lwpoly_construct_circle: Avoid division by zero (Raúl Marín Rodríguez)

References #4003

git-svn-id: http://svn.osgeo.org/postgis/branches/2.4@16362 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/NEWS b/NEWS
index ada83ba4e4cf50372518a42d5fd3d2e5875560a3..53f40b336339cd77fe27956ae9ce1d2f1e4c478e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,7 @@ PostGIS 2.4.4dev
  * Bug fixes *
   - #3978, Fix KNN when upgrading from 2.1 or older (Sandro Santilli)
   - #4004, Avoid memory exhaustion when building a btree index (Edmund Horner)
+  - #4003, lwpoly_construct_circle: Avoid division by zero (Raúl Marín Rodríguez)
 
 PostGIS 2.3.6
 2018/01/17

diff --git a/liblwgeom/lwpoly.c b/liblwgeom/lwpoly.c
index bb8097c486106b4ce44dfdc501177d57f3828785..81135621e2a199d8cc6dd92f30c4d92064a04cc8 100644 (file)
--- a/liblwgeom/lwpoly.c
+++ b/liblwgeom/lwpoly.c
@@ -120,13 +120,13 @@ LWPOLY*
 lwpoly_construct_circle(int srid, double x, double y, double radius, uint32_t segments_per_quarter, char exterior)
 {
        const int segments = 4*segments_per_quarter;
-       const double theta = 2*M_PI / segments;
+       double theta;
        LWPOLY *lwpoly;
        POINTARRAY *pa;
        POINT4D pt;
        uint32_t i;
 
-       if (segments_per_quarter < 1)
+       if (segments_per_quarter == 0)
        {
                lwerror("Need at least one segment per quarter-circle.");
                return NULL;
@@ -138,6 +138,8 @@ lwpoly_construct_circle(int srid, double x, double y, double radius, uint32_t se
                return NULL;
        }
 
+       theta = 2*M_PI / segments;
+
        lwpoly = lwpoly_construct_empty(srid, LW_FALSE, LW_FALSE);
        pa = ptarray_construct_empty(LW_FALSE, LW_FALSE, segments + 1);