Commit Graph

12 Commits

Author SHA1 Message Date
Lasse Collin 369f72fd65 Fix a buffer overflow in the LZMA encoder. It was due to my
misunderstanding of the code. There's no tiny fix for this
problem, so I also cleaned up the code in general.

This reduces the speed of the encoder 2-5 % in the fastest
compression mode ("lzma -1"). High compression modes should
have no noticeable performance difference.

This commit breaks things (especially LZMA_SYNC_FLUSH) but I
will fix them once the new format and LZMA2 has been roughly
implemented. Plain LZMA won't support LZMA_SYNC_FLUSH at all
and won't be supported in the new .lzma format. This may
change still but this is what it looks like now.

Support for known uncompressed size (that is, LZMA or LZMA2
without EOPM) is likely to go away. This means there will
be API changes.
2008-06-01 12:48:17 +03:00
Lasse Collin beeb810608 Prevent LZ encoder from hanging with known uncompressed
size. The "fix" breaks LZMA_SYNC_FLUSH at end of stream
with known uncompressed size, but since it currently seems
likely that support for encoding with known uncompressed
size will go away anyway, I'm not fixing this problem now.
2008-04-25 15:39:50 +03:00
Lasse Collin 6c5306e312 Fix wrong return type (uint32_t -> bool). 2008-04-24 18:39:57 +03:00
Lasse Collin 712cfe3ebf Fix data corruption in LZ encoder with LZMA_SYNC_FLUSH. 2008-04-24 18:38:00 +03:00
Lasse Collin f310c50286 Initialize the last byte of the dictionary to zero so that
lz_get_byte(lz, 0) returns zero. This was broken by
1a3b218598.
2008-03-11 15:17:16 +02:00
Lasse Collin 596fa1fac7 Always initialize lz->temp_size in lz_decoder.c. temp_size did
get initialized as a side-effect after allocating a new decoder,
but not when the decoder was reused.
2008-03-10 13:44:29 +02:00
Lasse Collin 1a3b218598 Don't memzero() the history buffer when initializing LZ
decoder. There's no danger of information leak here, so
it isn't required. Doing memzero() takes a lot of time
with large dictionaries, which could make it easier to
construct DoS attack to consume too much CPU time.
2008-02-02 14:51:06 +02:00
Lasse Collin ab5feaf1fc Fix LZMA_SYNC_FLUSH handling in LZ and LZMA encoders.
That code is now almost completely in LZ coder, where
it can be shared with other LZ77-based algorithms in
future.
2008-01-18 20:02:52 +02:00
Lasse Collin e22b37968d Major changes to LZ encoder, LZMA encoder, and range encoder.
These changes implement support for LZMA_SYNC_FLUSH in LZMA
encoder, and move the temporary buffer needed by range encoder
from lzma_range_encoder structure to lzma_lz_encoder.
2008-01-14 13:39:54 +02:00
Lasse Collin 9547e734a0 Don't use coder->lz.stream_end_was_reached in assertions
in match_c.h.
2008-01-14 12:09:52 +02:00
Lasse Collin f73c2ab607 Eliminate lzma_lz_encoder.must_move_pos. It's needed
only in one place which isn't performance criticial.
2008-01-10 17:13:42 +02:00
Lasse Collin 5d018dc035 Imported to git. 2007-12-09 00:42:33 +02:00