liblzma: Clarify lzma_lzma_preset() documentation in lzma12.h.

lzma_lzma_preset() does not guarentee that the lzma_options_lzma are
usable in an encoder even if it returns false (success). If liblzma
is built with default configurations, then the options will always be
usable. However if the match finders hc3, hc4, or bt4 are disabled, then
the options may not be usable depending on the preset level requested.

The documentation was updated to reflect this complexity, since this
behavior was unclear before.
This commit is contained in:
Jia Tan 2023-02-24 23:46:23 +08:00
parent 594f904673
commit 2caba3efe3
1 changed files with 5 additions and 0 deletions

View File

@ -555,6 +555,11 @@ do { \
* This function is available only if LZMA1 or LZMA2 encoder has been enabled
* when building liblzma.
*
* If features (like certain match finders) have been disabled at build time,
* then the function may return success (false) even though the resulting
* LZMA1/LZMA2 options may not be usable for encoder initialization
* (LZMA_OPTIONS_ERROR).
*
* \param[out] options Pointer to LZMA1 or LZMA2 options to be filled
* \param preset Preset level bitwse-ORed with preset flags
*