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