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 * $FreeBSD: head/lib/libutil/humanize_number.c 256130 2013-10-07 22:22:57Z jmg $
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 = 7;
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 /* validate args */
58 if (buf == NULL)
59 return (-1);
60 if (scale < 0)
61 return (-1);
62 else if (scale >= maxscale &&
63 ((scale & ~(HN_AUTOSCALE|HN_GETSCALE)) != 0))
64 return (-1);
65 if ((flags & HN_DIVISOR_1000) && (flags & HN_IEC_PREFIXES))
66 return (-1);
67
68 /* Since so many callers don't check -1, NUL terminate the buffer */
69 if (len > 0)
70 buf[0] = '\0';
71
72 if (suffix == NULL)
73 suffix = "";
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)) && i < maxscale; i++) {
149 remainder = quotient % divisor;
150 quotient /= divisor;
151 }
152
153 if (scale & HN_GETSCALE)
154 return (i);
155 } else {
156 for (i = 0; i < scale && i < maxscale; i++) {
157 remainder = quotient % divisor;
158 quotient /= divisor;
159 }
160 }
161
162 /*
163 * Generate base output
164 */
165 r = snprintf(buf, len, "%" PRId64 "%s%s%s",
166 sign * (quotient + (remainder + divisor / 2) / divisor),
167 sep, SCALE2PREFIX(i), suffix);
168
169 if ((flags & HN_FRACTIONAL) && (u_int)r + 3 <= len && i) {
170 /*
171 * If FRACTIONAL is specified output up to two fractional
172 * digits, unless the value was not divided out.
173 */
174 int64_t frac;
175 int n;
176
177 n = (int)len - r - 2;
178 frac = 1;
179 if (n > 2) /* max 2 fractional digits */
180 n = 2;
181
182 while (n) {
183 frac = frac * 10;
184 --n;
185 }
186 s1 = (int)quotient + ((remainder * frac + divisor / 2) /
187 divisor / frac);
188 s2 = ((remainder * frac + divisor / 2) / divisor) % frac;
189 r = snprintf(buf, len, "%d%s%d%s%s%s",
190 sign * s1, localeconv()->decimal_point, s2,
191 sep, SCALE2PREFIX(i), suffix);
192 } else if ((flags & HN_DECIMAL) && (u_int)r + 3 <= len &&
193 (((quotient == 9 && remainder < divisordeccut) ||
194 quotient < 9) && i > 0)) {
195 /*
196 * If DECIMAL is specified and the value is <= 9.9 after
197 * rounding, and it fits, add one fractional digit.
198 */
199 s1 = (int)quotient + ((remainder * 10 + divisor / 2) /
200 divisor / 10);
201 s2 = ((remainder * 10 + divisor / 2) / divisor) % 10;
202 r = snprintf(buf, len, "%d%s%d%s%s%s",
203 sign * s1, localeconv()->decimal_point, s2,
204 sep, SCALE2PREFIX(i), suffix);
205 }
206 return (r);
207 }
208