Hi Philippe,
On 11:08 Sun 27 Sep , Philippe Mathieu-Daudé wrote:
> Introduce freq_to_str() to convert frequency values in human
> friendly units using the SI units for Hertz.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> ---
> include/qemu/cutils.h | 12 ++++++++++++
> util/cutils.c | 10 ++++++++++
> 2 files changed, 22 insertions(+)
>
> diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
> index eb59852dfdf..0186c846e9c 100644
> --- a/include/qemu/cutils.h
> +++ b/include/qemu/cutils.h
> @@ -158,6 +158,18 @@ int qemu_strtosz_metric(const char *nptr, const char
> **end, uint64_t *result);
>
> char *size_to_str(uint64_t val);
>
> +/**
> + * freq_to_str:
> + * @freq_hz: frequency to stringify
> + *
> + * Return human readable string for frequency @freq_hz.
> + * Use SI units like KHz, MHz, and so forth.
> + *
> + * The caller is responsible for releasing the value returned with g_free()
> + * after use.
> + */
> +char *freq_to_str(uint64_t freq_hz);
> +
> /* used to print char* safely */
> #define STR_OR_NULL(str) ((str) ? (str) : "null")
>
> diff --git a/util/cutils.c b/util/cutils.c
> index 36ce712271f..dab837fd8b8 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -885,6 +885,16 @@ char *size_to_str(uint64_t val)
> return g_strdup_printf("%0.3g %sB", (double)val / div, suffixes[i]);
> }
>
> +char *freq_to_str(uint64_t freq_hz)
> +{
> + static const char *suffixes[] = { "", "K", "M", "G", "T", "P", "E" };
> + unsigned unit_index = log10(freq_hz) / 3;
> +
> + return g_strdup_printf("%0.3g %sHz",
> + freq_hz / pow(10.0, unit_index * 3.0),
> + suffixes[unit_index]);
You could end up going out of your 'suffixes' array if freq_hz is very
high. Also, to avoid the complexity of log10/pow, maybe something like:
double freq = freq_hz;
size_t idx = 0;
while (freq >= 1000.0 && idx < ARRAY_LENGTH(suffixes)) {
freq /= 1000.0;
idx++;
}
return g_strdup_printf("%0.3g %sHz", freq, suffixes[idx]);
is enough?
--
Luc
> +}
> +
> int qemu_pstrcmp0(const char **str1, const char **str2)
> {
> return g_strcmp0(*str1, *str2);
> --
> 2.26.2
>
