expand_number.c revision 211343 
1/*-
2 * Copyright (c) 2007 Eric Anderson <anderson@FreeBSD.org>
3 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/lib/libutil/expand_number.c 211343 2010-08-15 18:32:06Z des $");
30
31#include <sys/types.h>
32#include <ctype.h>
33#include <errno.h>
34#include <inttypes.h>
35#include <libutil.h>
36#include <stdint.h>
37
38/*
39 * Convert an expression of the following forms to a uint64_t.
40 *	1) A positive decimal number.
41 *	2) A positive decimal number followed by a 'b' or 'B' (mult by 1).
42 *	3) A positive decimal number followed by a 'k' or 'K' (mult by 1 << 10).
43 *	4) A positive decimal number followed by a 'm' or 'M' (mult by 1 << 20).
44 *	5) A positive decimal number followed by a 'g' or 'G' (mult by 1 << 30).
45 *	6) A positive decimal number followed by a 't' or 'T' (mult by 1 << 40).
46 *	7) A positive decimal number followed by a 'p' or 'P' (mult by 1 << 50).
47 *	8) A positive decimal number followed by a 'e' or 'E' (mult by 1 << 60).
48 */
49int
50expand_number(const char *buf, uint64_t *num)
51{
52	uint64_t number;
53	unsigned shift;
54	char *endptr;
55
56	number = strtoumax(buf, &endptr, 0);
57
58	if (endptr == buf) {
59		/* No valid digits. */
60		errno = EINVAL;
61		return (-1);
62	}
63
64	switch (tolower((unsigned char)*endptr)) {
65	case 'e':
66		shift = 60;
67		break;
68	case 'p':
69		shift = 50;
70		break;
71	case 't':
72		shift = 40;
73		break;
74	case 'g':
75		shift = 30;
76		break;
77	case 'm':
78		shift = 20;
79		break;
80	case 'k':
81		shift = 10;
82		break;
83	case 'b':
84	case '\0': /* No unit. */
85		*num = number;
86		return (0);
87	default:
88		/* Unrecognized unit. */
89		errno = EINVAL;
90		return (-1);
91	}
92
93	if ((number << shift) >> shift != number) {
94		/* Overflow */
95		errno = ERANGE;
96		return (-1);
97	}
98
99	*num = number << shift;
100	return (0);
101}
102