + }; + + auto stream = MUST(try_make<FixedMemoryStream>(compressed)); + auto decompressor = MUST(Compress::XzDecompressor::create(move(stream))); + auto buffer = MUST(decompressor->read_until_eof(PAGE_SIZE)); + EXPECT_EQ("\x80\x80\x80"sv.bytes(), buffer.span()); +} + // The following tests are based on test files from the XZ utils package, which have been placed in the public domain: // https://tukaani.org/xz/xz-5.4.1.tar.xz (subdirectory /xz-5.4.1/tests/files) // Test descriptions have been taken from the README file in the test files directory. diff --git a/Userland/Libraries/LibCompress/Lzma.cpp b/Userland/Libraries/LibCompress/Lzma.cpp index 43a73ffd71..0ff8a38339 100644 --- a/Userland/Libraries/LibCompress/Lzma.cpp +++ b/Userland/Libraries/LibCompress/Lzma.cpp @@ -295,7 +295,7 @@ ErrorOr<u16> LzmaDecompressor::decode_symbol_using_reverse_bit_tree(size_t bit_c ErrorOr<void> LzmaDecompressor::decode_literal_to_output_buffer() { u8 previous_byte = 0; - if (m_total_decoded_bytes > 0) { + if (m_dictionary->seekback_limit() > 0) { auto read_bytes = MUST(m_dictionary->read_with_seekback({ &previous_byte, sizeof(previous_byte) }, 1)); VERIFY(read_bytes.size() == sizeof(previous_byte)); } |