1 /* $NetBSD: cprojf.c,v 1.3 2010/09/20 17:51:38 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2010 The NetBSD Foundation, Inc.
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, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 * imported and modified include for newlib 2010/10/03
29 * Marco Atzeri <marco_atzeri@yahoo.it>
30 */
31
32 #include <sys/cdefs.h>
33 /*__RCSID("$NetBSD: cprojf.c,v 1.3 2010/09/20 17:51:38 christos Exp $"); */
34
35 #include <complex.h>
36 #include <math.h>
37
38 #include "../common/fdlibm.h"
39
40 /*
41 * cprojf(float complex z)
42 *
43 * These functions return the value of the projection (not stereographic!)
44 * onto the Riemann sphere.
45 *
46 * z projects to z, except that all complex infinities (even those with one
47 * infinite part and one NaN part) project to positive infinity on the real axis.
48 * If z has an infinite part, then cproj(z) shall be equivalent to:
49 *
50 * INFINITY + I * copysign(0.0, cimag(z))
51 */
52
53 float complex
cprojf(float complex z)54 cprojf(float complex z)
55 {
56 float_complex w = { .z = z };
57
58 if (isinf(crealf(z)) || isinf(cimagf(z))) {
59 #ifdef __INFINITY
60 REAL_PART(w) = __INFINITY;
61 #else
62 REAL_PART(w) = INFINITY;
63 #endif
64 IMAG_PART(w) = copysignf(0.0, cimagf(z));
65 }
66
67 return (w.z);
68 }
69
