Re: [BUG]

[Shigio YAMAGUCHI]

On Sat, 14 Sep 2013 01:22:12 +0900
Hideki IWAMOTO <address@hidden> wrote:

> Hi. Yamaguchi san.
> 
> There are some problems in searching using the pattern
> which contains '^' at the head.
> 
> ======== example 1 ========
> $ cat a.c
> vsprintf
> sprintf
> asprintf
> $ global -sx '^v?sprintf'
> vsprintf            1 a.c              vsprintf
> $ global -sx '^(v)?sprintf'
> sprintf             2 a.c              sprintf
> vsprintf            1 a.c              vsprintf
> ===========================
> 
> Although '^v?sprintf should be equivalent to '^(v)?sprintf',
> the former does not match 'sprintf'. 
> 
> I think that the following code in gtags_first() is broken
> and it should be removed.
> 
>   617                 const char *p;
>   618                 /*
>   619                  * If the pattern include '^' + some non regular 
> expression
>   620                  * characters like '^aaa[0-9]', we take prefix read 
> method
>   621                  * with the non regular expression part as the prefix.
>   622                  */
>   623                 if (!(flags & GTOP_IGNORECASE) && *pattern == '^' && 
> *(p = pattern + 1) && !isregexchar(*p)) {
>   624                         int i = 0;
>   625 
>   626                         while (*p && !isregexchar(*p) && i < IDENTLEN)
>   627                                 prefix[i++] = *p++;
>   628                         prefix[i] = '\0';
>   629                         key = prefix;
>   630                         dbflags |= DBOP_PREFIX;
>   631                 } else {
> 
> 
> Reducing the length of the string copied to prefix[] by 1 byte
> does not solve the following problem. 
> 
> ======== example 2 ========
> $ cat b.c
> geta
> seta
> $ global -sx '^get|^set'
> get                 1 b.c              geta
> $ global -sx '(^get)|(^set)'
> get                 1 b.c              geta
> set                 2 b.c              seta
> ===========================
> 

Hi iwamoto san,

You are right. It was a wrong optimization.
How about the following?

[This code replaces the 617-631]

        /*
         * If the pattern is '^' + <non regular expression> like '^aaa',
         * we take prefix read method with the non regular expression part
         * as a prefix.
         */
        if (!(flags & GTOP_IGNORECASE) && *pattern == '^' && !isregex(pattern + 
1)) {
                key = pattern + 1;
                dbflags |= DBOP_PREFIX;
        } else {

This code rescues '^' + <non regular expression> like '^set' at least.

[removed]
$ /usr/bin/time global -xs '^set' > /tmp/out1
        0.44 real         0.30 user         0.12 sys
[using this code]
$ /usr/bin/time global -xs '^set' > /tmp/out2
        0.08 real         0.05 user         0.02 sys
$ diff /tmp/out1 /tmp/out2
$
(tested using FreeBSD kernel source)

This code works well in the following cases too:

$ global -sx ^v?sprintf
sprintf             2 a.c              sprintf
vsprintf            1 a.c              vsprintf
$ global -sx ^(v)?sprintf
sprintf             2 a.c              sprintf
vsprintf            1 a.c              vsprintf
$ global -sx ^get|^set
geta                1 b.c              geta
seta                2 b.c              seta
$ global -sx (^get)|(^set)
geta                1 b.c              geta
seta                2 b.c              seta

> -- 
> Hideki IWAMOTO <address@hidden>
-- 
Shigio YAMAGUCHI <address@hidden>
PGP fingerprint: D1CB 0B89 B346 4AB6 5663  C4B6 3CA5 BBB3 57BE DDA3