1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 #pragma weak __ctan = ctan
31
32 /* INDENT OFF */
33 /*
34 * dcomplex ctan(dcomplex z);
35 *
36 * If z = x+iy, then since ctan(iz) = i*ctanh(z), we have
37 *
38 * ctan(z) = ctan((-1)*(-z)) = ctan(i*i*(-z))
39 * = i*ctanh(i*(-z)) = i*ctanh(i*(-x-yi))
40 * = i*ctanh(y-ix)
41 * = -Im(ctanh(y-ix))+i*Re(ctanh(y-ix))
42 */
43 /* INDENT ON */
44
45 #include "libm.h"
46 #include "complex_wrapper.h"
47
48 dcomplex
ctan(dcomplex z)49 ctan(dcomplex z) {
50 double x, y;
51 dcomplex ans, ct;
52
53 x = D_RE(z);
54 y = D_IM(z);
55 D_RE(z) = y;
56 D_IM(z) = -x;
57 ct = ctanh(z);
58 D_RE(ans) = -D_IM(ct);
59 D_IM(ans) = D_RE(ct);
60 return (ans);
61 }
62