1 /* $OpenBSD: s_round.c,v 1.6 2013/07/03 04:46:36 espie 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 #include <float.h> 30 #include <math.h> 31 32 #include "math_private.h" 33 34 double 35 round(double x) 36 { 37 double t; 38 39 if (isinf(x) || isnan(x)) 40 return (x); 41 42 if (x >= 0.0) { 43 t = floor(x); 44 if (t - x <= -0.5) 45 t += 1.0; 46 return (t); 47 } else { 48 t = floor(-x); 49 if (t + x <= -0.5) 50 t += 1.0; 51 return (-t); 52 } 53 } 54 55 #if LDBL_MANT_DIG == DBL_MANT_DIG 56 __strong_alias(roundl, round); 57 #endif /* LDBL_MANT_DIG == DBL_MANT_DIG */ 58