2 * June 30, 2001 Manuel Novoa III
4 * All-integer version (hey, not everyone has floating point) of
5 * make_human_readable_str, modified from similar code I had written
6 * for busybox several months ago.
9 * 1) I'm using an unsigned long long to hold the product size * block_size,
10 * as df (which calls this routine) could request a representation of a
11 * partition size in bytes > max of unsigned long. If long longs aren't
12 * available, it would be possible to do what's needed using polynomial
13 * representations (say, powers of 1024) and manipulating coefficients.
14 * The base ten "bytes" output could be handled similarly.
16 * 2) The output of "ls -sh" can be misaligned because this routine always
17 * outputs a decimal point and a tenths digit when display_unit != 0.
18 * Hence, it isn't uncommon for the returned string to have a length
19 * of 5 or 6 instead of <= 4 (as assumed).
21 * It might be nice to add a flag to indicate no decimal digits in
22 * that case. This could be either an additional parameter, or a
23 * special value of display_unit. Such a flag would also be nice for du.
25 * Some code to omit the decimal point and tenths digit is sketched out
26 * and "#if 0"'d below.
32 const char *make_human_readable_str(unsigned long size,
33 unsigned long block_size,
34 unsigned long display_unit)
36 /* The code will adjust for additional (appended) units. */
37 static const char zero_and_units[] = { '0', 0, 'k', 'M', 'G', 'T' };
38 static const char fmt[] = "%Lu";
39 static const char fmt_tenths[] = "%Lu.%d%c";
41 static char str[21]; /* Sufficient for 64 bit unsigned integers. */
43 unsigned long long val;
52 val = ((unsigned long long) size) * block_size;
58 val += display_unit/2; /* Deal with rounding. */
59 val /= display_unit; /* Don't combine with the line above!!! */
62 while ((val >= KILOBYTE)
63 && (u < zero_and_units + sizeof(zero_and_units) - 1)) {
66 frac = ((((int)(val % KILOBYTE)) * 10) + (KILOBYTE/2)) / KILOBYTE;
69 if (frac >= 10) { /* We need to round up here. */
74 /* Sample code to omit decimal point and tenths digit. */
75 if ( /* no_tenths */ 1 ) {
79 f = "%Lu%*c" /* fmt_no_tenths */ ;
85 /* If f==fmt then 'frac' and 'u' are ignored. */
86 snprintf(str, sizeof(str), f, val, frac, *u);