path: root/Documentation
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authorDave Rodgman <dave.rodgman@arm.com>2019-04-05 18:38:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-04-05 16:02:30 -1000
commitb11ed18efa8f3dc58b259b812588317b765b1cfc (patch)
treef98183968067ec487a0fd4e732d3fa7ac7ff29cf /Documentation
parent6147e136ff5071609b54f18982dea87706288e21 (diff)
lib/lzo: fix bugs for very short or empty input
For very short input data (0 - 1 bytes), lzo-rle was not behaving correctly. Fix this behaviour and update documentation accordingly. For zero-length input, lzo v0 outputs an end-of-stream marker only, which was misinterpreted by lzo-rle as a bitstream version number. Ensure bitstream versions > 0 require a minimum stream length of 5. Also fixes a bug in handling the tail for very short inputs when a bitstream version is present. Link: http://lkml.kernel.org/r/20190326165857.34613-1-dave.rodgman@arm.com Signed-off-by: Dave Rodgman <dave.rodgman@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
1 files changed, 5 insertions, 3 deletions
diff --git a/Documentation/lzo.txt b/Documentation/lzo.txt
index f79934225d8d..ca983328976b 100644
--- a/Documentation/lzo.txt
+++ b/Documentation/lzo.txt
@@ -102,9 +102,11 @@ Byte sequences
dictionary which is empty, and that it will always be
invalid at this place.
- 17 : bitstream version. If the first byte is 17, the next byte
- gives the bitstream version (version 1 only). If the first byte
- is not 17, the bitstream version is 0.
+ 17 : bitstream version. If the first byte is 17, and compressed
+ stream length is at least 5 bytes (length of shortest possible
+ versioned bitstream), the next byte gives the bitstream version
+ (version 1 only).
+ Otherwise, the bitstream version is 0.
18..21 : copy 0..3 literals
state = (byte - 17) = 0..3 [ copy <state> literals ]