--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/security/util/IOUtils.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2009, 2017 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
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * IOUtils: A collection of IO-related public static methods.
+ */
+
+package sun.security.util;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+
+public class IOUtils {
+
+    /**
+     * Read up to <code>length</code> of bytes from <code>in</code>
+     * until EOF is detected.
+     * @param is input stream, must not be null
+     * @param length number of bytes to read
+     * @param readAll if true, an EOFException will be thrown if not enough
+     *        bytes are read.
+     * @return bytes read
+     * @throws IOException Any IO error or a premature EOF is detected
+     */
+    public static byte[] readFully(InputStream is, int length, boolean readAll)
+            throws IOException {
+        if (length < 0) {
+            throw new IOException("Invalid length");
+        }
+        byte[] output = {};
+        int pos = 0;
+        while (pos < length) {
+            int bytesToRead;
+            if (pos >= output.length) { // Only expand when there's no room
+                bytesToRead = Math.min(length - pos, output.length + 1024);
+                if (output.length < pos + bytesToRead) {
+                    output = Arrays.copyOf(output, pos + bytesToRead);
+                }
+            } else {
+                bytesToRead = output.length - pos;
+            }
+            int cc = is.read(output, pos, bytesToRead);
+            if (cc < 0) {
+                if (readAll) {
+                    throw new EOFException("Detect premature EOF");
+                } else {
+                    if (output.length != pos) {
+                        output = Arrays.copyOf(output, pos);
+                    }
+                    break;
+                }
+            }
+            pos += cc;
+        }
+        return output;
+    }
+}