Allow WKTReader to read Inf ordinates (#1166)

Author: dr-jts

modules/core/src/main/java/org/locationtech/jts/geom/PrecisionModel.java

@@ -412,15 +412,15 @@ public void toExternal(Coordinate internal, Coordinate external) {
    * uniform rounding behaviour no matter where the number is
    * on the number line.
    * <p>
-   * This method has no effect on NaN values.
+   * This method has no effect on NaN and infinite values.
    * <p>
    * <b>Note:</b> Java's <code>Math#rint</code> uses the "Banker's Rounding" algorithm,
    * which is not suitable for precision operations elsewhere in JTS.
    */
   public double makePrecise(double val) 
   {
   	// don't change NaN values
-  	if (Double.isNaN(val)) return val;
+  	if (Double.isNaN(val) || Double.isInfinite(val)) return val;
 
   	if (modelType == FLOATING_SINGLE) {
   		float floatSingleVal = (float) val;

modules/core/src/main/java/org/locationtech/jts/io/WKTReader.java

@@ -80,6 +80,8 @@
  * <li>The reader uses <tt>Double.parseDouble</tt> to perform the conversion of ASCII
  * numbers to floating point.  This means it supports the Java
  * syntax for floating point literals (including scientific notation).
+ * <li><tt>NaN</tt> and <tt>Inf</tt> ordinate symbols are supported (case-insensitive), 
+ * which convert to the corresponding IEE-754 value
  * </ul>
  * <h3>Syntax</h3>
  * The following syntax specification describes the version of Well-Known Text
@@ -131,7 +133,7 @@
  * <i>Coordinate:
  *         Number Number Number<sub>opt</sub> Number<sub>opt</sub></i>
  *
- * <i>Number:</i> A Java-style floating-point number (including <tt>NaN</tt>, with arbitrary case)
+ * <i>Number:</i> A Java-style floating-point number (including <tt>NaN</tt> and <tt>Inf</tt>, with arbitrary case)
  *
  * <i>Dimension:</i>
  *         <b>Z</b>|<b> Z</b>|<b>M</b>|<b> M</b>|<b>ZM</b>|<b> ZM</b>
@@ -159,6 +161,8 @@
  * POINT M (0 0 0)
  * POINTZM (0 0 0 0)
  * POINT ZM (0 0 0 0)
+ * 
+ * POINT (Inf Nan)
  * </pre>
  *
  *@version 1.7
@@ -170,6 +174,7 @@ public class WKTReader
   private static final String L_PAREN = "(";
   private static final String R_PAREN = ")";
   private static final String NAN_SYMBOL = "NaN";
+  private static final String INF_SYMBOL = "Inf";
 
   private GeometryFactory geometryFactory;
   private CoordinateSequenceFactory csFactory;
@@ -517,6 +522,10 @@ private double getNextNumber(StreamTokenizer tokenizer) throws IOException,
         if (tokenizer.sval.equalsIgnoreCase(NAN_SYMBOL)) {
           return Double.NaN;
         }
+        if (tokenizer.sval.equalsIgnoreCase(INF_SYMBOL)) {
+          return Double.POSITIVE_INFINITY;
+        }
+        //TODO: handle -Inf ?
         else {
           try {
             return Double.parseDouble(tokenizer.sval);

modules/core/src/test/java/org/locationtech/jts/io/WKTReaderTest.java

@@ -464,6 +464,13 @@ public void testNaN() throws Exception {
     assertTrue(isEqual(seq, pt3.getCoordinateSequence()));
   }
 
+  public void testInf() throws ParseException {
+    Point pt = (Point) readerXY.read("POINT ( Inf INF )");
+    CoordinateSequence cs = pt.getCoordinateSequence();
+    assertEquals(Double.POSITIVE_INFINITY, cs.getOrdinate(0, Coordinate.X));
+    assertEquals(Double.POSITIVE_INFINITY, cs.getOrdinate(0, Coordinate.Y));
+  }
+  
   public void testLargeNumbers() throws Exception {
     PrecisionModel precisionModel = new PrecisionModel(1E9);
     GeometryFactory geometryFactory = new GeometryFactory(precisionModel, 0);

modules/core/src/test/java/org/locationtech/jts/operation/buffer/BufferTest.java

@@ -694,31 +694,24 @@ public void testInvalidCoordPoint() {
 
   public void testInvalidCoordsLine() {
     // works for Inf ordinates as well
-    Geometry geom = read("LINESTRING (NaN NaN, NaN NaN)");
+    Geometry geom = read("LINESTRING (Inf Inf, NaN NaN)");
     checkBufferPolygonEmpty(geom, 1, true);
   }
-
+  
   public void testInvalidCoordShell() {
     // using Inf ordinates creates a valid ring with equal endpoints
-    // this would be simpler if JTS WKT supported Inf
-    Geometry geom = getGeometryFactory().createPolygon( infCoords(5) );
+    Geometry geom = (Polygon) read("POLYGON ((Inf Inf, Inf Inf, Inf Inf, Inf Inf, Inf Inf))");
     checkBufferPolygonEmpty(geom, 1, true);
   }
 
   public void testInvalidCoordHole() {
     // using Inf ordinates creates a valid ring with equal endpoints
-    // this would be simpler if JTS WKT supported Inf
     Polygon poly = (Polygon) read("POLYGON ((1 9, 9 9, 9 1, 1 1, 1 9), (3 7, 7 7, 7 3, 3 3, 3 7))");
-
-    LinearRing shell = poly.getExteriorRing();
-    LinearRing hole =  poly.getInteriorRingN(0);
-    LinearRing infHole = getGeometryFactory().createLinearRing( infCoords(5) );
-    Geometry polyInfHole = getGeometryFactory().createPolygon( 
-        shell, new LinearRing[] { hole, infHole } );
+    Polygon polyInfHole = (Polygon) read("POLYGON ((1 9, 9 9, 9 1, 1 1, 1 9), (3 7, 7 7, 7 3, 3 3, 3 7), (Inf Inf, Inf Inf, Inf Inf, Inf Inf, Inf Inf))");
 
     Geometry bufferOrig = poly.buffer(1);
     Geometry bufferInf = polyInfHole.buffer(1);
-    // buffers should be same since inf hole is skipped
+    // buffers should be same since inf hole is dropped
     checkEqual(bufferOrig, bufferInf);
   }