mingw-w64/mingw-w64-crt/complex/ctanh.def.h

/*
 This Software is provided under the Zope Public License (ZPL) Version 2.1.

 Copyright (c) 2009, 2010 by the mingw-w64 project

 See the AUTHORS file for the list of contributors to the mingw-w64 project.

 This license has been certified as open source. It has also been designated
 as GPL compatible by the Free Software Foundation (FSF).

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 modification, are permitted provided that the following conditions are met:

   1. Redistributions in source code must retain the accompanying copyright
      notice, this list of conditions, and the following disclaimer.
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      copyright notice, this list of conditions, and the following disclaimer
      in the documentation and/or other materials provided with the
      distribution.
   3. Names of the copyright holders must not be used to endorse or promote
      products derived from this software without prior written permission
      from the copyright holders.
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      not give you the right to use Servicemarks (sm) or Trademarks (tm) of
      the copyright holders.  Use of them is covered by separate agreement
      with the copyright holders.
   5. If any files are modified, you must cause the modified files to carry
      prominent notices stating that you changed the files and the date of
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 Disclaimer

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY EXPRESSED
 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
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*/

__FLT_TYPE __complex__ __cdecl
__FLT_ABI(ctanh) (__FLT_TYPE __complex__ z)
{
  __complex__ __FLT_TYPE ret;
  __FLT_TYPE s, c, d;

  if (!isfinite (__real__ z) || !isfinite (__imag__ z))
  {
    if (isinf (__real__ z))
    {
      __real__ ret = __FLT_ABI(copysign) (__FLT_CST(1.0), __real__ z);

      /* fmod will return NaN if __imag__ z is infinity. This is actually
	 OK, because imaginary infinity returns a + or - zero (unspecified).
	 For +x, sin (x) is negative if fmod (x, 2pi) > pi.
	 For -x, sin (x) is positive if fmod (x, 2pi) < pi.
	 We use epsilon to ensure that the zeros are detected properly with
	 float and long double comparisons.  */
      s = __FLT_ABI(fmod) (__imag__ z, __FLT_PI);
      if (signbit (__imag__ z))
	__imag__ ret = s + __FLT_PI_2 < -__FLT_EPSILON ? 0.0 : -0.0;
      else
	__imag__ ret = s - __FLT_PI_2 > __FLT_EPSILON ? -0.0 : 0.0;
      return ret;
    }

    if (__imag__ z == __FLT_CST(0.0))
      return z;

    __real__ ret = __FLT_NAN;
    __imag__ ret = __FLT_NAN;
    return ret;
  }

  __FLT_ABI(sincos) (__FLT_CST(2.0) * __imag__ z, &s, &c);

  d = (__FLT_ABI(cosh) (__FLT_CST(2.0) * __real__ z) + c);

  if (d == __FLT_CST(0.0))
  {
    __complex__ __FLT_TYPE ez = __FLT_ABI(cexp) (z);
    __complex__ __FLT_TYPE emz = __FLT_ABI(cexp) (-z);

    return (ez - emz) / (ez + emz);
  }

  __real__ ret = __FLT_ABI(sinh) (__FLT_CST(2.0) * __real__ z) / d;
  __imag__ ret = s / d;
  return ret;
}