|
|
- /* $OpenBSD: fmt_scaled.c,v 1.12 2013/11/29 19:00:51 deraadt 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((unsigned char)*p) && isspace((unsigned char)*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((unsigned char)*p) &&
- (isdigit((unsigned char)*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((unsigned char)scale_chars[i])) {
-
- /* If it ends with alphanumerics after the scale char, bad. */
- if (isalnum((unsigned char)*(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;
- }
- }
-
- /* Invalid unit or character */
- errno = EINVAL;
- 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
|