/*
 * Copyright (c) 1988, 1993, 1994
 *      The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * @(#) Copyright (c) 1988, 1993, 1994 The Regents of the University of California.  All rights reserved.
 * @(#)sleep.c  8.3 (Berkeley) 4/2/94
 * $FreeBSD: src/bin/sleep/sleep.c,v 1.9.2.1 2001/08/01 05:23:25 obrien Exp $
 * $DragonFly: src/bin/sleep/sleep.c,v 1.7 2005/02/27 15:57:15 liamfoy Exp $
 */

#include <ctype.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

static void usage(void);

int
main(int argc, char **argv)
{
        struct timespec time_to_sleep;
        long l;
        int ch, neg;
        char *p;

        setlocale(LC_ALL, "");

        while ((ch = getopt(argc, argv, "")) != -1)
                switch(ch) {
                default:
                        usage();
                        /* NOTREACHED */
                }
        argc -= optind;
        argv += optind;

        if (argc != 1) {
                usage();
                /* NOTREACHED */
        }

        p = argv[0];

        /* Skip over leading whitespaces. */
        while (isspace(*p))
                ++p;

        /* Check for optional `+' or `-' sign. */
        neg = 0;
        if (*p == '-') {
                neg = 1;
                ++p;
        }
        else if (*p == '+')
                ++p;

        /* Calculate seconds. */
        if (isdigit(*p)) {
                l = strtol(p, &p, 10);
                if (l > INT_MAX) {
                        /*
                         * Avoid overflow when `seconds' is huge.  This assumes
                         * that the maximum value for a time_t is <= INT_MAX.
                         */
                        l = INT_MAX;
                }
        } else
                l = 0;
        time_to_sleep.tv_sec = (time_t)l;

        /* Calculate nanoseconds. */
        time_to_sleep.tv_nsec = 0;

        if (*p == '.') {                /* Decimal point. */
                l = 100000000L;
                do {
                        if (isdigit(*++p))
                                time_to_sleep.tv_nsec += (*p - '0') * l;
                        else
                                break;
                } while (l /= 10);
        }

        if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0))
                nanosleep(&time_to_sleep, NULL);

        exit(0);
}

static void
usage(void)
{
        fprintf(stderr, "usage: sleep seconds\n");
        exit(1);
}