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
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/types.h>
37#include <assert.h>
38#include <inttypes.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <locale.h>
43#include <libutil.h>
44
45static const int maxscale = 6;
46
47int
48humanize_number(char *buf, size_t len, int64_t quotient,
49    const char *suffix, int scale, int flags)
50{
51	const char *prefixes, *sep;
52	int	i, r, remainder, s1, s2, sign;
53	int	divisordeccut;
54	int64_t	divisor, max;
55	size_t	baselen;
56
57	/* Since so many callers don't check -1, NUL terminate the buffer */
58	if (len > 0)
59		buf[0] = '\0';
60
61	/* validate args */
62	if (buf == NULL || suffix == NULL)
63		return (-1);
64	if (scale < 0)
65		return (-1);
66	else if (scale > maxscale &&
67	    ((scale & ~(HN_AUTOSCALE|HN_GETSCALE)) != 0))
68		return (-1);
69	if ((flags & HN_DIVISOR_1000) && (flags & HN_IEC_PREFIXES))
70		return (-1);
71
72	/* setup parameters */
73	remainder = 0;
74
75	if (flags & HN_IEC_PREFIXES) {
76		baselen = 2;
77		/*
78		 * Use the prefixes for power of two recommended by
79		 * the International Electrotechnical Commission
80		 * (IEC) in IEC 80000-3 (i.e. Ki, Mi, Gi...).
81		 *
82		 * HN_IEC_PREFIXES implies a divisor of 1024 here
83		 * (use of HN_DIVISOR_1000 would have triggered
84		 * an assertion earlier).
85		 */
86		divisor = 1024;
87		divisordeccut = 973;	/* ceil(.95 * 1024) */
88		if (flags & HN_B)
89			prefixes = "B\0\0Ki\0Mi\0Gi\0Ti\0Pi\0Ei";
90		else
91			prefixes = "\0\0\0Ki\0Mi\0Gi\0Ti\0Pi\0Ei";
92	} else {
93		baselen = 1;
94		if (flags & HN_DIVISOR_1000) {
95			divisor = 1000;
96			divisordeccut = 950;
97			if (flags & HN_B)
98				prefixes = "B\0\0k\0\0M\0\0G\0\0T\0\0P\0\0E";
99			else
100				prefixes = "\0\0\0k\0\0M\0\0G\0\0T\0\0P\0\0E";
101		} else {
102			divisor = 1024;
103			divisordeccut = 973;	/* ceil(.95 * 1024) */
104			if (flags & HN_B)
105				prefixes = "B\0\0K\0\0M\0\0G\0\0T\0\0P\0\0E";
106			else
107				prefixes = "\0\0\0K\0\0M\0\0G\0\0T\0\0P\0\0E";
108		}
109	}
110
111#define	SCALE2PREFIX(scale)	(&prefixes[(scale) * 3])
112
113	if (quotient < 0) {
114		sign = -1;
115		quotient = -quotient;
116		baselen += 2;		/* sign, digit */
117	} else {
118		sign = 1;
119		baselen += 1;		/* digit */
120	}
121	if (flags & HN_NOSPACE)
122		sep = "";
123	else {
124		sep = " ";
125		baselen++;
126	}
127	baselen += strlen(suffix);
128
129	/* Check if enough room for `x y' + suffix + `\0' */
130	if (len < baselen + 1)
131		return (-1);
132
133	if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
134		/* See if there is additional columns can be used. */
135		for (max = 1, i = len - baselen; i-- > 0;)
136			max *= 10;
137
138		/*
139		 * Divide the number until it fits the given column.
140		 * If there will be an overflow by the rounding below,
141		 * divide once more.
142		 */
143		for (i = 0;
144		    (quotient >= max || (quotient == max - 1 &&
145		    (remainder >= divisordeccut || remainder >=
146		    divisor / 2))) && i < maxscale; i++) {
147			remainder = quotient % divisor;
148			quotient /= divisor;
149		}
150
151		if (scale & HN_GETSCALE)
152			return (i);
153	} else {
154		for (i = 0; i < scale && i < maxscale; i++) {
155			remainder = quotient % divisor;
156			quotient /= divisor;
157		}
158	}
159
160	/* If a value <= 9.9 after rounding and ... */
161	/*
162	 * XXX - should we make sure there is enough space for the decimal
163	 * place and if not, don't do HN_DECIMAL?
164	 */
165	if (((quotient == 9 && remainder < divisordeccut) || quotient < 9) &&
166	    i > 0 && flags & HN_DECIMAL) {
167		s1 = (int)quotient + ((remainder * 10 + divisor / 2) /
168		    divisor / 10);
169		s2 = ((remainder * 10 + divisor / 2) / divisor) % 10;
170		r = snprintf(buf, len, "%d%s%d%s%s%s",
171		    sign * s1, localeconv()->decimal_point, s2,
172		    sep, SCALE2PREFIX(i), suffix);
173	} else
174		r = snprintf(buf, len, "%" PRId64 "%s%s%s",
175		    sign * (quotient + (remainder + divisor / 2) / divisor),
176		    sep, SCALE2PREFIX(i), suffix);
177
178	return (r);
179}
180