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+/* $OpenBSD: fmt_scaled.c,v 1.21 2022/03/11 07:29:53 dtucker 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.
+ */
+
+/* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */
+
+/*
+ * 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 "includes.h"
+
+#ifndef HAVE_FMT_SCALED
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.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 const unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
+static const char scale_chars[] = "BKMGTPE";
+static const 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 */
+ if (fpart > LLONG_MAX / 10) {
+ errno = ERANGE;
+ return -1;
+ }
+ fpart *= 10;
+ if (i > LLONG_MAX - fpart) {
+ errno = ERANGE;
+ return -1;
+ }
+ fpart += i;
+ } else { /* normal digit */
+ if (++ndigits >= MAX_DIGITS) {
+ errno = ERANGE;
+ return -1;
+ }
+ if (whole > LLONG_MAX / 10) {
+ errno = ERANGE;
+ return -1;
+ }
+ whole *= 10;
+ if (i > LLONG_MAX - whole) {
+ errno = ERANGE;
+ return -1;
+ }
+ whole += i;
+ }
+ }
+
+ if (sign)
+ whole *= 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];
+
+ /* check for overflow and underflow after scaling */
+ if (whole > LLONG_MAX / scale_fact ||
+ whole < LLONG_MIN / scale_fact) {
+ errno = ERANGE;
+ return -1;
+ }
+
+ /* scale whole part */
+ whole *= scale_fact;
+
+ /* truncate fpart so it doesn't overflow.
+ * then scale fractional part.
+ */
+ while (fpart >= LLONG_MAX / scale_fact ||
+ fpart <= LLONG_MIN / scale_fact) {
+ fpart /= 10;
+ fract_digits--;
+ }
+ fpart *= scale_fact;
+ if (fract_digits > 0) {
+ for (i = 0; i < fract_digits -1; i++)
+ fpart /= 10;
+ }
+ if (sign == -1)
+ whole -= fpart;
+ else
+ 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;
+
+ /* Not every negative long long has a positive representation. */
+ if (number == LLONG_MIN) {
+ errno = ERANGE;
+ return -1;
+ }
+
+ abval = llabs(number);
+
+ /* Also check for numbers that are just too darned big to format. */
+ if (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;
+ } else if (fract < 0) {
+ /* shouldn't happen */
+ 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
+
+#endif /* HAVE_FMT_SCALED */