--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.net.http/share/classes/java/net/http/internal/hpack/IntegerWriter.java	Wed Feb 07 14:17:24 2018 +0000
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2015, 2018, 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.
+ */
+package java.net.http.internal.hpack;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+
+final class IntegerWriter {
+
+    private static final int NEW                = 0;
+    private static final int CONFIGURED         = 1;
+    private static final int FIRST_BYTE_WRITTEN = 2;
+    private static final int DONE               = 4;
+
+    private int state = NEW;
+
+    private int payload;
+    private int N;
+    private int value;
+
+    //
+    //      0   1   2   3   4   5   6   7
+    //    +---+---+---+---+---+---+---+---+
+    //    |   |   |   |   |   |   |   |   |
+    //    +---+---+---+-------------------+
+    //    |<--------->|<----------------->|
+    //       payload           N=5
+    //
+    // payload is the contents of the left-hand side part of the octet;
+    //         it is truncated to fit into 8-N bits, where 1 <= N <= 8;
+    //
+    public IntegerWriter configure(int value, int N, int payload) {
+        if (state != NEW) {
+            throw new IllegalStateException("Already configured");
+        }
+        if (value < 0) {
+            throw new IllegalArgumentException("value >= 0: value=" + value);
+        }
+        checkPrefix(N);
+        this.value = value;
+        this.N = N;
+        this.payload = payload & 0xFF & (0xFFFFFFFF << N);
+        state = CONFIGURED;
+        return this;
+    }
+
+    public boolean write(ByteBuffer output) {
+        if (state == NEW) {
+            throw new IllegalStateException("Configure first");
+        }
+        if (state == DONE) {
+            return true;
+        }
+
+        if (!output.hasRemaining()) {
+            return false;
+        }
+        if (state == CONFIGURED) {
+            int max = (2 << (N - 1)) - 1;
+            if (value < max) {
+                output.put((byte) (payload | value));
+                state = DONE;
+                return true;
+            }
+            output.put((byte) (payload | max));
+            value -= max;
+            state = FIRST_BYTE_WRITTEN;
+        }
+        if (state == FIRST_BYTE_WRITTEN) {
+            while (value >= 128 && output.hasRemaining()) {
+                output.put((byte) (value % 128 + 128));
+                value /= 128;
+            }
+            if (!output.hasRemaining()) {
+                return false;
+            }
+            output.put((byte) value);
+            state = DONE;
+            return true;
+        }
+        throw new InternalError(Arrays.toString(
+                new Object[]{state, payload, N, value}));
+    }
+
+    private static void checkPrefix(int N) {
+        if (N < 1 || N > 8) {
+            throw new IllegalArgumentException("1 <= N <= 8: N= " + N);
+        }
+    }
+
+    public IntegerWriter reset() {
+        state = NEW;
+        return this;
+    }
+}