Grow ByteArrayDataOutputStream exponentially (https://issues.jboss.or…

…g/browse/JGRP-2002)

src/org/jgroups/util/ByteArrayDataOutputStream.java

@@ -13,25 +13,30 @@
  * @since  3.5
  */
 public class ByteArrayDataOutputStream implements DataOutput {
-    protected byte[] buf;
-    protected int    pos;
+    protected byte[]  buf;
+    protected int     pos;
+    protected boolean grow_exponentially; // if true, the buffer will double every time
 
     public ByteArrayDataOutputStream() {
-        this(32);
+        this(32, false);
     }
 
     public ByteArrayDataOutputStream(int capacity) {
-        this.buf=new byte[capacity];
+        this(capacity, false);
     }
 
-    public ByteArrayDataOutputStream position(int pos) {
-        this.pos=checkBounds(pos); return this;
+    public ByteArrayDataOutputStream(int capacity, boolean grow_exponentially) {
+        this.buf=new byte[capacity];
+        this.grow_exponentially=grow_exponentially;
     }
 
-    public int        position()      {return pos;}
-    public byte[]     buffer()        {return buf;}
-    public Buffer     getBuffer()     {return new Buffer(buf, 0, pos);}
-    public ByteBuffer getByteBuffer() {return ByteBuffer.wrap(buf, 0, pos);}
+    public ByteArrayDataOutputStream position(int pos)            {this.pos=checkBounds(pos); return this;}
+    public int                       position()                   {return pos;}
+    public byte[]                    buffer()                     {return buf;}
+    public Buffer                    getBuffer()                  {return new Buffer(buf, 0, pos);}
+    public ByteBuffer                getByteBuffer()              {return ByteBuffer.wrap(buf, 0, pos);}
+    public boolean                   growExponentially()          {return grow_exponentially;}
+    public ByteArrayDataOutputStream growExponentially(boolean b) {grow_exponentially=b; return this;}
 
 
     public void write(int b) {
@@ -181,10 +186,21 @@ protected int checkBounds(int pos) {
         return pos;
     }
 
+    /** Grows the buffer; whether it grow linearly or exponentially depends on grow_exponentially */
     protected void ensureCapacity(int bytes) {
-        if(pos + bytes > buf.length) {
-            int new_size=buf.length + bytes + 32;
-            buf=Arrays.copyOf(buf, new_size);
+        int minCapacity=pos+bytes;
+
+        if(minCapacity - buf.length > 0) {
+            int newCapacity=this.grow_exponentially? buf.length << 1 : buf.length + bytes + 32;
+            if(newCapacity - minCapacity < 0)
+                newCapacity=minCapacity;
+            if(newCapacity < 0) {
+                if(minCapacity < 0) // overflow
+                    throw new OutOfMemoryError();
+                newCapacity=Integer.MAX_VALUE;
+            }
+            // System.out.printf("growing buffer from %d -> %d (pos=%d, bytes=%d)\n", buf.length, newCapacity, pos, bytes);
+            buf=Arrays.copyOf(buf, newCapacity);
         }
     }
 }

src/org/jgroups/util/Util.java

@@ -521,20 +521,20 @@ public static byte[] objectToByteBuffer(Object obj) throws Exception {
             return TYPE_NULL_ARRAY;
 
         if(obj instanceof Streamable) {
-            final ByteArrayDataOutputStream out=new ByteArrayDataOutputStream(512);
+            final ByteArrayDataOutputStream out=new ByteArrayDataOutputStream(512, true);
             out.write(TYPE_STREAMABLE);
             writeGenericStreamable((Streamable)obj,out);
             return Arrays.copyOf(out.buf,out.position());
         }
 
         Byte type=PRIMITIVE_TYPES.get(obj.getClass());
         if(type == null) { // will throw an exception if object is not serializable
-            final ByteArrayOutputStream out_stream=new ByteArrayOutputStream(512);
+            final ByteArrayDataOutputStream out_stream=new ByteArrayDataOutputStream(512, true);
             out_stream.write(TYPE_SERIALIZABLE);
-            try(ObjectOutputStream out=new ObjectOutputStream(out_stream)) {
+            try(ObjectOutputStream out=new ObjectOutputStream(new OutputStreamAdapter(out_stream))) {
                 out.writeObject(obj);
                 out.flush();
-                return out_stream.toByteArray();
+                return Arrays.copyOf(out_stream.buffer(), out_stream.position());
             }
         }
 
@@ -597,20 +597,20 @@ public static Buffer objectToBuffer(Object obj) throws Exception {
             return new Buffer(TYPE_NULL_ARRAY);
 
         if(obj instanceof Streamable) {
-            final ByteArrayDataOutputStream out=new ByteArrayDataOutputStream(512);
+            final ByteArrayDataOutputStream out=new ByteArrayDataOutputStream(512, true);
             out.write(TYPE_STREAMABLE);
             writeGenericStreamable((Streamable)obj,out);
             return out.getBuffer();
         }
 
         Byte type=PRIMITIVE_TYPES.get(obj.getClass());
         if(type == null) { // will throw an exception if object is not serializable
-            final ByteArrayOutputStream out_stream=new ByteArrayOutputStream(512);
+            final ByteArrayDataOutputStream out_stream=new ByteArrayDataOutputStream(512, true);
             out_stream.write(TYPE_SERIALIZABLE);
-            try(ObjectOutputStream out=new ObjectOutputStream(out_stream)) {
+            try(ObjectOutputStream out=new ObjectOutputStream(new OutputStreamAdapter(out_stream))) {
                 out.writeObject(obj);
                 out.flush();
-                return new Buffer(out_stream.toByteArray());
+                return out_stream.getBuffer();
             }
         }