added a test for LZ4F_compressEnd()

which actively tries to make it write out of bound.
For this scenario to be possible,
it's necessary to set dstCapacity < LZ4F_compressBound()

When a compression operation fails,
the CCtx context is left in an undefined state,
therefore compression cannot resume.
As a consequence :
- round trip tests must be aborted, since there is nothing valid to decompress
- most users avoid this situation, by ensuring that dstCapacity >= LZ4F_compressBound()

For these reasons, this use case was poorly tested up to now.

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/lz4frame.h b/lib/lz4frame.h
index fc30f6f..599f17e 100644
--- a/lib/lz4frame.h
+++ b/lib/lz4frame.h
@@ -295,6 +295,7 @@ LZ4FLIB_API size_t LZ4F_compressUpdate(LZ4F_cctx* cctx,
  * `cOptPtr` is optional : it's possible to provide NULL, all options will be set to default.
  * @return : nb of bytes written into dstBuffer (can be zero, when there is no data stored within cctx)
  *           or an error code if it fails (which can be tested using LZ4F_isError())
+ *  Note : LZ4F_flush() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr).
  */
 LZ4FLIB_API size_t LZ4F_flush(LZ4F_cctx* cctx,
                               void* dstBuffer, size_t dstCapacity,
@@ -307,6 +308,7 @@ LZ4FLIB_API size_t LZ4F_flush(LZ4F_cctx* cctx,
  * `cOptPtr` is optional : NULL can be provided, in which case all options will be set to default.
  * @return : nb of bytes written into dstBuffer, necessarily >= 4 (endMark),
  *           or an error code if it fails (which can be tested using LZ4F_isError())
+ *  Note : LZ4F_compressEnd() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr).
  *  A successful call to LZ4F_compressEnd() makes `cctx` available again for another compression task.
  */
 LZ4FLIB_API size_t LZ4F_compressEnd(LZ4F_cctx* cctx,