1/*	$NetBSD: fmt_scaled.c,v 1.8 2019/01/27 02:08:33 pgoyette Exp $	*/
2/*	$OpenBSD: fmt_scaled.c,v 1.9 2007/03/20 03:42:52 tedu Exp $	*/
3
4/*
5 * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */
31
32/*
33 * fmt_scaled: Format numbers scaled for human comprehension
34 * scan_scaled: Scan numbers in this format.
35 *
36 * "Human-readable" output uses 4 digits max, and puts a unit suffix at
37 * the end.  Makes output compact and easy-to-read esp. on huge disks.
38 * Formatting code was originally in OpenBSD "df", converted to library routine.
39 * Scanning code written for OpenBSD libutil.
40 */
41
42#include "includes.h"
43__RCSID("$NetBSD: fmt_scaled.c,v 1.8 2019/01/27 02:08:33 pgoyette Exp $");
44
45#ifndef HAVE_FMT_SCALED
46#include <stdio.h>
47#include <stdlib.h>
48#include <errno.h>
49#include <string.h>
50#include <ctype.h>
51#include <limits.h>
52
53#include "fmt_scaled.h"
54
55typedef enum {
56	NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
57} unit_type;
58
59/* These three arrays MUST be in sync!  XXX make a struct */
60static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
61static char scale_chars[] = "BKMGTPE";
62static long long scale_factors[] = {
63	1LL,
64	1024LL,
65	1024LL*1024,
66	1024LL*1024*1024,
67	1024LL*1024*1024*1024,
68	1024LL*1024*1024*1024*1024,
69	1024LL*1024*1024*1024*1024*1024,
70};
71#define	SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
72
73#define MAX_DIGITS (SCALE_LENGTH * 3)	/* XXX strlen(sprintf("%lld", -1)? */
74
75/** Convert the given input string "scaled" into numeric in "result".
76 * Return 0 on success, -1 and errno set on error.
77 */
78int
79scan_scaled(const char *scaled, long long *result)
80{
81	const char *p = scaled;
82	int sign = 0;
83	unsigned int i, ndigits = 0, fract_digits = 0;
84	long long scale_fact = 1, whole = 0, fpart = 0;
85
86	/* Skip leading whitespace */
87	while (isascii((unsigned char)*p) && isspace((unsigned char)*p))
88		++p;
89
90	/* Then at most one leading + or - */
91	while (*p == '-' || *p == '+') {
92		if (*p == '-') {
93			if (sign) {
94				errno = EINVAL;
95				return -1;
96			}
97			sign = -1;
98			++p;
99		} else if (*p == '+') {
100			if (sign) {
101				errno = EINVAL;
102				return -1;
103			}
104			sign = +1;
105			++p;
106		}
107	}
108
109	/* Main loop: Scan digits, find decimal point, if present.
110	 * We don't allow exponentials, so no scientific notation
111	 * (but note that E for Exa might look like e to some!).
112	 * Advance 'p' to end, to get scale factor.
113	 */
114	for (; isascii((unsigned char)*p) && (isdigit((unsigned char)*p) || *p=='.'); ++p) {
115		if (*p == '.') {
116			if (fract_digits > 0) {	/* oops, more than one '.' */
117				errno = EINVAL;
118				return -1;
119			}
120			fract_digits = 1;
121			continue;
122		}
123
124		i = (*p) - '0';			/* whew! finally a digit we can use */
125		if (fract_digits > 0) {
126			if (fract_digits >= MAX_DIGITS-1)
127				/* ignore extra fractional digits */
128				continue;
129			fract_digits++;		/* for later scaling */
130			fpart *= 10;
131			fpart += i;
132		} else {				/* normal digit */
133			if (++ndigits >= MAX_DIGITS) {
134				errno = ERANGE;
135				return -1;
136			}
137			whole *= 10;
138			whole += i;
139		}
140	}
141
142	if (sign) {
143		whole *= sign;
144		fpart *= sign;
145	}
146
147	/* If no scale factor given, we're done. fraction is discarded. */
148	if (!*p) {
149		*result = whole;
150		return 0;
151	}
152
153	/* Validate scale factor, and scale whole and fraction by it. */
154	for (i = 0; i < SCALE_LENGTH; i++) {
155
156		/** Are we there yet? */
157		if (*p == scale_chars[i] ||
158			*p == tolower((unsigned char)scale_chars[i])) {
159
160			/* If it ends with alphanumerics after the scale char, bad. */
161			if (isalnum((unsigned char)*(p+1))) {
162				errno = EINVAL;
163				return -1;
164			}
165			scale_fact = scale_factors[i];
166
167			/* scale whole part */
168			whole *= scale_fact;
169
170			/* truncate fpart so it does't overflow.
171			 * then scale fractional part.
172			 */
173			while (fpart >= LLONG_MAX / scale_fact) {
174				fpart /= 10;
175				fract_digits--;
176			}
177			fpart *= scale_fact;
178			if (fract_digits > 0) {
179				for (i = 0; i < fract_digits -1; i++)
180					fpart /= 10;
181			}
182			whole += fpart;
183			*result = whole;
184			return 0;
185		}
186	}
187	errno = ERANGE;
188	return -1;
189}
190
191/* Format the given "number" into human-readable form in "result".
192 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
193 * Return 0 on success, -1 and errno set if error.
194 */
195int
196fmt_scaled(long long number, char *result)
197{
198	long long abval, fract = 0;
199	unsigned int i;
200	unit_type unit = NONE;
201
202	abval = (number < 0LL) ? -number : number;	/* no long long_abs yet */
203
204	/* Not every negative long long has a positive representation.
205	 * Also check for numbers that are just too darned big to format
206	 */
207	if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
208		errno = ERANGE;
209		return -1;
210	}
211
212	/* scale whole part; get unscaled fraction */
213	for (i = 0; i < SCALE_LENGTH; i++) {
214		if (abval/1024 < scale_factors[i]) {
215			unit = units[i];
216			fract = (i == 0) ? 0 : abval % scale_factors[i];
217			number /= scale_factors[i];
218			if (i > 0)
219				fract /= scale_factors[i - 1];
220			break;
221		}
222	}
223
224	fract = (10 * fract + 512) / 1024;
225	/* if the result would be >= 10, round main number */
226	if (fract == 10) {
227		if (number >= 0)
228			number++;
229		else
230			number--;
231		fract = 0;
232	}
233
234	if (number == 0)
235		strlcpy(result, "0B", FMT_SCALED_STRSIZE);
236	else if (unit == NONE || number >= 100 || number <= -100) {
237		if (fract >= 5) {
238			if (number >= 0)
239				number++;
240			else
241				number--;
242		}
243		(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
244			number, scale_chars[unit]);
245	} else
246		(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
247			number, fract, scale_chars[unit]);
248
249	return 0;
250}
251
252#ifdef	MAIN
253/*
254 * This is the original version of the program in the man page.
255 * Copy-and-paste whatever you need from it.
256 */
257int
258main(int argc, char **argv)
259{
260	char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
261	long long ninput = 10483892, result;
262
263	if (scan_scaled(cinput, &result) == 0)
264		printf("\"%s\" -> %lld\n", cinput, result);
265	else
266		perror(cinput);
267
268	if (fmt_scaled(ninput, buf) == 0)
269		printf("%lld -> \"%s\"\n", ninput, buf);
270	else
271		fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
272
273	return 0;
274}
275#endif
276
277#endif /* HAVE_FMT_SCALED */
278