/*-
 * 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>

int
expand_number(const char *buf, uint64_t *num)
{
	char *endptr;
	uintmax_t umaxval;
	uint64_t number;
	unsigned shift;
	int serrno;

	serrno = errno;
	errno = 0;
	umaxval = strtoumax(buf, &endptr, 0);
	if (umaxval > UINT64_MAX)
		errno = ERANGE;
	if (errno != 0)
		return (-1);
	errno = serrno;
	number = umaxval;

	switch (tolower((unsigned char)*endptr)) {
	case 'e':
		shift = 60;
		break;
	case 'p':
		shift = 50;
		break;
	case 't':
		shift = 40;
		break;
	case 'g':
		shift = 30;
		break;
	case 'm':
		shift = 20;
		break;
	case 'k':
		shift = 10;
		break;
	case 'b':
	case '\0': /* No unit. */
		*num = number;
		return (0);
	default:
		/* Unrecognized unit. */
		errno = EINVAL;
		return (-1);
	}

	if ((number << shift) >> shift != number) {
		/* Overflow */
		errno = ERANGE;
		return (-1);
	}
	*num = number << shift;
	return (0);
}