From 8cab60cd2b08d1b209575c11ba2e3d786be7e9d7 Mon Sep 17 00:00:00 2001
From: Sean Busbey <busbey@apache.org>
Date: Tue, 12 Mar 2019 23:26:30 -0500
Subject: [PATCH] HBASE-22044 Restore compat for ByteBufferUtils. Also
 deprecated because it will be IA.Private in HBase 3.0

(cherry picked from commit f13a897bf7484f0bc512048e7a16f0d8f04cc238)

Signed-off-by: Andrew Purtell <apurtell@apache.org>
---
 .../hadoop/hbase/util/ByteBufferUtils.java    | 24 +++++++++++++++++++
 1 file changed, 24 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 36fdec5148e..fb687fa1243 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
@@ -36,8 +36,10 @@ import sun.nio.ch.DirectBuffer;
 /**
  * Utility functions for working with byte buffers, such as reading/writing
  * variable-length long numbers.
+ * @deprecated This class will become IA.Private in HBase 3.0. Downstream folks should avoid using it.
  */
 @SuppressWarnings("restriction")
+@Deprecated
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 public final class ByteBufferUtils {
@@ -650,6 +652,28 @@ public final class ByteBufferUtils {
     }
   }
 
+  /**
+   * 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.
+   */
+  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.