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sortix--sortix/libm/complex/cprojl.c
Jonas 'Sortie' Termansen 5980be9b3c Add Sortix Math Library.
This work is based in part on code from NetBSD libm, libc and kernel.

The library is partly public domain and partly BSD-style licensed.
2013-12-17 14:30:39 +01:00

64 lines
2.3 KiB
C

/* $NetBSD: cprojl.c,v 1.6 2011/11/02 02:34:56 christos Exp $ */
/*-
* Copyright (c) 2010 The NetBSD Foundation, Inc.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: cprojl.c,v 1.6 2011/11/02 02:34:56 christos Exp $");
#include <complex.h>
#include <math.h>
#include "../src/math_private.h"
/*
* cprojl(long double complex z)
*
* These functions return the value of the projection (not stereographic!)
* onto the Riemann sphere.
*
* z projects to z, except that all complex infinities (even those with one
* infinite part and one NaN part) project to positive infinity on the real axis.
* If z has an infinite part, then cproj(z) shall be equivalent to:
*
* INFINITY + I * copysign(0.0, cimag(z))
*/
long double complex
cprojl(long double complex z)
{
long_double_complex w = { .z = z };
/*CONSTCOND*/
if (isinf(creall(z)) || isinf(cimagl(z))) {
#ifdef __INFINITY
REAL_PART(w) = HUGE_VAL;
#else
REAL_PART(w) = INFINITY;
#endif
IMAG_PART(w) = copysignl(0.0, cimagl(z));
}
return (w.z);
}