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      1 /*-
      2  * Copyright (c) 2003, Steven G. Kargl
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice unmodified, this list of conditions, and the following
     10  *    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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include <sys/cdefs.h>
     28 #if defined(LIBM_SCCS) && !defined(lint)
     29 __RCSID("$NetBSD: s_round.c,v 1.3 2013/11/11 23:57:34 joerg Exp $");
     30 #if 0
     31 __FBSDID("$FreeBSD: src/lib/msun/src/s_round.c,v 1.1 2004/06/07 08:05:36 das Exp $");
     32 #endif
     33 #endif
     34 
     35 #include <math.h>
     36 
     37 #ifndef __HAVE_LONG_DOUBLE
     38 __strong_alias(_roundl, round)
     39 __weak_alias(roundl, round)
     40 #endif
     41 
     42 double
     43 round(double x)
     44 {
     45 	double t;
     46 	int i;
     47 
     48 	i = fpclassify(x);
     49 	if (i == FP_INFINITE || i == FP_NAN)
     50 		return (x);
     51 
     52 	if (x >= 0.0) {
     53 		t = floor(x);
     54 		if (x - t >= 0.5)
     55 			t += 1.0;
     56 		return (t);
     57 	} else {
     58 		x = -x;
     59 		t = floor(x);
     60 		if (x - t >= 0.5)
     61 			t += 1.0;
     62 		return (-t);
     63 	}
     64 }
     65