LZ4 HC doesn't support match references that are exactly 65535 bytes backwards

xiaoyin0208 / lz4

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LZ4 HC doesn't support match references that are exactly 65535 bytes backwards #46

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago

Hi Yann,

If you give LZ4 HC a sequence such as

[1, 2, 3, 4, 5, 6, [...65530 incompressible bytes...], 1, 2, 3, 4, 5, 6, [other 
bytes]]

LZ4 HC won't be able to compress it because it always cheks ref > 
ip-MAX_DISTANCE instead of ref >= ip-MAX_DISTANCE (see attached patch for more 
details).

Thank you!

Original issue reported on code.google.com by jpou...@gmail.com on 29 Nov 2012 at 10:58

Attachments:

LZ4_HC_MAX_DISTANCE.patch

GoogleCodeExporter commented 8 years ago

Thanks Adrien. Clear and simple. I'll update it.

Original comment by yann.col...@gmail.com on 30 Nov 2012 at 10:45

Changed state: Accepted

GoogleCodeExporter commented 8 years ago

Thanks, Yann!

Original comment by jpou...@gmail.com on 30 Nov 2012 at 10:47

GoogleCodeExporter commented 8 years ago

The RC version in attached file integrates your proposed correction regarding 
extended LZ4 HC detection window.

Original comment by yann.col...@gmail.com on 30 Nov 2012 at 12:50

Attachments:

lz4_rc84.zip

GoogleCodeExporter commented 8 years ago

Looks good. For what it's worth, all my Java tests pass with this RC.

Original comment by jpou...@gmail.com on 30 Nov 2012 at 1:05

GoogleCodeExporter commented 8 years ago

Corrected into r84.

Original comment by yann.col...@gmail.com on 30 Nov 2012 at 1:25

Changed state: Fixed