expand_number.c revision 211304 
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 211304 2010-08-14 14:34:36Z 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 int64_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	char *endptr;
54
55	number = strtoumax(buf, &endptr, 0);
56
57	if (endptr == buf) {
58		/* No valid digits. */
59		errno = EINVAL;
60		return (-1);
61	}
62
63	if (*endptr == '\0') {
64		/* No unit. */
65		*num = number;
66		return (0);
67	}
68
69#define SHIFT(n, b)							\
70	do { if ((n << b) < n) goto overflow; n <<= b; } while (0)
71
72	switch (tolower((unsigned char)*endptr)) {
73	case 'e':
74		SHIFT(number, 10);
75	case 'p':
76		SHIFT(number, 10);
77	case 't':
78		SHIFT(number, 10);
79	case 'g':
80		SHIFT(number, 10);
81	case 'm':
82		SHIFT(number, 10);
83	case 'k':
84		SHIFT(number, 10);
85	case 'b':
86		break;
87	default:
88		/* Unrecognized unit. */
89		errno = EINVAL;
90		return (-1);
91	}
92
93	*num = number;
94	return (0);
95
96overflow:
97	/* Overflow */
98	errno = ERANGE;
99	return (-1);
100}
101