From 928275271da25eb3a8c7470b427542f3003ce79f Mon Sep 17 00:00:00 2001
From: Thomas Becker
Date: Thu, 6 Jun 2013 12:59:18 +0200
Subject: 409953 More efficient implementation of BufferUtil.writeTo(...)

---
 .../java/org/eclipse/jetty/util/BufferUtil.java    | 17 ++++--------
 .../org/eclipse/jetty/util/BufferUtilTest.java     | 30 +++++++++++++---------
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java b/jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java
index bff42a4ac4..85ee7a6327 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java
@@ -84,7 +84,7 @@ import java.nio.charset.Charset;
  */
 public class BufferUtil
 {
-    static final int TEMP_BUFFER_SIZE = 4096;
+    static final int TEMP_BUFFER_SIZE = 512;
     static final byte SPACE = 0x20;
     static final byte MINUS = '-';
     static final byte[] DIGIT =
@@ -439,18 +439,11 @@ public class BufferUtil
         else
         {
             byte[] bytes = new byte[TEMP_BUFFER_SIZE];
-            int j = 0;
-            for (int i = buffer.position(); i < buffer.limit(); i++)
-            {
-                bytes[j] = buffer.get(i);
-                j++;
-                if (j == TEMP_BUFFER_SIZE)
-                {
-                    out.write(bytes);
-                    j = 0;
-                }
+            while(buffer.hasRemaining()){
+                int byteCountToWrite = Math.min(buffer.remaining(), TEMP_BUFFER_SIZE);
+                buffer.get(bytes, 0, byteCountToWrite);
+                out.write(bytes,0 , byteCountToWrite);
             }
-            out.write(bytes, 0, j);
         }
     }
 
diff --git a/jetty-util/src/test/java/org/eclipse/jetty/util/BufferUtilTest.java b/jetty-util/src/test/java/org/eclipse/jetty/util/BufferUtilTest.java
index 77372d8209..886474e5b4 100644
--- a/jetty-util/src/test/java/org/eclipse/jetty/util/BufferUtilTest.java
+++ b/jetty-util/src/test/java/org/eclipse/jetty/util/BufferUtilTest.java
@@ -241,24 +241,30 @@ public class BufferUtilTest
             "ignored.")
     public void testWriteToMicrobenchmark() throws IOException
     {
-        int capacity = 1024 * 1024;
-        int iterations = 30;
+        int capacity = 1024 * 128;
+        int iterations = 100;
+        int testRuns = 10;
         byte[] bytes = new byte[capacity];
         new Random().nextBytes(bytes);
         ByteBuffer buffer = BufferUtil.allocate(capacity);
         BufferUtil.append(buffer, bytes, 0, capacity);
-        long start = System.nanoTime();
-        for (int i = 0; i < iterations; i++)
+        long startTest = System.nanoTime();
+        for (int i = 0; i < testRuns; i++)
         {
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            long startRun = System.nanoTime();
-            BufferUtil.writeTo(buffer.asReadOnlyBuffer(), out);
-            long elapsedRun = System.nanoTime() - startRun;
-            LOG.warn("run elapsed={}ms", elapsedRun / 1000);
-            assertThat("Bytes in out equal bytes in buffer", Arrays.equals(bytes, out.toByteArray()), is(true));
+            long start = System.nanoTime();
+            for (int j = 0; j < iterations; j++)
+            {
+                ByteArrayOutputStream out = new ByteArrayOutputStream();
+                long startRun = System.nanoTime();
+                BufferUtil.writeTo(buffer.asReadOnlyBuffer(), out);
+                long elapsedRun = System.nanoTime() - startRun;
+//                LOG.warn("run elapsed={}ms", elapsedRun / 1000);
+                assertThat("Bytes in out equal bytes in buffer", Arrays.equals(bytes, out.toByteArray()), is(true));
+            }
+            long elapsed = System.nanoTime() - start;
+            LOG.warn("elapsed={}ms average={}ms", elapsed / 1000, elapsed/iterations/1000);
         }
-        long elapsed = System.nanoTime() - start;
-        LOG.warn("elapsed={}ms average={}ms", elapsed / 1000, elapsed/iterations/1000);
+        LOG.warn("overall average: {}ms", (System.nanoTime() - startTest) / testRuns / iterations / 1000);
     }
 
     @Test
-- 
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