`lib/deprecated` is no longer built by zstd's bundled build files. However,
users may try to build these files when they import the source tree into
their own build systems. And if they have `-Wdeprecated-declarations` on,
this can produce warnings.
This PR migrates these files away from using deprecated declarations.
This addresses #2767.
PR #2850 attempted to fix a determinism bug that was uncovered by OSS-Fuzz. It
succeeded in addressing that source of non-determinism, but introduced a new
one: it was possible, when index reduction occurred, to map indices in the
window to the reserved value, which would cause them to be zeroed, potentially
altering parsing of the input.
This PR addresses this issue. It makes sure that the bottom of the window is
always `>= ZSTD_WINDOW_START_INDEX`.
I'm not sure if this makes #2850 redundant. I think it's probably still
valuable to have that protection as well.
Credit to OSS-Fuzz for discovering this issue.
Previously, if an index was equal to `reducerValue + 1`, it would get remapped
during index reduction to 1 i.e. `ZSTD_DUBT_UNSORTED_MARK`. This can affect the
parsing of the input slightly, by causing tree nodes to be nullified when they
otherwise wouldn't be. This hardly matters from a correctness or efficiency
perspective, but it does impact determinism.
So this commit changes index reduction to avoid mapping indices to collide with
`ZSTD_DUBT_UNSORTED_MARK`.
Since we're now hashing the position ahead even if we find a long match and
don't search that next position, we can write it back into the hashtable even
in long matches. This seems to cost us no speed, and improves compression
ratio slightly!
Aside from maybe a latency win in the loop, this means that when we find a
short match, we've already done the hash we need to check the next long match.
It's a bit strange, because this is hitting the dictionary special case where
the dictionary is contiguous with the input and still runs in the single-
segment path.
We should probably change that to hit the `extDict` path instead?
This removes the old `ZSTD_compressBlock_fast_generic()` and renames the new
`ZSTD_compressBlock_fast_generic_pipelined()` to replace it. This is
functionally a no-op.
Unrolling the loop to handle 2 positions in each iteration allows us to reduce
the frequency of some operations that don't need to happen at every position.
One such operation is the step calculation, which is a very rough heuristic
anyways. It's fine if we do this a position later. The other operation is the
repcode check. But since the repcode check already tries expanding back one
position, we're really not missing much of importance by only trying it every
other position.
This commit also slightly reorders some operations.
Amusingly, it seems to be a non-trivial performance hit to add in final
searches or even hash table insertions during cleanup. So let's not. It seems
to not make any meaningful difference in compression ratio.
This PR fixes an incorrect comparison in figuring out `minChain` in
`ZSTD_dedicatedDictSearch_lazy_loadDictionary()`. This incorrect comparison
had been masked by the fact that `idx` was always 1, until @terrelln changed
that in #2726.
Credit-to: OSS-Fuzz
`open()`'s mode bits are only applied to files that are created by the call.
If the output file already exists, but is not readable, the `fopen()` would
fail, preventing us from removing it, which would mean that the file would
not end up with the correct permission bits.
It's not clear to me why the `fopen()` is there at all. `UTIL_isRegularFile()`
should be sufficient, AFAICT.
This commit introduces a GitHub action that is triggered on release creation,
which creates the release tarball, compresses it, hashes it, signs it, and
attaches all of those files to the release.
This commit addresses #2491.
Note that a downside of this solution is that it is global: `umask()` affects
all file creation calls in the process. I believe this is safe since
`fileio.c` functions should only ever be used in the zstd binary, and these
are (almost) the only files ever created by zstd, and AIUI they're only
created in a single thread. So we can get away with messing with global state.
Note that this doesn't change the permissions of files created by `dibio.c`.
I'm not sure what those should be...
W. Felix Handte