In previous version, main function would return early when detecting a job error.
Late threads resources were therefore not collected back into pools.
New version just register the error, but continue the collecting process.
All buffers and context should be released back to pool before leaving main function.
Result from getBuffer and getCCtx could be NULL when allocation fails.
Now correctly checks : job creation stop and last job reports an allocation error.
releaseBuffer and releaseCCtx are now also compatible with NULL input.
Identified a new potential issue :
when early job fails, later jobs are not collected for resource retrieval.
Since the result of mt compression is a single frame,
changed naming, which implied the concatenation of multiple frames.
minor : ensures that content size is written in header
The new strategy involves cutting frame at block level.
The result is a single frame, preserving ZSTD_getDecompressedSize()
As a consequence, bench can now make a full round-trip,
since the result is compatible with ZSTD_decompress().
This strategy will not make it possible to decode the frame with multiple threads
since the exact cut between independent blocks is not known.
MT decoding needs further discussions.
use ZSTD_freeCCtxPool() to release the partially created pool.
avoids to duplicate logic.
Also : identified a new difficult corner case :
when freeing the Pool, all CCtx should be previously released back to the pool.
Otherwise, it means some CCtx are still in use.
There is currently no clear policy on what to do in such a case.
Note : it's supposed to never happen.
Since pool creation/usage is static, it has no external user,
which limits risks.
When the overflow protection kicks in, it makes sure that ip - ctx->base
isn't too large. However, it didn't ensure that saved offsets are
still valid. This change ensures that any valid offsets (<= windowLog)
are still representable after the update.
The bug would shop up on line 1056, when `offset_1 > current + 1`, which
causes an underflow. This in turn, would cause a segfault on line 1063.
The input must necessarily be longer than 1 GB for this issue to occur.
Even then, it only occurs if one of the last 3 matches is larger than
the chain size and block size.
Yann Collet
Nick Terrell
Przemyslaw Skibinski
Yann Collet