diff --git a/include/ndnboost/regex/pending/object_cache.hpp b/include/ndnboost/regex/pending/object_cache.hpp
new file mode 100644
index 0000000..d0a088c
--- /dev/null
+++ b/include/ndnboost/regex/pending/object_cache.hpp
@@ -0,0 +1,165 @@
+/*
+ *
+ * Copyright (c) 2004
+ * John Maddock
+ *
+ * Use, modification and distribution are 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)
+ *
+ */
+
+ /*
+  *   LOCATION:    see http://www.boost.org for most recent version.
+  *   FILE         object_cache.hpp
+  *   VERSION      see <ndnboost/version.hpp>
+  *   DESCRIPTION: Implements a generic object cache.
+  */
+
+#ifndef NDNBOOST_REGEX_OBJECT_CACHE_HPP
+#define NDNBOOST_REGEX_OBJECT_CACHE_HPP
+
+#include <map>
+#include <list>
+#include <stdexcept>
+#include <string>
+#include <ndnboost/config.hpp>
+#include <ndnboost/shared_ptr.hpp>
+#ifdef NDNBOOST_HAS_THREADS
+#include <ndnboost/regex/pending/static_mutex.hpp>
+#endif
+
+namespace ndnboost{
+
+template <class Key, class Object>
+class object_cache
+{
+public:
+   typedef std::pair< ::ndnboost::shared_ptr<Object const>, Key const*> value_type;
+   typedef std::list<value_type> list_type;
+   typedef typename list_type::iterator list_iterator;
+   typedef std::map<Key, list_iterator> map_type;
+   typedef typename map_type::iterator map_iterator;
+   typedef typename list_type::size_type size_type;
+   static ndnboost::shared_ptr<Object const> get(const Key& k, size_type l_max_cache_size);
+
+private:
+   static ndnboost::shared_ptr<Object const> do_get(const Key& k, size_type l_max_cache_size);
+
+   struct data
+   {
+      list_type   cont;
+      map_type    index;
+   };
+
+   // Needed by compilers not implementing the resolution to DR45. For reference,
+   // see http://www.open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#45.
+   friend struct data;
+};
+
+template <class Key, class Object>
+ndnboost::shared_ptr<Object const> object_cache<Key, Object>::get(const Key& k, size_type l_max_cache_size)
+{
+#ifdef NDNBOOST_HAS_THREADS
+   static ndnboost::static_mutex mut = NDNBOOST_STATIC_MUTEX_INIT;
+
+   ndnboost::static_mutex::scoped_lock l(mut);
+   if(l)
+   {
+      return do_get(k, l_max_cache_size);
+   }
+   //
+   // what do we do if the lock fails?
+   // for now just throw, but we should never really get here...
+   //
+   ::ndnboost::throw_exception(std::runtime_error("Error in thread safety code: could not acquire a lock"));
+#if defined(NDNBOOST_NO_UNREACHABLE_RETURN_DETECTION) || defined(NDNBOOST_NO_EXCEPTIONS)
+   return ndnboost::shared_ptr<Object>();
+#endif
+#else
+   return do_get(k, l_max_cache_size);
+#endif
+}
+
+template <class Key, class Object>
+ndnboost::shared_ptr<Object const> object_cache<Key, Object>::do_get(const Key& k, size_type l_max_cache_size)
+{
+   typedef typename object_cache<Key, Object>::data object_data;
+   typedef typename map_type::size_type map_size_type;
+   static object_data s_data;
+
+   //
+   // see if the object is already in the cache:
+   //
+   map_iterator mpos = s_data.index.find(k);
+   if(mpos != s_data.index.end())
+   {
+      //
+      // Eureka! 
+      // We have a cached item, bump it up the list and return it:
+      //
+      if(--(s_data.cont.end()) != mpos->second)
+      {
+         // splice out the item we want to move:
+         list_type temp;
+         temp.splice(temp.end(), s_data.cont, mpos->second);
+         // and now place it at the end of the list:
+         s_data.cont.splice(s_data.cont.end(), temp, temp.begin());
+         NDNBOOST_ASSERT(*(s_data.cont.back().second) == k);
+         // update index with new position:
+         mpos->second = --(s_data.cont.end());
+         NDNBOOST_ASSERT(&(mpos->first) == mpos->second->second);
+         NDNBOOST_ASSERT(&(mpos->first) == s_data.cont.back().second);
+      }
+      return s_data.cont.back().first;
+   }
+   //
+   // if we get here then the item is not in the cache,
+   // so create it:
+   //
+   ndnboost::shared_ptr<Object const> result(new Object(k));
+   //
+   // Add it to the list, and index it:
+   //
+   s_data.cont.push_back(value_type(result, static_cast<Key const*>(0)));
+   s_data.index.insert(std::make_pair(k, --(s_data.cont.end())));
+   s_data.cont.back().second = &(s_data.index.find(k)->first);
+   map_size_type s = s_data.index.size();
+   NDNBOOST_ASSERT(s_data.index[k]->first.get() == result.get());
+   NDNBOOST_ASSERT(&(s_data.index.find(k)->first) == s_data.cont.back().second);
+   NDNBOOST_ASSERT(s_data.index.find(k)->first == k);
+   if(s > l_max_cache_size)
+   {
+      //
+      // We have too many items in the list, so we need to start
+      // popping them off the back of the list, but only if they're
+      // being held uniquely by us:
+      //
+      list_iterator pos = s_data.cont.begin();
+      list_iterator last = s_data.cont.end();
+      while((pos != last) && (s > l_max_cache_size))
+      {
+         if(pos->first.unique())
+         {
+            list_iterator condemmed(pos);
+            ++pos;
+            // now remove the items from our containers, 
+            // then order has to be as follows:
+            NDNBOOST_ASSERT(s_data.index.find(*(condemmed->second)) != s_data.index.end());
+            s_data.index.erase(*(condemmed->second));
+            s_data.cont.erase(condemmed); 
+            --s;
+         }
+         else
+            ++pos;
+      }
+      NDNBOOST_ASSERT(s_data.index[k]->first.get() == result.get());
+      NDNBOOST_ASSERT(&(s_data.index.find(k)->first) == s_data.cont.back().second);
+      NDNBOOST_ASSERT(s_data.index.find(k)->first == k);
+   }
+   return result;
+}
+
+}
+
+#endif
diff --git a/include/ndnboost/regex/pending/static_mutex.hpp b/include/ndnboost/regex/pending/static_mutex.hpp
new file mode 100644
index 0000000..c7d2659
--- /dev/null
+++ b/include/ndnboost/regex/pending/static_mutex.hpp
@@ -0,0 +1,179 @@
+/*
+ *
+ * Copyright (c) 2004
+ * John Maddock
+ *
+ * Use, modification and distribution are 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)
+ *
+ */
+ 
+ /*
+  *   LOCATION:    see http://www.boost.org for most recent version.
+  *   FILE         static_mutex.hpp
+  *   VERSION      see <ndnboost/version.hpp>
+  *   DESCRIPTION: Declares static_mutex lock type, there are three different
+  *                implementations: POSIX pthreads, WIN32 threads, and portable,
+  *                these are described in more detail below.
+  */
+
+#ifndef NDNBOOST_REGEX_STATIC_MUTEX_HPP
+#define NDNBOOST_REGEX_STATIC_MUTEX_HPP
+
+#include <ndnboost/config.hpp>
+#include <ndnboost/regex/config.hpp> // dll import/export options.
+
+#ifdef NDNBOOST_HAS_PTHREADS
+#include <pthread.h>
+#endif
+
+#if defined(NDNBOOST_HAS_PTHREADS) && defined(PTHREAD_MUTEX_INITIALIZER)
+//
+// pthreads version:
+// simple wrap around a pthread_mutex_t initialized with
+// PTHREAD_MUTEX_INITIALIZER.
+//
+namespace ndnboost{
+
+class static_mutex;
+
+#define NDNBOOST_STATIC_MUTEX_INIT { PTHREAD_MUTEX_INITIALIZER, }
+
+class NDNBOOST_REGEX_DECL scoped_static_mutex_lock
+{
+public:
+   scoped_static_mutex_lock(static_mutex& mut, bool lk = true);
+   ~scoped_static_mutex_lock();
+   inline bool locked()const
+   {
+      return m_have_lock;
+   }
+   inline operator void const*()const
+   {
+      return locked() ? this : 0;
+   }
+   void lock();
+   void unlock();
+private:
+   static_mutex& m_mutex;
+   bool m_have_lock;
+};
+
+class static_mutex
+{
+public:
+   typedef scoped_static_mutex_lock scoped_lock;
+   pthread_mutex_t m_mutex;
+};
+
+} // namespace ndnboost
+#elif defined(NDNBOOST_HAS_WINTHREADS)
+//
+// Win32 version:
+// Use a 32-bit int as a lock, along with a test-and-set
+// implementation using InterlockedCompareExchange.
+//
+
+#include <ndnboost/cstdint.hpp>
+
+namespace ndnboost{
+
+class NDNBOOST_REGEX_DECL scoped_static_mutex_lock;
+
+class static_mutex
+{
+public:
+   typedef scoped_static_mutex_lock scoped_lock;
+   ndnboost::int32_t m_mutex;
+};
+
+#define NDNBOOST_STATIC_MUTEX_INIT { 0, }
+
+class NDNBOOST_REGEX_DECL scoped_static_mutex_lock
+{
+public:
+   scoped_static_mutex_lock(static_mutex& mut, bool lk = true);
+   ~scoped_static_mutex_lock();
+   operator void const*()const
+   {
+      return locked() ? this : 0;
+   }
+   bool locked()const
+   {
+      return m_have_lock;
+   }
+   void lock();
+   void unlock();
+private:
+   static_mutex& m_mutex;
+   bool m_have_lock;
+   scoped_static_mutex_lock(const scoped_static_mutex_lock&);
+   scoped_static_mutex_lock& operator=(const scoped_static_mutex_lock&);
+};
+
+} // namespace
+
+#else
+//
+// Portable version of a static mutex based on Boost.Thread library:
+// This has to use a single mutex shared by all instances of static_mutex
+// because ndnboost::call_once doesn't alow us to pass instance information
+// down to the initialisation proceedure.  In fact the initialisation routine
+// may need to be called more than once - but only once per instance.
+//
+// Since this preprocessor path is almost never taken, we hide these header
+// dependencies so that build tools don't find them.
+//
+#define B1 <ndnboost/thread/once.hpp>
+#define B2 <ndnboost/thread/recursive_mutex.hpp>
+#include B1
+#include B2
+#undef B1
+#undef B2
+
+namespace ndnboost{
+
+class NDNBOOST_REGEX_DECL scoped_static_mutex_lock;
+extern "C" NDNBOOST_REGEX_DECL void ndnboost_regex_free_static_mutex();
+
+class NDNBOOST_REGEX_DECL static_mutex
+{
+public:
+   typedef scoped_static_mutex_lock scoped_lock;
+   static void init();
+   static ndnboost::recursive_mutex* m_pmutex;
+   static ndnboost::once_flag m_once;
+};
+
+#define NDNBOOST_STATIC_MUTEX_INIT {  }
+
+class NDNBOOST_REGEX_DECL scoped_static_mutex_lock
+{
+public:
+   scoped_static_mutex_lock(static_mutex& mut, bool lk = true);
+   ~scoped_static_mutex_lock();
+   operator void const*()const;
+   bool locked()const;
+   void lock();
+   void unlock();
+private:
+   ndnboost::recursive_mutex::scoped_lock* m_plock;
+   bool m_have_lock;
+};
+
+inline scoped_static_mutex_lock::operator void const*()const
+{
+   return locked() ? this : 0;
+}
+
+inline bool scoped_static_mutex_lock::locked()const
+{
+   return m_have_lock;
+}
+
+} // namespace
+
+#endif
+
+#endif
diff --git a/include/ndnboost/regex/pending/unicode_iterator.hpp b/include/ndnboost/regex/pending/unicode_iterator.hpp
new file mode 100644
index 0000000..d66d3b9
--- /dev/null
+++ b/include/ndnboost/regex/pending/unicode_iterator.hpp
@@ -0,0 +1,776 @@
+/*
+ *
+ * Copyright (c) 2004
+ * John Maddock
+ *
+ * Use, modification and distribution are 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)
+ *
+ */
+ 
+ /*
+  *   LOCATION:    see http://www.boost.org for most recent version.
+  *   FILE         unicode_iterator.hpp
+  *   VERSION      see <ndnboost/version.hpp>
+  *   DESCRIPTION: Iterator adapters for converting between different Unicode encodings.
+  */
+
+/****************************************************************************
+
+Contents:
+~~~~~~~~~
+
+1) Read Only, Input Adapters:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+template <class BaseIterator, class U8Type = ::ndnboost::uint8_t>
+class u32_to_u8_iterator;
+
+Adapts sequence of UTF-32 code points to "look like" a sequence of UTF-8.
+
+template <class BaseIterator, class U32Type = ::ndnboost::uint32_t>
+class u8_to_u32_iterator;
+
+Adapts sequence of UTF-8 code points to "look like" a sequence of UTF-32.
+
+template <class BaseIterator, class U16Type = ::ndnboost::uint16_t>
+class u32_to_u16_iterator;
+
+Adapts sequence of UTF-32 code points to "look like" a sequence of UTF-16.
+
+template <class BaseIterator, class U32Type = ::ndnboost::uint32_t>
+class u16_to_u32_iterator;
+
+Adapts sequence of UTF-16 code points to "look like" a sequence of UTF-32.
+
+2) Single pass output iterator adapters:
+
+template <class BaseIterator>
+class utf8_output_iterator;
+
+Accepts UTF-32 code points and forwards them on as UTF-8 code points.
+
+template <class BaseIterator>
+class utf16_output_iterator;
+
+Accepts UTF-32 code points and forwards them on as UTF-16 code points.
+
+****************************************************************************/
+
+#ifndef NDNBOOST_REGEX_UNICODE_ITERATOR_HPP
+#define NDNBOOST_REGEX_UNICODE_ITERATOR_HPP
+#include <ndnboost/cstdint.hpp>
+#include <ndnboost/assert.hpp>
+#include <ndnboost/iterator/iterator_facade.hpp>
+#include <ndnboost/static_assert.hpp>
+#include <ndnboost/throw_exception.hpp>
+#include <stdexcept>
+#ifndef NDNBOOST_NO_STD_LOCALE
+#include <sstream>
+#include <ios>
+#endif
+#include <limits.h> // CHAR_BIT
+
+namespace ndnboost{
+
+namespace detail{
+
+static const ::ndnboost::uint16_t high_surrogate_base = 0xD7C0u;
+static const ::ndnboost::uint16_t low_surrogate_base = 0xDC00u;
+static const ::ndnboost::uint32_t ten_bit_mask = 0x3FFu;
+
+inline bool is_high_surrogate(::ndnboost::uint16_t v)
+{
+   return (v & 0xFFFFFC00u) == 0xd800u;
+}
+inline bool is_low_surrogate(::ndnboost::uint16_t v)
+{
+   return (v & 0xFFFFFC00u) == 0xdc00u;
+}
+template <class T>
+inline bool is_surrogate(T v)
+{
+   return (v & 0xFFFFF800u) == 0xd800;
+}
+
+inline unsigned utf8_byte_count(ndnboost::uint8_t c)
+{
+   // if the most significant bit with a zero in it is in position
+   // 8-N then there are N bytes in this UTF-8 sequence:
+   ndnboost::uint8_t mask = 0x80u;
+   unsigned result = 0;
+   while(c & mask)
+   {
+      ++result;
+      mask >>= 1;
+   }
+   return (result == 0) ? 1 : ((result > 4) ? 4 : result);
+}
+
+inline unsigned utf8_trailing_byte_count(ndnboost::uint8_t c)
+{
+   return utf8_byte_count(c) - 1;
+}
+
+#ifdef NDNBOOST_MSVC
+#pragma warning(push)
+#pragma warning(disable:4100)
+#endif
+inline void invalid_utf32_code_point(::ndnboost::uint32_t val)
+{
+#ifndef NDNBOOST_NO_STD_LOCALE
+   std::stringstream ss;
+   ss << "Invalid UTF-32 code point U+" << std::showbase << std::hex << val << " encountered while trying to encode UTF-16 sequence";
+   std::out_of_range e(ss.str());
+#else
+   std::out_of_range e("Invalid UTF-32 code point encountered while trying to encode UTF-16 sequence");
+#endif
+   ndnboost::throw_exception(e);
+}
+#ifdef NDNBOOST_MSVC
+#pragma warning(pop)
+#endif
+
+
+} // namespace detail
+
+template <class BaseIterator, class U16Type = ::ndnboost::uint16_t>
+class u32_to_u16_iterator
+   : public ndnboost::iterator_facade<u32_to_u16_iterator<BaseIterator, U16Type>, U16Type, std::bidirectional_iterator_tag, const U16Type>
+{
+   typedef ndnboost::iterator_facade<u32_to_u16_iterator<BaseIterator, U16Type>, U16Type, std::bidirectional_iterator_tag, const U16Type> base_type;
+
+#if !defined(NDNBOOST_NO_STD_ITERATOR_TRAITS) && !defined(NDNBOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
+   typedef typename std::iterator_traits<BaseIterator>::value_type base_value_type;
+
+   NDNBOOST_STATIC_ASSERT(sizeof(base_value_type)*CHAR_BIT == 32);
+   NDNBOOST_STATIC_ASSERT(sizeof(U16Type)*CHAR_BIT == 16);
+#endif
+
+public:
+   typename base_type::reference
+      dereference()const
+   {
+      if(m_current == 2)
+         extract_current();
+      return m_values[m_current];
+   }
+   bool equal(const u32_to_u16_iterator& that)const
+   {
+      if(m_position == that.m_position)
+      {
+         // Both m_currents must be equal, or both even
+         // this is the same as saying their sum must be even:
+         return (m_current + that.m_current) & 1u ? false : true;
+      }
+      return false;
+   }
+   void increment()
+   {
+      // if we have a pending read then read now, so that we know whether
+      // to skip a position, or move to a low-surrogate:
+      if(m_current == 2)
+      {
+         // pending read:
+         extract_current();
+      }
+      // move to the next surrogate position:
+      ++m_current;
+      // if we've reached the end skip a position:
+      if(m_values[m_current] == 0)
+      {
+         m_current = 2;
+         ++m_position;
+      }
+   }
+   void decrement()
+   {
+      if(m_current != 1)
+      {
+         // decrementing an iterator always leads to a valid position:
+         --m_position;
+         extract_current();
+         m_current = m_values[1] ? 1 : 0;
+      }
+      else
+      {
+         m_current = 0;
+      }
+   }
+   BaseIterator base()const
+   {
+      return m_position;
+   }
+   // construct:
+   u32_to_u16_iterator() : m_position(), m_current(0)
+   {
+      m_values[0] = 0;
+      m_values[1] = 0;
+      m_values[2] = 0;
+   }
+   u32_to_u16_iterator(BaseIterator b) : m_position(b), m_current(2)
+   {
+      m_values[0] = 0;
+      m_values[1] = 0;
+      m_values[2] = 0;
+   }
+private:
+
+   void extract_current()const
+   {
+      // begin by checking for a code point out of range:
+      ::ndnboost::uint32_t v = *m_position;
+      if(v >= 0x10000u)
+      {
+         if(v > 0x10FFFFu)
+            detail::invalid_utf32_code_point(*m_position);
+         // split into two surrogates:
+         m_values[0] = static_cast<U16Type>(v >> 10) + detail::high_surrogate_base;
+         m_values[1] = static_cast<U16Type>(v & detail::ten_bit_mask) + detail::low_surrogate_base;
+         m_current = 0;
+         NDNBOOST_ASSERT(detail::is_high_surrogate(m_values[0]));
+         NDNBOOST_ASSERT(detail::is_low_surrogate(m_values[1]));
+      }
+      else
+      {
+         // 16-bit code point:
+         m_values[0] = static_cast<U16Type>(*m_position);
+         m_values[1] = 0;
+         m_current = 0;
+         // value must not be a surrogate:
+         if(detail::is_surrogate(m_values[0]))
+            detail::invalid_utf32_code_point(*m_position);
+      }
+   }
+   BaseIterator m_position;
+   mutable U16Type m_values[3];
+   mutable unsigned m_current;
+};
+
+template <class BaseIterator, class U32Type = ::ndnboost::uint32_t>
+class u16_to_u32_iterator
+   : public ndnboost::iterator_facade<u16_to_u32_iterator<BaseIterator, U32Type>, U32Type, std::bidirectional_iterator_tag, const U32Type>
+{
+   typedef ndnboost::iterator_facade<u16_to_u32_iterator<BaseIterator, U32Type>, U32Type, std::bidirectional_iterator_tag, const U32Type> base_type;
+   // special values for pending iterator reads:
+   NDNBOOST_STATIC_CONSTANT(U32Type, pending_read = 0xffffffffu);
+
+#if !defined(NDNBOOST_NO_STD_ITERATOR_TRAITS) && !defined(NDNBOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
+   typedef typename std::iterator_traits<BaseIterator>::value_type base_value_type;
+
+   NDNBOOST_STATIC_ASSERT(sizeof(base_value_type)*CHAR_BIT == 16);
+   NDNBOOST_STATIC_ASSERT(sizeof(U32Type)*CHAR_BIT == 32);
+#endif
+
+public:
+   typename base_type::reference
+      dereference()const
+   {
+      if(m_value == pending_read)
+         extract_current();
+      return m_value;
+   }
+   bool equal(const u16_to_u32_iterator& that)const
+   {
+      return m_position == that.m_position;
+   }
+   void increment()
+   {
+      // skip high surrogate first if there is one:
+      if(detail::is_high_surrogate(*m_position)) ++m_position;
+      ++m_position;
+      m_value = pending_read;
+   }
+   void decrement()
+   {
+      --m_position;
+      // if we have a low surrogate then go back one more:
+      if(detail::is_low_surrogate(*m_position)) 
+         --m_position;
+      m_value = pending_read;
+   }
+   BaseIterator base()const
+   {
+      return m_position;
+   }
+   // construct:
+   u16_to_u32_iterator() : m_position()
+   {
+      m_value = pending_read;
+   }
+   u16_to_u32_iterator(BaseIterator b) : m_position(b)
+   {
+      m_value = pending_read;
+   }
+   //
+   // Range checked version:
+   //
+   u16_to_u32_iterator(BaseIterator b, BaseIterator start, BaseIterator end) : m_position(b)
+   {
+      m_value = pending_read;
+      //
+      // The range must not start with a low surrogate, or end in a high surrogate,
+      // otherwise we run the risk of running outside the underlying input range.
+      // Likewise b must not be located at a low surrogate.
+      //
+      ndnboost::uint16_t val;
+      if(start != end)
+      {
+         if((b != start) && (b != end))
+         {
+            val = *b;
+            if(detail::is_surrogate(val) && ((val & 0xFC00u) == 0xDC00u))
+               invalid_code_point(val);
+         }
+         val = *start;
+         if(detail::is_surrogate(val) && ((val & 0xFC00u) == 0xDC00u))
+            invalid_code_point(val);
+         val = *--end;
+         if(detail::is_high_surrogate(val))
+            invalid_code_point(val);
+      }
+   }
+private:
+   static void invalid_code_point(::ndnboost::uint16_t val)
+   {
+#ifndef NDNBOOST_NO_STD_LOCALE
+      std::stringstream ss;
+      ss << "Misplaced UTF-16 surrogate U+" << std::showbase << std::hex << val << " encountered while trying to encode UTF-32 sequence";
+      std::out_of_range e(ss.str());
+#else
+      std::out_of_range e("Misplaced UTF-16 surrogate encountered while trying to encode UTF-32 sequence");
+#endif
+      ndnboost::throw_exception(e);
+   }
+   void extract_current()const
+   {
+      m_value = static_cast<U32Type>(static_cast< ::ndnboost::uint16_t>(*m_position));
+      // if the last value is a high surrogate then adjust m_position and m_value as needed:
+      if(detail::is_high_surrogate(*m_position))
+      {
+         // precondition; next value must have be a low-surrogate:
+         BaseIterator next(m_position);
+         ::ndnboost::uint16_t t = *++next;
+         if((t & 0xFC00u) != 0xDC00u)
+            invalid_code_point(t);
+         m_value = (m_value - detail::high_surrogate_base) << 10;
+         m_value |= (static_cast<U32Type>(static_cast< ::ndnboost::uint16_t>(t)) & detail::ten_bit_mask);
+      }
+      // postcondition; result must not be a surrogate:
+      if(detail::is_surrogate(m_value))
+         invalid_code_point(static_cast< ::ndnboost::uint16_t>(m_value));
+   }
+   BaseIterator m_position;
+   mutable U32Type m_value;
+};
+
+template <class BaseIterator, class U8Type = ::ndnboost::uint8_t>
+class u32_to_u8_iterator
+   : public ndnboost::iterator_facade<u32_to_u8_iterator<BaseIterator, U8Type>, U8Type, std::bidirectional_iterator_tag, const U8Type>
+{
+   typedef ndnboost::iterator_facade<u32_to_u8_iterator<BaseIterator, U8Type>, U8Type, std::bidirectional_iterator_tag, const U8Type> base_type;
+   
+#if !defined(NDNBOOST_NO_STD_ITERATOR_TRAITS) && !defined(NDNBOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
+   typedef typename std::iterator_traits<BaseIterator>::value_type base_value_type;
+
+   NDNBOOST_STATIC_ASSERT(sizeof(base_value_type)*CHAR_BIT == 32);
+   NDNBOOST_STATIC_ASSERT(sizeof(U8Type)*CHAR_BIT == 8);
+#endif
+
+public:
+   typename base_type::reference
+      dereference()const
+   {
+      if(m_current == 4)
+         extract_current();
+      return m_values[m_current];
+   }
+   bool equal(const u32_to_u8_iterator& that)const
+   {
+      if(m_position == that.m_position)
+      {
+         // either the m_current's must be equal, or one must be 0 and 
+         // the other 4: which means neither must have bits 1 or 2 set:
+         return (m_current == that.m_current)
+            || (((m_current | that.m_current) & 3) == 0);
+      }
+      return false;
+   }
+   void increment()
+   {
+      // if we have a pending read then read now, so that we know whether
+      // to skip a position, or move to a low-surrogate:
+      if(m_current == 4)
+      {
+         // pending read:
+         extract_current();
+      }
+      // move to the next surrogate position:
+      ++m_current;
+      // if we've reached the end skip a position:
+      if(m_values[m_current] == 0)
+      {
+         m_current = 4;
+         ++m_position;
+      }
+   }
+   void decrement()
+   {
+      if((m_current & 3) == 0)
+      {
+         --m_position;
+         extract_current();
+         m_current = 3;
+         while(m_current && (m_values[m_current] == 0))
+            --m_current;
+      }
+      else
+         --m_current;
+   }
+   BaseIterator base()const
+   {
+      return m_position;
+   }
+   // construct:
+   u32_to_u8_iterator() : m_position(), m_current(0)
+   {
+      m_values[0] = 0;
+      m_values[1] = 0;
+      m_values[2] = 0;
+      m_values[3] = 0;
+      m_values[4] = 0;
+   }
+   u32_to_u8_iterator(BaseIterator b) : m_position(b), m_current(4)
+   {
+      m_values[0] = 0;
+      m_values[1] = 0;
+      m_values[2] = 0;
+      m_values[3] = 0;
+      m_values[4] = 0;
+   }
+private:
+
+   void extract_current()const
+   {
+      ndnboost::uint32_t c = *m_position;
+      if(c > 0x10FFFFu)
+         detail::invalid_utf32_code_point(c);
+      if(c < 0x80u)
+      {
+         m_values[0] = static_cast<unsigned char>(c);
+         m_values[1] = static_cast<unsigned char>(0u);
+         m_values[2] = static_cast<unsigned char>(0u);
+         m_values[3] = static_cast<unsigned char>(0u);
+      }
+      else if(c < 0x800u)
+      {
+         m_values[0] = static_cast<unsigned char>(0xC0u + (c >> 6));
+         m_values[1] = static_cast<unsigned char>(0x80u + (c & 0x3Fu));
+         m_values[2] = static_cast<unsigned char>(0u);
+         m_values[3] = static_cast<unsigned char>(0u);
+      }
+      else if(c < 0x10000u)
+      {
+         m_values[0] = static_cast<unsigned char>(0xE0u + (c >> 12));
+         m_values[1] = static_cast<unsigned char>(0x80u + ((c >> 6) & 0x3Fu));
+         m_values[2] = static_cast<unsigned char>(0x80u + (c & 0x3Fu));
+         m_values[3] = static_cast<unsigned char>(0u);
+      }
+      else
+      {
+         m_values[0] = static_cast<unsigned char>(0xF0u + (c >> 18));
+         m_values[1] = static_cast<unsigned char>(0x80u + ((c >> 12) & 0x3Fu));
+         m_values[2] = static_cast<unsigned char>(0x80u + ((c >> 6) & 0x3Fu));
+         m_values[3] = static_cast<unsigned char>(0x80u + (c & 0x3Fu));
+      }
+      m_current= 0;
+   }
+   BaseIterator m_position;
+   mutable U8Type m_values[5];
+   mutable unsigned m_current;
+};
+
+template <class BaseIterator, class U32Type = ::ndnboost::uint32_t>
+class u8_to_u32_iterator
+   : public ndnboost::iterator_facade<u8_to_u32_iterator<BaseIterator, U32Type>, U32Type, std::bidirectional_iterator_tag, const U32Type>
+{
+   typedef ndnboost::iterator_facade<u8_to_u32_iterator<BaseIterator, U32Type>, U32Type, std::bidirectional_iterator_tag, const U32Type> base_type;
+   // special values for pending iterator reads:
+   NDNBOOST_STATIC_CONSTANT(U32Type, pending_read = 0xffffffffu);
+
+#if !defined(NDNBOOST_NO_STD_ITERATOR_TRAITS) && !defined(NDNBOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
+   typedef typename std::iterator_traits<BaseIterator>::value_type base_value_type;
+
+   NDNBOOST_STATIC_ASSERT(sizeof(base_value_type)*CHAR_BIT == 8);
+   NDNBOOST_STATIC_ASSERT(sizeof(U32Type)*CHAR_BIT == 32);
+#endif
+
+public:
+   typename base_type::reference
+      dereference()const
+   {
+      if(m_value == pending_read)
+         extract_current();
+      return m_value;
+   }
+   bool equal(const u8_to_u32_iterator& that)const
+   {
+      return m_position == that.m_position;
+   }
+   void increment()
+   {
+      // We must not start with a continuation character:
+      if((static_cast<ndnboost::uint8_t>(*m_position) & 0xC0) == 0x80)
+         invalid_sequence();
+      // skip high surrogate first if there is one:
+      unsigned c = detail::utf8_byte_count(*m_position);
+      if(m_value == pending_read)
+      {
+         // Since we haven't read in a value, we need to validate the code points:
+         for(unsigned i = 0; i < c; ++i)
+         {
+            ++m_position;
+            // We must have a continuation byte:
+            if((i != c - 1) && ((static_cast<ndnboost::uint8_t>(*m_position) & 0xC0) != 0x80))
+               invalid_sequence();
+         }
+      }
+      else
+      {
+         std::advance(m_position, c);
+      }
+      m_value = pending_read;
+   }
+   void decrement()
+   {
+      // Keep backtracking until we don't have a trailing character:
+      unsigned count = 0;
+      while((*--m_position & 0xC0u) == 0x80u) ++count;
+      // now check that the sequence was valid:
+      if(count != detail::utf8_trailing_byte_count(*m_position))
+         invalid_sequence();
+      m_value = pending_read;
+   }
+   BaseIterator base()const
+   {
+      return m_position;
+   }
+   // construct:
+   u8_to_u32_iterator() : m_position()
+   {
+      m_value = pending_read;
+   }
+   u8_to_u32_iterator(BaseIterator b) : m_position(b)
+   {
+      m_value = pending_read;
+   }
+   //
+   // Checked constructor:
+   //
+   u8_to_u32_iterator(BaseIterator b, BaseIterator start, BaseIterator end) : m_position(b)
+   {
+      m_value = pending_read;
+      //
+      // We must not start with a continuation character, or end with a 
+      // truncated UTF-8 sequence otherwise we run the risk of going past
+      // the start/end of the underlying sequence:
+      //
+      if(start != end)
+      {
+         unsigned char v = *start;
+         if((v & 0xC0u) == 0x80u)
+            invalid_sequence();
+         if((b != start) && (b != end) && ((*b & 0xC0u) == 0x80u))
+            invalid_sequence();
+         BaseIterator pos = end;
+         do
+         {
+            v = *--pos;
+         }
+         while((start != pos) && ((v & 0xC0u) == 0x80u));
+         std::ptrdiff_t extra = detail::utf8_byte_count(v);
+         if(std::distance(pos, end) < extra)
+            invalid_sequence();
+      }
+   }
+private:
+   static void invalid_sequence()
+   {
+      std::out_of_range e("Invalid UTF-8 sequence encountered while trying to encode UTF-32 character");
+      ndnboost::throw_exception(e);
+   }
+   void extract_current()const
+   {
+      m_value = static_cast<U32Type>(static_cast< ::ndnboost::uint8_t>(*m_position));
+      // we must not have a continuation character:
+      if((m_value & 0xC0u) == 0x80u)
+         invalid_sequence();
+      // see how many extra bytes we have:
+      unsigned extra = detail::utf8_trailing_byte_count(*m_position);
+      // extract the extra bits, 6 from each extra byte:
+      BaseIterator next(m_position);
+      for(unsigned c = 0; c < extra; ++c)
+      {
+         ++next;
+         m_value <<= 6;
+         // We must have a continuation byte:
+         if((static_cast<ndnboost::uint8_t>(*next) & 0xC0) != 0x80)
+            invalid_sequence();
+         m_value += static_cast<ndnboost::uint8_t>(*next) & 0x3Fu;
+      }
+      // we now need to remove a few of the leftmost bits, but how many depends
+      // upon how many extra bytes we've extracted:
+      static const ndnboost::uint32_t masks[4] = 
+      {
+         0x7Fu,
+         0x7FFu,
+         0xFFFFu,
+         0x1FFFFFu,
+      };
+      m_value &= masks[extra];
+      // check the result:
+      if(m_value > static_cast<U32Type>(0x10FFFFu))
+         invalid_sequence();
+   }
+   BaseIterator m_position;
+   mutable U32Type m_value;
+};
+
+template <class BaseIterator>
+class utf16_output_iterator
+{
+public:
+   typedef void                                   difference_type;
+   typedef void                                   value_type;
+   typedef ndnboost::uint32_t*                       pointer;
+   typedef ndnboost::uint32_t&                       reference;
+   typedef std::output_iterator_tag               iterator_category;
+
+   utf16_output_iterator(const BaseIterator& b)
+      : m_position(b){}
+   utf16_output_iterator(const utf16_output_iterator& that)
+      : m_position(that.m_position){}
+   utf16_output_iterator& operator=(const utf16_output_iterator& that)
+   {
+      m_position = that.m_position;
+      return *this;
+   }
+   const utf16_output_iterator& operator*()const
+   {
+      return *this;
+   }
+   void operator=(ndnboost::uint32_t val)const
+   {
+      push(val);
+   }
+   utf16_output_iterator& operator++()
+   {
+      return *this;
+   }
+   utf16_output_iterator& operator++(int)
+   {
+      return *this;
+   }
+   BaseIterator base()const
+   {
+      return m_position;
+   }
+private:
+   void push(ndnboost::uint32_t v)const
+   {
+      if(v >= 0x10000u)
+      {
+         // begin by checking for a code point out of range:
+         if(v > 0x10FFFFu)
+            detail::invalid_utf32_code_point(v);
+         // split into two surrogates:
+         *m_position++ = static_cast<ndnboost::uint16_t>(v >> 10) + detail::high_surrogate_base;
+         *m_position++ = static_cast<ndnboost::uint16_t>(v & detail::ten_bit_mask) + detail::low_surrogate_base;
+      }
+      else
+      {
+         // 16-bit code point:
+         // value must not be a surrogate:
+         if(detail::is_surrogate(v))
+            detail::invalid_utf32_code_point(v);
+         *m_position++ = static_cast<ndnboost::uint16_t>(v);
+      }
+   }
+   mutable BaseIterator m_position;
+};
+
+template <class BaseIterator>
+class utf8_output_iterator
+{
+public:
+   typedef void                                   difference_type;
+   typedef void                                   value_type;
+   typedef ndnboost::uint32_t*                       pointer;
+   typedef ndnboost::uint32_t&                       reference;
+   typedef std::output_iterator_tag               iterator_category;
+
+   utf8_output_iterator(const BaseIterator& b)
+      : m_position(b){}
+   utf8_output_iterator(const utf8_output_iterator& that)
+      : m_position(that.m_position){}
+   utf8_output_iterator& operator=(const utf8_output_iterator& that)
+   {
+      m_position = that.m_position;
+      return *this;
+   }
+   const utf8_output_iterator& operator*()const
+   {
+      return *this;
+   }
+   void operator=(ndnboost::uint32_t val)const
+   {
+      push(val);
+   }
+   utf8_output_iterator& operator++()
+   {
+      return *this;
+   }
+   utf8_output_iterator& operator++(int)
+   {
+      return *this;
+   }
+   BaseIterator base()const
+   {
+      return m_position;
+   }
+private:
+   void push(ndnboost::uint32_t c)const
+   {
+      if(c > 0x10FFFFu)
+         detail::invalid_utf32_code_point(c);
+      if(c < 0x80u)
+      {
+         *m_position++ = static_cast<unsigned char>(c);
+      }
+      else if(c < 0x800u)
+      {
+         *m_position++ = static_cast<unsigned char>(0xC0u + (c >> 6));
+         *m_position++ = static_cast<unsigned char>(0x80u + (c & 0x3Fu));
+      }
+      else if(c < 0x10000u)
+      {
+         *m_position++ = static_cast<unsigned char>(0xE0u + (c >> 12));
+         *m_position++ = static_cast<unsigned char>(0x80u + ((c >> 6) & 0x3Fu));
+         *m_position++ = static_cast<unsigned char>(0x80u + (c & 0x3Fu));
+      }
+      else
+      {
+         *m_position++ = static_cast<unsigned char>(0xF0u + (c >> 18));
+         *m_position++ = static_cast<unsigned char>(0x80u + ((c >> 12) & 0x3Fu));
+         *m_position++ = static_cast<unsigned char>(0x80u + ((c >> 6) & 0x3Fu));
+         *m_position++ = static_cast<unsigned char>(0x80u + (c & 0x3Fu));
+      }
+   }
+   mutable BaseIterator m_position;
+};
+
+} // namespace ndnboost
+
+#endif // NDNBOOST_REGEX_UNICODE_ITERATOR_HPP
+