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 
46 static const int maxscale = 6;
47 
48 int
humanize_number(char * buf,size_t len,int64_t quotient,const char * suffix,int scale,int flags)49 humanize_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