discovered by oss-fuzz
It's a bug in the test itself :
ZSTD_compressBound() as an upper bound of the compress size
only works for data compressed "normally".
But in situations where many flushes are forcefully introduced,
this creates many more blocks,
each of which has a potential to increase the size by 3 bytes.
In extreme cases (lots of small incompressible blocks), the expansion can go beyond ZSTD_compressBound().
This situation is similar when using the CompressSequences() API
with Explicit Block Delimiters.
In which case, each explicit block acts like a deliberate flush.
When employed by a fuzzer, it's possible to generate scenarios like the one described above,
with tons of incompressible blocks of small sizes,
thus going beyond ZSTD_compressBound().
fix : when using Explicit Block Delimiters, use a larger bound, to account for this scenario.
It's a bug in the test itself, in exceptional circumstances (no more space for additional sequence).
There should be enough room for all cases to work fine from now on,
and if not, we have an additional `assert()` to catch that situation.
* Extract out common portion of `lib/Makefile` into `lib/libzstd.mk`.
Most relevantly, the way we find library files.
* Use `lib/libzstd.mk` in the other Makefiles instead of repeating the
same code.
* Add a test `tests/test-variants.sh` that checks that the builds of
`make -C programs allVariants` are correct, and run it in Actions.
* Adds support for ASM files in the CMake build.
The Meson build is not updated because it lists every file in zstd,
and supports ASM off the bat, so the Huffman ASM commit will just add
the ASM file to the list.
The Visual Studios build is not updated because I'm not adding ASM
support to Visual Studios yet.
* Add a Huffman round trip fuzzer
* Fix two minor bugs in Huffman that aren't exposed in zstd
- Incorrect weight comparison (weights are allowed to be equal to
table log).
- HUF_compress1X_usingCTable_internal() can return compressed
size >= source size, so the assert that `cSize <= 65535` isn't
correct, and it needs to be checked instead.
Compress the input twice in the `simple_round_trip` and
`dictionary_round_trip` fuzzers with exactly the same parameters, but
reusing the context. Then ensure that the compressed output is
identical.
This flag forces zstd to always load the prefix in ext-dict mode, even
if it happens to be contiguous, to force determinism. It also applies to
dictionaries that are re-processed.
A determinism test case is also added, which fails without
`ZSTD_c_deterministicRefPrefix` and passes with it set.
Question: Should this be the default behavior? It isn't in this PR.
* Switch to yearless copyright per FB policy
* Fix up SPDX-License-Identifier lines in `contrib/linux-kernel` sources
* Add zstd copyright/license header to the `contrib/linux-kernel` sources
* Update the `tests/test-license.py` to check for yearless copyright
* Improvements to `tests/test-license.py`
* Check `contrib/linux-kernel` in `tests/test-license.py`
* Fix compiler version regex, which was broken for multi-digit
versions.
* Fix compiler detection for gcc.
* Disable `pointer-overflow` instead of `integer-overflow` for gcc
versions newer than 8.0.0.
* Fix bug introduced in PR #2271
* Fix long-standing bug that is impossible to trigger inside of zstd
* Add a fuzzer that makes sure the normalized count always round trips
correctly
