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From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Jessica Yu <jeyu@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
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Subject: Re: [PATCH v3] sscanf: implement basic character sets
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	<87bn77gi34.fsf@rasmusvillemoes.dk>
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Date: Wed, 24 Feb 2016 01:01:57 +0100
In-Reply-To: <87bn77gi34.fsf@rasmusvillemoes.dk> (Rasmus Villemoes's message
	of "Tue, 23 Feb 2016 23:47:11 +0100")
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On Tue, Feb 23 2016, Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:

> On that note, it seems that your field width handling is off-by-one.

Sorry about that, it's me who's off-by-one.

Rasmus


> To get rid of the allocation, why not use a small bitmap? Something like
>
> {
>   char *s = (char *)va_arg(args, char *);
>   DECLARE_BITMAP(map, 256) = {0};
>   bool negate = false;
>
>   /* a field width is required, and must provide room for at least a '\0' */
>   if (field_width <= 0)
>     return num;
>

should be

/* a field width is required */
if (field_width < 0)

and

>   while (test_bit((u8)*str, map) && --field_width) {

should be field_width--, exactly as in your code.