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