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

#include <math.h>

#include "proj.h"

#include "proj_internal.h"

#define ONE_TOL 1.00000000000001

#define ATOL 1e-50

double aasin(PJ_CONTEXT *ctx, double v) {

    double av;

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

        if (av > ONE_TOL)

            proj_context_errno_set(

                ctx, PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN);

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

    }

    return asin(v);

}

double aacos(PJ_CONTEXT *ctx, double v) {

    double av;

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

        if (av > ONE_TOL)

            proj_context_errno_set(

                ctx, PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN);

        return (v < 0. ? M_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));

}