GTIFSetFromProj4(): avoid unlikely floating point division by zero (C…

…ID 1589229)

libgeotiff/geotiff_proj4.c

@@ -1,5 +1,4 @@
 /******************************************************************************
- * $Id$
  *
  * Project:  libgeotiff
  * Purpose:  Code to convert a normalized GeoTIFF definition into a PROJ.4
@@ -9,23 +8,7 @@
  ******************************************************************************
  * Copyright (c) 1999, Frank Warmerdam
  *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
+ * SPDX-License-Identifier: MIT
  ******************************************************************************
  */
 
@@ -238,7 +221,7 @@ int GTIFSetFromProj4( GTIF *gtif, const char *proj4 )
         dfSemiMajor = OSR_GDV(papszNV,"a",0.0);
         dfSemiMinor = OSR_GDV(papszNV,"b",0.0);
         dfInvFlattening = OSR_GDV(papszNV,"rf",0.0);
-        if( dfSemiMinor != 0.0 && dfInvFlattening == 0.0 )
+        if( dfSemiMajor != 0.0 && dfSemiMinor != 0.0 && dfInvFlattening == 0.0 )
             dfInvFlattening = -1.0 / (dfSemiMinor/dfSemiMajor - 1.0);
     }