Application: gvSIG desktop

/* arc sin, cosine, tan2 and sqrt that will NOT fail */

#ifndef lint

static const char SCCSID[]="@(#)aasincos.c        4.6        93/12/12        GIE        REL";

#endif

#include <projects.h>

#define ONE_TOL         1.00000000000001

#define TOL        0.000000001

#define ATOL 1e-50

        double

aasin(double v) {

        double av;

        if ((av = fabs(v)) >= 1.) {

                if (av > ONE_TOL)

                        pj_errno = -19;

                return (v < 0. ? -HALFPI : HALFPI);

        }

        return asin(v);

}

        double

aacos(double v) {

        double av;

        if ((av = fabs(v)) >= 1.) {

                if (av > ONE_TOL)

                        pj_errno = -19;

                return (v < 0. ? PI : 0.);

        }

        return acos(v);

}

        double

asqrt(double v) { return ((v <= 0) ? 0. : sqrt(v)); }

        double

aatan2(double n, double d) {

        return ((fabs(n) < ATOL && fabs(d) < ATOL) ? 0. : atan2(n,d));

}