/*
 * 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 __ctanhf = ctanhf

#include "libm.h"               /* expf/expm1f/fabsf/sincosf/sinf/tanhf */
#include "complex_wrapper.h"

/* INDENT OFF */
static const float four = 4.0F, two = 2.0F, one = 1.0F, zero = 0.0F;
/* INDENT ON */

fcomplex
ctanhf(fcomplex z) {
        float r, u, v, t, x, y, S, C;
        int hx, ix, hy, iy;
        fcomplex ans;

        x = F_RE(z);
        y = F_IM(z);
        hx = THE_WORD(x);
        ix = hx & 0x7fffffff;
        hy = THE_WORD(y);
        iy = hy & 0x7fffffff;
        x = fabsf(x);
        y = fabsf(y);

        if (iy == 0) {          /* ctanh(x,0) = (x,0) for x = 0 or NaN */
                F_RE(ans) = tanhf(x);
                F_IM(ans) = zero;
        } else if (iy >= 0x7f800000) {  /* y is inf or NaN */
                if (ix < 0x7f800000)    /* catanh(finite x,inf/nan) is nan */
                        F_RE(ans) = F_IM(ans) = y - y;
                else if (ix == 0x7f800000) {    /* x is inf */
                        F_RE(ans) = one;
                        F_IM(ans) = zero;
                } else {
                        F_RE(ans) = x + y;
                        F_IM(ans) = y - y;
                }
        } else if (ix >= 0x41600000) {
                /*
                 * |x| > 14 = prec/2 (14,28,34,60)
                 * ctanh z ~ 1 + i (sin2y)/(exp(2x))
                 */
                F_RE(ans) = one;
                if (iy < 0x7f000000)    /* t = sin(2y) */
                        S = sinf(y + y);
                else {
                        (void) sincosf(y, &S, &C);
                        S = (S + S) * C;
                }
                if (ix >= 0x7f000000) { /* |x| > max/2 */
                        if (ix >= 0x7f800000) { /* |x| is inf or NaN */
                                if (ix > 0x7f800000)    /* x is NaN */
                                        F_RE(ans) = F_IM(ans) = x + y;
                                else
                                        F_IM(ans) = zero * S;   /* x is inf */
                        } else
                                F_IM(ans) = S * expf(-x);       /* underflow */
                } else
                        F_IM(ans) = (S + S) * expf(-(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 */
                (void) sincosf(y, &S, &C);
                t = expm1f(x + x);
                r = (four * C) * (t + one);
                u = t * t;
                v = one / (u + r * C);
                F_RE(ans) = (u + two * t) * v;
                F_IM(ans) = (r * S) * v;
        }
        if (hx < 0)
                F_RE(ans) = -F_RE(ans);
        if (hy < 0)
                F_IM(ans) = -F_IM(ans);
        return (ans);
}