1 files changed, 67 insertions, 0 deletions
diff --git a/src/boost/tools/quickbook/src/iterator.hpp b/src/boost/tools/quickbook/src/iterator.hpp
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+++ b/src/boost/tools/quickbook/src/iterator.hpp
@@ -0,0 +1,67 @@
+/*=============================================================================
+    Copyright (c) 2010 Daniel James
+
+    Use, modification and distribution is subject to the Boost Software
+    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+    http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+
+#if !defined(BOOST_SPIRIT_QUICKBOOK_ITERATOR_HPP)
+#define BOOST_SPIRIT_QUICKBOOK_ITERATOR_HPP
+
+#include <iterator>
+#include <boost/iterator/iterator_traits.hpp>
+#include <boost/operators.hpp>
+#include <boost/range/iterator_range.hpp>
+#include "string_view.hpp"
+
+namespace quickbook
+{
+    template <typename Iterator>
+    struct lookback_iterator
+        : boost::forward_iterator_helper<
+              lookback_iterator<Iterator>,
+              typename boost::iterator_value<Iterator>::type,
+              typename boost::iterator_difference<Iterator>::type,
+              typename boost::iterator_pointer<Iterator>::type,
+              typename boost::iterator_reference<Iterator>::type>
+    {
+        lookback_iterator() {}
+        explicit lookback_iterator(Iterator i) : original_(i), base_(i) {}
+
+        friend bool operator==(
+            lookback_iterator const& x, lookback_iterator const& y)
+        {
+            return x.base_ == y.base_;
+        }
+
+        lookback_iterator& operator++()
+        {
+            ++base_;
+            return *this;
+        }
+
+        typename boost::iterator_reference<Iterator>::type operator*() const
+        {
+            return *base_;
+        }
+
+        Iterator base() const { return base_; }
+
+        typedef boost::iterator_range<std::reverse_iterator<Iterator> >
+            lookback_range;
+
+        lookback_range lookback() const
+        {
+            return lookback_range(base_, original_);
+        }
+
+      private:
+        Iterator original_;
+        Iterator base_;
+    };
+
+    typedef lookback_iterator<string_iterator> parse_iterator;
+}
+
+#endif