7 This directory contains bunch of files to test handling of .xz files
8 in .xz decoder implementations. Many of the files have been created
9 by hand with a hex editor, thus there is no better "source code" than
10 the files themselves. All the test files (*.xz) and this README have
11 been put into the public domain.
16 Good files (good-*.xz) must decode successfully without requiring
17 a lot of CPU time or RAM.
19 Unsupported files (unsupported-*.xz) are good files, but headers
20 indicate features not supported by the current file format
23 Bad files (bad-*.xz) must cause the decoder to give an error. Like
24 with the good files, these files must not require a lot of CPU time
25 or RAM before they get detected to be broken.
28 2. Descriptions of Individual Files
32 good-0-empty.xz has one Stream with no Blocks.
34 good-0pad-empty.xz has one Stream with no Blocks followed by
35 four-byte Stream Padding.
37 good-0cat-empty.xz has two zero-Block Streams concatenated without
40 good-0catpad-empty.xz has two zero-Block Streams concatenated with
41 four-byte Stream Padding between the Streams.
43 good-1-check-none.xz has one Stream with one Block with two
44 uncompressed LZMA2 chunks and no integrity check.
46 good-1-check-crc32.xz has one Stream with one Block with two
47 uncompressed LZMA2 chunks and CRC32 check.
49 good-1-check-crc64.xz is like good-1-check-crc32.xz but with CRC64.
51 good-1-check-sha256.xz is like good-1-check-crc32.xz but with
54 good-2-lzma2.xz has one Stream with two Blocks with one uncompressed
55 LZMA2 chunk in each Block.
57 good-1-block_header-1.xz has both Compressed Size and Uncompressed
58 Size in the Block Header. This has also four extra bytes of Header
61 good-1-block_header-2.xz has known Compressed Size.
63 good-1-block_header-3.xz has known Uncompressed Size.
65 good-1-delta-lzma2.tiff.xz is an image file that compresses
66 better with Delta+LZMA2 than with plain LZMA2.
68 good-1-x86-lzma2.xz uses the x86 filter (BCJ) and LZMA2. The
69 uncompressed file is compress_prepared_bcj_x86 found from the tests
72 good-1-sparc-lzma2.xz uses the SPARC filter and LZMA. The
73 uncompressed file is compress_prepared_bcj_sparc found from the tests
76 good-1-lzma2-1.xz has two LZMA2 chunks, of which the second sets
79 good-1-lzma2-2.xz has two LZMA2 chunks, of which the second resets
80 the state without specifying new properties.
82 good-1-lzma2-3.xz has two LZMA2 chunks, of which the first is
83 uncompressed and the second is LZMA. The first chunk resets dictionary
84 and the second sets new properties.
86 good-1-3delta-lzma2.xz has three Delta filters and LZMA2.
89 2.2. Unsupported Files
91 unsupported-check.xz uses Check ID 0x02 which isn't supported by
92 the current version of the file format. It is implementation-defined
93 how this file handled (it may reject it, or decode it possibly with
96 unsupported-block_header.xz has a non-nul byte in Header Padding,
97 which may indicate presence of a new unsupported field.
99 unsupported-filter_flags-1.xz has unsupported Filter ID 0x7F.
101 unsupported-filter_flags-2.xz specifies only Delta filter in the
102 List of Filter Flags, but Delta isn't allowed as the last filter in
103 the chain. It could be a little more correct to detect this file as
104 corrupt instead of unsupported, but saying it is unsupported is
105 simpler in case of liblzma.
107 unsupported-filter_flags-3.xz specifies two LZMA2 filters in the
108 List of Filter Flags. LZMA2 is allowed only as the last filter in the
109 chain. It could be a little more correct to detect this file as
110 corrupt instead of unsupported, but saying it is unsupported is
111 simpler in case of liblzma.
116 bad-0pad-empty.xz has one Stream with no Blocks followed by
117 five-byte Stream Padding. Stream Padding must be a multiple of four
118 bytes, thus this file is corrupt.
120 bad-0catpad-empty.xz has two zero-Block Streams concatenated with
121 five-byte Stream Padding between the Streams.
123 bad-0cat-alone.xz is good-0-empty.xz concatenated with an empty
126 bad-0cat-header_magic.xz is good-0cat-empty.xz but with one byte
127 wrong in the Header Magic Bytes field of the second Stream. liblzma
128 gives LZMA_DATA_ERROR for this. (LZMA_FORMAT_ERROR is used only if
129 the first Stream of a file has invalid Header Magic Bytes.)
131 bad-0-header_magic.xz is good-0-empty.xz but with one byte wrong
132 in the Header Magic Bytes field. liblzma gives LZMA_FORMAT_ERROR for
135 bad-0-footer_magic.xz is good-0-empty.xz but with one byte wrong
136 in the Footer Magic Bytes field. liblzma gives LZMA_DATA_ERROR for
139 bad-0-empty-truncated.xz is good-0-empty.xz without the last byte
142 bad-0-nonempty_index.xz has no Blocks but Index claims that there is
145 bad-0-backward_size.xz has wrong Backward Size in Stream Footer.
147 bad-1-stream_flags-1.xz has different Stream Flags in Stream Header
150 bad-1-stream_flags-2.xz has wrong CRC32 in Stream Header.
152 bad-1-stream_flags-3.xz has wrong CRC32 in Stream Footer.
154 bad-1-vli-1.xz has two-byte variable-length integer in the
155 Uncompressed Size field in Block Header while one-byte would be enough
156 for that value. It's important that the file gets rejected due to too
157 big integer encoding instead of due to Uncompressed Size not matching
158 the value stored in the Block Header. That is, the decoder must not
159 try to decode the Compressed Data field.
161 bad-1-vli-2.xz has ten-byte variable-length integer as Uncompressed
162 Size in Block Header. It's important that the file gets rejected due
163 to too big integer encoding instead of due to Uncompressed Size not
164 matching the value stored in the Block Header. That is, the decoder
165 must not try to decode the Compressed Data field.
167 bad-1-block_header-1.xz has Block Header that ends in the middle of
168 the Filter Flags field.
170 bad-1-block_header-2.xz has Block Header that has Compressed Size and
171 Uncompressed Size but no List of Filter Flags field.
173 bad-1-block_header-3.xz has wrong CRC32 in Block Header.
175 bad-1-block_header-4.xz has too big Compressed Size in Block Header
176 (2^64 - 1 bytes while maximum is a little less, because the whole
177 Block must stay smaller than 2^64). It's important that the file
178 gets rejected due to invalid Compressed Size value; the decoder
179 must not try decoding the Compressed Data field.
181 bad-1-block_header-5.xz has zero as Compressed Size in Block Header.
183 bad-2-index-1.xz has wrong Total Sizes in Index.
185 bad-2-index-2.xz has wrong Uncompressed Sizes in Index.
187 bad-2-index-3.xz has non-nul byte in Index Padding.
189 bad-2-index-4.xz wrong CRC32 in Index.
191 bad-2-index-5.xz has zero as Total Size. It is important that the file
192 gets rejected specifically due to Total Size having an invalid value.
194 bad-2-compressed_data_padding.xz has non-nul byte in the padding of
195 the Compressed Data field of the first Block.
197 bad-1-check-crc32.xz has wrong Check (CRC32).
199 bad-1-check-crc64.xz has wrong Check (CRC64).
201 bad-1-check-sha256.xz has wrong Check (SHA-256).
203 bad-1-lzma2-1.xz has LZMA2 stream whose first chunk (uncompressed)
204 doesn't reset the dictionary.
206 bad-1-lzma2-2.xz has two LZMA2 chunks, of which the second chunk
207 indicates dictionary reset, but the LZMA compressed data tries to
208 repeat data from the previous chunk.
210 bad-1-lzma2-3.xz sets new invalid properties (lc=8, lp=0, pb=0) in
213 bad-1-lzma2-4.xz has two LZMA2 chunks, of which the first is
214 uncompressed and the second is LZMA. The first chunk resets dictionary
215 as it should, but the second chunk tries to reset state without
216 specifying properties for LZMA.
218 bad-1-lzma2-5.xz is like bad-1-lzma2-4.xz but doesn't try to reset
219 anything in the header of the second chunk.
221 bad-1-lzma2-6.xz has reserved LZMA2 control byte value (0x03).
223 bad-1-lzma2-7.xz has EOPM at LZMA level.