Detect more truncated compact Rinex files.

src/main/java/org/orekit/gnss/HatanakaCompressFilter.java

@@ -671,6 +671,9 @@ public class HatanakaCompressFilter implements DataFilter {
             // read the first two lines of the file
             final String line1 = reader.readLine();
             final String line2 = reader.readLine();
+            if (line1 == null || line2 == null) {
+                throw new OrekitException(OrekitMessages.NOT_A_SUPPORTED_HATANAKA_COMPRESSED_FILE, name);
+            }
 
             // extract format version
             final int cVersion100 = (int) FastMath.rint(100 * parseDouble(line1, 0, 9));

src/test/java/org/orekit/gnss/HatanakaCompressFilterTest.java

@@ -78,6 +78,16 @@ public class HatanakaCompressFilterTest {
         doTestWrong("rinex/truncateB_U_20190320000_15M_30S_MO.crx", OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE);
     }
 
+    @Test
+    public void testTruncatedCompactHeader() throws IOException {
+        doTestWrong("rinex/truncateC_U_20190320000_15M_30S_MO.crx", OrekitMessages.NOT_A_SUPPORTED_HATANAKA_COMPRESSED_FILE);
+    }
+
+    @Test
+    public void testEmpty() throws IOException {
+        doTestWrong("rinex/emptyFile_U_20190320000_15M_30S_MO.crx", OrekitMessages.NOT_A_SUPPORTED_HATANAKA_COMPRESSED_FILE);
+    }
+
     @Test
     public void testBadClockReset() throws IOException {
         doTestWrong("rinex/badclkrst_U_20190320000_10M_10M_MO.crx", OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE);

src/test/resources/rinex/truncateC_U_20190320000_15M_30S_MO.crx

+3.0                 COMPACT RINEX FORMAT                    CRINEX VERS   / TYPE