math/s_cproj.c

   1 /* Compute projection of complex double value to Riemann sphere.
   2    Copyright (C) 1997-2013 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
  23
  24 __complex__ double
  25 __cproj (__complex__ double x)
  26 {
  27   if (isnan (__real__ x) && isnan (__imag__ x))
  28     return x;
  29   else if (!isfinite (__real__ x) || !isfinite (__imag__ x))
  30     {
  31       __complex__ double res;
  32
  33       __real__ res = INFINITY;
  34       __imag__ res = __copysign (0.0, __imag__ x);
  35
  36       return res;
  37     }
  38
  39   return x;
  40 }
  41 weak_alias (__cproj, cproj)
  42 #ifdef NO_LONG_DOUBLE
  43 strong_alias (__cproj, __cprojl)
  44 weak_alias (__cproj, cprojl)
  45 #endif