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1 | /* $NetBSD: cprojl.c,v 1.7 2014/10/10 00:48:18 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 | #include <sys/cdefs.h> | |
29 | __RCSID("$NetBSD: cprojl.c,v 1.7 2014/10/10 00:48:18 christos Exp $"); | |
30 | ||
31 | #include <complex.h> | |
32 | #include <math.h> | |
33 | ||
34 | #include "../common/fdlibm.h" | |
35 | ||
36 | /* | |
37 | * cprojl(long double complex z) | |
38 | * | |
39 | * These functions return the value of the projection (not stereographic!) | |
40 | * onto the Riemann sphere. | |
41 | * | |
42 | * z projects to z, except that all complex infinities (even those with one | |
43 | * infinite part and one NaN part) project to positive infinity on the real axis. | |
44 | * If z has an infinite part, then cproj(z) shall be equivalent to: | |
45 | * | |
46 | * INFINITY + I * copysign(0.0, cimag(z)) | |
47 | */ | |
1ed15161 PM |
48 | |
49 | /* On platforms where long double is as wide as double. */ | |
50 | #ifdef _LDBL_EQ_DBL | |
4c2556e9 AU |
51 | long double complex |
52 | cprojl(long double complex z) | |
53 | { | |
54 | long_double_complex w = { .z = z }; | |
55 | ||
56 | /*CONSTCOND*/ | |
57 | if (isinf(creall(z)) || isinf(cimagl(z))) { | |
58 | #ifdef __INFINITY | |
59 | REAL_PART(w) = HUGE_VAL; | |
60 | #else | |
61 | REAL_PART(w) = INFINITY; | |
62 | #endif | |
63 | IMAG_PART(w) = copysignl(0.0L, cimagl(z)); | |
64 | } | |
65 | ||
66 | return (w.z); | |
67 | } | |
1ed15161 | 68 | #endif |