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-rw-r--r--math/s_cproj.c51
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diff --git a/math/s_cproj.c b/math/s_cproj.c
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+/* Compute projection of complex double value to Riemann sphere.
+ Copyright (C) 1997, 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <complex.h>
+#include <math.h>
+
+
+__complex__ double
+__cproj (__complex__ double x)
+{
+ __complex__ double res;
+
+ if (isnan (__real__ x) && isnan (__imag__ x))
+ return x;
+ else if (!isfinite (__real__ x) || !isfinite (__imag__ x))
+ {
+ __real__ res = INFINITY;
+ __imag__ res = __copysign (0.0, __imag__ x);
+ }
+ else
+ {
+ double den = __real__ x * __real__ x + __imag__ x * __imag__ x + 1.0;
+
+ __real__ res = (2.0 * __real__ x) / den;
+ __imag__ res = (2.0 * __imag__ x) / den;
+ }
+
+ return res;
+}
+weak_alias (__cproj, cproj)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__cproj, __cprojl)
+weak_alias (__cproj, cprojl)
+#endif