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			241 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			241 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
| 
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| .xz Test Files
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| ----------------
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| 
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| 0. Introduction
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| 
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|     This directory contains bunch of files to test handling of .xz files
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|     in .xz decoder implementations. Many of the files have been created
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|     by hand with a hex editor, thus there is no better "source code" than
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|     the files themselves. All the test files (*.xz) and this README have
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|     been put into the public domain.
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| 
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| 
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| 1. File Types
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| 
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|     Good files (good-*.xz) must decode successfully without requiring
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|     a lot of CPU time or RAM.
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| 
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|     Unsupported files (unsupported-*.xz) are good files, but headers
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|     indicate features not supported by the current file format
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|     specification.
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| 
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|     Bad files (bad-*.xz) must cause the decoder to give an error. Like
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|     with the good files, these files must not require a lot of CPU time
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|     or RAM before they get detected to be broken.
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| 
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| 
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| 2. Descriptions of Individual Files
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| 
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| 2.1. Good Files
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| 
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|     good-0-empty.xz has one Stream with no Blocks.
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| 
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|     good-0pad-empty.xz has one Stream with no Blocks followed by
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|     four-byte Stream Padding.
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| 
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|     good-0cat-empty.xz has two zero-Block Streams concatenated without
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|     Stream Padding.
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| 
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|     good-0catpad-empty.xz has two zero-Block Streams concatenated with
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|     four-byte Stream Padding between the Streams.
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| 
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|     good-1-check-none.xz has one Stream with one Block with two
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|     uncompressed LZMA2 chunks and no integrity check.
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| 
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|     good-1-check-crc32.xz has one Stream with one Block with two
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|     uncompressed LZMA2 chunks and CRC32 check.
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| 
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|     good-1-check-crc64.xz is like good-1-check-crc32.xz but with CRC64.
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| 
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|     good-1-check-sha256.xz is like good-1-check-crc32.xz but with
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|     SHA256.
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| 
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|     good-2-lzma2.xz has one Stream with two Blocks with one uncompressed
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|     LZMA2 chunk in each Block.
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| 
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|     good-1-block_header-1.xz has both Compressed Size and Uncompressed
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|     Size in the Block Header. This has also four extra bytes of Header
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|     Padding.
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| 
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|     good-1-block_header-2.xz has known Compressed Size.
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| 
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|     good-1-block_header-3.xz has known Uncompressed Size.
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| 
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|     good-1-delta-lzma2.tiff.xz is an image file that compresses
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|     better with Delta+LZMA2 than with plain LZMA2.
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| 
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|     good-1-x86-lzma2.xz uses the x86 filter (BCJ) and LZMA2. The
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|     uncompressed file is compress_prepared_bcj_x86 found from the tests
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|     directory.
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| 
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|     good-1-sparc-lzma2.xz uses the SPARC filter and LZMA. The
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|     uncompressed file is compress_prepared_bcj_sparc found from the tests
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|     directory.
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| 
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|     good-1-lzma2-1.xz has two LZMA2 chunks, of which the second sets
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|     new properties.
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| 
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|     good-1-lzma2-2.xz has two LZMA2 chunks, of which the second resets
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|     the state without specifying new properties.
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| 
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|     good-1-lzma2-3.xz has two LZMA2 chunks, of which the first is
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|     uncompressed and the second is LZMA. The first chunk resets dictionary
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|     and the second sets new properties.
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| 
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|     good-1-lzma2-4.xz has three LZMA2 chunks: First is LZMA, second is
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|     uncompressed with dictionary reset, and third is LZMA with new
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|     properties but without dictionary reset.
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| 
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|     good-1-lzma2-5.xz has an empty LZMA2 stream with only the end of
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|     payload marker. XZ Utils 5.0.1 and older incorrectly see this file
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|     as corrupt.
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| 
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|     good-1-3delta-lzma2.xz has three Delta filters and LZMA2.
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| 
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| 
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| 2.2. Unsupported Files
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| 
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|     unsupported-check.xz uses Check ID 0x02 which isn't supported by
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|     the current version of the file format. It is implementation-defined
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|     how this file handled (it may reject it, or decode it possibly with
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|     a warning).
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| 
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|     unsupported-block_header.xz has a non-null byte in Header Padding,
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|     which may indicate presence of a new unsupported field.
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| 
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|     unsupported-filter_flags-1.xz has unsupported Filter ID 0x7F.
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| 
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|     unsupported-filter_flags-2.xz specifies only Delta filter in the
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|     List of Filter Flags, but Delta isn't allowed as the last filter in
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|     the chain. It could be a little more correct to detect this file as
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|     corrupt instead of unsupported, but saying it is unsupported is
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|     simpler in case of liblzma.
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| 
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|     unsupported-filter_flags-3.xz specifies two LZMA2 filters in the
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|     List of Filter Flags. LZMA2 is allowed only as the last filter in the
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|     chain. It could be a little more correct to detect this file as
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|     corrupt instead of unsupported, but saying it is unsupported is
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|     simpler in case of liblzma.
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| 
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| 
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| 2.3. Bad Files
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| 
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|     bad-0pad-empty.xz has one Stream with no Blocks followed by
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|     five-byte Stream Padding. Stream Padding must be a multiple of four
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|     bytes, thus this file is corrupt.
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| 
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|     bad-0catpad-empty.xz has two zero-Block Streams concatenated with
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|     five-byte Stream Padding between the Streams.
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| 
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|     bad-0cat-alone.xz is good-0-empty.xz concatenated with an empty
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|     LZMA_Alone file.
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| 
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|     bad-0cat-header_magic.xz is good-0cat-empty.xz but with one byte
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|     wrong in the Header Magic Bytes field of the second Stream. liblzma
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|     gives LZMA_DATA_ERROR for this. (LZMA_FORMAT_ERROR is used only if
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|     the first Stream of a file has invalid Header Magic Bytes.)
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| 
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|     bad-0-header_magic.xz is good-0-empty.xz but with one byte wrong
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|     in the Header Magic Bytes field. liblzma gives LZMA_FORMAT_ERROR for
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|     this.
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| 
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|     bad-0-footer_magic.xz is good-0-empty.xz but with one byte wrong
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|     in the Footer Magic Bytes field. liblzma gives LZMA_DATA_ERROR for
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|     this.
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| 
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|     bad-0-empty-truncated.xz is good-0-empty.xz without the last byte
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|     of the file.
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| 
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|     bad-0-nonempty_index.xz has no Blocks but Index claims that there is
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|     one Block.
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| 
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|     bad-0-backward_size.xz has wrong Backward Size in Stream Footer.
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| 
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|     bad-1-stream_flags-1.xz has different Stream Flags in Stream Header
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|     and Stream Footer.
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| 
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|     bad-1-stream_flags-2.xz has wrong CRC32 in Stream Header.
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| 
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|     bad-1-stream_flags-3.xz has wrong CRC32 in Stream Footer.
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| 
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|     bad-1-vli-1.xz has two-byte variable-length integer in the
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|     Uncompressed Size field in Block Header while one-byte would be enough
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|     for that value. It's important that the file gets rejected due to too
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|     big integer encoding instead of due to Uncompressed Size not matching
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|     the value stored in the Block Header. That is, the decoder must not
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|     try to decode the Compressed Data field.
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| 
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|     bad-1-vli-2.xz has ten-byte variable-length integer as Uncompressed
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|     Size in Block Header. It's important that the file gets rejected due
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|     to too big integer encoding instead of due to Uncompressed Size not
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|     matching the value stored in the Block Header. That is, the decoder
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|     must not try to decode the Compressed Data field.
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| 
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|     bad-1-block_header-1.xz has Block Header that ends in the middle of
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|     the Filter Flags field.
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| 
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|     bad-1-block_header-2.xz has Block Header that has Compressed Size and
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|     Uncompressed Size but no List of Filter Flags field.
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| 
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|     bad-1-block_header-3.xz has wrong CRC32 in Block Header.
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| 
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|     bad-1-block_header-4.xz has too big Compressed Size in Block Header
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|     (2^63 - 1 bytes while maximum is a little less, because the whole
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|     Block must stay smaller than 2^63). It's important that the file
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|     gets rejected due to invalid Compressed Size value; the decoder
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|     must not try decoding the Compressed Data field.
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| 
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|     bad-1-block_header-5.xz has zero as Compressed Size in Block Header.
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| 
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|     bad-1-block_header-6.xz has corrupt Block Header which may crash
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|     xz -lvv in XZ Utils 5.0.3 and earlier. It was fixed in the commit
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|     c0297445064951807803457dca1611b3c47e7f0f.
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| 
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|     bad-2-index-1.xz has wrong Unpadded Sizes in Index.
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| 
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|     bad-2-index-2.xz has wrong Uncompressed Sizes in Index.
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| 
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|     bad-2-index-3.xz has non-null byte in Index Padding.
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| 
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|     bad-2-index-4.xz wrong CRC32 in Index.
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| 
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|     bad-2-index-5.xz has zero as Unpadded Size. It is important that the
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|     file gets rejected specifically due to Unpadded Size having an invalid
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|     value.
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| 
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|     bad-2-compressed_data_padding.xz has non-null byte in the padding of
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|     the Compressed Data field of the first Block.
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| 
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|     bad-1-check-crc32.xz has wrong Check (CRC32).
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| 
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|     bad-1-check-crc64.xz has wrong Check (CRC64).
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| 
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|     bad-1-check-sha256.xz has wrong Check (SHA-256).
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| 
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|     bad-1-lzma2-1.xz has LZMA2 stream whose first chunk (uncompressed)
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|     doesn't reset the dictionary.
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| 
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|     bad-1-lzma2-2.xz has two LZMA2 chunks, of which the second chunk
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|     indicates dictionary reset, but the LZMA compressed data tries to
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|     repeat data from the previous chunk.
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| 
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|     bad-1-lzma2-3.xz sets new invalid properties (lc=8, lp=0, pb=0) in
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|     the middle of Block.
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| 
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|     bad-1-lzma2-4.xz has two LZMA2 chunks, of which the first is
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|     uncompressed and the second is LZMA. The first chunk resets dictionary
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|     as it should, but the second chunk tries to reset state without
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|     specifying properties for LZMA.
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| 
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|     bad-1-lzma2-5.xz is like bad-1-lzma2-4.xz but doesn't try to reset
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|     anything in the header of the second chunk.
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| 
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|     bad-1-lzma2-6.xz has reserved LZMA2 control byte value (0x03).
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| 
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|     bad-1-lzma2-7.xz has EOPM at LZMA level.
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| 
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|     bad-1-lzma2-8.xz is like good-1-lzma2-4.xz but doesn't set new
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|     properties in the third LZMA2 chunk.
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| 
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