From 463b5cf21b6fe6e0e8b08615f3e47beb31f39025 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Wed, 31 Aug 2016 07:15:10 +0200
Subject: [PATCH] [#5773] AbstractByteBuf.forEachByteDesc(ByteProcessor) starts
 from wrong index

Motivation:

We introduced a regression in 1abdbe6f6798732447df6dd3af15f6cd871d6279 which let the iteration start from the wrong index.

Modifications:

Fix start index and add tests.

Result:

Fix regression.
---
 .../java/io/netty/buffer/AbstractByteBuf.java |  2 +-
 .../io/netty/buffer/AbstractByteBufTest.java  | 46 +++++++++++++++++++
 .../io/netty/buffer/SlicedByteBufTest.java    | 12 +++++
 .../WrappedUnpooledUnsafeByteBufTest.java     | 12 +++++
 4 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java b/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java
index 3b9d2b1137..5c8c837b02 100644
--- a/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java
+++ b/buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java
@@ -1274,7 +1274,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
     public int forEachByteDesc(ByteProcessor processor) {
         ensureAccessible();
         try {
-            return forEachByteDesc0(writerIndex, readerIndex, processor);
+            return forEachByteDesc0(writerIndex - 1, readerIndex, processor);
         } catch (Exception e) {
             PlatformDependent.throwException(e);
             return -1;
diff --git a/buffer/src/test/java/io/netty/buffer/AbstractByteBufTest.java b/buffer/src/test/java/io/netty/buffer/AbstractByteBufTest.java
index f4e6b90c79..53ec4b1156 100644
--- a/buffer/src/test/java/io/netty/buffer/AbstractByteBufTest.java
+++ b/buffer/src/test/java/io/netty/buffer/AbstractByteBufTest.java
@@ -3203,6 +3203,52 @@ public abstract class AbstractByteBufTest {
         assertEquals(0, buffer2.refCnt());
     }
 
+    @Test
+    public void testForEachByteDesc2() {
+        byte[] expected = {1, 2, 3, 4};
+        ByteBuf buf = newBuffer(expected.length);
+        try {
+            buf.writeBytes(expected);
+            final byte[] bytes = new byte[expected.length];
+            int i = buf.forEachByteDesc(new ByteProcessor() {
+                private int index = bytes.length - 1;
+
+                @Override
+                public boolean process(byte value) throws Exception {
+                    bytes[index--] = value;
+                    return true;
+                }
+            });
+            assertEquals(-1, i);
+            assertArrayEquals(expected, bytes);
+        } finally {
+            buf.release();
+        }
+    }
+
+    @Test
+    public void testForEachByte2() {
+        byte[] expected = {1, 2, 3, 4};
+        ByteBuf buf = newBuffer(expected.length);
+        try {
+            buf.writeBytes(expected);
+            final byte[] bytes = new byte[expected.length];
+            int i = buf.forEachByte(new ByteProcessor() {
+                private int index;
+
+                @Override
+                public boolean process(byte value) throws Exception {
+                    bytes[index++] = value;
+                    return true;
+                }
+            });
+            assertEquals(-1, i);
+            assertArrayEquals(expected, bytes);
+        } finally {
+            buf.release();
+        }
+    }
+
     private static void assertTrueAndRelease(ByteBuf buf, boolean actual) {
         try {
             assertTrue(actual);
diff --git a/buffer/src/test/java/io/netty/buffer/SlicedByteBufTest.java b/buffer/src/test/java/io/netty/buffer/SlicedByteBufTest.java
index 1ab56d4904..f126138233 100644
--- a/buffer/src/test/java/io/netty/buffer/SlicedByteBufTest.java
+++ b/buffer/src/test/java/io/netty/buffer/SlicedByteBufTest.java
@@ -126,6 +126,18 @@ public class SlicedByteBufTest extends AbstractByteBufTest {
         // ignore for SlicedByteBuf
     }
 
+    @Test
+    @Override
+    public void testForEachByteDesc2() {
+        // Ignore for SlicedByteBuf
+    }
+
+    @Test
+    @Override
+    public void testForEachByte2() {
+        // Ignore for SlicedByteBuf
+    }
+
     @Test(expected = UnsupportedOperationException.class)
     @Override
     public void testDuplicateCapacityChange() {
diff --git a/buffer/src/test/java/io/netty/buffer/WrappedUnpooledUnsafeByteBufTest.java b/buffer/src/test/java/io/netty/buffer/WrappedUnpooledUnsafeByteBufTest.java
index 645074b384..81480afb19 100644
--- a/buffer/src/test/java/io/netty/buffer/WrappedUnpooledUnsafeByteBufTest.java
+++ b/buffer/src/test/java/io/netty/buffer/WrappedUnpooledUnsafeByteBufTest.java
@@ -123,4 +123,16 @@ public class WrappedUnpooledUnsafeByteBufTest extends BigEndianUnsafeDirectByteB
     public void testLittleEndianWithExpand() {
         super.testLittleEndianWithExpand();
     }
+
+    @Test
+    @Override
+    public void testForEachByteDesc2() {
+        // Ignore
+    }
+
+    @Test
+    @Override
+    public void testForEachByte2() {
+        // Ignore
+    }
 }