humanize_number.c revision 194794 
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 * 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__FBSDID("$FreeBSD: head/lib/libutil/humanize_number.c 194794 2009-06-23 23:27:35Z delphij $");
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
45int
46humanize_number(char *buf, size_t len, int64_t bytes,
47    const char *suffix, int scale, int flags)
48{
49	const char *prefixes, *sep;
50	int	b, i, r, maxscale, s1, s2, sign;
51	int64_t	divisor, max;
52	size_t	baselen;
53
54	assert(buf != NULL);
55	assert(suffix != NULL);
56	assert(scale >= 0);
57
58	if (flags & HN_DIVISOR_1000) {
59		/* SI for decimal multiplies */
60		divisor = 1000;
61		if (flags & HN_B)
62			prefixes = "B\0k\0M\0G\0T\0P\0E";
63		else
64			prefixes = "\0\0k\0M\0G\0T\0P\0E";
65	} else {
66		/*
67		 * binary multiplies
68		 * XXX IEC 60027-2 recommends Ki, Mi, Gi...
69		 */
70		divisor = 1024;
71		if (flags & HN_B)
72			prefixes = "B\0K\0M\0G\0T\0P\0E";
73		else
74			prefixes = "\0\0K\0M\0G\0T\0P\0E";
75	}
76
77#define	SCALE2PREFIX(scale)	(&prefixes[(scale) << 1])
78	maxscale = 7;
79
80	if (scale >= maxscale &&
81	    (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
82		return (-1);
83
84	if (buf == NULL || suffix == NULL)
85		return (-1);
86
87	if (len > 0)
88		buf[0] = '\0';
89	if (bytes < 0) {
90		sign = -1;
91		bytes *= -100;
92		baselen = 3;		/* sign, digit, prefix */
93	} else {
94		sign = 1;
95		bytes *= 100;
96		baselen = 2;		/* digit, prefix */
97	}
98	if (flags & HN_NOSPACE)
99		sep = "";
100	else {
101		sep = " ";
102		baselen++;
103	}
104	baselen += strlen(suffix);
105
106	/* Check if enough room for `x y' + suffix + `\0' */
107	if (len < baselen + 1)
108		return (-1);
109
110	if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
111		/* See if there is additional columns can be used. */
112		for (max = 100, i = len - baselen; i-- > 0;)
113			max *= 10;
114
115		/*
116		 * Divide the number until it fits the given column.
117		 * If there will be an overflow by the rounding below,
118		 * divide once more.
119		 */
120		for (i = 0; bytes >= max - 50 && i < maxscale; i++)
121			bytes /= divisor;
122
123		if (scale & HN_GETSCALE)
124			return (i);
125	} else
126		for (i = 0; i < scale && i < maxscale; i++)
127			bytes /= divisor;
128
129	/* If a value <= 9.9 after rounding and ... */
130	if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
131		/* baselen + \0 + .N */
132		if (len < baselen + 1 + 2)
133			return (-1);
134		b = ((int)bytes + 5) / 10;
135		s1 = b / 10;
136		s2 = b % 10;
137		r = snprintf(buf, len, "%d%s%d%s%s%s",
138		    sign * s1, localeconv()->decimal_point, s2,
139		    sep, SCALE2PREFIX(i), suffix);
140	} else
141		r = snprintf(buf, len, "%" PRId64 "%s%s%s",
142		    sign * ((bytes + 50) / 100),
143		    sep, SCALE2PREFIX(i), suffix);
144
145	return (r);
146}
147