From 12bb5ff595870928eec5965db2ac718339752c3e Mon Sep 17 00:00:00 2001
From: Nick Dimiduk <ndimiduk@apache.org>
Date: Thu, 25 Jun 2020 11:09:58 -0700
Subject: [PATCH] HBASE-22504 Addendum: restore findCommonPrefix

Address incompatibility issue raised in 2.3.0RC0 vote thread.
---
 .../hadoop/hbase/util/ByteBufferUtils.java    | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java
index e29ead5a16cc..ae87e32d7819 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java
@@ -737,6 +737,28 @@ public static void copyFromBufferToBuffer(ByteBuffer in, ByteBuffer out, int sou
     }
   }
 
+  /**
+   * Find length of common prefix of two parts in the buffer
+   * @param buffer Where parts are located.
+   * @param offsetLeft Offset of the first part.
+   * @param offsetRight Offset of the second part.
+   * @param limit Maximal length of common prefix.
+   * @return Length of prefix.
+   */
+  @SuppressWarnings("unused")
+  public static int findCommonPrefix(ByteBuffer buffer, int offsetLeft,
+      int offsetRight, int limit) {
+    int prefix = 0;
+
+    for (; prefix < limit; ++prefix) {
+      if (buffer.get(offsetLeft + prefix) != buffer.get(offsetRight + prefix)) {
+        break;
+      }
+    }
+
+    return prefix;
+  }
+
   /**
    * Find length of common prefix in two arrays.
    * @param left Array to be compared.