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) This routine always outputs a decimal point and a tenths digit when
17 * display_unit != 0. Hence, it isn't uncommon for the returned string
18 * to have a length of 5 or 6.
20 * It might be nice to add a flag to indicate no decimal digits in
21 * that case. This could be either an additional parameter, or a
22 * special value of display_unit. Such a flag would also be nice for du.
24 * Some code to omit the decimal point and tenths digit is sketched out
25 * and "#if 0"'d below.
31 const char *make_human_readable_str(unsigned long size,
32 unsigned long block_size,
33 unsigned long display_unit)
35 /* The code will adjust for additional (appended) units. */
36 static const char zero_and_units[] = { '0', 0, 'k', 'M', 'G', 'T' };
37 static const char fmt[] = "%Lu";
38 static const char fmt_tenths[] = "%Lu.%d%c";
40 static char str[21]; /* Sufficient for 64 bit unsigned integers. */
42 unsigned long long val;
51 val = ((unsigned long long) size) * block_size;
57 val += display_unit/2; /* Deal with rounding. */
58 val /= display_unit; /* Don't combine with the line above!!! */
61 while ((val >= KILOBYTE)
62 && (u < zero_and_units + sizeof(zero_and_units) - 1)) {
65 frac = ((((int)(val % KILOBYTE)) * 10) + (KILOBYTE/2)) / KILOBYTE;
68 if (frac >= 10) { /* We need to round up here. */
73 /* Sample code to omit decimal point and tenths digit. */
74 if ( /* no_tenths */ 1 ) {
78 f = "%Lu%*c" /* fmt_no_tenths */ ;
84 /* If f==fmt then 'frac' and 'u' are ignored. */
85 snprintf(str, sizeof(str), f, val, frac, *u);