LUCENE-4671: Fix CharsRef.subSequence method

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1431019 13f79535-47bb-0310-9956-ffa450edef68

lucene/CHANGES.txt

@@ -324,6 +324,8 @@ Bug Fixes
 
 * LUCENE-4662: Add missing elided articles and prepositions to FrenchAnalyzer's
   DEFAULT_ARTICLES list passed to ElisionFilter.  (David Leunen via Steve Rowe)
+
+* LUCENE-4671: Fix CharsRef.subSequence method.  (Tim Smith via Robert Muir)
     
 Changes in Runtime Behavior
   

lucene/core/src/java/org/apache/lucene/util/CharsRef.java

@@ -218,7 +218,7 @@ public final class CharsRef implements Comparable<CharsRef>, CharSequence, Clone
     if (start < 0 || end > length || start > end) {
       throw new IndexOutOfBoundsException();
     }
-    return new CharsRef(chars, offset + start, offset + end);
+    return new CharsRef(chars, offset + start, end - start);
   }
   
   /** @deprecated This comparator is only a transition mechanism */

lucene/core/src/test/org/apache/lucene/util/TestCharsRef.java

@@ -116,11 +116,28 @@ public class TestCharsRef extends LuceneTestCase {
   }
   
   // LUCENE-3590: fix off-by-one in subsequence, and fully obey interface
+  // LUCENE-4671: fix subSequence
   public void testCharSequenceSubSequence() {
-    CharSequence c = new CharsRef("abc");
+    CharSequence sequences[] =  {
+        new CharsRef("abc"),
+        new CharsRef("0abc".toCharArray(), 1, 3),
+        new CharsRef("abc0".toCharArray(), 0, 3),
+        new CharsRef("0abc0".toCharArray(), 1, 3)
+    };
+    
+    for (CharSequence c : sequences) {
+      doTestSequence(c);
+    }
+  }
+    
+  private void doTestSequence(CharSequence c) {
     
     // slice
     assertEquals("a", c.subSequence(0, 1).toString());
+    // mid subsequence
+    assertEquals("b", c.subSequence(1, 2).toString());
+    // end subsequence
+    assertEquals("bc", c.subSequence(1, 3).toString());
     // empty subsequence
     assertEquals("", c.subSequence(0, 0).toString());