utils: provide size_to_str()

Moving the algorithm from print_type_size() into size_to_str() so that
other component can also leverage it. With that, refactor
print_type_size().

The assert() in that logic is removed though, since even UINT64_MAX
would not overflow.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1494562661-9063-3-git-send-email-peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Peter Xu 2017-05-12 12:17:40 +08:00 committed by Dr. David Alan Gilbert
parent 99e15582de
commit 22951aaaeb
3 changed files with 32 additions and 16 deletions

View file

@ -619,3 +619,28 @@ const char *qemu_ether_ntoa(const MACAddr *mac)
return ret;
}
/*
* Return human readable string for size @val.
* @val can be anything that uint64_t allows (no more than "16 EiB").
* Use IEC binary units like KiB, MiB, and so forth.
* Caller is responsible for passing it to g_free().
*/
char *size_to_str(uint64_t val)
{
static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
unsigned long div;
int i;
/*
* The exponent (returned in i) minus one gives us
* floor(log2(val * 1024 / 1000). The correction makes us
* switch to the higher power when the integer part is >= 1000.
* (see e41b509d68afb1f for more info)
*/
frexp(val / (1000.0 / 1024.0), &i);
i = (i - 1) / 10;
div = 1ULL << (i * 10);
return g_strdup_printf("%0.3g %sB", (double)val / div, suffixes[i]);
}