xref: /freebsd/lib/libutil/expand_number.c (revision 0e1497aefd602cea581d2380d22e67dfdcac6b4e)
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("$FreeBSD$");
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  */
49 int
50 expand_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