[PATCH] Allow a hyphenated range in get_options, with cleanup

[PATCH] Allow a hyphenated range in get_options, with cleanup

[Derek Fults]

This allows a hyphenated range of positive numbers in the string passed
to command line helper function, get_options.    
Currently the command line option "isolcpus=" takes as its argument a
list of cpus.  
Format: <cpu number>,...,<cpu number>
This can get extremely long when isolating the majority of cpus on a
large system.  Valid values of <cpu_number>  include all cpus, 0 to
"number of CPUs in system - 1".


Signed-off-by: Derek Fults <dfults@sgi.com>  

Index: linux/lib/cmdline.c
===================================================================
--- linux.orig/lib/cmdline.c	2006-09-19 22:42:06.000000000 -0500
+++ linux/lib/cmdline.c	2006-10-31 14:57:25.553572860 -0600
@@ -29,6 +29,7 @@
  *	0 : no int in string
  *	1 : int found, no subsequent comma
  *	2 : int found including a subsequent comma
+ *  -(int): int found with a subsequent hyphen to denote a range.
  */
 
 int get_option (char **str, int *pint)
@@ -44,7 +45,16 @@
 		(*str)++;
 		return 2;
 	}
+	if (**str == '-') {
+		int x, inc_counter= 0, upper_range = 0;
 
+		(*str)++;
+		upper_range = simple_strtol((*str), NULL, 0);
+		inc_counter = upper_range - *pint;
+		for (x =*pint; x < upper_range; x++)
+			*pint++ = x;
+		return -inc_counter;
+	}
 	return 1;
 }
 
@@ -55,7 +65,8 @@
  *	@ints: integer array
  *
  *	This function parses a string containing a comma-separated
- *	list of integers.  The parse halts when the array is
+ *	list of integers, a hyphen-separated range of _positive_ integers,
+ *	or a combination of both.  The parse halts when the array is
  *	full, or when no more numbers can be retrieved from the
  *	string.
  *
@@ -75,6 +86,11 @@
 		i++;
 		if (res == 1)
 			break;
+		if (res < 0)
+			/* Decrement the result by one to leave out the
+			   last number in the range.  The next iteration
+			   will handle the upper number in the range */
+			i += ((-res) - 1);
 	}
 	ints[0] = i - 1;
 	return (char *)str;

Re: [PATCH] Allow a hyphenated range in get_options, with cleanup

[Randy Dunlap]

On Tue, 31 Oct 2006 15:07:03 -0600 Derek Fults wrote:

> This allows a hyphenated range of positive numbers in the string passed
> to command line helper function, get_options.    
> Currently the command line option "isolcpus=" takes as its argument a
> list of cpus.  
> Format: <cpu number>,...,<cpu number>
> This can get extremely long when isolating the majority of cpus on a
> large system.  Valid values of <cpu_number>  include all cpus, 0 to
> "number of CPUs in system - 1".
> 
> 
> Signed-off-by: Derek Fults <dfults@sgi.com>  
> 
> Index: linux/lib/cmdline.c
> ===================================================================
> --- linux.orig/lib/cmdline.c	2006-09-19 22:42:06.000000000 -0500
> +++ linux/lib/cmdline.c	2006-10-31 14:57:25.553572860 -0600
> @@ -29,6 +29,7 @@
>   *	0 : no int in string
>   *	1 : int found, no subsequent comma
>   *	2 : int found including a subsequent comma
> + *  -(int): int found with a subsequent hyphen to denote a range.

Does the returned value matter?  Is it used later?  (it appears to be)

If not, I think that we would rather reserved negative return
values to indicate errors.

Or if so, the comment should say what property the negative value
has.

>   */
>  
>  int get_option (char **str, int *pint)
> @@ -44,7 +45,16 @@
>  		(*str)++;
>  		return 2;
>  	}
> +	if (**str == '-') {
> +		int x, inc_counter= 0, upper_range = 0;

space after '='

>  
> +		(*str)++;
> +		upper_range = simple_strtol((*str), NULL, 0);
> +		inc_counter = upper_range - *pint;
> +		for (x =*pint; x < upper_range; x++)

space after '='

> +			*pint++ = x;
> +		return -inc_counter;
> +	}
>  	return 1;
>  }
>  
> @@ -55,7 +65,8 @@
>   *	@ints: integer array
>   *
>   *	This function parses a string containing a comma-separated
> - *	list of integers.  The parse halts when the array is
> + *	list of integers, a hyphen-separated range of _positive_ integers,
> + *	or a combination of both.  The parse halts when the array is
>   *	full, or when no more numbers can be retrieved from the
>   *	string.
>   *
> @@ -75,6 +86,11 @@
>  		i++;
>  		if (res == 1)
>  			break;
> +		if (res < 0)
> +			/* Decrement the result by one to leave out the
> +			   last number in the range.  The next iteration
> +			   will handle the upper number in the range */
> +			i += ((-res) - 1);
>  	}
>  	ints[0] = i - 1;
>  	return (char *)str;
> -

---
~Randy

Re: [PATCH] Allow a hyphenated range in get_options, with cleanup

[Andi Kleen]

Derek Fults <dfults@sgi.com> writes:

> This allows a hyphenated range of positive numbers in the string passed
> to command line helper function, get_options.    
> Currently the command line option "isolcpus=" takes as its argument a
> list of cpus.  
> Format: <cpu number>,...,<cpu number>
> This can get extremely long when isolating the majority of cpus on a
> large system.  Valid values of <cpu_number>  include all cpus, 0 to
> "number of CPUs in system - 1".

It would be better if you defined a separate function for this
instead of defining such a weird calling convention.

The common code with get_options could be factored out into a helper.

-Andi