busybox/libbb/human_readable.c
Kevin Cernekee ccb070450e fdisk: initial stab at GPT partition support
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2010-10-25 02:00:24 +02:00

198 lines
5.2 KiB
C

/* vi: set sw=4 ts=4: */
/*
* 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 always 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.
*
* It might be nice to add a flag to indicate no decimal digits in
* that case. This could be either an additional parameter, or a
* special value of display_unit. Such a flag would also be nice for du.
*
* Some code to omit the decimal point and tenths digit is sketched out
* and "#if 0"'d below.
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include "libbb.h"
const char* FAST_FUNC make_human_readable_str(unsigned long long val,
unsigned long block_size, unsigned long display_unit)
{
static const char unit_chars[] ALIGN1 = {
'\0', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
};
static char *str;
unsigned frac; /* 0..9 - the fractional digit */
const char *u;
const char *fmt;
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
}
if (!str) {
/* sufficient for any width of val */
str = xmalloc(sizeof(val)*3 + 2 + 3);
}
sprintf(str, fmt, val, frac, *u);
return str;
}
/* vda's implementations of the similar idea */
/* Convert unsigned long long value into compact 5-char representation.
* String is not terminated (buf[5] is untouched) */
void FAST_FUNC smart_ulltoa5(unsigned long long ul, char buf[5], const char *scale)
{
const char *fmt;
char c;
unsigned v, u, idx = 0;
if (ul > 99999) { // do not scale if 99999 or less
ul *= 10;
do {
ul /= 1024;
idx++;
} while (ul >= 100000);
}
v = ul; // ullong divisions are expensive, avoid them
fmt = " 123456789";
u = v / 10;
v = v % 10;
if (!idx) {
// 99999 or less: use "12345" format
// u is value/10, v is last digit
c = buf[0] = " 123456789"[u/1000];
if (c != ' ') fmt = "0123456789";
c = buf[1] = fmt[u/100%10];
if (c != ' ') fmt = "0123456789";
c = buf[2] = fmt[u/10%10];
if (c != ' ') fmt = "0123456789";
buf[3] = fmt[u%10];
buf[4] = "0123456789"[v];
} else {
// value has been scaled into 0..9999.9 range
// u is value, v is 1/10ths (allows for 92.1M format)
if (u >= 100) {
// value is >= 100: use "1234M', " 123M" formats
c = buf[0] = " 123456789"[u/1000];
if (c != ' ') fmt = "0123456789";
c = buf[1] = fmt[u/100%10];
if (c != ' ') fmt = "0123456789";
v = u % 10;
u = u / 10;
buf[2] = fmt[u%10];
} else {
// value is < 100: use "92.1M" format
c = buf[0] = " 123456789"[u/10];
if (c != ' ') fmt = "0123456789";
buf[1] = fmt[u%10];
buf[2] = '.';
}
buf[3] = "0123456789"[v];
buf[4] = scale[idx]; /* typically scale = " kmgt..." */
}
}
/* Convert unsigned long long value into compact 4-char
* representation. Examples: "1234", "1.2k", " 27M", "123T"
* String is not terminated (buf[4] is untouched) */
void FAST_FUNC smart_ulltoa4(unsigned long long ul, char buf[4], const char *scale)
{
const char *fmt;
char c;
unsigned v, u, idx = 0;
if (ul > 9999) { // do not scale if 9999 or less
ul *= 10;
do {
ul /= 1024;
idx++;
} while (ul >= 10000);
}
v = ul; // ullong divisions are expensive, avoid them
fmt = " 123456789";
u = v / 10;
v = v % 10;
if (!idx) {
// 9999 or less: use "1234" format
// u is value/10, v is last digit
c = buf[0] = " 123456789"[u/100];
if (c != ' ') fmt = "0123456789";
c = buf[1] = fmt[u/10%10];
if (c != ' ') fmt = "0123456789";
buf[2] = fmt[u%10];
buf[3] = "0123456789"[v];
} else {
// u is value, v is 1/10ths (allows for 9.2M format)
if (u >= 10) {
// value is >= 10: use "123M', " 12M" formats
c = buf[0] = " 123456789"[u/100];
if (c != ' ') fmt = "0123456789";
v = u % 10;
u = u / 10;
buf[1] = fmt[u%10];
} else {
// value is < 10: use "9.2M" format
buf[0] = "0123456789"[u];
buf[1] = '.';
}
buf[2] = "0123456789"[v];
buf[3] = scale[idx]; /* typically scale = " kmgt..." */
}
}