| Message ID | 20200927090820.61859-2-f4bug@amsat.org |
|---|---|
| State | New |
| Headers | show |
| Series | qdev-clock: Minor improvements to the Clock API | expand |
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 <f4bug@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 >
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]); +} + int qemu_pstrcmp0(const char **str1, const char **str2) { return g_strcmp0(*str1, *str2);
Introduce freq_to_str() to convert frequency values in human friendly units using the SI units for Hertz. Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- include/qemu/cutils.h | 12 ++++++++++++ util/cutils.c | 10 ++++++++++ 2 files changed, 22 insertions(+)