address comment

ulysses-you · ulysses-you · commit 9fcc06b46d43 · 2021-10-16T18:28:36.000+08:00
diff --git a/common/unsafe/src/main/java/org/apache/spark/unsafe/types/ByteArray.java b/common/unsafe/src/main/java/org/apache/spark/unsafe/types/ByteArray.java
@@ -49,7 +49,7 @@ public static long getPrefix(byte[] bytes) {
     return getPrefix(bytes, Platform.BYTE_ARRAY_OFFSET, bytes.length);
   }
 
-  protected static long getPrefix(Object base, long offset, int numBytes) {
+  static long getPrefix(Object base, long offset, int numBytes) {
     // Since JVMs are either 4-byte aligned or 8-byte aligned, we check the size of the bytes.
     // If size is 0, just return 0.
     // If size is between 1 and 4 (inclusive), assume data is 4-byte aligned under the hood and
diff --git a/common/unsafe/src/test/java/org/apache/spark/unsafe/array/ByteArraySuite.java b/common/unsafe/src/test/java/org/apache/spark/unsafe/array/ByteArraySuite.java
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.unsafe.array;
+
+import org.apache.spark.unsafe.Platform;
+import org.apache.spark.unsafe.types.ByteArray;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ByteArraySuite {
+  private long getPrefixByByte(byte[] bytes) {
+    final int minLen = Math.min(bytes.length, 8);
+    long p = 0;
+    for (int i = 0; i < minLen; ++i) {
+      p |= ((long) Platform.getByte(bytes, Platform.BYTE_ARRAY_OFFSET + i) & 0xff)
+              << (56 - 8 * i);
+    }
+    return p;
+  }
+
+  @Test
+  public void testGetPrefix() {
+    for (int i = 0; i <= 9; i++) {
+      byte[] bytes = new byte[i];
+      int prefix = i - 1;
+      while (prefix >= 0) {
+        bytes[prefix] = (byte) prefix;
+        prefix -= 1;
+      }
+
+      long result = ByteArray.getPrefix(bytes);
+      long expected = getPrefixByByte(bytes);
+      Assert.assertEquals(result, expected);
+    }
+  }
+}

Original file line number	Diff line number	Diff line change
`@@ -49,7 +49,7 @@ public static long getPrefix(byte[] bytes) {`
`49`	`49`	`return getPrefix(bytes, Platform.BYTE_ARRAY_OFFSET, bytes.length);`
`50`	`50`	`}`
`51`	`51`
`52`		`- protected static long getPrefix(Object base, long offset, int numBytes) {`
	`52`	`+ static long getPrefix(Object base, long offset, int numBytes) {`
`53`	`53`	`// Since JVMs are either 4-byte aligned or 8-byte aligned, we check the size of the bytes.`
`54`	`54`	`// If size is 0, just return 0.`
`55`	`55`	`// If size is between 1 and 4 (inclusive), assume data is 4-byte aligned under the hood and`