From 17d54c6bb898e27cbb386c214921ad4feaf106f8 Mon Sep 17 00:00:00 2001
From: Matthew Brandyberry <mbrandy@us.ibm.com>
Date: Fri, 31 Jul 2015 17:27:55 -0500
Subject: [PATCH 1/2] [SPARK-9483] Fix UTF8String.getPrefix for big-endian.

Previous code assumed little-endian.
---
 .../org/apache/spark/unsafe/types/UTF8String.java  | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java b/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
index c38953f65d7d7..5285dbadaefd6 100644
--- a/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
+++ b/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
@@ -20,6 +20,7 @@
 import javax.annotation.Nonnull;
 import java.io.Serializable;
 import java.io.UnsupportedEncodingException;
+import java.nio.ByteOrder;
 import java.util.Arrays;
 
 import org.apache.spark.unsafe.PlatformDependent;
@@ -161,18 +162,25 @@ public long getPrefix() {
     // If size is greater than 4, assume we have at least 8 bytes of data to fetch.
     // After getting the data, we use a mask to mask out data that is not part of the string.
     long p;
+    long mask = 0;
     if (numBytes >= 8) {
       p = PlatformDependent.UNSAFE.getLong(base, offset);
     } else  if (numBytes > 4) {
+      mask = (1L << (8 - numBytes) * 8) - 1;
       p = PlatformDependent.UNSAFE.getLong(base, offset);
-      p = p & ((1L << numBytes * 8) - 1);
     } else if (numBytes > 0) {
+      mask = (1L << (8 - numBytes) * 8) - 1;
       p = (long) PlatformDependent.UNSAFE.getInt(base, offset);
-      p = p & ((1L << numBytes * 8) - 1);
+      if (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN) {
+        p <<= 32;
+      }
     } else {
       p = 0;
     }
-    p = java.lang.Long.reverseBytes(p);
+    if (ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN) {
+      p = java.lang.Long.reverseBytes(p);
+    }
+    p &= ~mask;
     return p;
   }
 

From ec31df8ce5b32b747224212bef15e3f85d96a572 Mon Sep 17 00:00:00 2001
From: Matthew Brandyberry <mbrandy@us.ibm.com>
Date: Mon, 3 Aug 2015 16:19:15 -0500
Subject: [PATCH 2/2] [SPARK-9483] Changes from review comments.

- Introduce static byteOrder variable
- Branch on byteOrder at top-level for readability.
---
 .../apache/spark/unsafe/types/UTF8String.java | 40 ++++++++++++-------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java b/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
index 5285dbadaefd6..bd6b60159967c 100644
--- a/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
+++ b/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
@@ -51,6 +51,8 @@ public final class UTF8String implements Comparable<UTF8String>, Serializable {
     5, 5, 5, 5,
     6, 6};
 
+  private static ByteOrder byteOrder = ByteOrder.nativeOrder();
+
   public static final UTF8String EMPTY_UTF8 = UTF8String.fromString("");
 
   /**
@@ -163,22 +165,32 @@ public long getPrefix() {
     // After getting the data, we use a mask to mask out data that is not part of the string.
     long p;
     long mask = 0;
-    if (numBytes >= 8) {
-      p = PlatformDependent.UNSAFE.getLong(base, offset);
-    } else  if (numBytes > 4) {
-      mask = (1L << (8 - numBytes) * 8) - 1;
-      p = PlatformDependent.UNSAFE.getLong(base, offset);
-    } else if (numBytes > 0) {
-      mask = (1L << (8 - numBytes) * 8) - 1;
-      p = (long) PlatformDependent.UNSAFE.getInt(base, offset);
-      if (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN) {
-        p <<= 32;
+    if (byteOrder == ByteOrder.LITTLE_ENDIAN) {
+      if (numBytes >= 8) {
+        p = PlatformDependent.UNSAFE.getLong(base, offset);
+      } else if (numBytes > 4) {
+        p = PlatformDependent.UNSAFE.getLong(base, offset);
+        mask = (1L << (8 - numBytes) * 8) - 1;
+      } else if (numBytes > 0) {
+        p = (long) PlatformDependent.UNSAFE.getInt(base, offset);
+        mask = (1L << (8 - numBytes) * 8) - 1;
+      } else {
+        p = 0;
       }
-    } else {
-      p = 0;
-    }
-    if (ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN) {
       p = java.lang.Long.reverseBytes(p);
+    } else {
+      // byteOrder == ByteOrder.BIG_ENDIAN
+      if (numBytes >= 8) {
+        p = PlatformDependent.UNSAFE.getLong(base, offset);
+      } else if (numBytes > 4) {
+        p = PlatformDependent.UNSAFE.getLong(base, offset);
+        mask = (1L << (8 - numBytes) * 8) - 1;
+      } else if (numBytes > 0) {
+        p = ((long) PlatformDependent.UNSAFE.getInt(base, offset)) << 32;
+        mask = (1L << (8 - numBytes) * 8) - 1;
+      } else {
+        p = 0;
+      }
     }
     p &= ~mask;
     return p;