Re: [PATCH] Re: sscanf("-1", "%d", &i) fails, returns 0

[Richard B. Johnson]

On Fri, 8 Nov 2002, Randy.Dunlap wrote:

> On Fri, 8 Nov 2002, Richard B. Johnson wrote:
> 
> | On Fri, 8 Nov 2002, Randy.Dunlap wrote:
> |
> | > On Sat, 9 Nov 2002, Douglas Gilbert wrote:
> | >
> | > | In lk 2.5.46-bk3 the expression in the subject line
> | > | fails to write into "i" and returns 0. Drop the minus
> | > | sign and it works.
> | >
> | > Here's an unobstrusive patch to correct that.
> | > Please apply.
> | >
> | > --
> | > ~Randy
> | > -
> |
> | I was thinking that if anybody ever had to change any of this
> | stuff, it might be a good idea to do the indirection only once?
> | All those "splats" over and over again are costly.
> 
> Sure, it looks cleaner that way, although gcc has already put <*dig>
> in a local register; i.e., it's not pulled from memory for each test.
> Here's a (tested) version that does that.
> 
> -- 
> ~Randy
> 
> 
> 
> --- ./lib/vsprintf.c%signed	Mon Nov  4 14:30:49 2002
> +++ ./lib/vsprintf.c	Fri Nov  8 12:03:15 2002
> @@ -517,6 +517,7 @@
>  {
>  	const char *str = buf;
>  	char *next;
> +	char *dig, onedig;
>  	int num = 0;
>  	int qualifier;
>  	int base;
> @@ -638,12 +639,14 @@
>  		while (isspace(*str))
>  			str++;
> 
> -		if (!*str
> -                    || (base == 16 && !isxdigit(*str))
> -                    || (base == 10 && !isdigit(*str))
> -                    || (base == 8 && (!isdigit(*str) || *str > '7'))
> -                    || (base == 0 && !isdigit(*str)))
> -			break;
> +		dig = (*str == '-') ? (str + 1) : str;
> +		onedig = *dig;
> +		if (!onedig
> +                    || (base == 16 && !isxdigit(onedig))
> +                    || (base == 10 && !isdigit(onedig))
> +                    || (base == 8 && (!isdigit(onedig) || onedig > '7'))
> +                    || (base == 0 && !isdigit(onedig)))
> +				break;
> 
>  		switch(qualifier) {
>  		case 'h':
> 

I like it much better.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
   Bush : The Fourth Reich of America