1 /* $NetBSD: humanize_number.c,v 1.16 2012/03/17 20:01:14 christos Exp $ */
2
3 /*
4 * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center, by Luke Mewburn and by Tomas Svensson.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 #if defined(LIBC_SCCS) && !defined(lint)
35 __RCSID("$NetBSD: humanize_number.c,v 1.16 2012/03/17 20:01:14 christos Exp $");
36 #endif /* LIBC_SCCS and not lint */
37
38 #include "namespace.h"
39 #include <assert.h>
40 #include <inttypes.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <locale.h>
45
46 int
humanize_number(char * buf,size_t len,int64_t bytes,const char * suffix,int scale,int flags)47 humanize_number(char *buf, size_t len, int64_t bytes,
48 const char *suffix, int scale, int flags)
49 {
50 const char *prefixes, *sep;
51 int b, r, s1, s2, sign;
52 int64_t divisor, max, post = 1;
53 size_t i, baselen, maxscale;
54
55 _DIAGASSERT(buf != NULL);
56 _DIAGASSERT(suffix != NULL);
57 _DIAGASSERT(scale >= 0);
58
59 if (flags & HN_DIVISOR_1000) {
60 /* SI for decimal multiplies */
61 divisor = 1000;
62 if (flags & HN_B)
63 prefixes = "B\0k\0M\0G\0T\0P\0E";
64 else
65 prefixes = "\0\0k\0M\0G\0T\0P\0E";
66 } else {
67 /*
68 * binary multiplies
69 * XXX IEC 60027-2 recommends Ki, Mi, Gi...
70 */
71 divisor = 1024;
72 if (flags & HN_B)
73 prefixes = "B\0K\0M\0G\0T\0P\0E";
74 else
75 prefixes = "\0\0K\0M\0G\0T\0P\0E";
76 }
77
78 #define SCALE2PREFIX(scale) (&prefixes[(scale) << 1])
79 maxscale = 7;
80
81 if ((size_t)scale >= maxscale &&
82 (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
83 return (-1);
84
85 if (buf == NULL || suffix == NULL)
86 return (-1);
87
88 if (len > 0)
89 buf[0] = '\0';
90 if (bytes < 0) {
91 sign = -1;
92 baselen = 3; /* sign, digit, prefix */
93 if (-bytes < INT64_MAX / 100)
94 bytes *= -100;
95 else {
96 bytes = -bytes;
97 post = 100;
98 baselen += 2;
99 }
100 } else {
101 sign = 1;
102 baselen = 2; /* digit, prefix */
103 if (bytes < INT64_MAX / 100)
104 bytes *= 100;
105 else {
106 post = 100;
107 baselen += 2;
108 }
109 }
110 if (flags & HN_NOSPACE)
111 sep = "";
112 else {
113 sep = " ";
114 baselen++;
115 }
116 baselen += strlen(suffix);
117
118 /* Check if enough room for `x y' + suffix + `\0' */
119 if (len < baselen + 1)
120 return (-1);
121
122 if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
123 /* See if there is additional columns can be used. */
124 for (max = 100, i = len - baselen; i-- > 0;)
125 max *= 10;
126
127 /*
128 * Divide the number until it fits the given column.
129 * If there will be an overflow by the rounding below,
130 * divide once more.
131 */
132 for (i = 0; bytes >= max - 50 && i < maxscale; i++)
133 bytes /= divisor;
134
135 if (scale & HN_GETSCALE) {
136 _DIAGASSERT(__type_fit(int, i));
137 return (int)i;
138 }
139 } else
140 for (i = 0; i < (size_t)scale && i < maxscale; i++)
141 bytes /= divisor;
142 bytes *= post;
143
144 /* If a value <= 9.9 after rounding and ... */
145 if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
146 /* baselen + \0 + .N */
147 if (len < baselen + 1 + 2)
148 return (-1);
149 b = ((int)bytes + 5) / 10;
150 s1 = b / 10;
151 s2 = b % 10;
152 r = snprintf(buf, len, "%d%s%d%s%s%s",
153 sign * s1, localeconv()->decimal_point, s2,
154 sep, SCALE2PREFIX(i), suffix);
155 } else
156 r = snprintf(buf, len, "%" PRId64 "%s%s%s",
157 sign * ((bytes + 50) / 100),
158 sep, SCALE2PREFIX(i), suffix);
159
160 return (r);
161 }
162