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.
of the so called simple filters. If there is demand, limited
support for LZMA_SYNC_FLUSH may be added in future.
After this commit, using LZMA_SYNC_FLUSH shouldn't cause
undefined behavior in any situation.
encoder and decoder, and put the shared things to
block_private.h. Improved the checks a little so that
they may detect too big Compressed Size at initialization
time if lzma_options_block.total_size or .total_limit is
known.
Allow encoding and decoding Blocks with combinations of
fields that are not allowed by the file format specification.
Doing this requires that the application passes such a
combination in lzma_options_lzma; liblzma doesn't do that,
but it's not impossible that someone could find them useful
in some custom file format.
- Added lzma_memlimit_max() and lzma_memlimit_reached()
API functions.
- Added simple estimation of malloc()'s memory usage
overhead.
- Fixed integer overflow detection in lzma_memlimit_alloc().
- Made some white space cleanups and added more comments.
The description of lzma_memlimit_max() in memlimit.h is bad
and should be improved.
lzma_metadata.header_metadata_size == LZMA_VLI_VALUE_UNKNOWN
is not allowed at all. To indicate missing Header Metadata
Block, header_metadata_size must be set to zero. This is
what Metadata decoder does after this patch too.
Note that other missing fields in lzma_metadata are still
indicated with LZMA_VLI_VALUE_UNKNOWN. This isn't as
illogical as it sounds at first, because missing Size of
Header Metadata Block means that Header Metadata Block is
not present in the Stream. With other Metadata fields,
a missing field means only that the value is unknown.
liblzma as easy as using zlib, because the easy API
don't require developers to know any fancy LZMA options.
Note that Multi-Block Stream encoding is currently broken.
The easy API should be OK, the bug(s) are elsewhere.
This leaves one known alignment bug unfixed: If repeat count
doesn't fit into 28-bit integer, the encoder has to split
this to multiple Subblocks with Subblock Type `Repeating Data'.
The extra Subblocks may have wrong alignment. Correct alignment
is restored after the split Repeating Data has been completely
written out.
Since the encoder doesn't even try to fix the alignment unless
the size of Data is at least 4 bytes, to trigger this bug you
need at least 4 GiB of repeating data with sequence length of
4 or more bytes. Since the worst thing done by this bug is
misaligned data (no data corruption), this bug simply isn't
worth fixing, because a proper fix isn't simple.
The API for handing Subfilters was changed to make it
consistent with LZMA_SYNC_FLUSH.
A few sanity checks were added for Subfilter handling. Some
small bugs were fixed. More comments were added.
function is still shared between encoder and decoder, but the
actual coding is in separate files for encoder and decoder.
There are now separate functions for the actual delta
calculation depending on if Delta is the last filter in the
chain or not. If it is the last, the new code copies the
data from input to output buffer and does the delta
calculation at the same time. The old code first copied the
data, then did the delta in the target buffer, which required
reading through the data twice.
Support for LZMA_SYNC_FLUSH was added to the Delta encoder.
This doesn't change anything in the file format.
a forward port of b7b22fcb979a16d3a47c8001f058c9f7d4416068
from lzma-utils-legacy.git. I don't know if the new code base
builds on Windows, but this is a start.
too early if we hit End of Input while decoding a Subblock of
type Repeating Data. To keep the loop termination condition
elegant, the order of enumerations in coder->sequence were
changed.
To keep the case-labels in roughly the same order as the
enumerations in coder->sequence, large chunks of code was
moved around. This made the diff big and ugly compared to
the amount of the actual changes made.
in ia64_coder_init(). It triggered assert() in
simple_coder.c, and could have caused a buffer overflow.
This error was probably a copypaste mistake, since most
of the simple filters use unfiltered_max = 4.
table-based version from LZMA SDK 4.57. This should be
fast on most systems.
A simpler and smaller alternative version is also provided.
On some CPUs this can be even a little faster than the
default table-based version (see comments in fastpos.h),
but on most systems the table-based code is faster.
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.
Lasse Collin