.xz Test Files ---------------- 0. Introduction This directory contains bunch of files to test handling of .xz files in .xz decoder implementations. Many of the files have been created by hand with a hex editor, thus there is no better "source code" than the files themselves. All the test files (*.xz) and this README have been put into the public domain. 1. File Types Good files (good-*.xz) must decode successfully without requiring a lot of CPU time or RAM. Unsupported files (unsupported-*.xz) are good files, but headers indicate features not supported by the current file format specification. Bad files (bad-*.xz) must cause the decoder to give an error. Like with the good files, these files must not require a lot of CPU time or RAM before they get detected to be broken. 2. Descriptions of Individual Files 2.1. Good Files good-0-empty.xz has one Stream with no Blocks. good-0pad-empty.xz has one Stream with no Blocks followed by four-byte Stream Padding. good-0cat-empty.xz has two zero-Block Streams concatenated without Stream Padding. good-0catpad-empty.xz has two zero-Block Streams concatenated with four-byte Stream Padding between the Streams. good-1-check-none.xz has one Stream with one Block with two uncompressed LZMA2 chunks and no integrity check. good-1-check-crc32.xz has one Stream with one Block with two uncompressed LZMA2 chunks and CRC32 check. good-1-check-crc64.xz is like good-1-check-crc32.xz but with CRC64. good-1-check-sha256.xz is like good-1-check-crc32.xz but with SHA256. good-2-lzma2.xz has one Stream with two Blocks with one uncompressed LZMA2 chunk in each Block. good-1-block_header-1.xz has both Compressed Size and Uncompressed Size in the Block Header. This has also four extra bytes of Header Padding. good-1-block_header-2.xz has known Compressed Size. good-1-block_header-3.xz has known Uncompressed Size. good-1-delta-lzma2.tiff.xz is an image file that compresses better with Delta+LZMA2 than with plain LZMA2. good-1-x86-lzma2.xz uses the x86 filter (BCJ) and LZMA2. The uncompressed file is compress_prepared_bcj_x86 found from the tests directory. good-1-sparc-lzma2.xz uses the SPARC filter and LZMA. The uncompressed file is compress_prepared_bcj_sparc found from the tests directory. good-1-lzma2-1.xz has two LZMA2 chunks, of which the second sets new properties. good-1-lzma2-2.xz has two LZMA2 chunks, of which the second resets the state without specifying new properties. good-1-lzma2-3.xz has two LZMA2 chunks, of which the first is uncompressed and the second is LZMA. The first chunk resets dictionary and the second sets new properties. good-1-lzma2-4.xz has three LZMA2 chunks: First is LZMA, second is uncompressed with dictionary reset, and third is LZMA with new properties but without dictionary reset. good-1-3delta-lzma2.xz has three Delta filters and LZMA2. 2.2. Unsupported Files unsupported-check.xz uses Check ID 0x02 which isn't supported by the current version of the file format. It is implementation-defined how this file handled (it may reject it, or decode it possibly with a warning). unsupported-block_header.xz has a non-null byte in Header Padding, which may indicate presence of a new unsupported field. unsupported-filter_flags-1.xz has unsupported Filter ID 0x7F. unsupported-filter_flags-2.xz specifies only Delta filter in the List of Filter Flags, but Delta isn't allowed as the last filter in the chain. It could be a little more correct to detect this file as corrupt instead of unsupported, but saying it is unsupported is simpler in case of liblzma. unsupported-filter_flags-3.xz specifies two LZMA2 filters in the List of Filter Flags. LZMA2 is allowed only as the last filter in the chain. It could be a little more correct to detect this file as corrupt instead of unsupported, but saying it is unsupported is simpler in case of liblzma. 2.3. Bad Files bad-0pad-empty.xz has one Stream with no Blocks followed by five-byte Stream Padding. Stream Padding must be a multiple of four bytes, thus this file is corrupt. bad-0catpad-empty.xz has two zero-Block Streams concatenated with five-byte Stream Padding between the Streams. bad-0cat-alone.xz is good-0-empty.xz concatenated with an empty LZMA_Alone file. bad-0cat-header_magic.xz is good-0cat-empty.xz but with one byte wrong in the Header Magic Bytes field of the second Stream. liblzma gives LZMA_DATA_ERROR for this. (LZMA_FORMAT_ERROR is used only if the first Stream of a file has invalid Header Magic Bytes.) bad-0-header_magic.xz is good-0-empty.xz but with one byte wrong in the Header Magic Bytes field. liblzma gives LZMA_FORMAT_ERROR for this. bad-0-footer_magic.xz is good-0-empty.xz but with one byte wrong in the Footer Magic Bytes field. liblzma gives LZMA_DATA_ERROR for this. bad-0-empty-truncated.xz is good-0-empty.xz without the last byte of the file. bad-0-nonempty_index.xz has no Blocks but Index claims that there is one Block. bad-0-backward_size.xz has wrong Backward Size in Stream Footer. bad-1-stream_flags-1.xz has different Stream Flags in Stream Header and Stream Footer. bad-1-stream_flags-2.xz has wrong CRC32 in Stream Header. bad-1-stream_flags-3.xz has wrong CRC32 in Stream Footer. bad-1-vli-1.xz has two-byte variable-length integer in the Uncompressed Size field in Block Header while one-byte would be enough for that value. It's important that the file gets rejected due to too big integer encoding instead of due to Uncompressed Size not matching the value stored in the Block Header. That is, the decoder must not try to decode the Compressed Data field. bad-1-vli-2.xz has ten-byte variable-length integer as Uncompressed Size in Block Header. It's important that the file gets rejected due to too big integer encoding instead of due to Uncompressed Size not matching the value stored in the Block Header. That is, the decoder must not try to decode the Compressed Data field. bad-1-block_header-1.xz has Block Header that ends in the middle of the Filter Flags field. bad-1-block_header-2.xz has Block Header that has Compressed Size and Uncompressed Size but no List of Filter Flags field. bad-1-block_header-3.xz has wrong CRC32 in Block Header. bad-1-block_header-4.xz has too big Compressed Size in Block Header (2^63 - 1 bytes while maximum is a little less, because the whole Block must stay smaller than 2^63). It's important that the file gets rejected due to invalid Compressed Size value; the decoder must not try decoding the Compressed Data field. bad-1-block_header-5.xz has zero as Compressed Size in Block Header. bad-2-index-1.xz has wrong Unpadded Sizes in Index. bad-2-index-2.xz has wrong Uncompressed Sizes in Index. bad-2-index-3.xz has non-null byte in Index Padding. bad-2-index-4.xz wrong CRC32 in Index. bad-2-index-5.xz has zero as Unpadded Size. It is important that the file gets rejected specifically due to Unpadded Size having an invalid value. bad-2-compressed_data_padding.xz has non-null byte in the padding of the Compressed Data field of the first Block. bad-1-check-crc32.xz has wrong Check (CRC32). bad-1-check-crc64.xz has wrong Check (CRC64). bad-1-check-sha256.xz has wrong Check (SHA-256). bad-1-lzma2-1.xz has LZMA2 stream whose first chunk (uncompressed) doesn't reset the dictionary. bad-1-lzma2-2.xz has two LZMA2 chunks, of which the second chunk indicates dictionary reset, but the LZMA compressed data tries to repeat data from the previous chunk. bad-1-lzma2-3.xz sets new invalid properties (lc=8, lp=0, pb=0) in the middle of Block. bad-1-lzma2-4.xz has two LZMA2 chunks, of which the first is uncompressed and the second is LZMA. The first chunk resets dictionary as it should, but the second chunk tries to reset state without specifying properties for LZMA. bad-1-lzma2-5.xz is like bad-1-lzma2-4.xz but doesn't try to reset anything in the header of the second chunk. bad-1-lzma2-6.xz has reserved LZMA2 control byte value (0x03). bad-1-lzma2-7.xz has EOPM at LZMA level. bad-1-lzma2-8.xz is like good-1-lzma2-4.xz but doesn't set new properties in the third LZMA2 chunk.