LWGEOM_angle()

Datum LWGEOM_angle

(

PG_FUNCTION_ARGS

)

Definition at line 2702 of file lwgeom_functions_basic.c.

{
        GSERIALIZED *seri_geoms[4];
        LWGEOM *geom_unser;
        LWPOINT *lwpoint;
        POINT2D points[4];
        double az1, az2;
        double result;
        int32_t srids[4];
        int i = 0;
        int j = 0;
        int err_code = 0;
        int n_args = PG_NARGS();
 
        /* no deserialize, checking for common error first*/
        for (i = 0; i < n_args; i++)
        {
                seri_geoms[i] = PG_GETARG_GSERIALIZED_P(i);
                if (gserialized_is_empty(seri_geoms[i]))
                { /* empty geom */
                        if (i == 3)
                        {
                                n_args = 3;
                        }
                        else
                        {
                                err_code = 1;
                                break;
                        }
                }
                else
                {
                        if (gserialized_get_type(seri_geoms[i]) != POINTTYPE)
                        { /* geom type */
                                err_code = 2;
                                break;
                        }
                        else
                        {
                                srids[i] = gserialized_get_srid(seri_geoms[i]);
                                if (srids[0] != srids[i])
                                { /* error on srid*/
                                        err_code = 3;
                                        break;
                                }
                        }
                }
        }
        if (err_code > 0)
                switch (err_code)
                {
                default: /*always executed*/
                        for (j = 0; j <= i; j++)
                                PG_FREE_IF_COPY(seri_geoms[j], j);
                /*FALLTHROUGH*/
                case 1:
                        lwpgerror("Empty geometry");
                        PG_RETURN_NULL();
                        break;
 
                case 2:
                        lwpgerror("Argument must be POINT geometries");
                        PG_RETURN_NULL();
                        break;
 
                case 3:
                        lwpgerror("Operation on mixed SRID geometries");
                        PG_RETURN_NULL();
                        break;
                }
        /* extract points */
        for (i = 0; i < n_args; i++)
        {
                geom_unser = lwgeom_from_gserialized(seri_geoms[i]);
                lwpoint = lwgeom_as_lwpoint(geom_unser);
                if (!lwpoint)
                {
                        for (j = 0; j < n_args; j++)
                                PG_FREE_IF_COPY(seri_geoms[j], j);
                        lwpgerror("Error unserializing geometry");
                        PG_RETURN_NULL();
                }
 
                if (!getPoint2d_p(lwpoint->point, 0, &points[i]))
                {
                        /* // can't free serialized geom, it might be needed by lw
                        for (j=0;j<n_args;j++)
                                PG_FREE_IF_COPY(seri_geoms[j], j); */
                        lwpgerror("Error extracting point");
                        PG_RETURN_NULL();
                }
                /* lwfree(geom_unser);don't do, lw may rely on this memory
                lwpoint_free(lwpoint); dont do , this memory is needed ! */
        }
        /* // can't free serialized geom, it might be needed by lw
        for (j=0;j<n_args;j++)
                PG_FREE_IF_COPY(seri_geoms[j], j); */
 
        /* compute azimuth for the 2 pairs of points
         * note that angle is not defined identically for 3 points or 4 points*/
        if (n_args == 3)
        { /* we rely on azimuth to complain if points are identical */
                if (!azimuth_pt_pt(&points[0], &points[1], &az1))
                        PG_RETURN_NULL();
                if (!azimuth_pt_pt(&points[2], &points[1], &az2))
                        PG_RETURN_NULL();
        }
        else
        {
                if (!azimuth_pt_pt(&points[0], &points[1], &az1))
                        PG_RETURN_NULL();
                if (!azimuth_pt_pt(&points[2], &points[3], &az2))
                        PG_RETURN_NULL();
        }
        result = az2 - az1;
        result += (result < 0) * 2 * M_PI; /* we dont want negative angle*/
        PG_RETURN_FLOAT8(result);
}

References azimuth_pt_pt(), getPoint2d_p(), gserialized_get_srid(), gserialized_get_type(), gserialized_is_empty(), lwgeom_as_lwpoint(), lwgeom_from_gserialized(), LWPOINT::point, POINTTYPE, and result.

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