};
-#define DECOMP_DIR "testdata/compression/lzxpress-huffman/decompressed"
-#define COMP_DIR "testdata/compression/lzxpress-huffman/compressed"
-#define MORE_COMP_DIR "testdata/compression/lzxpress-huffman/more-compressed"
+#define DECOMP_DIR "testdata/compression/decompressed"
+#define COMP_DIR "testdata/compression/compressed-huffman"
+#define MORE_COMP_DIR "testdata/compression/compressed-more-huffman"
#define VARRGH(...) __VA_ARGS__
--- /dev/null
+# Test vectors for MS-XCA [de-]compression
+
+There are currently two supported varients of the Xpress Compression
+Algorithm, "Plain LZ77" and "LZ77 + Huffman". For each we two
+directories of files compressed on Windows, corresponding to the two
+compression levels that Windows offers.
+
+The subdirectories are
+
+./decompressed - test files to compress with .decomp extension.
+./compressed-huffman - LZ77+Huffman compressed, with .lzhuff extension.
+./compressed-more-huffman - LZ77+Huffman compressed, with .lzhuff extension.
+./compressed-plain - Plain LZ77 compressed, with .lzplain extension.
+./compressed-more-plain - Plain LZ77 compressed, with .lzplain extension.
+
+where the more-compressed-* versions have the files that Windows put
+more effort into compressing (largely in vain -- they are similar in
+size). Windows probably does not use this more effortful compression
+in network protocols, but these files must be decompressible.
+
+The compressed files were made using the Windows Compression API,
+which uses the same underlying code as MS-XCA, but which puts some
+annoying hurdles in the way. In particular, it won't perform
+LZ77+Huffman compression on any file smaller than 300 bytes. The
+relationship between the two is covered in various messages in
+
+https://lists.samba.org/archive/cifs-protocol/2022-October/
+https://lists.samba.org/archive/cifs-protocol/2022-November/
+
+To recreate these files or add more, use
+lib/compression/tests/scripts/generate-windows-test-vectors.c under
+Cygwin or MSYS2. This file is also in the decompressed directory.
+
+Some of the decompressed files were found via fuzzing, some are designed
+to test one aspect or another of the format, while others are public
+domain texts.
+
+These are used in compression and decompression tests.
+
+- For decompression tests, we need the decompressed versions to
+ compare against.
+
+- For compression tests, we do not assert that the compressed file is
+ identical to the Windows compressed file. Exact equality is not
+ expected by MS-XCA, which leaves room for implementation tricks, but
+ the size of the compressed file allows us to make ballpark
+ assertions about expected compression ratios.
+++ /dev/null
-# Test vectors for LZ77+Huffman [de-]compression
-
-The three subdirectories contain files that correspond to each other
-
-./decompressed - test files to compress with .decomp extension.
-./compressed - files compressed as if for Windows SMB, with .lzhuff
- extension.
-./more-compressed - files compressed more thoroughly by Windows, using
- more effort than SMB does, with .lzhuff extension.
- Only some of the decompressed files have been
- compressed in this way.
-
-The compressed files were compressed on Windows, using the Compression
-API, which uses the same underlying code as MS-XCA, but which puts
-some annoying hurdles in the way. In particular, it won't compress any
-file smaller than 300 bytes. The relationship between the two is
-covered in various messages in
-
-https://lists.samba.org/archive/cifs-protocol/2022-October/
-https://lists.samba.org/archive/cifs-protocol/2022-November/
-
-Some of the decompressed files were found via fuzzing, some are designed
-to test one aspect or another of the format, while others are public
-domain texts.
-
-These are used in LZ77 + Huffman compression and decompression tests.
-
-- For decompression tests, we need the decompressed versions to
- compare against.
-
-- For compression tests, we do not assert that the compressed file is
- identical to the Windows compressed file. Exact equality is not
- expected by MS-XCA, which leaves room for implementation tricks, but
- the size of the compressed file allows us to make ballpark
- assertions about expected compression ratios.
projects / thirdparty / samba.git / commitdiff
