Re: [RFC] [Patch 2/8] statistics infrastructure - prerequisite: parser enhancement

[Andrew Morton <akpm@osdl.org>]

Martin Peschke <mp3@de.ibm.com> wrote:
>
> This patch adds two match_* derivates for 64 bit operands to the parser
> library.
> 
>   void match_strcpy(char *, substring_t *);
>   char *match_strdup(substring_t *);
> +int match_u64(substring_t *, u64 *result, int);
> +int match_s64(substring_t *, s64 *result, int);

Your email client does space-stuffing, so this won't apply (ok, it might
apply if my email client knew how to space-unstuff, but it doesn't).

> diff -Nurp a/lib/parser.c b/lib/parser.c
> --- a/lib/parser.c	2006-03-20 06:53:29.000000000 +0100
> +++ b/lib/parser.c	2006-05-15 17:56:25.000000000 +0200
> @@ -140,6 +140,64 @@ static int match_number(substring_t *s,
>   }
> 
>   /**
> + * match_u64: scan a number in the given base from a substring_t
> + * @s: substring to be scanned
> + * @result: resulting integer on success
> + * @base: base to use when converting string
> + *
> + * Description: Given a &substring_t and a base, attempts to parse the substring
> + * as a number in that base. On success, sets @result to the u64 represented
> + * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
> + */
> +int match_u64(substring_t *s, u64 *result, int base)
> +{
> +	char *endp;
> +	char *buf;
> +	int ret;
> +
> +	buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +	memcpy(buf, s->from, s->to - s->from);
> +	buf[s->to - s->from] = '\0';
> +	*result = simple_strtoull(buf, &endp, base);
> +	ret = 0;
> +	if (endp == buf)
> +		ret = -EINVAL;
> +	kfree(buf);
> +	return ret;
> +}
> +
> +/**
> + * match_s64: scan a number in the given base from a substring_t
> + * @s: substring to be scanned
> + * @result: resulting integer on success
> + * @base: base to use when converting string
> + *
> + * Description: Given a &substring_t and a base, attempts to parse the substring
> + * as a number in that base. On success, sets @result to the s64 represented
> + * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
> + */
> +int match_s64(substring_t *s, s64 *result, int base)
> +{
> +	char *endp;
> +	char *buf;
> +	int ret;
> +
> +	buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +	memcpy(buf, s->from, s->to - s->from);
> +	buf[s->to - s->from] = '\0';
> +	*result = simple_strtoll(buf, &endp, base);
> +	ret = 0;
> +	if (endp == buf)
> +		ret = -EINVAL;
> +	kfree(buf);
> +	return ret;
> +}

These are identical.  If we _really_ need one for signed and one for
unsigned then we could at least do

match_s64(..., s64 *result, ...)
{
	return match_u64(..., (u64 *)result, ...);
}

That's if we do need one for signed and one for unsigned..