--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/org/msgpack/unpacker/UnpackerStack.java	Sat Oct 18 15:06:15 2014 +0900
@@ -0,0 +1,98 @@
+//
+// MessagePack for Java
+//
+// Copyright (C) 2009 - 2013 FURUHASHI Sadayuki
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+package org.msgpack.unpacker;
+
+import org.msgpack.MessageTypeException;
+
+public final class UnpackerStack {
+    private int top;
+    private byte[] types;
+    private int[] counts;
+
+    public static final int MAX_STACK_SIZE = 128;
+
+    private static final byte TYPE_INVALID = 0;
+    private static final byte TYPE_ARRAY = 1;
+    private static final byte TYPE_MAP = 2;
+
+    public UnpackerStack() {
+        this.top = 0;
+        this.types = new byte[MAX_STACK_SIZE];
+        this.counts = new int[MAX_STACK_SIZE];
+        this.types[0] = TYPE_INVALID;
+    }
+
+    public void pushArray(int size) {
+        top++;
+        types[top] = TYPE_ARRAY;
+        counts[top] = size;
+    }
+
+    public void pushMap(int size) {
+        top++;
+        types[top] = TYPE_MAP;
+        counts[top] = size * 2;
+    }
+
+    /**
+     * throws MessageTypeException if stack is invalid
+     */
+    public void checkCount() {
+        if (counts[top] > 0) {
+            return;
+        }
+
+        if (types[top] == TYPE_ARRAY) {
+            throw new MessageTypeException(
+                    "Array is end but readArrayEnd() is not called");
+        } else if (types[top] == TYPE_MAP) {
+            throw new MessageTypeException(
+                    "Map is end but readMapEnd() is not called");
+        } else { // empty
+            return;
+        }
+    }
+
+    public void reduceCount() {
+        counts[top]--;
+    }
+
+    public void pop() {
+        top--;
+    }
+
+    public int getDepth() {
+        return top;
+    }
+
+    public int getTopCount() {
+        return counts[top];
+    }
+
+    public boolean topIsArray() {
+        return types[top] == TYPE_ARRAY;
+    }
+
+    public boolean topIsMap() {
+        return types[top] == TYPE_MAP;
+    }
+
+    public void clear() {
+        top = 0;
+    }
+}