Inspired by #3395,
offer a new capability to set all parameters defined in a ZSTD_compressionParameters structure
with a single symbol invocation
to improve user code brevity.
Reported by @shulib :
the specification for 4-streams mode
doesn't work when the amount of literals to compress is 5 bytes.
Extending it, it also doesn't work for sizes 1 or 2.
This patch updates the specification and the implementation
to require a minimum of 6 literals to trigger or accept the 4-streams mode.
The impact is expected to be a no-op :
the 4-streams mode is never triggered for such small quantity of literals anyway,
since it would be wasteful (it costs ~7.3 bytes more than single-stream mode).
An informal lower limit is set at ~256 bytes,
so the technical minimum is very far from this limit.
This is just meant for completeness of the specification.
```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora \) -prune -o -type f);
do
sed -i 's/Facebook, Inc\./Meta Platforms, Inc. and affiliates./' $f;
done
```
When spawning a Windows thread we have small worker wrapper function that translates
between the interfaces of Windows and POSIX threads.
This wrapper is given a pointer that might get stale before the worker starts running,
resulting in UB and crashes.
This commit adds synchronization so that we know the wrapper has finished reading the data
it needs before we allow the main thread to resume execution.
1. If threads are resized the threads' `ZSTD_pthread_t` might move
while the worker still holds a pointer into it (see more details in #3120).
2. The join operation was waiting for a thread and then return its `thread.arg`
as a return value, but since the `ZSTD_pthread_t thread` was passed by value it
would have a stale `arg` that wouldn't match the thread's actual return value.
This fix changes the `ZSTD_pthread_join` API and removes support for returning
a value. This means that we are diverging from the `pthread_join` API and this
is no longer just an alias.
In the future, if needed, we could return a Windows thread's return value using
`GetExitCodeThread`, but as this path wouldn't be excised in any case, it's
preferable to not add it right now.
Fix `zdict.h` static linking only section so if you include it twice it
still exposes the static linking only symbols. E.g. this pattern:
```
```
This can easily happen when a header you include includes `zdict.h`.
`ZSTD_LIB_MINIFY` broke in 8bf699aa59372d7c2bb4216bcf8037cab7dae51e.
This commit fixes the macro and the static library shrinks from ~600K to 324K
with ZSTD_LIB_MINIFY set.
Fixes#3066.
1. Follow the scheme introduced in PR #2501 for both `zdict.h` and `zstd_errors.h`.
2. If the `*_VISIBLE` macro isn't set, but the `*_VISIBILITY` macro is, use that.
Also make this change for `zstd.h`, since we probably shouldn't have changed
that macro name without backward compatibility in the first place.
3. Change all references to `*_VISIBILITY` to `*_VISIBLE`.
Fixes#3359.
fixed#3323, reported by @nigeltao
Completed documentation around this risk
(which is largely theoretical,
I can't see that happening in any "real world" scenario,
but an erroneous @srcSize value could indeed trigger it).
Fix an off-by-one error in the compressor that emits corrupt blocks if:
* Zstd is compiled in 32-bit mode
* The windowLog == 25 exactly
* An offset of 2^25-3, 2^25-2, 2^25-1, or 2^25 is emitted
* The bitstream had 7 bits leftover before writing the offset
This bug has been present since before v1.0, but wasn't able to easily
be triggered, since until somewhat recently zstd wasn't able to find
matches that were within 128KB of the window size.
Add a test case, and fix 2 bugs in `ZSTD_compressSequences()`:
* The `ZSTD_isRLE()` check was incorrect. It wouldn't produce
corruption, but it could waste CPU and not emit RLE even if the block
was RLE
* One windowSize was `1 << windowLog`, not `1u << windowLog`
Thanks to @tansy for finding the issue, and giving us a reproducer!
Fixes Issue #3350.
Delete unaligned memory access code from the legacy codebase by removing all the
non-memcpy functions. We don't care about speed at all for this codebase, only
simplicity.
Fix an instance of `NULL + 0` in `ZSTD_decompressStream()`. Also, improve our
`stream_decompress` fuzzer to pass `NULL` in/out buffers to
`ZSTD_decompressStream()`, and fix 2 issues that were immediately surfaced.
Fixes#3351
Instead of using packed attribute hack, just use aligned attribute. It
improves code generation on armv6 and armv7, and slightly improves code
generation on aarch64. GCC generates identical code to regular aligned
access on ARMv6 for all versions between 4.5 and trunk, except GCC 5
which is buggy and generates the same (bad) code as packed access:
https://gcc.godbolt.org/z/hq37rz7sb
