1/* Return arc hyperbole cosine for double value.
2 Copyright (C) 1997-2016 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#include <complex.h>
21#include <math.h>
22#include <math_private.h>
23
24
25__complex__ double
26__cacosh (__complex__ double x)
27{
28 __complex__ double res;
29 int rcls = fpclassify (__real__ x);
30 int icls = fpclassify (__imag__ x);
31
32 if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
33 {
34 if (icls == FP_INFINITE)
35 {
36 __real__ res = HUGE_VAL;
37
38 if (rcls == FP_NAN)
39 __imag__ res = __nan ("");
40 else
41 __imag__ res = __copysign ((rcls == FP_INFINITE
42 ? (__real__ x < 0.0
43 ? M_PI - M_PI_4 : M_PI_4)
44 : M_PI_2), __imag__ x);
45 }
46 else if (rcls == FP_INFINITE)
47 {
48 __real__ res = HUGE_VAL;
49
50 if (icls >= FP_ZERO)
51 __imag__ res = __copysign (signbit (__real__ x) ? M_PI : 0.0,
52 __imag__ x);
53 else
54 __imag__ res = __nan ("");
55 }
56 else
57 {
58 __real__ res = __nan ("");
59 __imag__ res = __nan ("");
60 }
61 }
62 else if (rcls == FP_ZERO && icls == FP_ZERO)
63 {
64 __real__ res = 0.0;
65 __imag__ res = __copysign (M_PI_2, __imag__ x);
66 }
67 else
68 {
69 __complex__ double y;
70
71 __real__ y = -__imag__ x;
72 __imag__ y = __real__ x;
73
74 y = __kernel_casinh (y, 1);
75
76 if (signbit (__imag__ x))
77 {
78 __real__ res = __real__ y;
79 __imag__ res = -__imag__ y;
80 }
81 else
82 {
83 __real__ res = -__real__ y;
84 __imag__ res = __imag__ y;
85 }
86 }
87
88 return res;
89}
90weak_alias (__cacosh, cacosh)
91#ifdef NO_LONG_DOUBLE
92strong_alias (__cacosh, __cacoshl)
93weak_alias (__cacosh, cacoshl)
94#endif
95