OpenBSD-4.6/lib/libutil/fmt_scaled.c
/* $OpenBSD: fmt_scaled.c,v 1.10 2009/06/20 15:00:04 martynas Exp $ */
/*
* Copyright (c) 2001, 2002, 2003 Ian F. Darwin. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* fmt_scaled: Format numbers scaled for human comprehension
* scan_scaled: Scan numbers in this format.
*
* "Human-readable" output uses 4 digits max, and puts a unit suffix at
* the end. Makes output compact and easy-to-read esp. on huge disks.
* Formatting code was originally in OpenBSD "df", converted to library routine.
* Scanning code written for OpenBSD libutil.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include "util.h"
typedef enum {
NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
} unit_type;
/* These three arrays MUST be in sync! XXX make a struct */
static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
static char scale_chars[] = "BKMGTPE";
static long long scale_factors[] = {
1LL,
1024LL,
1024LL*1024,
1024LL*1024*1024,
1024LL*1024*1024*1024,
1024LL*1024*1024*1024*1024,
1024LL*1024*1024*1024*1024*1024,
};
#define SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
#define MAX_DIGITS (SCALE_LENGTH * 3) /* XXX strlen(sprintf("%lld", -1)? */
/* Convert the given input string "scaled" into numeric in "result".
* Return 0 on success, -1 and errno set on error.
*/
int
scan_scaled(char *scaled, long long *result)
{
char *p = scaled;
int sign = 0;
unsigned int i, ndigits = 0, fract_digits = 0;
long long scale_fact = 1, whole = 0, fpart = 0;
/* Skip leading whitespace */
while (isascii(*p) && isspace(*p))
++p;
/* Then at most one leading + or - */
while (*p == '-' || *p == '+') {
if (*p == '-') {
if (sign) {
errno = EINVAL;
return -1;
}
sign = -1;
++p;
} else if (*p == '+') {
if (sign) {
errno = EINVAL;
return -1;
}
sign = +1;
++p;
}
}
/* Main loop: Scan digits, find decimal point, if present.
* We don't allow exponentials, so no scientific notation
* (but note that E for Exa might look like e to some!).
* Advance 'p' to end, to get scale factor.
*/
for (; isascii(*p) && (isdigit(*p) || *p=='.'); ++p) {
if (*p == '.') {
if (fract_digits > 0) { /* oops, more than one '.' */
errno = EINVAL;
return -1;
}
fract_digits = 1;
continue;
}
i = (*p) - '0'; /* whew! finally a digit we can use */
if (fract_digits > 0) {
if (fract_digits >= MAX_DIGITS-1)
/* ignore extra fractional digits */
continue;
fract_digits++; /* for later scaling */
fpart *= 10;
fpart += i;
} else { /* normal digit */
if (++ndigits >= MAX_DIGITS) {
errno = ERANGE;
return -1;
}
whole *= 10;
whole += i;
}
}
if (sign) {
whole *= sign;
fpart *= sign;
}
/* If no scale factor given, we're done. fraction is discarded. */
if (!*p) {
*result = whole;
return 0;
}
/* Validate scale factor, and scale whole and fraction by it. */
for (i = 0; i < SCALE_LENGTH; i++) {
/* Are we there yet? */
if (*p == scale_chars[i] ||
*p == tolower(scale_chars[i])) {
/* If it ends with alphanumerics after the scale char, bad. */
if (isalnum(*(p+1))) {
errno = EINVAL;
return -1;
}
scale_fact = scale_factors[i];
/* scale whole part */
whole *= scale_fact;
/* truncate fpart so it does't overflow.
* then scale fractional part.
*/
while (fpart >= LLONG_MAX / scale_fact) {
fpart /= 10;
fract_digits--;
}
fpart *= scale_fact;
if (fract_digits > 0) {
for (i = 0; i < fract_digits -1; i++)
fpart /= 10;
}
whole += fpart;
*result = whole;
return 0;
}
}
errno = ERANGE;
return -1;
}
/* Format the given "number" into human-readable form in "result".
* Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
* Return 0 on success, -1 and errno set if error.
*/
int
fmt_scaled(long long number, char *result)
{
long long abval, fract = 0;
unsigned int i;
unit_type unit = NONE;
abval = llabs(number);
/* Not every negative long long has a positive representation.
* Also check for numbers that are just too darned big to format
*/
if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
errno = ERANGE;
return -1;
}
/* scale whole part; get unscaled fraction */
for (i = 0; i < SCALE_LENGTH; i++) {
if (abval/1024 < scale_factors[i]) {
unit = units[i];
fract = (i == 0) ? 0 : abval % scale_factors[i];
number /= scale_factors[i];
if (i > 0)
fract /= scale_factors[i - 1];
break;
}
}
fract = (10 * fract + 512) / 1024;
/* if the result would be >= 10, round main number */
if (fract == 10) {
if (number >= 0)
number++;
else
number--;
fract = 0;
}
if (number == 0)
strlcpy(result, "0B", FMT_SCALED_STRSIZE);
else if (unit == NONE || number >= 100 || number <= -100) {
if (fract >= 5) {
if (number >= 0)
number++;
else
number--;
}
(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
number, scale_chars[unit]);
} else
(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
number, fract, scale_chars[unit]);
return 0;
}
#ifdef MAIN
/*
* This is the original version of the program in the man page.
* Copy-and-paste whatever you need from it.
*/
int
main(int argc, char **argv)
{
char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
long long ninput = 10483892, result;
if (scan_scaled(cinput, &result) == 0)
printf("\"%s\" -> %lld\n", cinput, result);
else
perror(cinput);
if (fmt_scaled(ninput, buf) == 0)
printf("%lld -> \"%s\"\n", ninput, buf);
else
fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
return 0;
}
#endif