0. Introduction
- This directory contains bunch of files to test handling of .xz
- and .lzma files in 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 and
- this README have been put into the public domain.
+ This directory contains bunch of files to test handling of .xz,
+ .lzma (LZMA_Alone), and .lz (lzip) files in 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 and this README have been put into the public domain.
1. File Types
- Good files (good-*.xz, good-*.lzma) must decode successfully
- without requiring a lot of CPU time or RAM.
+ Good files (good-*) must decode successfully without requiring
+ a lot of CPU time or RAM.
- Unsupported files (unsupported-*.xz) are good files, but headers
+ Unsupported files (unsupported-*) are good files, but headers
indicate features not supported by the current file format
specification.
- Bad files (bad-*.xz, bad-*.lzma) 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.
+ Bad files (bad-*) 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 .xz Files
bad-too_small_size-without_eopm-3.lzma is like -1 above but instead
of a literal the problem occurs in the middle of a match.
+
+4. Descriptions of Individual .lz (lzip) Files
+
+4.1. Good Files
+
+ good-1-v0.lz contains a single version 0 member. lzip 1.17 and
+ *older* can decompress this; support for version 0 was removed
+ in lzip 1.18.
+
+ good-1-v0-trailing-1.lz is like good-1-v0.lz but contains
+ trailing data that the decompressor must ignore.
+
+ good-1-v1.lz contains a single version 1 member. lzip 1.3 and
+ newer can decompress this.
+
+ good-1-v1-trailing-1.lz is like good-1-v1.lz but contains
+ trailing data that the decompressor must ignore.
+
+ good-1-v1-trailing-2.lz is like good-1-v1.lz but contains
+ trailing data whose first three bytes match the .lz magic bytes.
+ With lzip >= 1.20 this file results in an error unless one uses
+ the command line option --loose-trailing. lzip 1.3 to 1.19 decode
+ this file successfully by default. XZ Utils uses the old behavior
+ because it allows lzma_code() to stop at the first byte of the
+ trailing data as long as the first byte isn't 0x4C (L in US-ASCII);
+ otherwise the first 1-3 bytes that equal to the magic bytes are
+ consumed and lost in lzma_code(), and this is visible in xz too:
+
+ $ ( xz -dc ; cat ) < good-1-v1-trailing-2.lz
+ Hello
+ World!
+ Trailing garbage
+
+ $ ( xz -dc --single-stream ; cat ) < good-1-v1-trailing-2.lz
+ Hello
+ World!
+ LZITrailing garbage
+
+ good-2-v0-v1.lz contains two members of which the first is
+ version 0 and the second version 1. lzip versions 1.3 to 1.17
+ (inclusive) can decompress this.
+
+ good-2-v1-v0.lz contains two members of which the first is
+ version 1 and the second version 0. lzip versions 1.3 to 1.17
+ (inclusive) can decompress this.
+
+ good-2-v1-v1.lz contains two version 1 members. lzip versions 1.3
+ and newer can decompress this.
+
+
+4.2. Unsupported Files
+
+ unsupported-1-v234.lz is like good-1-v1.lz except the version
+ field has been set to 234 (0xEA) which, as of writing, isn't
+ defined or supported by any .lz implementation.
+
+
+4.3. Bad Files
+
+ bad-1-v1-magic-1.lz is like good-1-v1.lz but the first magic byte
+ is wrong.
+
+ bad-1-v1-magic-2.lz is like good-1-v1.lz but the last (fourth)
+ magic byte is wrong.
+
+ bad-1-v1-dict-1.lz has too low value in the dictionary size field.
+
+ bad-1-v1-dict-2.lz has too high value in the dictionary size field.
+
+ bad-1-v1-crc32.lz has wrong CRC32 value.
+
+ bad-1-v0-uncomp-size.lz is version 0 format with incorrect value
+ in the uncompressed size field.
+
+ bad-1-v1-uncomp-size.lz is version 1 format with incorrect value
+ in the uncompressed size field.
+
+ bad-1-v1-member-size.lz has incorrect value in the member size
+ field.
+
+ bad-1-v1-trailing-magic.lz has the four .lz magic bytes as trailing
+ data. This should be detected as a truncated file and thus result
+ in an error. That is, the last four bytes of the file should not be
+ ignored as trailing garbage. lzip >= 1.18 matches this behavior
+ while older versions ignore the last four bytes and don't indicate
+ an error.
+
projects / thirdparty / xz.git / commitdiff
