From 2351663f3aa8d5526a3c5d59277c9a751370e84b Mon Sep 17 00:00:00 2001
From: Robert Muir <rmuir@apache.org>
Date: Wed, 9 Jan 2013 19:31:23 +0000
Subject: [PATCH] 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                            |  2 ++
 .../java/org/apache/lucene/util/CharsRef.java |  2 +-
 .../org/apache/lucene/util/TestCharsRef.java  | 19 ++++++++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 770155943df..5b32d7d4ec5 100644
--- a/lucene/CHANGES.txt
+++ b/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
   
diff --git a/lucene/core/src/java/org/apache/lucene/util/CharsRef.java b/lucene/core/src/java/org/apache/lucene/util/CharsRef.java
index 60537bfdeb9..30e95439c76 100644
--- a/lucene/core/src/java/org/apache/lucene/util/CharsRef.java
+++ b/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 */
diff --git a/lucene/core/src/test/org/apache/lucene/util/TestCharsRef.java b/lucene/core/src/test/org/apache/lucene/util/TestCharsRef.java
index 4237a6d0478..1997bcc4296 100644
--- a/lucene/core/src/test/org/apache/lucene/util/TestCharsRef.java
+++ b/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());