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 <[email protected]>
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
48 static const int maxscale = 6;
49
50 int
humanize_number(char * buf,size_t len,int64_t quotient,const char * suffix,int scale,int flags)51 humanize_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