Bounds-checking iterator wrapper, for use with Codec::encode/decode.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@641315 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 67 insertions, 0 deletions

diff --git a/cpp/src/qpid/BoundedIterator.h b/cpp/src/qpid/BoundedIterator.h
new file mode 100644
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+++ b/cpp/src/qpid/BoundedIterator.h
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+#ifndef QPID_BOUNDEDITERATOR_H
+#define QPID_BOUNDEDITERATOR_H
+
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
+#include <boost/iterator/iterator_adaptor.hpp>
+#include "qpid/Exception.h"
+
+namespace qpid {
+
+struct OutOfBoundsException : public Exception {};
+    
+
+/**
+ * Iterator wrapper that throws an exception if iterated beyound the bounds.
+ */
+template <class Iter>
+class BoundedIterator :
+        public boost::iterator_adaptor<BoundedIterator<Iter>, Iter>
+{
+  public:
+    BoundedIterator(const Iter& begin, const Iter& end_) :
+        BoundedIterator::iterator_adaptor_(begin), end(end_) {}
+
+    operator Iter() const { return this->base_reference(); }
+    
+  private:
+    typename boost::iterator_reference<Iter>::type dereference() const {
+        if (this->base_reference() == end) throw OutOfBoundsException();
+        return *(this->base_reference());
+    }
+    
+    void increment() {
+        if (this->base_reference() == end) throw OutOfBoundsException();
+        ++this->base_reference();
+    }
+
+    /** Advance requires Iter to be comparable */
+    void advance(typename boost::iterator_difference<Iter>::type n) {
+        this->base_reference() += n;
+        if (this->base_reference() > end) throw OutOfBoundsException();
+    }
+    
+    Iter end;
+    friend class boost::iterator_core_access;
+};
+} // namespace qpid
+
+#endif  /*!QPID_BOUNDEDITERATOR_H*/