freebsd-dev/lib/libutil/expand_number.c
Dag-Erling Smørgrav bbb2703b4f Simplify expand_number() by combining the (unrolled) loop with the
switch.  Since expand_number() does not accept negative numbers, switch
from int64_t to uint64_t; this makes it easier to check for overflow.

MFC after:	3 weeks
2010-08-14 14:34:36 +00:00

101 lines
3.0 KiB
C

/*-
* Copyright (c) 2007 Eric Anderson <anderson@FreeBSD.org>
* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <libutil.h>
#include <stdint.h>
/*
* Convert an expression of the following forms to a int64_t.
* 1) A positive decimal number.
* 2) A positive decimal number followed by a 'b' or 'B' (mult by 1).
* 3) A positive decimal number followed by a 'k' or 'K' (mult by 1 << 10).
* 4) A positive decimal number followed by a 'm' or 'M' (mult by 1 << 20).
* 5) A positive decimal number followed by a 'g' or 'G' (mult by 1 << 30).
* 6) A positive decimal number followed by a 't' or 'T' (mult by 1 << 40).
* 7) A positive decimal number followed by a 'p' or 'P' (mult by 1 << 50).
* 8) A positive decimal number followed by a 'e' or 'E' (mult by 1 << 60).
*/
int
expand_number(const char *buf, uint64_t *num)
{
uint64_t number;
char *endptr;
number = strtoumax(buf, &endptr, 0);
if (endptr == buf) {
/* No valid digits. */
errno = EINVAL;
return (-1);
}
if (*endptr == '\0') {
/* No unit. */
*num = number;
return (0);
}
#define SHIFT(n, b) \
do { if ((n << b) < n) goto overflow; n <<= b; } while (0)
switch (tolower((unsigned char)*endptr)) {
case 'e':
SHIFT(number, 10);
case 'p':
SHIFT(number, 10);
case 't':
SHIFT(number, 10);
case 'g':
SHIFT(number, 10);
case 'm':
SHIFT(number, 10);
case 'k':
SHIFT(number, 10);
case 'b':
break;
default:
/* Unrecognized unit. */
errno = EINVAL;
return (-1);
}
*num = number;
return (0);
overflow:
/* Overflow */
errno = ERANGE;
return (-1);
}