Am 11.02.23 um 14:48 schrieb René Scharfe:

Am 11.02.23 um 08:01 schrieb Masahiro Yamada:

quoted

On Sat, Feb 11, 2023 at 7:03 AM René Scharfe [off-list ref] wrote:

quoted

We already use eight bits for the lookup table values in sane_ctype.
Perhaps it's time to move GIT_GLOB_SPECIAL, GIT_REGEX_SPECIAL,
GIT_PATHSPEC_MAGIC and GIT_PUNCT to their own table to make room for
flags for isprint(), isgraph() and isblank().

I think that is a good idea.

If we can have more room for isupper() and islower(),
we will be able to delete sane_iscase().


(I was thinking 'unsigned short', but having two tables is OK.)



So, how can I proceed with this patchset?



[A] After somebody refactors ctype.c table,
    I will rebase this series on top of that.

[B] keep isblank() and isgraph() local to wildmatch.c
    until that happens, so I can proceed without
    depending on the ctype.c refactoring.

    Apparently, wildmatch.c is not using a pointer
    increment with isblank() or isgraph().

[C] If 'somebody' in [A] is supposed to me,
    my v2 will include ctype refactoring.

[D] We need more tests first. :)  I sent patches to test the current
classifiers separately.  A similar test for isblank would have helped
you detect the mismatch quickly.  Full test coverage also gives
confidence when tinkering with the existing classifiers.

1c149ab2dd (ctype: support iscntrl, ispunct, isxdigit and isprint,
2012-10-15) added an implementation of isprint that evaluated its
argument only once, by the way, but the one from 0fcec2ce54
(format-patch: make rfc2047 encoding more strict, 2012-10-18)
replaced it.

Widening the element type of the lookup table would work, but might
impact performance.  I guess it would be slower, but perhaps we'd
have to measure it to be sure.  Splitting the table into unrelated
subsets would avoid that.

Deciding which flags to move requires knowing the full target set,
I think.  The punctuation-related flags looked to me like good
candidates until I saw the original isprint implementation which
uses them and several of the others.  So I'm not so sure anymore,
but here's a patch that moves them out:

Perhaps:

[E] Implement isblank and isgraph as inline functions and leave the
lookup table integration for later:

   #undef isblank
   #define isblank(x) sane_isblank(x)
   static inline int sane_isblank(int c) {return c == ' ' || c == '\t';}

   #undef isgraph
   #define isgraph(x) sane_isgraph(x)
   static inline int sane_isgraph(int c) {return isprint(c) && c != ' ';}

The Lazy Way™ ;)

René