When a compressed file has been deteriorated through hardware error
or accidental overwriting, some unrelated data could be leaked.
Make sure to zero fill the buffer when this happens.
This commit addresses issues where little-endian variables are emitted
raw to a log or output stream which is to be interpreted by the user.
Outputting data in non-native endianness can cause confusion for anybody
attempting to debug issues with a file system.
Compressed records may be written as full clusters even though cluster
tails are meaningless. This is to avoid the lower levels doing a read-
modify-write cycle. Be sure to zero the meaningless bytes to avoid
leaking information.
Contributed by Eric Biggers
This patch changes the algorithm to use hash chains instead of binary
trees, with much stronger hashing. It also introduces useful (for
performance) parameters, such as the "nice match length" and "maximum
search depth", that are similar to those used in other commonly used
compression algorithms such as zlib's DEFLATE implementation.
The speed improvement is very significant, with some loss of compression
rate. The compression rate is still better than then Windows one.
Contributed by Eric Biggers
Windows 8 does not zero any more the end of a compression block beyond
what is needed to reach the end of a file. We must now be careful not
to decompress more data than needed.
