Fix warnings: ex_getln.c: init_history(): NP dereference: FP.

Problem    : Dereference of null pointer @ 4199.
Diagnostic : False positive.
Rationale  : Suggested error path implies that newlen == 0 and
             newlen > hislen, which implies hislen < 0, which is
             impossible (hislen is always between 0 and 10000).
Resolution : Refactor code.
             Asserting oldlen >= 0 should have sufficed, but
             for some reason analyzer doesn't follow implications in
             that case.
             Asserting newlen != 0 || newlen <= hislen works.
             But the chance has been taken to do extensive
             refactoring of this function, as it was difficult to
             understand as it was.
             As a result of refactoring, assert is not needed anymore,
             as we don't call clear_hist_entry() in refactored version.
Refactor   : - Rework algorithm:
               * Drop guard for OOM case, which can't happen now.
               * Drop empty/growing/shrinking cases. Simplify to always
                 doing the same.
               * Perform circular array reordering in all cases
                 (before, it only did when shrinking).
               * Work in batches through memcpy/memset, instead of one
                 entry at a time, as it did before.
             - Inline variable declarations.
             - Replace `ssize_t` by `int`.
             - Introduce oldlen as entry value of hislen.
             - Add a lot of comments.

Helped-by: Scott Prager <splinterofchaos@gmail.com>
Helped-by: oni-link <knil.ino@gmail.com>

0 files changed, 0 insertions, 0 deletions