* `ZSTD_decompressDCtx()` did not use the dictionary loaded by
`ZSTD_DCtx_loadDictionary()`.
* Add a unit test.
* A stacked diff uses `ZSTD_decompressDCtx()` in the
`dictionary_round_trip` and `dictionary_decompress` fuzzers.
Zstd compression sometimes does different stuff when it has at least
`ZSTD_compressBound()` output bytes, or not. Half of the time fuzz with
`ZSTD_compressBound() - 1` output bytes. Ensure that we have at least
one byte of overhead by disabling either the dictionary ID or checksum.
`ZSTD_compress2()` wouldn't wait for multithreaded compression to
finish. We didn't find this because ZSTDMT will block when it can
compress all in one go, but it can't do that if it doesn't have enough
output space, or if `ZSTD_c_rsyncable` is enabled.
Since we will already sometimes block when using `ZSTD_e_end`, I've
changed `ZSTD_e_end` and `ZSTD_e_flush` to guarantee maximum forward
progress. This simplifies the API, and helps users avoid the easy bug
that was made in `ZSTD_compress2()`
* Found by the libfuzzer fuzzers.
* Added a test case that catches the problem.
* I will make the fuzzers sometimes allocate less than
`ZSTD_compressBound()` output space.
It wasn't using the ZSTD_CCtx_params correctly. It must actualize
the compression parameters by calling ZSTD_getCParamsFromCCtxParams()
to get the real window log.
Tested by updating the streaming memory usage example in the next
commit. The CHECK() failed before this patch, and passes after.
I also added a unit test to zstreamtest.c that failed before this
patch, and passes after.
* After loading a dictionary only create the cdict once we've started the
compression job. This allows the user to pass the dictionary before they
set other settings, and is in line with the rest of the API.
* Add tests that mix the 3 dictionary loading APIs.
* Add extra tests for `ZSTD_CCtx_loadDictionary()`.
* The first 2 tests added fail before this patch.
* Run the regression test suite.
The order you set parameters in the advanced API is not supposed to matter.
However, once you call `ZSTD_CCtx_refCDict()` the compression parameters
cannot be changed. Remove that restriction, and document what parameters
are used when using a CDict.
If the CCtx is in dictionary mode, then the CDict's parameters are used.
If the CCtx is not in dictionary mode, then its requested parameters are
used.
Introduces a new utility function `ZSTD_findFrameCompressedSize_internal` which
is equivalent to `ZSTD_findFrameCompressSize`, but accepts an additional output
parameter `bound` that computes an upper-bound for the compressed data in the frame.
The new API function is named `ZSTD_decompressBound` to be consistent with
`zstd_compressBound` (the inverse operation). Clients will now be able to compute an upper-bound for
their compressed payloads instead of guessing a large size.
Implements https://github.com/facebook/zstd/issues/1536.
* Move all ZSTDMT parameter setting code to ZSTD_CCtxParams_*Parameter().
ZSTDMT now calls these functions, so we can keep all the logic in the
same place.
* Clean up `ZSTD_CCtx_setParameter()` to only add extra checks where needed.
* Clean up `ZSTDMT_initJobCCtxParams()` by copying all parameters by default,
and then zeroing the ones that need to be zeroed. We've missed adding several
parameters here, and it makes more sense to only have to update it if you
change something in ZSTDMT.
* Add `ZSTDMT_cParam_clampBounds()` to clamp a parameter into its valid
range. Use this to keep backwards compatibility when setting ZSTDMT parameters,
which clamp into the valid range.
Test a positive compression level with uncompressed literals,
and a negative compression level with compressed literals.
I double checked the `results.csv` and made sure that the compressed
sizes make sense.
Pull request #1499 added a new test, which uses 'head -c'. The '-c'
option is non-portable (not in POSIX). Instead use 'dd'. Similar issue
has been resolved in the past (#1321).
fseek() doesn't indicate when it moves past the end of a file.
Consequently, if a file is truncated within its last block, the error would't be detected.
This PR adds a test scenario that induces this situation using a small compressed file of only one block in size.
This test is added to tests/playTests.sh
Check is implemented by ensuring that the filehandle position is equal to the filesize upon exit.
