Re: [Libguestfs] [PATCH nbdinfo v2 1/3] common/utils: Add function to convert sizes to human-readable

On Mon, Sep 20, 2021 at 06:25:34PM +0200, Laszlo Ersek wrote: > On 09/20/21 13:04, Richard W.M. Jones wrote:

>> +/* If you allocate a buffer of at least this length in bytes and pass >> + * it as the first parameter to human_size, then it will not overrun. >> + */ >> +#define HUMAN_SIZE_LONGEST 64 > > (5) The integer constant expression > > ((sizeof (uint64_t) * 8 + 2) / 3 + 1) > > would be more frugal (but we might not care). > > If we take the number of three-bit groups in the word, and divide that > by three -- rounded up --, we get the number of necessary octal digits. > The number of decimal digits needed never exceeds the number of octal > digits needed, so this is safe. Add one character for the NUL terminator.) Yeah I was just guessing here. FWIW gnulib really does the hard work: https://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/human.h;h=...