[postgis-tickets] r15671 - Do not call getPointxx_p on empty or null pointarray

[Daniel Baston]

Should callers be doing this type of checking themselves, instead of
incurring the penalty on all point access?

On Fri, Sep 8, 2017 at 5:46 PM, Sandro Santilli <strk at kbt.io> wrote:

> Author: strk
> Date: 2017-09-08 14:46:17 -0700 (Fri, 08 Sep 2017)
> New Revision: 15671
>
> Modified:
>    trunk/liblwgeom/lwpoint.c
> Log:
> Do not call getPointxx_p on empty or null pointarray
>
> Add more 0 returns on error
>
> Modified: trunk/liblwgeom/lwpoint.c
> ===================================================================
> --- trunk/liblwgeom/lwpoint.c   2017-09-08 21:46:10 UTC (rev 15670)
> +++ trunk/liblwgeom/lwpoint.c   2017-09-08 21:46:17 UTC (rev 15671)
> @@ -39,24 +39,24 @@
>  int
>  lwpoint_getPoint2d_p(const LWPOINT *point, POINT2D *out)
>  {
> -       return getPoint2d_p(point->point, 0, out);
> +       return lwpoint_is_empty(point) ? 0 : getPoint2d_p(point->point, 0,
> out);
>  }
>
>  /* convenience functions to hide the POINTARRAY */
>  int
>  lwpoint_getPoint3dz_p(const LWPOINT *point, POINT3DZ *out)
>  {
> -       return getPoint3dz_p(point->point,0,out);
> +       return lwpoint_is_empty(point) ? 0 : getPoint3dz_p(point->point,0,
> out);
>  }
>  int
>  lwpoint_getPoint3dm_p(const LWPOINT *point, POINT3DM *out)
>  {
> -       return getPoint3dm_p(point->point,0,out);
> +       return lwpoint_is_empty(point) ? 0 : getPoint3dm_p(point->point,0,
> out);
>  }
>  int
>  lwpoint_getPoint4d_p(const LWPOINT *point, POINT4D *out)
>  {
> -       return getPoint4d_p(point->point,0,out);
> +       return lwpoint_is_empty(point) ? 0 : getPoint4d_p(point->point,0,
> out);
>  }
>
>  double
> @@ -64,7 +64,10 @@
>  {
>         POINT4D pt;
>         if ( lwpoint_is_empty(point) )
> +       {
>                 lwerror("lwpoint_get_x called with empty geometry");
> +               return 0;
> +       }
>         getPoint4d_p(point->point, 0, &pt);
>         return pt.x;
>  }
> @@ -74,7 +77,10 @@
>  {
>         POINT4D pt;
>         if ( lwpoint_is_empty(point) )
> +       {
>                 lwerror("lwpoint_get_y called with empty geometry");
> +               return 0;
> +       }
>         getPoint4d_p(point->point, 0, &pt);
>         return pt.y;
>  }
> @@ -84,9 +90,15 @@
>  {
>         POINT4D pt;
>         if ( lwpoint_is_empty(point) )
> +       {
>                 lwerror("lwpoint_get_z called with empty geometry");
> +               return 0;
> +       }
>         if ( ! FLAGS_GET_Z(point->flags) )
> +       {
>                 lwerror("lwpoint_get_z called without z dimension");
> +               return 0;
> +       }
>         getPoint4d_p(point->point, 0, &pt);
>         return pt.z;
>  }
> @@ -96,9 +108,15 @@
>  {
>         POINT4D pt;
>         if ( lwpoint_is_empty(point) )
> +       {
>                 lwerror("lwpoint_get_m called with empty geometry");
> +               return 0;
> +       }
>         if ( ! FLAGS_GET_M(point->flags) )
> +       {
>                 lwerror("lwpoint_get_m called without m dimension");
> +               return 0;
> +       }
>         getPoint4d_p(point->point, 0, &pt);
>         return pt.m;
>  }
>
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