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/*
* June 30, 2001 Manuel Novoa III
*
* All-integer version (hey, not everyone has floating point) of
* make_human_readable_str, modified from similar code I had written
* for busybox several months ago.
*
* Notes:
* 1) I'm using an unsigned long long to hold the product size * block_size,
* as df (which calls this routine) could request a representation of a
* partition size in bytes > max of unsigned long. If long longs aren't
* available, it would be possible to do what's needed using polynomial
* representations (say, powers of 1024) and manipulating coefficients.
* The base ten "bytes" output could be handled similarly.
*
* 2) This routine outputs a decimal point and a tenths digit when
* display_unit == 0. Hence, it isn't uncommon for the returned string
* to have a length of 5 or 6.
*
* If block_size is also 0, no decimal digits are printed.
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include <stdio.h>
enum {
KILOBYTE = 1024,
MEGABYTE = (KILOBYTE*1024),
GIGABYTE = (MEGABYTE*1024)
};
static const char *
make_human_readable_str(unsigned long long val,
unsigned long block_size, unsigned long display_unit)
{
static const char unit_chars[] = {
'\0', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
};
unsigned frac; /* 0..9 - the fractional digit */
const char *u;
const char *fmt;
static char str[21]; /* Sufficient for 64 bit unsigned integers. */
if (val == 0)
return "0";
fmt = "%llu";
if (block_size > 1)
val *= block_size;
frac = 0;
u = unit_chars;
if (display_unit) {
val += display_unit/2; /* Deal with rounding */
val /= display_unit; /* Don't combine with the line above! */
/* will just print it as ulonglong (below) */
} else {
while ((val >= 1024)
/* && (u < unit_chars + sizeof(unit_chars) - 1) - always true */
) {
fmt = "%llu.%u%c";
u++;
frac = (((unsigned)val % 1024) * 10 + 1024/2) / 1024;
val /= 1024;
}
if (frac >= 10) { /* we need to round up here */
++val;
frac = 0;
}
#if 1
/* If block_size is 0, dont print fractional part */
if (block_size == 0) {
if (frac >= 5) {
++val;
}
fmt = "%llu%*c";
frac = 1;
}
#endif
}
snprintf(str, sizeof(str), fmt, val, frac, *u);
return str;
}
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