I stole the algorithm from print_type_size(). I didn't generalize it since that's using [KM...]iB while here we need [KM...]B to finally be able to stands for page sizes (and even more general).
Signed-off-by: Peter Xu <pet...@redhat.com> --- include/qemu-common.h | 1 + util/cutils.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/include/qemu-common.h b/include/qemu-common.h index d218821..d7d0448 100644 --- a/include/qemu-common.h +++ b/include/qemu-common.h @@ -145,6 +145,7 @@ void qemu_hexdump(const char *buf, FILE *fp, const char *prefix, size_t size); int parse_debug_env(const char *name, int max, int initial); const char *qemu_ether_ntoa(const MACAddr *mac); +char *size_to_str(double val); void page_size_init(void); /* returns non-zero if dump is in progress, otherwise zero is diff --git a/util/cutils.c b/util/cutils.c index 50ad179..5aaf370 100644 --- a/util/cutils.c +++ b/util/cutils.c @@ -619,3 +619,29 @@ const char *qemu_ether_ntoa(const MACAddr *mac) return ret; } + +/* + * Sample output: + * + * 1 -> "1 B" + * 528 -> "0.516 KB" + * 4096 -> "4 KB" + * 2402958 -> "2.29 MB" + * 1073741824 -> "1 GB" + * + * Please free the buffer after use. + */ +char *size_to_str(double val) +{ + static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' }; + unsigned long div; + int i; + + frexp(val, &i); + i /= 10; + assert(i < sizeof(suffixes)); + div = 1ULL << (i * 10); + + return g_strdup_printf("%0.3g %c%s", val / div, + suffixes[i], i ? "B" : ""); +} -- 2.7.4