1/*	$OpenBSD: fmt_scaled.c,v 1.17 2018/05/14 04:39:04 djm Exp $	*/
2
3/*
4 * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */
30
31/*
32 * fmt_scaled: Format numbers scaled for human comprehension
33 * scan_scaled: Scan numbers in this format.
34 *
35 * "Human-readable" output uses 4 digits max, and puts a unit suffix at
36 * the end.  Makes output compact and easy-to-read esp. on huge disks.
37 * Formatting code was originally in OpenBSD "df", converted to library routine.
38 * Scanning code written for OpenBSD libutil.
39 */
40
41#include "includes.h"
42
43#ifndef HAVE_FMT_SCALED
44
45#include <stdio.h>
46#include <stdlib.h>
47#include <errno.h>
48#include <string.h>
49#include <ctype.h>
50#include <limits.h>
51
52typedef enum {
53	NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
54} unit_type;
55
56/* These three arrays MUST be in sync!  XXX make a struct */
57static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
58static char scale_chars[] = "BKMGTPE";
59static long long scale_factors[] = {
60	1LL,
61	1024LL,
62	1024LL*1024,
63	1024LL*1024*1024,
64	1024LL*1024*1024*1024,
65	1024LL*1024*1024*1024*1024,
66	1024LL*1024*1024*1024*1024*1024,
67};
68#define	SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
69
70#define MAX_DIGITS (SCALE_LENGTH * 3)	/* XXX strlen(sprintf("%lld", -1)? */
71
72/* Convert the given input string "scaled" into numeric in "result".
73 * Return 0 on success, -1 and errno set on error.
74 */
75int
76scan_scaled(char *scaled, long long *result)
77{
78	char *p = scaled;
79	int sign = 0;
80	unsigned int i, ndigits = 0, fract_digits = 0;
81	long long scale_fact = 1, whole = 0, fpart = 0;
82
83	/* Skip leading whitespace */
84	while (isascii((unsigned char)*p) && isspace((unsigned char)*p))
85		++p;
86
87	/* Then at most one leading + or - */
88	while (*p == '-' || *p == '+') {
89		if (*p == '-') {
90			if (sign) {
91				errno = EINVAL;
92				return -1;
93			}
94			sign = -1;
95			++p;
96		} else if (*p == '+') {
97			if (sign) {
98				errno = EINVAL;
99				return -1;
100			}
101			sign = +1;
102			++p;
103		}
104	}
105
106	/* Main loop: Scan digits, find decimal point, if present.
107	 * We don't allow exponentials, so no scientific notation
108	 * (but note that E for Exa might look like e to some!).
109	 * Advance 'p' to end, to get scale factor.
110	 */
111	for (; isascii((unsigned char)*p) &&
112	    (isdigit((unsigned char)*p) || *p=='.'); ++p) {
113		if (*p == '.') {
114			if (fract_digits > 0) {	/* oops, more than one '.' */
115				errno = EINVAL;
116				return -1;
117			}
118			fract_digits = 1;
119			continue;
120		}
121
122		i = (*p) - '0';			/* whew! finally a digit we can use */
123		if (fract_digits > 0) {
124			if (fract_digits >= MAX_DIGITS-1)
125				/* ignore extra fractional digits */
126				continue;
127			fract_digits++;		/* for later scaling */
128			if (fpart > LLONG_MAX / 10) {
129				errno = ERANGE;
130				return -1;
131			}
132			fpart *= 10;
133			if (i > LLONG_MAX - fpart) {
134				errno = ERANGE;
135				return -1;
136			}
137			fpart += i;
138		} else {				/* normal digit */
139			if (++ndigits >= MAX_DIGITS) {
140				errno = ERANGE;
141				return -1;
142			}
143			if (whole > LLONG_MAX / 10) {
144				errno = ERANGE;
145				return -1;
146			}
147			whole *= 10;
148			if (i > LLONG_MAX - whole) {
149				errno = ERANGE;
150				return -1;
151			}
152			whole += i;
153		}
154	}
155
156	if (sign) {
157		whole *= sign;
158		fpart *= sign;
159	}
160
161	/* If no scale factor given, we're done. fraction is discarded. */
162	if (!*p) {
163		*result = whole;
164		return 0;
165	}
166
167	/* Validate scale factor, and scale whole and fraction by it. */
168	for (i = 0; i < SCALE_LENGTH; i++) {
169
170		/* Are we there yet? */
171		if (*p == scale_chars[i] ||
172			*p == tolower((unsigned char)scale_chars[i])) {
173
174			/* If it ends with alphanumerics after the scale char, bad. */
175			if (isalnum((unsigned char)*(p+1))) {
176				errno = EINVAL;
177				return -1;
178			}
179			scale_fact = scale_factors[i];
180
181			/* check for overflow and underflow after scaling */
182			if (whole > LLONG_MAX / scale_fact ||
183			    whole < LLONG_MIN / scale_fact) {
184				errno = ERANGE;
185				return -1;
186			}
187
188			/* scale whole part */
189			whole *= scale_fact;
190
191			/* truncate fpart so it doesn't overflow.
192			 * then scale fractional part.
193			 */
194			while (fpart >= LLONG_MAX / scale_fact) {
195				fpart /= 10;
196				fract_digits--;
197			}
198			fpart *= scale_fact;
199			if (fract_digits > 0) {
200				for (i = 0; i < fract_digits -1; i++)
201					fpart /= 10;
202			}
203			whole += fpart;
204			*result = whole;
205			return 0;
206		}
207	}
208
209	/* Invalid unit or character */
210	errno = EINVAL;
211	return -1;
212}
213
214/* Format the given "number" into human-readable form in "result".
215 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
216 * Return 0 on success, -1 and errno set if error.
217 */
218int
219fmt_scaled(long long number, char *result)
220{
221	long long abval, fract = 0;
222	unsigned int i;
223	unit_type unit = NONE;
224
225	abval = llabs(number);
226
227	/* Not every negative long long has a positive representation.
228	 * Also check for numbers that are just too darned big to format
229	 */
230	if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
231		errno = ERANGE;
232		return -1;
233	}
234
235	/* scale whole part; get unscaled fraction */
236	for (i = 0; i < SCALE_LENGTH; i++) {
237		if (abval/1024 < scale_factors[i]) {
238			unit = units[i];
239			fract = (i == 0) ? 0 : abval % scale_factors[i];
240			number /= scale_factors[i];
241			if (i > 0)
242				fract /= scale_factors[i - 1];
243			break;
244		}
245	}
246
247	fract = (10 * fract + 512) / 1024;
248	/* if the result would be >= 10, round main number */
249	if (fract >= 10) {
250		if (number >= 0)
251			number++;
252		else
253			number--;
254		fract = 0;
255	} else if (fract < 0) {
256		/* shouldn't happen */
257		fract = 0;
258	}
259
260	if (number == 0)
261		strlcpy(result, "0B", FMT_SCALED_STRSIZE);
262	else if (unit == NONE || number >= 100 || number <= -100) {
263		if (fract >= 5) {
264			if (number >= 0)
265				number++;
266			else
267				number--;
268		}
269		(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
270			number, scale_chars[unit]);
271	} else
272		(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
273			number, fract, scale_chars[unit]);
274
275	return 0;
276}
277
278#ifdef	MAIN
279/*
280 * This is the original version of the program in the man page.
281 * Copy-and-paste whatever you need from it.
282 */
283int
284main(int argc, char **argv)
285{
286	char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
287	long long ninput = 10483892, result;
288
289	if (scan_scaled(cinput, &result) == 0)
290		printf("\"%s\" -> %lld\n", cinput, result);
291	else
292		perror(cinput);
293
294	if (fmt_scaled(ninput, buf) == 0)
295		printf("%lld -> \"%s\"\n", ninput, buf);
296	else
297		fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
298
299	return 0;
300}
301#endif
302
303#endif /* HAVE_FMT_SCALED */
304