src/java.base/share/classes/java/io/ByteArrayOutputStream.java

rev 54801 : [mq]: 8223593-Refactor-code-for-reallocating-storage

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -27,10 +27,12 @@
 
 import java.nio.charset.Charset;
 import java.util.Arrays;
 import java.util.Objects;
 
+import jdk.internal.util.ArraysSupport;
+
 /**
  * This class implements an output stream in which the data is
  * written into a byte array. The buffer automatically grows as data
  * is written to it.
  * The data can be retrieved using {@code toByteArray()} and

@@ -82,52 +84,24 @@
     /**
      * Increases the capacity if necessary to ensure that it can hold
      * at least the number of elements specified by the minimum
      * capacity argument.
      *
-     * @param  minCapacity the desired minimum capacity
-     * @throws OutOfMemoryError if {@code minCapacity < 0}.  This is
-     * interpreted as a request for the unsatisfiably large capacity
+     * @param  minCapacity the desired minimum capacity.
+     * @throws OutOfMemoryError if {@code minCapacity < 0} and
+     * {@code minCapacity - buf.length > 0}.  This is interpreted as a
+     * request for the unsatisfiably large capacity.
      * {@code (long) Integer.MAX_VALUE + (minCapacity - Integer.MAX_VALUE)}.
      */
     private void ensureCapacity(int minCapacity) {
         // overflow-conscious code
-        if (minCapacity - buf.length > 0)
-            grow(minCapacity);
-    }
-
-    /**
-     * The maximum size of array to allocate.
-     * Some VMs reserve some header words in an array.
-     * Attempts to allocate larger arrays may result in
-     * OutOfMemoryError: Requested array size exceeds VM limit
-     */
-    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
-
-    /**
-     * Increases the capacity to ensure that it can hold at least the
-     * number of elements specified by the minimum capacity argument.
-     *
-     * @param minCapacity the desired minimum capacity
-     */
-    private void grow(int minCapacity) {
-        // overflow-conscious code
         int oldCapacity = buf.length;
-        int newCapacity = oldCapacity << 1;
-        if (newCapacity - minCapacity < 0)
-            newCapacity = minCapacity;
-        if (newCapacity - MAX_ARRAY_SIZE > 0)
-            newCapacity = hugeCapacity(minCapacity);
-        buf = Arrays.copyOf(buf, newCapacity);
+        int growAtLeastBy = minCapacity - oldCapacity;
+        if (growAtLeastBy > 0) {
+            buf = Arrays.copyOf(buf, ArraysSupport.newCapacity(oldCapacity,
+                    growAtLeastBy, oldCapacity));
     }
-
-    private static int hugeCapacity(int minCapacity) {
-        if (minCapacity < 0) // overflow
-            throw new OutOfMemoryError();
-        return (minCapacity > MAX_ARRAY_SIZE) ?
-            Integer.MAX_VALUE :
-            MAX_ARRAY_SIZE;
     }
 
     /**
      * Writes the specified byte to this {@code ByteArrayOutputStream}.
      *