Re: [PATCH RESEND 1/2] perf string: Add strcmp_prefix()

[Arnaldo Carvalho de Melo]

Em Fri, Mar 18, 2022 at 05:22:44PM +0800, Wei Li escreveu:
> Add a helper to check whether a string has the given prefix.
> This function is stolen from fs/xattr.c

Can't you use strstarts()? See tools/include/linux/string.h.

- Arnaldo
 
> Signed-off-by: Wei Li <liwei391@xxxxxxxxxx>
> ---
>  tools/perf/util/string.c  | 17 +++++++++++++++++
>  tools/perf/util/string2.h |  1 +
>  2 files changed, 18 insertions(+)
> 
> diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
> index f6d90cdd9225..0ed3e2d0b70f 100644
> --- a/tools/perf/util/string.c
> +++ b/tools/perf/util/string.c
> @@ -209,6 +209,23 @@ int strtailcmp(const char *s1, const char *s2)
>  	return 0;
>  }
>  
> +/**
> + * strcmp_prefix - check string for given prefix
> + * @str: the target string to check
> + * @prefix: the given prefix to match
> + *
> + * Return the rest string in @str if @str has the given @prefix, return NULL
> + * otherwise.
> + */
> +const char *strcmp_prefix(const char *str, const char *prefix)
> +{
> +	while (*prefix && *str == *prefix) {
> +		str++;
> +		prefix++;
> +	}
> +	return *prefix ? NULL : str;
> +}
> +
>  char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints)
>  {
>  	/*
> diff --git a/tools/perf/util/string2.h b/tools/perf/util/string2.h
> index 56c30fef9682..58929ad928f7 100644
> --- a/tools/perf/util/string2.h
> +++ b/tools/perf/util/string2.h
> @@ -20,6 +20,7 @@ static inline bool strisglob(const char *str)
>  	return strpbrk(str, "*?[") != NULL;
>  }
>  int strtailcmp(const char *s1, const char *s2);
> +const char *strcmp_prefix(const char *str, const char *prefix);
>  
>  char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints);
>  
> -- 
> 2.25.1

-- 

- Arnaldo