SimpleMergedByteBuffers: ArrayOutOfBoundsFix

This fixes SimpleMergedByteBuffers.getNextBuffer to avoid an ArrayOutOfBounds fix when the buffer has been fully consumed.
We must always check the currentBuffer index before we can attempt to access the array.
In addition the EMPTY_BUFFER_ARRAY can not contain the empty buffer because it makes logic which compares the array length invalid.

Author: jentfoo

gradle.properties

@@ -1,3 +1,3 @@
 group = org.threadly
-version = 4.12-SNAPSHOT
+version = 4.12
 threadlyVersion = 5.41

src/main/java/org/threadly/litesockets/buffers/SimpleMergedByteBuffers.java

@@ -12,7 +12,7 @@
  * 
  */
 public class SimpleMergedByteBuffers extends AbstractMergedByteBuffers {
-  private static final ByteBuffer[] EMPTY_BUFFER_ARRAY = new ByteBuffer[] {IOUtils.EMPTY_BYTEBUFFER};
+  private static final ByteBuffer[] EMPTY_BUFFER_ARRAY = new ByteBuffer[] {};
 
 
   private final ByteBuffer[] bba;
@@ -66,14 +66,12 @@ private void doGet(final byte[] destBytes, int start, int len) {
   }
 
   private ByteBuffer getNextBuffer() {
-    while(!this.bba[this.currentBuffer].hasRemaining() && bba.length > currentBuffer+1 ) {
-      this.bba[this.currentBuffer] = null;
+    ByteBuffer nextBuffer = IOUtils.EMPTY_BYTEBUFFER;
+    while(bba.length > currentBuffer && ! (nextBuffer = bba[currentBuffer]).hasRemaining()) {
+      bba[currentBuffer] = null;
       currentBuffer++;
     }
-    if(bba[this.currentBuffer].hasRemaining()) {
-      return bba[currentBuffer];
-    }
-    return IOUtils.EMPTY_BYTEBUFFER;
+    return nextBuffer;
   }
 
   @Override
@@ -138,9 +136,11 @@ public int nextBufferSize() {
   @Override
   public ByteBuffer popBuffer() {
     ByteBuffer bb = getNextBuffer();
-    consumedSize += bb.remaining();
-    currentBuffer++;
-    return bb.duplicate();
+    if (bb.hasRemaining()) {
+      consumedSize += bb.remaining();
+      currentBuffer++;
+    }
+    return bb;
   }
 
   @Override
@@ -154,12 +154,7 @@ public int remaining() {
 
   @Override
   public boolean hasRemaining() {
-    for(int i=currentBuffer; i<bba.length; i++) {
-      if(bba[i].hasRemaining()) {
-        return true;
-      }
-    }
-    return false;
+    return getNextBuffer().hasRemaining();
   }
 
   @Override
@@ -236,11 +231,11 @@ public void discardFromEnd(int size) {
   @Override
   protected byte get(int pos) {
     int currentPos = 0;
-    for(ByteBuffer bb: this.bba) {
-      if(bb != null && bb.remaining() > pos-currentPos) {
-        return bb.get(pos-currentPos);
+    for (int i = currentBuffer; i < this.bba.length; i++) {
+      if(this.bba[i].remaining() > pos-currentPos) {
+        return this.bba[i].get(pos-currentPos);
       } else {
-        currentPos+=bb.remaining();
+        currentPos+=this.bba[i].remaining();
       }
     }
     return 0;

src/test/java/org/threadly/litesockets/buffers/SimpleMergedByteBuffersTests.java

@@ -62,7 +62,6 @@ public void GetArrayOffset() throws IOException {
 
   @Test
   public void getInts() {
-    
     ByteBuffer[] bba = new ByteBuffer[200]; 
     for(int i = 0; i<200; i++) {
       ByteBuffer bb = ByteBuffer.allocate(4);
@@ -238,7 +237,6 @@ public void popZeroBuffer() {
 
   @Test
   public void popBuffer() {
-
     Random rnd = new Random();
     int size = Math.abs(rnd.nextInt(300))+10;
     MergedByteBuffers mbb = new SimpleMergedByteBuffers(false, ByteBuffer.allocate(size), ByteBuffer.allocate(rnd.nextInt(300)), ByteBuffer.allocate(rnd.nextInt(300)), ByteBuffer.allocate(rnd.nextInt(300)));