Hello Jean-Christophe,
On Thu, Sep 02, 2010 at 04:10:20PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> Show a '%w' or %W thing.
> This will show a frequency or byte at format xxx[.xxx] [ kMG]
> the precision can not excess the base kMG of the current unit
> otherwise it will be automatically reduce
> if no precision is specified and there is rest we will use a default
> precision of 3 as 66.667 M
> base will be typically 1000 for Hz or B and 1024 for iB
I see this used e.g. as:
printk("%WiB", somevalue)
right? hmm, what if somevalue is say 5? If I understand correctly the
output then is: "5 iB".
>
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@xxxxxxxxxxxx>
> ---
> include/linux/kernel.h | 20 +++++++++++++
> lib/vsprintf.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 93 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index e9e2f07..b605946 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -5,6 +5,26 @@
> #include <linux/barebox-wrapper.h>
>
> /*
> + * This looks more complex than it should be. But we need to
> + * get the type for the ~ right in round_down (it needs to be
> + * as wide as the result!), and we want to evaluate the macro
> + * arguments just once each.
> + */
> +#define __round_mask(x, y) ((__typeof__(x))((y)-1))
> +#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
> +#define round_down(x, y) ((x) & ~__round_mask(x, y))
> +
> +#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
> +#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
> +#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
> +#define DIV_ROUND_CLOSEST(x, divisor)( \
> +{ \
> + typeof(divisor) __divisor = divisor; \
> + (((x) + ((__divisor) / 2)) / (__divisor)); \
> +} \
> +)
> +
> +/*
> * min()/max()/clamp() macros that also do
> * strict type-checking.. See the
> * "unnecessary" pointer comparison.
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 6066845..add8bd5 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -254,6 +254,71 @@ static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int
> }
>
> /*
> + * Show a '%w' or %W thing. This will show a frequency or byte
> + * at format xxx[.xxx] [ kMG]
> + * the precision can not excess the base kMG of the current unit
> + * otherwise it will be automatically reduce
> + * if no precision is specified and there is rest we will use a default
> + * precision of 3 as 66.667 M
> + * base will be typically 1000 for Hz or B and 1024 for iB
> + */
> +static char *unit_string(char *buf, char *end, long val, int base, int field_width, int precision, int flags)
> +{
> + long rest = 0;
> + long integer;
> + long pr = 3;
> + long pr_mul = 1;
> + long unit = 1;
> + char format[] = " kMG";
> + int pow, i;
> +
> + for (pow = 0; pow < strlen(format) - 1; pow++) {
> + if (val < unit * base)
> + break;
> + unit *= base;
> + }
> +
> + integer = val / unit;
> +
> + if (precision != -1) {
> + if (precision > pow * 3)
> + precision = pow * 3;
> + pr = precision;
> + }
> +
> + for (i = 0; i < pr; i++) {
> + pr_mul *= 10;
> + }
> +
> + if (val % unit) {
> + rest = DIV_ROUND_CLOSEST(pr_mul * (val - (integer * unit)), unit);
> +
> + if (rest >= pr_mul) {
> + rest -= pr_mul;
> + integer++;
> + }
> + }
> +
> + buf = number(buf, end, integer, 10, field_width, -1, 0);
> +
> + if (rest != 0 || precision != -1) {
> + if (buf < end)
> + *buf = '.';
> + buf++;
> + buf = number(buf, end, rest, 10, -1, pr, 0);
> + }
> +
> + if (buf < end)
> + *buf = ' ';
> + buf++;
> + if (buf < end && pow != 0)
> + *buf = format[pow];
> + buf++;
> +
> + return buf;
> +}
> +
> +/*
> * Show a '%p' thing. A kernel extension is that the '%p' is followed
> * by an extra set of alphanumeric characters that are extended format
> * specifiers.
I think the kernel documents all available formats in a single place.
(Is that here in barebox? If yes, please add your new formats here,
too.)
> @@ -421,6 +486,14 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
> str = string(str, end, va_arg(args, char *), field_width, precision, flags);
> continue;
>
> + case 'W':
> + str = unit_string(str, end, va_arg(args, long), 1024, field_width, precision, flags);
> + continue;
> +
> + case 'w':
> + str = unit_string(str, end, va_arg(args, long), 1000, field_width, precision, flags);
> + continue;
> +
> case 'p':
> str = pointer(fmt+1, str, end,
> va_arg(args, void *),
> --
> 1.7.1
>
>
> _______________________________________________
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> http://lists.infradead.org/mailman/listinfo/barebox
>
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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