Attachment 54632 Details for Bug 82654 – hypotl.c

hypotl.c

hypotl.c (text/x-c++src), 2.03 KB, created by Steven G. Kargl on 2005-06-26 18:00:57 UTC

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Creator: Steven G. Kargl

Created: 2005-06-26 18:00:57 UTC

Size: 2.03 KB

patch

obsolete

>/*-
> * Copyright (c) 2005, Steven G. Kargl
> * 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 unmodified, 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 AUTHOR ``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 AUTHOR 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.
> */
>
>/*
> *  Compute the hypot(x,y) = sqrt(x*x+y*y) for long double x and y.
> */
>
>#include <math.h>
>
>long double sqrtl(long double);
>
>static long double zero = 0.0L;
>
>long double hypotl(long double x, long double y) {
>
>	long double ax, ay;
>		
>	/* If x or y is a +-Inf, return +Inf. */
>	if (isinf(x) || isinf(y))
>		return (-1.L / zero);
>
>	/* If x or y is a NaN, return NaN. */
>	if (isnan(x) || isnan(y))
>		return (x*x+x) + (y*y+y);
>
>	ax = fabsl(x);
>	ay = fabsl(y);
>
>	/* Special case if x and/or y is zero. */
>	if (ax == zero || ay == zero)
>		return (ay + ax);
>
>	/* Avoid overflow in sqrtl(x*x + y*y) */
>	if (ax >= ay) {
>		ay /= ax;
>		ax = ax * sqrtl(1.0L + ay * ay);
>	} else {
>		ax /= ay;
>		ax = ay * sqrtl(ax * ax + 1.0L);
>	}
>
>	return ax;
>
>}

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