Re: [PATCH v3 22/30] grep: factor test for \0 in grep patterns into a function

> Factor the test for \0 in grep patterns into a function. Since commit
> 9eceddeec6 ("Use kwset in grep", 2011-08-21) any pattern containing a
> \0 is considered fixed as regcomp() can't handle it.
> 
> This change makes later changes that make use of either has_null() or
> is_fixed() (but not both) smaller.
> 
> While I'm at it make the comment conform to the style guide, i.e. add
> an opening "/*\n".
> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  grep.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/grep.c b/grep.c
> index bf6c2494fd..79eb681c6e 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -321,6 +321,18 @@ static NORETURN void compile_regexp_failed(const struct grep_pat *p,
>  	die("%s'%s': %s", where, p->pattern, error);
>  }
>  
> +static int has_null(const char *s, size_t len)
> +{
> +	/*
> +	 * regcomp cannot accept patterns with NULs so when using it
> +	 * we consider any pattern containing a NUL fixed.
> +	 */
> +	if (memchr(s, 0, len))
> +		return 1;
> +
> +	return 0;
> +}
> +
>  #ifdef USE_LIBPCRE
>  static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
>  {
> @@ -394,12 +406,6 @@ static int is_fixed(const char *s, size_t len)
>  {
>  	size_t i;
>  
> -	/* regcomp cannot accept patterns with NULs so we
> -	 * consider any pattern containing a NUL fixed.
> -	 */
> -	if (memchr(s, 0, len))
> -		return 1;
> -
>  	for (i = 0; i < len; i++) {
>  		if (is_regex_special(s[i]))
>  			return 0;
> @@ -451,7 +457,7 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
>  	 * simple string match using kws.  p->fixed tells us if we
>  	 * want to use kws.
>  	 */
> -	if (opt->fixed || is_fixed(p->pattern, p->patternlen))
> +	if (opt->fixed || has_null(p->pattern, p->patternlen) || is_fixed(p->pattern, p->patternlen))

>  		p->fixed = !icase || ascii_only;
>  	else
>  		p->fixed = 0;
> -- 
> 2.13.0.303.g4ebf302169
>