/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma weak __ctanhl = ctanhl

#include "libm.h"       /* expl/expm1l/fabsl/isinfl/isnanl/sincosl/sinl/tanhl */
#include "complex_wrapper.h"
#include "longdouble.h"

/* INDENT OFF */
static const long double four = 4.0L, two = 2.0L, one = 1.0L, zero = 0.0L;
/* INDENT ON */

ldcomplex
ctanhl(ldcomplex z) {
        long double r, u, v, t, x, y, S, C;
        int hx, ix, hy, iy;
        ldcomplex ans;

        x = LD_RE(z);
        y = LD_IM(z);
        hx = HI_XWORD(x);
        ix = hx & 0x7fffffff;
        hy = HI_XWORD(y);
        iy = hy & 0x7fffffff;
        x = fabsl(x);
        y = fabsl(y);

        if (y == zero) {        /* ctanh(x,0) = (x,0) for x = 0 or NaN */
                LD_RE(ans) = tanhl(x);
                LD_IM(ans) = zero;
        } else if (iy >= 0x7fff0000) {  /* y is inf or NaN */
                if (ix < 0x7fff0000)    /* catanh(finite x,inf/nan) is nan */
                        LD_RE(ans) = LD_IM(ans) = y - y;
                else if (isinfl(x)) {   /* x is inf */
                        LD_RE(ans) = one;
                        LD_IM(ans) = zero;
                } else {
                        LD_RE(ans) = x + y;
                        LD_IM(ans) = y - y;
                }
        } else if (ix >= 0x4004e000) {
                /* INDENT OFF */
                /*
                 * |x| > 60 = prec/2 (14,28,34,60)
                 * ctanh z ~ 1 + i (sin2y)/(exp(2x))
                 */
                /* INDENT ON */
                LD_RE(ans) = one;
                if (iy < 0x7ffe0000)    /* t = sin(2y) */
                        S = sinl(y + y);
                else {
                        (void) sincosl(y, &S, &C);
                        S = (S + S) * C;
                }
                if (ix >= 0x7ffe0000) { /* |x| > max/2 */
                        if (ix >= 0x7fff0000) { /* |x| is inf or NaN */
                                if (isnanl(x))  /* x is NaN */
                                        LD_RE(ans) = LD_IM(ans) = x + y;
                                else
                                        LD_IM(ans) = zero * S;  /* x is inf */
                        } else
                                LD_IM(ans) = S * expl(-x);      /* underflow */
                } else
                        LD_IM(ans) = (S + S) * expl(-(x + x));
                                                        /* 2 sin 2y / exp(2x) */
        } else {
                /* INDENT OFF */
                /*
                 *                        t*t+2t
                 *    ctanh z = ---------------------------
                 *               t*t+[4(t+1)(cos y)](cos y)
                 *
                 *                  [4(t+1)(cos y)]*(sin y)
                 *              i --------------------------
                 *                t*t+[4(t+1)(cos y)](cos y)
                 */
                /* INDENT ON */
                sincosl(y, &S, &C);
                t = expm1l(x + x);
                r = (four * C) * (t + one);
                u = t * t;
                v = one / (u + r * C);
                LD_RE(ans) = (u + two * t) * v;
                LD_IM(ans) = (r * S) * v;
        }
        if (hx < 0)
                LD_RE(ans) = -LD_RE(ans);
        if (hy < 0)
                LD_IM(ans) = -LD_IM(ans);
        return (ans);
}