Re: [PATCH 1/5] maint: ensure that MB_CUR_MAX is defined even when !MBS_SUPPORT

[Paolo Bonzini]

On 09/16/2011 03:03 PM, address@hidden wrote:
> Please remember that dfa.[ch] are shared code with gawk and I think
> also gettext (although I don't know how up to date gettext's version is).
>
> I'd really prefer not to have too many GREP_xxx kinds of things in those
> files.  (It's ok in the rest of grep, of course.:-)

We could separate the variables for dfa and the rest of grep.  Grep just 
needs "#define DFA_MB_CUR_MAX GREP_MB_CUR_MAX" then (and you can 
similarly "#define DFA_MB_CUR_MAX gawk_mb_cur_max" in gawk).

> For what it's worth, MB_CUR_MAX is a function call in GLIBC. There were
> some cases in gawk where I was losing a noticable amount of time calling
> it a lot.  So I set up a global variable gawk_mb_cur_max and initialize
> it in main(), since the result should never change during a single run of
> the program.  It made a difference.

Interesting.  We do have a field for mb_cur_max in dfaexec, but it is 
there because some UTF-8 regex can be run as if the locale was single 
byte.  I suspect however that awk programs (especially badly written 
ones!) do more regex compilation than grep, up to 1 compilation per 
match.  For grep it shouldn't really matter.

Having variables grep_mb_cur_max and dfa_mb_cur_max (separate for the 
reasons Arnold explained) would work, but it would make it impossible 
for the compiler to throw away the multibyte code when MBS_SUPPORT is zero.

Paolo