1 /* $OpenBSD: s_round.c,v 1.2 2011/07/06 00:02:42 martynas Exp $ */ 2 3 /*- 4 * Copyright (c) 2003, Steven G. Kargl 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice unmodified, this list of conditions, and the following 12 * disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* LINTLIBRARY */ 30 31 #include <sys/cdefs.h> 32 #include <float.h> 33 #include <math.h> 34 35 #include "math_private.h" 36 37 double 38 round(double x) 39 { 40 double t; 41 42 if (isinf(x) || isnan(x)) 43 return (x); 44 45 if (x >= 0.0) { 46 t = floor(x); 47 if (t - x <= -0.5) 48 t += 1.0; 49 return (t); 50 } else { 51 t = floor(-x); 52 if (t + x <= -0.5) 53 t += 1.0; 54 return (-t); 55 } 56 } 57 58 #if LDBL_MANT_DIG == 53 59 #ifdef lint 60 /* PROTOLIB1 */ 61 long double roundl(long double); 62 #else /* lint */ 63 __weak_alias(roundl, round); 64 #endif /* lint */ 65 #endif /* LDBL_MANT_DIG == 53 */ 66