1/*	$NetBSD: humanize_number.c,v 1.14 2008/04/28 20:22:59 martin Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
5 *
6 * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
7 * Copyright 2013 John-Mark Gurney <jmg@FreeBSD.org>
8 * All rights reserved.
9 *
10 * This code is derived from software contributed to The NetBSD Foundation
11 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
12 * NASA Ames Research Center, by Luke Mewburn and by Tomas Svensson.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 *    notice, this list of conditions and the following disclaimer in the
21 *    documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
27 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
34 */
35
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD$");
38
39#include <sys/types.h>
40#include <assert.h>
41#include <inttypes.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <locale.h>
46#include <libutil.h>
47
48static const int maxscale = 6;
49
50int
51humanize_number(char *buf, size_t len, int64_t quotient,
52    const char *suffix, int scale, int flags)
53{
54	const char *prefixes, *sep;
55	int	i, r, remainder, s1, s2, sign;
56	int	divisordeccut;
57	int64_t	divisor, max;
58	size_t	baselen;
59
60	/* Since so many callers don't check -1, NUL terminate the buffer */
61	if (len > 0)
62		buf[0] = '\0';
63
64	/* validate args */
65	if (buf == NULL || suffix == NULL)
66		return (-1);
67	if (scale < 0)
68		return (-1);
69	else if (scale > maxscale &&
70	    ((scale & ~(HN_AUTOSCALE|HN_GETSCALE)) != 0))
71		return (-1);
72	if ((flags & HN_DIVISOR_1000) && (flags & HN_IEC_PREFIXES))
73		return (-1);
74
75	/* setup parameters */
76	remainder = 0;
77
78	if (flags & HN_IEC_PREFIXES) {
79		baselen = 2;
80		/*
81		 * Use the prefixes for power of two recommended by
82		 * the International Electrotechnical Commission
83		 * (IEC) in IEC 80000-3 (i.e. Ki, Mi, Gi...).
84		 *
85		 * HN_IEC_PREFIXES implies a divisor of 1024 here
86		 * (use of HN_DIVISOR_1000 would have triggered
87		 * an assertion earlier).
88		 */
89		divisor = 1024;
90		divisordeccut = 973;	/* ceil(.95 * 1024) */
91		if (flags & HN_B)
92			prefixes = "B\0\0Ki\0Mi\0Gi\0Ti\0Pi\0Ei";
93		else
94			prefixes = "\0\0\0Ki\0Mi\0Gi\0Ti\0Pi\0Ei";
95	} else {
96		baselen = 1;
97		if (flags & HN_DIVISOR_1000) {
98			divisor = 1000;
99			divisordeccut = 950;
100			if (flags & HN_B)
101				prefixes = "B\0\0k\0\0M\0\0G\0\0T\0\0P\0\0E";
102			else
103				prefixes = "\0\0\0k\0\0M\0\0G\0\0T\0\0P\0\0E";
104		} else {
105			divisor = 1024;
106			divisordeccut = 973;	/* ceil(.95 * 1024) */
107			if (flags & HN_B)
108				prefixes = "B\0\0K\0\0M\0\0G\0\0T\0\0P\0\0E";
109			else
110				prefixes = "\0\0\0K\0\0M\0\0G\0\0T\0\0P\0\0E";
111		}
112	}
113
114#define	SCALE2PREFIX(scale)	(&prefixes[(scale) * 3])
115
116	if (quotient < 0) {
117		sign = -1;
118		quotient = -quotient;
119		baselen += 2;		/* sign, digit */
120	} else {
121		sign = 1;
122		baselen += 1;		/* digit */
123	}
124	if (flags & HN_NOSPACE)
125		sep = "";
126	else {
127		sep = " ";
128		baselen++;
129	}
130	baselen += strlen(suffix);
131
132	/* Check if enough room for `x y' + suffix + `\0' */
133	if (len < baselen + 1)
134		return (-1);
135
136	if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
137		/* See if there is additional columns can be used. */
138		for (max = 1, i = len - baselen; i-- > 0;)
139			max *= 10;
140
141		/*
142		 * Divide the number until it fits the given column.
143		 * If there will be an overflow by the rounding below,
144		 * divide once more.
145		 */
146		for (i = 0;
147		    (quotient >= max || (quotient == max - 1 &&
148		    (remainder >= divisordeccut || remainder >=
149		    divisor / 2))) && i < maxscale; i++) {
150			remainder = quotient % divisor;
151			quotient /= divisor;
152		}
153
154		if (scale & HN_GETSCALE)
155			return (i);
156	} else {
157		for (i = 0; i < scale && i < maxscale; i++) {
158			remainder = quotient % divisor;
159			quotient /= divisor;
160		}
161	}
162
163	/* If a value <= 9.9 after rounding and ... */
164	/*
165	 * XXX - should we make sure there is enough space for the decimal
166	 * place and if not, don't do HN_DECIMAL?
167	 */
168	if (((quotient == 9 && remainder < divisordeccut) || quotient < 9) &&
169	    i > 0 && flags & HN_DECIMAL) {
170		s1 = (int)quotient + ((remainder * 10 + divisor / 2) /
171		    divisor / 10);
172		s2 = ((remainder * 10 + divisor / 2) / divisor) % 10;
173		r = snprintf(buf, len, "%d%s%d%s%s%s",
174		    sign * s1, localeconv()->decimal_point, s2,
175		    sep, SCALE2PREFIX(i), suffix);
176	} else
177		r = snprintf(buf, len, "%" PRId64 "%s%s%s",
178		    sign * (quotient + (remainder + divisor / 2) / divisor),
179		    sep, SCALE2PREFIX(i), suffix);
180
181	return (r);
182}
183