Grow the histogram buffer if it is too small

When we serialize a histogram to a byte array, the intermediate
ByteBuffer that we pass may be too small which may result in silent
truncation of the encoded histogram.

This will manifest on the driver side as a decoding failure.

This change detects this case and grows the buffer by a
factor of 2 until it fits.

Fixes #369.

benchmark-framework/src/main/java/io/openmessaging/benchmark/worker/jackson/HistogramSerializer.java

@@ -17,6 +17,8 @@
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+import com.google.common.base.Preconditions;
+
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import org.HdrHistogram.Histogram;
@@ -30,16 +32,40 @@ public HistogramSerializer() {
         super(Histogram.class);
     }
 
+    static byte[] toByteArray(ByteBuffer buffer) {
+        byte[] encodedBuffer = new byte[buffer.remaining()];
+        buffer.get(encodedBuffer);
+        return encodedBuffer;
+    }
+
+    static ByteBuffer serializeHistogram(Histogram histo, ByteBuffer buffer) {
+        buffer.clear();
+        while (true) {
+            final int outBytes = histo.encodeIntoCompressedByteBuffer(buffer);
+            Preconditions.checkState(outBytes == buffer.position());
+            final int capacity = buffer.capacity();
+            if (outBytes < capacity) {
+                // encoding succesful
+                break;
+            }
+            // We filled the entire buffer, an indication that the buffer was not
+            // large enough, so we double the buffer and try again.
+            // See: https://github.com/HdrHistogram/HdrHistogram/issues/201
+            buffer = ByteBuffer.allocate(capacity * 2);
+        }
+        buffer.flip();
+        return buffer;
+    }
+
     @Override
     public void serialize(
             Histogram histogram, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)
             throws IOException {
         ByteBuffer buffer = threadBuffer.get();
-        buffer.clear();
-        histogram.encodeIntoCompressedByteBuffer(buffer);
-        byte[] arr = new byte[buffer.position()];
-        buffer.flip();
-        buffer.get(arr);
-        jsonGenerator.writeBinary(arr);
+        ByteBuffer newBuffer = serializeHistogram(histogram, buffer);
+        if (newBuffer != buffer) {
+            threadBuffer.set(newBuffer);
+        }
+        jsonGenerator.writeBinary(toByteArray(newBuffer));
     }
 }