comparison DEPENDENCIES/generic/include/boost/wave/util/flex_string.hpp @ 16:2665513ce2d3

Add boost headers

+/*=============================================================================
+    Boost.Wave: A Standard compliant C++ preprocessor library
+    http://www.boost.org/
+
+    Copyright (c) 2001 by Andrei Alexandrescu. Distributed under 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)
+=============================================================================*/
+
+// This code is taken from: 
+// Andrei Alexandrescu, Generic<Programming>: A Policy-Based basic_string 
+// Implementation. http://www.cuj.com/documents/s=7994/cujcexp1906alexandr/
+//
+// #HK030306: 
+//      - Moved into the namespace boost::wave::util 
+//      - Added a bunch of missing typename(s) 
+//      - Integrated with boost config
+//      - Added a missing header include
+//      - Added special constructors and operator= to allow CowString to be 
+//        a real COW-string (removed unnecessary data copying)
+//      - Fixed a string terminating bug in append
+//
+// #HK040109:
+//      - Incorporated the changes from Andrei's latest version of this class
+//
+// #HK070307:
+//      - Once again incorporated the changes from Andrei's latest version of 
+//        this class
+//
+// #HK090523:
+//      - Incorporated the changes from latest version of flex_string as 
+//        maintained in Loki
+//
+// #HK130910:
+//      - Removed the getline implementation which was borrowed from the SGI
+//        STL as the license for this code is not compatible with Boost.
+
+#ifndef FLEX_STRING_INC_
+#define FLEX_STRING_INC_
+
+/*
+////////////////////////////////////////////////////////////////////////////////
+template <typename E, class A = @>
+class StoragePolicy
+{
+    typedef E value_type;
+    typedef @ iterator;
+    typedef @ const_iterator;
+    typedef A allocator_type;
+    typedef @ size_type;
+    
+    StoragePolicy(const StoragePolicy& s);
+    StoragePolicy(const A&);
+    StoragePolicy(const E* s, size_type len, const A&);
+    StoragePolicy(size_type len, E c, const A&);
+    ~StoragePolicy();
+
+    iterator begin();
+    const_iterator begin() const;
+    iterator end();
+    const_iterator end() const;
+    
+    size_type size() const;
+    size_type max_size() const;
+    size_type capacity() const;
+
+    void reserve(size_type res_arg);
+
+    void append(const E* s, size_type sz);
+    
+    template <class InputIterator>
+    void append(InputIterator b, InputIterator e);
+
+    void resize(size_type newSize, E fill);
+
+    void swap(StoragePolicy& rhs);
+    
+    const E* c_str() const;
+    const E* data() const;
+    
+    A get_allocator() const;
+};
+////////////////////////////////////////////////////////////////////////////////
+*/
+
+#include <boost/config.hpp>
+#include <boost/assert.hpp>
+#include <boost/throw_exception.hpp>
+
+#include <boost/iterator/reverse_iterator.hpp>
+
+#include <boost/wave/wave_config.hpp>
+#if BOOST_WAVE_SERIALIZATION != 0
+#include <boost/serialization/serialization.hpp>
+#include <boost/serialization/split_free.hpp>
+#include <boost/serialization/collections_save_imp.hpp>
+#include <boost/serialization/collections_load_imp.hpp>
+#define BOOST_WAVE_FLEX_STRING_SERIALIZATION_HACK 1
+#endif
+
+#include <memory>
+#include <new>
+#include <string>
+#include <vector>
+#include <algorithm>
+#include <functional>
+#include <limits>
+#include <stdexcept>
+#include <ios>
+
+#include <cstddef>
+#include <cstring>
+#include <cstdlib>
+
+// this must occur after all of the includes and before any code appears
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_PREFIX
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+namespace boost {
+namespace wave {
+namespace util {
+
+namespace flex_string_details
+{
+    template <class InIt, class OutIt>
+    OutIt copy_n(InIt b, 
+        typename std::iterator_traits<InIt>::difference_type n, OutIt d)
+    {
+        for (/**/; n != 0; --n, ++b, ++d)
+        {
+            *d = *b;
+        }
+        return d;
+    }
+
+    template <class Pod, class T>
+    inline void pod_fill(Pod* b, Pod* e, T c)
+    {
+        switch ((e - b) & 7)
+        {
+        case 0:
+            while (b != e)
+            {
+                *b = c; ++b; BOOST_FALLTHROUGH;
+        case 7: *b = c; ++b; BOOST_FALLTHROUGH;
+        case 6: *b = c; ++b; BOOST_FALLTHROUGH;
+        case 5: *b = c; ++b; BOOST_FALLTHROUGH;
+        case 4: *b = c; ++b; BOOST_FALLTHROUGH;
+        case 3: *b = c; ++b; BOOST_FALLTHROUGH;
+        case 2: *b = c; ++b; BOOST_FALLTHROUGH;
+        case 1: *b = c; ++b;
+            }
+        }
+    }
+
+    template <class Pod>
+    inline void pod_move(const Pod* b, const Pod* e, Pod* d)
+    {
+        using namespace std;
+        memmove(d, b, (e - b) * sizeof(*b));
+    }
+
+    template <class Pod>
+    inline Pod* pod_copy(const Pod* b, const Pod* e, Pod* d)
+    {
+        const std::size_t s = e - b;
+        using namespace std;
+        memcpy(d, b, s * sizeof(*b));
+        return d + s;
+    }
+
+    template <typename T> struct get_unsigned
+    {
+        typedef T result;
+    };
+
+    template <> struct get_unsigned<char>
+    {
+        typedef unsigned char result;
+    };
+
+    template <> struct get_unsigned<signed char>
+    {
+        typedef unsigned char result;
+    };
+
+    template <> struct get_unsigned<short int>
+    {
+        typedef unsigned short int result;
+    };
+
+    template <> struct get_unsigned<int>
+    {
+        typedef unsigned int result;
+    };
+
+    template <> struct get_unsigned<long int>
+    {
+        typedef unsigned long int result;
+    };
+
+    enum Shallow {};
+}
+
+template <class T> class mallocator
+{
+public:
+    typedef T                 value_type;
+    typedef value_type*       pointer;
+    typedef const value_type* const_pointer;
+    typedef value_type&       reference;
+    typedef const value_type& const_reference;
+    typedef std::size_t       size_type;
+    //typedef unsigned int      size_type;
+    //typedef std::ptrdiff_t    difference_type;
+    typedef int               difference_type;
+
+    template <class U> 
+    struct rebind { typedef mallocator<U> other; };
+
+    mallocator() {}
+    mallocator(const mallocator&) {}
+    //template <class U> 
+    //mallocator(const mallocator<U>&) {}
+    ~mallocator() {}
+
+    pointer address(reference x) const { return &x; }
+    const_pointer address(const_reference x) const 
+    { 
+        return x;
+    }
+
+    pointer allocate(size_type n, const_pointer = 0) 
+    {
+        using namespace std;
+        void* p = malloc(n * sizeof(T));
+        if (!p) boost::throw_exception(std::bad_alloc());
+        return static_cast<pointer>(p);
+    }
+
+    void deallocate(pointer p, size_type) 
+    { 
+        using namespace std;
+        free(p); 
+    }
+
+    size_type max_size() const 
+    { 
+        return static_cast<size_type>(-1) / sizeof(T);
+    }
+
+    void construct(pointer p, const value_type& x) 
+    { 
+        new(p) value_type(x); 
+    }
+
+    void destroy(pointer p) 
+    { 
+        p->~value_type(); 
+    }
+
+private:
+    void operator=(const mallocator&);
+};
+
+template<> class mallocator<void>
+{
+  typedef void        value_type;
+  typedef void*       pointer;
+  typedef const void* const_pointer;
+
+  template <class U> 
+  struct rebind { typedef mallocator<U> other; };
+};
+
+template <class T>
+inline bool operator==(const mallocator<T>&, 
+                       const mallocator<T>&) {
+  return true;
+}
+
+template <class T>
+inline bool operator!=(const mallocator<T>&, 
+                       const mallocator<T>&) {
+  return false;
+}
+
+template <class Allocator>
+typename Allocator::pointer Reallocate(
+    Allocator& alloc,
+    typename Allocator::pointer p, 
+    typename Allocator::size_type oldObjCount,
+    typename Allocator::size_type newObjCount,
+    void*)
+{
+    // @@@ not implemented
+    return NULL;
+}
+
+template <class Allocator>
+typename Allocator::pointer Reallocate(
+    Allocator& alloc,
+    typename Allocator::pointer p, 
+    typename Allocator::size_type oldObjCount,
+    typename Allocator::size_type newObjCount,
+    mallocator<void>*)
+{
+    // @@@ not implemented
+    return NULL;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// class template SimpleStringStorage
+// Allocates memory with malloc
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename E, class A = std::allocator<E> >
+class SimpleStringStorage
+{
+    // The "public" below exists because MSVC can't do template typedefs
+public:
+    struct Data
+    {
+        Data() : pEnd_(buffer_), pEndOfMem_(buffer_) { buffer_[0] = E(0); }
+
+        E* pEnd_;
+        E* pEndOfMem_;
+        E buffer_[1];
+    };
+    static const Data emptyString_;
+
+    typedef typename A::size_type size_type;
+
+private:
+    Data* pData_;
+
+    void Init(size_type size, size_type capacity)
+    {
+        BOOST_ASSERT(size <= capacity);
+        if (capacity == 0) 
+        {
+            pData_ = const_cast<Data*>(&emptyString_);
+        }
+        else
+        {
+            // 11-17-2000: comment added: 
+            //     No need to allocate (capacity + 1) to 
+            //     accommodate the terminating 0, because Data already
+            //     has one character in there
+            pData_ = static_cast<Data*>(
+                malloc(sizeof(Data) + capacity * sizeof(E)));
+            if (!pData_) boost::throw_exception(std::bad_alloc());
+            pData_->pEnd_ = pData_->buffer_ + size;
+            pData_->pEndOfMem_ = pData_->buffer_ + capacity;
+        }
+    }
+
+private:
+    // Warning - this doesn't initialize pData_. Used in reserve()
+    SimpleStringStorage()
+    { }
+
+public:
+    typedef E value_type;
+    typedef E* iterator;
+    typedef const E* const_iterator;
+    typedef A allocator_type;
+
+    SimpleStringStorage(const SimpleStringStorage& rhs) 
+    {
+        const size_type sz = rhs.size();
+        Init(sz, sz);
+        if (sz) flex_string_details::pod_copy(rhs.begin(), rhs.end(), begin());
+    }
+
+    SimpleStringStorage(const SimpleStringStorage& s, 
+        flex_string_details::Shallow) 
+        : pData_(s.pData_)
+    {
+    }
+
+    SimpleStringStorage(const A&)
+    { pData_ = const_cast<Data*>(&emptyString_); }
+
+    SimpleStringStorage(const E* s, size_type len, const A&)
+    {
+        Init(len, len);
+        flex_string_details::pod_copy(s, s + len, begin());
+    }
+
+    SimpleStringStorage(size_type len, E c, const A&)
+    {
+        Init(len, len);
+        flex_string_details::pod_fill(begin(), end(), c);
+    }
+
+    SimpleStringStorage& operator=(const SimpleStringStorage& rhs)
+    {
+        const size_type sz = rhs.size();
+        reserve(sz);
+        flex_string_details::pod_copy(&*rhs.begin(), &*rhs.end(), begin());
+        pData_->pEnd_ = &*begin() + sz;
+        return *this;
+    }
+
+    ~SimpleStringStorage()
+    {
+        BOOST_ASSERT(begin() <= end());
+        if (pData_ != &emptyString_) free(pData_);
+    }
+
+    iterator begin()
+    { return pData_->buffer_; }
+
+    const_iterator begin() const
+    { return pData_->buffer_; }
+
+    iterator end()
+    { return pData_->pEnd_; }
+
+    const_iterator end() const
+    { return pData_->pEnd_; }
+
+    size_type size() const
+    { return pData_->pEnd_ - pData_->buffer_; }
+
+    size_type max_size() const
+    { return std::size_t(-1) / sizeof(E) - sizeof(Data) - 1; }
+
+    size_type capacity() const
+    { return pData_->pEndOfMem_ - pData_->buffer_; }
+
+    void reserve(size_type res_arg)
+    {
+        if (res_arg <= capacity())
+        {
+            // @@@ insert shrinkage here if you wish
+            return;
+        }
+
+        if (pData_ == &emptyString_) 
+        {
+            Init(0, res_arg);
+        }
+        else
+        {
+            const size_type sz = size();
+
+            void* p = realloc(pData_, 
+                sizeof(Data) + res_arg * sizeof(E));
+            if (!p) boost::throw_exception(std::bad_alloc());
+        
+            if (p != pData_)
+            {
+                pData_ = static_cast<Data*>(p);
+                pData_->pEnd_ = pData_->buffer_ + sz;
+            }
+            pData_->pEndOfMem_ = pData_->buffer_ + res_arg;
+        }
+    }
+
+    void append(const E* s, size_type sz)
+    {
+        const size_type neededCapacity = size() + sz;
+
+        if (capacity() < neededCapacity)
+        {
+            const iterator b = begin();
+            static std::less_equal<const E*> le;
+            if (le(b, s) && le(s, end()))
+            {
+               // aliased
+                const size_type offset = s - b;
+                reserve(neededCapacity);
+                s = begin() + offset;
+            }
+            else
+            {
+                reserve(neededCapacity);
+            }
+        }
+        flex_string_details::pod_copy(s, s + sz, end());
+        pData_->pEnd_ += sz;
+    }
+
+    template <class InputIterator>
+    void append(InputIterator b, InputIterator e)
+    {
+        // @@@ todo: optimize this depending on iterator type
+        for (; b != e; ++b)
+        {
+            *this += *b;
+        }
+    }
+
+    void resize(size_type newSize, E fill)
+    {
+        const int delta = int(newSize - size());
+        if (delta == 0) return;
+
+        if (delta > 0)
+        {
+            if (newSize > capacity()) 
+            {
+                reserve(newSize);
+            }
+            E* e = &*end();
+            flex_string_details::pod_fill(e, e + delta, fill);
+        }
+        pData_->pEnd_ = pData_->buffer_ + newSize;
+    }
+
+    void swap(SimpleStringStorage& rhs)
+    {
+        std::swap(pData_, rhs.pData_);
+    }
+    
+    const E* c_str() const
+    {
+        if (pData_ != &emptyString_) *pData_->pEnd_ = E();
+        return pData_->buffer_; 
+    }
+
+    const E* data() const
+    { return pData_->buffer_; }
+    
+    A get_allocator() const
+    { return A(); }
+};
+
+template <typename E, class A>
+const typename SimpleStringStorage<E, A>::Data
+SimpleStringStorage<E, A>::emptyString_ = 
+    typename SimpleStringStorage<E, A>::Data();
+
+////////////////////////////////////////////////////////////////////////////////
+// class template AllocatorStringStorage
+// Allocates with your allocator
+// Takes advantage of the Empty Base Optimization if available
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename E, class A = std::allocator<E> >
+class AllocatorStringStorage : public A
+{
+    typedef typename A::size_type size_type;
+    typedef typename SimpleStringStorage<E, A>::Data Data;
+
+    void* Alloc(size_type sz, const void* p = 0)
+    {
+        return A::allocate(1 + (sz - 1) / sizeof(E), 
+            static_cast<const char*>(p));
+    }
+
+    void* Realloc(void* p, size_type oldSz, size_type newSz)
+    {
+        void* r = Alloc(newSz);
+        flex_string_details::pod_copy(p, p + Min(oldSz, newSz), r);
+        Free(p, oldSz);
+        return r;
+    }
+
+    void Free(void* p, size_type sz)
+    {
+        A::deallocate(static_cast<E*>(p), sz);
+    }
+
+    Data* pData_;
+
+    void Init(size_type size, size_type cap)
+    {
+        BOOST_ASSERT(size <= cap);
+
+        if (cap == 0)
+        {
+            pData_ = const_cast<Data*>(
+                &SimpleStringStorage<E, A>::emptyString_);
+        }
+        else
+        {
+            pData_ = static_cast<Data*>(Alloc(
+                cap * sizeof(E) + sizeof(Data)));
+            pData_->pEnd_ = pData_->buffer_ + size;
+            pData_->pEndOfMem_ = pData_->buffer_ + cap;
+        }
+    }
+
+public:
+    typedef E value_type;
+    typedef E* iterator;
+    typedef const E* const_iterator;
+    typedef A allocator_type;
+
+    AllocatorStringStorage() 
+    : A(), pData_(0)
+    {
+    }
+
+    AllocatorStringStorage(const AllocatorStringStorage& rhs) 
+    : A(rhs.get_allocator())
+    {
+        const size_type sz = rhs.size();
+        Init(sz, sz);
+        if (sz) flex_string_details::pod_copy(rhs.begin(), rhs.end(), begin());
+    }
+
+    AllocatorStringStorage(const AllocatorStringStorage& s, 
+        flex_string_details::Shallow) 
+    : A(s.get_allocator())
+    {
+        pData_ = s.pData_;
+    }
+
+    AllocatorStringStorage(const A& a) : A(a)
+    { 
+        pData_ = const_cast<Data*>(
+            &SimpleStringStorage<E, A>::emptyString_);
+    }
+
+    AllocatorStringStorage(const E* s, size_type len, const A& a)
+    : A(a)
+    {
+        Init(len, len);
+        flex_string_details::pod_copy(s, s + len, begin());
+    }
+
+    AllocatorStringStorage(size_type len, E c, const A& a)
+    : A(a)
+    {
+        Init(len, len);
+        flex_string_details::pod_fill(&*begin(), &*end(), c);
+    }
+
+    AllocatorStringStorage& operator=(const AllocatorStringStorage& rhs)
+    {
+        const size_type sz = rhs.size();
+        reserve(sz);
+        flex_string_details::pod_copy(&*rhs.begin(), &*rhs.end(), begin());
+        pData_->pEnd_ = &*begin() + rhs.size();
+        return *this;
+    }
+
+    ~AllocatorStringStorage()
+    {
+        if (capacity())
+        {
+            Free(pData_, 
+                sizeof(Data) + capacity() * sizeof(E));
+        }
+    }
+
+    iterator begin()
+    { return pData_->buffer_; }
+
+    const_iterator begin() const
+    { return pData_->buffer_; }
+
+    iterator end()
+    { return pData_->pEnd_; }
+
+    const_iterator end() const
+    { return pData_->pEnd_; }
+
+    size_type size() const
+    { return size_type(end() - begin()); }
+
+    size_type max_size() const
+    { return A::max_size(); }
+
+    size_type capacity() const
+    { return size_type(pData_->pEndOfMem_ - pData_->buffer_); }
+
+    void resize(size_type n, E c)
+    {
+        reserve(n);
+        iterator newEnd = begin() + n;
+        iterator oldEnd = end();
+        if (newEnd > oldEnd) 
+        {
+            // Copy the characters
+            flex_string_details::pod_fill(oldEnd, newEnd, c);
+        }
+        if (capacity()) pData_->pEnd_ = newEnd;
+    }
+
+    void reserve(size_type res_arg)
+    {
+        if (res_arg <= capacity())
+        {
+            // @@@ shrink to fit here 
+            return;
+        }
+
+        A& myAlloc = *this;
+        AllocatorStringStorage newStr(myAlloc);
+        newStr.Init(size(), res_arg);
+
+        flex_string_details::pod_copy(begin(), end(), newStr.begin());
+
+        swap(newStr);
+    }
+
+    template <class ForwardIterator>
+    void append(ForwardIterator b, ForwardIterator e)
+    {
+        const size_type 
+            sz = std::distance(b, e),
+            neededCapacity = size() + sz;
+
+        if (capacity() < neededCapacity)
+        {
+//             typedef std::less_equal<const E*> le_type;
+//             BOOST_ASSERT(!(le_type()(begin(), &*b) && le_type()(&*b, end())));
+            reserve(neededCapacity);
+        }
+        std::copy(b, e, end());
+        pData_->pEnd_ += sz;
+    }
+
+    void swap(AllocatorStringStorage& rhs)
+    {
+        // @@@ The following line is commented due to a bug in MSVC
+        //std::swap(lhsAlloc, rhsAlloc);
+        std::swap(pData_, rhs.pData_);
+    }
+
+    const E* c_str() const
+    { 
+        if (pData_ != &SimpleStringStorage<E, A>::emptyString_) 
+        {
+            *pData_->pEnd_ = E();
+        }
+        return &*begin(); 
+    }
+
+    const E* data() const
+    { return &*begin(); }
+
+    A get_allocator() const
+    { return *this; }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// class template VectorStringStorage
+// Uses std::vector
+// Takes advantage of the Empty Base Optimization if available
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename E, class A = std::allocator<E> >
+class VectorStringStorage : protected std::vector<E, A>
+{
+    typedef std::vector<E, A> base;
+
+public: // protected:
+    typedef E value_type;
+    typedef typename base::iterator iterator;
+    typedef typename base::const_iterator const_iterator;
+    typedef A allocator_type;
+    typedef typename A::size_type size_type;
+    
+    VectorStringStorage(const VectorStringStorage& s) : base(s)
+    { }
+    
+    VectorStringStorage(const A& a) : base(1, E(), a)
+    { }
+    
+    VectorStringStorage(const E* s, size_type len, const A& a)
+    : base(a)
+    {
+        base::reserve(len + 1);
+        base::insert(base::end(), s, s + len);
+        // Terminating zero
+        base::insert(base::end(), E());
+    }
+
+    VectorStringStorage(size_type len, E c, const A& a)
+    : base(len + 1, c, a)
+    {
+        // Terminating zero
+        base::back() = E();
+    }
+    
+    VectorStringStorage& operator=(const VectorStringStorage& rhs)
+    {
+        base& v = *this;
+        v = rhs;
+        return *this;
+    }
+   
+    iterator begin()
+    { return base::begin(); }
+    
+    const_iterator begin() const
+    { return base::begin(); }
+    
+    iterator end()
+    { return base::end() - 1; }
+    
+    const_iterator end() const
+    { return base::end() - 1; }
+    
+    size_type size() const
+    { return base::size() - 1; }
+
+    size_type max_size() const
+    { return base::max_size() - 1; }
+
+    size_type capacity() const
+    { return base::capacity() - 1; }
+
+    void reserve(size_type res_arg)
+    { 
+        BOOST_ASSERT(res_arg < max_size());
+        base::reserve(res_arg + 1); 
+    }
+    
+    void append(const E* s, size_type sz)
+    {
+        // Check for aliasing because std::vector doesn't do it.
+        static std::less_equal<const E*> le;
+        if (!base::empty())
+        {
+            const E* start = &base::front();
+            if (le(start, s) && le(s, start + size()))
+            {
+                // aliased
+                const size_type offset = s - start;
+                reserve(size() + sz);
+                s = &base::front() + offset;
+            }
+        }
+        base::insert(end(), s, s + sz);
+    }
+    
+    template <class InputIterator>
+    void append(InputIterator b, InputIterator e)
+    {
+        base::insert(end(), b, e);
+    }
+
+    void resize(size_type n, E c)
+    {
+        base::reserve(n + 1);
+        base::back() = c;
+        base::resize(n + 1, c);
+        base::back() = E();
+    }
+
+    void swap(VectorStringStorage& rhs)
+    { base::swap(rhs); }
+    
+    const E* c_str() const
+    { return &*begin(); }
+
+    const E* data() const
+    { return &*begin(); }
+    
+    A get_allocator() const
+    { return base::get_allocator(); }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// class template SmallStringOpt
+// Builds the small string optimization over any other storage
+////////////////////////////////////////////////////////////////////////////////
+
+template <class Storage, unsigned int threshold, 
+    typename Align = typename Storage::value_type*>
+class SmallStringOpt
+{
+public:
+    typedef typename Storage::value_type value_type;
+    typedef value_type* iterator;
+    typedef const value_type* const_iterator;
+    typedef typename Storage::allocator_type allocator_type;
+    typedef typename allocator_type::size_type size_type;
+    
+private:
+  enum { temp1 = threshold * sizeof(value_type) > sizeof(Storage) 
+        ? threshold  * sizeof(value_type) 
+        : sizeof(Storage) };
+    
+    enum { temp2 = temp1 > sizeof(Align) ? temp1 : sizeof(Align) };
+
+public:
+    enum { maxSmallString = 
+    (temp2 + sizeof(value_type) - 1) / sizeof(value_type) };
+    
+private:
+    enum { magic = maxSmallString + 1 };
+    
+    union
+    {
+        mutable value_type buf_[maxSmallString + 1];
+        Align align_;
+    };
+
+    Storage& GetStorage()
+    {
+        BOOST_ASSERT(buf_[maxSmallString] == magic);
+        Storage* p = reinterpret_cast<Storage*>(&buf_[0]);
+        return *p;
+    }
+
+    const Storage& GetStorage() const
+    {
+        BOOST_ASSERT(buf_[maxSmallString] == magic);
+        const Storage *p = reinterpret_cast<const Storage*>(&buf_[0]);
+        return *p;
+    }
+
+    bool Small() const
+    {
+        return buf_[maxSmallString] != magic;
+    }
+
+public:
+  SmallStringOpt(const SmallStringOpt& s)
+    {
+        if (s.Small())
+        {
+            flex_string_details::pod_copy(
+                s.buf_, 
+                s.buf_ + s.size(), 
+                buf_);
+        }
+        else
+        {
+            new(buf_) Storage(s.GetStorage());
+        }
+        buf_[maxSmallString] = s.buf_[maxSmallString];
+    }
+
+    SmallStringOpt(const allocator_type&)
+    {
+        buf_[maxSmallString] = maxSmallString;
+    }
+
+    SmallStringOpt(const value_type* s, size_type len, const allocator_type& a)
+    {
+        if (len <= maxSmallString)
+        {
+            flex_string_details::pod_copy(s, s + len, buf_);
+            buf_[maxSmallString] = value_type(maxSmallString - len);
+        }
+        else
+        {
+            new(buf_) Storage(s, len, a);
+            buf_[maxSmallString] = magic;
+        }
+    }
+
+    SmallStringOpt(size_type len, value_type c, const allocator_type& a)
+    {
+        if (len <= maxSmallString)
+        {
+            flex_string_details::pod_fill(buf_, buf_ + len, c);
+            buf_[maxSmallString] = value_type(maxSmallString - len);
+        }
+        else
+        {
+            new(buf_) Storage(len, c, a);
+            buf_[maxSmallString] = magic;
+        }
+    }
+
+    SmallStringOpt& operator=(const SmallStringOpt& rhs)
+    {
+        reserve(rhs.size());
+        resize(0, 0);
+        append(rhs.data(), rhs.size());
+        return *this;
+    }
+
+    ~SmallStringOpt()
+    {
+        if (!Small()) GetStorage().~Storage();
+    }
+
+    iterator begin()
+    {
+        if (Small()) return buf_;
+        return &*GetStorage().begin(); 
+    }
+
+    const_iterator begin() const
+    {
+        if (Small()) return buf_;
+        return &*GetStorage().begin(); 
+    }
+
+    iterator end()
+    {
+        if (Small()) return buf_ + maxSmallString - buf_[maxSmallString];
+        return &*GetStorage().end(); 
+    }
+
+    const_iterator end() const
+    {
+        if (Small()) return buf_ + maxSmallString - buf_[maxSmallString];
+        return &*GetStorage().end(); 
+    }
+
+    size_type size() const
+    {
+        BOOST_ASSERT(!Small() || maxSmallString >= buf_[maxSmallString]);
+        return Small() 
+            ? maxSmallString - buf_[maxSmallString] 
+            : GetStorage().size();
+    }
+
+    size_type max_size() const
+    { return get_allocator().max_size(); }
+
+    size_type capacity() const
+    { return Small() ? maxSmallString : GetStorage().capacity(); }
+
+    void reserve(size_type res_arg)
+    {
+        if (Small())
+        {
+            if (res_arg <= maxSmallString) return;
+            SmallStringOpt temp(*this);
+            this->~SmallStringOpt();
+            new(buf_) Storage(temp.data(), temp.size(), 
+                temp.get_allocator());
+            buf_[maxSmallString] = magic;
+            GetStorage().reserve(res_arg);
+        }
+        else
+        {
+            GetStorage().reserve(res_arg);
+        }
+        BOOST_ASSERT(capacity() >= res_arg);
+    }
+
+    void append(const value_type* s, size_type sz)
+    {
+        if (!Small())
+        {
+            GetStorage().append(s, sz);
+        }
+        else
+        {
+            // append to a small string
+            const size_type neededCapacity = 
+                maxSmallString - buf_[maxSmallString] + sz;
+
+            if (maxSmallString < neededCapacity)
+            {
+                // need to change storage strategy
+                allocator_type alloc;
+                Storage temp(alloc);
+                temp.reserve(neededCapacity);
+                temp.append(buf_, maxSmallString - buf_[maxSmallString]);
+                temp.append(s, sz);
+                buf_[maxSmallString] = magic;
+                new(buf_) Storage(temp.get_allocator());
+                GetStorage().swap(temp);
+            }
+            else
+            {
+                flex_string_details::pod_move(s, s + sz, 
+                    buf_ + maxSmallString - buf_[maxSmallString]);
+                buf_[maxSmallString] -= value_type(sz);
+            }
+        }
+    }
+
+    template <class InputIterator>
+    void append(InputIterator b, InputIterator e)
+    {
+        // @@@ todo: optimize this depending on iterator type
+        for (; b != e; ++b)
+        {
+            *this += *b;
+        }
+    }
+
+    void resize(size_type n, value_type c)
+    {
+        if (Small())
+        {
+            if (n > maxSmallString)
+            {
+                // Small string resized to big string
+                SmallStringOpt temp(*this); // can't throw
+                // 11-17-2001: correct exception safety bug
+                Storage newString(temp.data(), temp.size(), 
+                    temp.get_allocator());
+                newString.resize(n, c);
+                // We make the reasonable assumption that an empty Storage
+                //     constructor won't throw
+                this->~SmallStringOpt();
+                new(&buf_[0]) Storage(temp.get_allocator());
+                buf_[maxSmallString] = value_type(magic);
+                GetStorage().swap(newString);
+            }
+            else
+            {
+                // Small string resized to small string
+                // 11-17-2001: bug fix: terminating zero not copied
+                size_type toFill = n > size() ? n - size() : 0;
+                flex_string_details::pod_fill(end(), end() + toFill, c);
+                buf_[maxSmallString] = value_type(maxSmallString - n);
+            }
+        }
+        else
+        {
+            if (n > maxSmallString)
+            {
+                // Big string resized to big string
+                GetStorage().resize(n, c);
+            }
+            else
+            {
+                // Big string resized to small string
+                // 11-17=2001: bug fix in the BOOST_ASSERTion below
+                BOOST_ASSERT(capacity() > n);
+                SmallStringOpt newObj(data(), n, get_allocator());
+                newObj.swap(*this);
+            }
+        }
+    }
+
+    void swap(SmallStringOpt& rhs)
+    {
+        if (Small())
+        {
+            if (rhs.Small())
+            {
+                // Small swapped with small
+                std::swap_ranges(buf_, buf_ + maxSmallString + 1, 
+                    rhs.buf_);
+            }
+            else
+            {
+                // Small swapped with big
+                // Make a copy of myself - can't throw
+                SmallStringOpt temp(*this);
+                // Nuke myself
+                this->~SmallStringOpt();
+                // Make an empty storage for myself (likely won't throw)
+                new(buf_) Storage(0, value_type(), rhs.get_allocator());
+                buf_[maxSmallString] = magic;
+                // Recurse to this same function
+                swap(rhs);
+                // Nuke rhs
+                rhs.~SmallStringOpt();
+                // Build the new small string into rhs
+                new(&rhs) SmallStringOpt(temp);
+            }
+        }
+        else
+        {
+            if (rhs.Small())
+            {
+                // Big swapped with small
+                // Already implemented, recurse with reversed args
+                rhs.swap(*this);
+            }
+            else
+            {
+                // Big swapped with big
+                GetStorage().swap(rhs.GetStorage());
+            }
+        }
+    }
+
+    const value_type* c_str() const
+    { 
+        if (!Small()) return GetStorage().c_str(); 
+        buf_[maxSmallString - buf_[maxSmallString]] = value_type();
+        return buf_;
+    }
+
+    const value_type* data() const
+    { return Small() ? buf_ : GetStorage().data(); }
+    
+    allocator_type get_allocator() const
+    { return allocator_type(); }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// class template CowString
+// Implements Copy on Write over any storage
+////////////////////////////////////////////////////////////////////////////////
+
+template <
+    typename Storage, 
+    typename Align = BOOST_DEDUCED_TYPENAME Storage::value_type*
+>
+class CowString
+{
+    typedef typename Storage::value_type E;
+    typedef typename flex_string_details::get_unsigned<E>::result RefCountType;
+
+public:
+    typedef E value_type;
+    typedef typename Storage::iterator iterator;
+    typedef typename Storage::const_iterator const_iterator;
+    typedef typename Storage::allocator_type allocator_type;
+    typedef typename allocator_type::size_type size_type;
+    typedef typename Storage::reference reference;
+    
+private:
+    union
+    {
+        mutable char buf_[sizeof(Storage)];
+        Align align_;
+    };
+
+    Storage& Data() const
+    { 
+        Storage* p = reinterpret_cast<Storage*>(&buf_[0]);
+        return *p;
+    }
+
+    RefCountType GetRefs() const
+    {
+        const Storage& d = Data();
+        BOOST_ASSERT(d.size() > 0);
+        BOOST_ASSERT(static_cast<RefCountType>(*d.begin()) != 0);
+        return *d.begin();
+    }
+    
+    RefCountType& Refs()
+    {
+        Storage& d = Data();
+        BOOST_ASSERT(d.size() > 0);
+        return reinterpret_cast<RefCountType&>(*d.begin());
+    }
+    
+    void MakeUnique() const
+    {
+        BOOST_ASSERT(GetRefs() >= 1);
+        if (GetRefs() == 1) return;
+
+        union
+        {
+            char buf_[sizeof(Storage)];
+            Align align_;
+        } temp;
+
+        --(*Data().begin()); // decrement the use count of the remaining object
+
+        Storage* p = reinterpret_cast<Storage*>(&temp.buf_[0]);
+        new(buf_) Storage(
+            *new(p) Storage(Data()), 
+            flex_string_details::Shallow());
+        *Data().begin() = 1;
+    }
+
+public:
+    CowString(const CowString& s)
+    {
+        if (s.GetRefs() == (std::numeric_limits<RefCountType>::max)())
+        {
+            // must make a brand new copy
+            new(buf_) Storage(s.Data()); // non shallow
+            Refs() = 1;
+        }
+        else
+        {
+            new(buf_) Storage(s.Data(), flex_string_details::Shallow());
+            ++Refs();
+        }
+        BOOST_ASSERT(Data().size() > 0);
+    }
+    
+    CowString(const allocator_type& a)
+    {
+        new(buf_) Storage(1, 1, a);
+    }
+    
+    CowString(const E* s, size_type len, const allocator_type& a)
+    {
+        // Warning - MSVC's debugger has trouble tracing through the code below.
+        // It seems to be a const-correctness issue
+        //
+        new(buf_) Storage(a);
+        Data().reserve(len + 1);
+        Data().resize(1, 1);
+        Data().append(s, s + len);
+    }
+
+    CowString(size_type len, E c, const allocator_type& a)
+    {
+        new(buf_) Storage(len + 1, c, a);
+        Refs() = 1;
+    }
+    
+    CowString& operator=(const CowString& rhs)
+    {
+//        CowString(rhs).swap(*this);
+        if (--Refs() == 0) 
+            Data().~Storage();
+        if (rhs.GetRefs() == (std::numeric_limits<RefCountType>::max)())
+        {
+            // must make a brand new copy
+            new(buf_) Storage(rhs.Data()); // non shallow
+            Refs() = 1;
+        }
+        else
+        {
+            new(buf_) Storage(rhs.Data(), flex_string_details::Shallow());
+            ++Refs();
+        }
+        BOOST_ASSERT(Data().size() > 0);
+        return *this;
+    }
+
+    ~CowString()
+    {
+        BOOST_ASSERT(Data().size() > 0);
+        if (--Refs() == 0) 
+            Data().~Storage();
+    }
+
+    iterator begin()
+    {
+        BOOST_ASSERT(Data().size() > 0);
+        MakeUnique();
+        return Data().begin() + 1; 
+    }
+    
+    const_iterator begin() const
+    {
+        BOOST_ASSERT(Data().size() > 0);
+        return Data().begin() + 1; 
+    }
+    
+    iterator end()
+    {
+        MakeUnique();
+        return Data().end(); 
+    }
+    
+    const_iterator end() const
+    {
+        return Data().end(); 
+    }
+    
+    size_type size() const
+    {
+        BOOST_ASSERT(Data().size() > 0);
+        return Data().size() - 1;
+    }
+
+    size_type max_size() const
+    { 
+        BOOST_ASSERT(Data().max_size() > 0);
+        return Data().max_size() - 1;
+    }
+
+    size_type capacity() const
+    { 
+        BOOST_ASSERT(Data().capacity() > 0);
+        return Data().capacity() - 1;
+    }
+
+    void resize(size_type n, E c)
+    {
+        BOOST_ASSERT(Data().size() > 0);
+        MakeUnique();
+        Data().resize(n + 1, c);
+    }
+
+    template <class FwdIterator>
+    void append(FwdIterator b, FwdIterator e)
+    {
+        MakeUnique();
+        Data().append(b, e);
+    }
+    
+    void reserve(size_type res_arg)
+    {
+        if (capacity() > res_arg) return;
+        MakeUnique();
+        Data().reserve(res_arg + 1);
+    }
+    
+    void swap(CowString& rhs)
+    {
+        Data().swap(rhs.Data());
+    }
+    
+    const E* c_str() const
+    { 
+        BOOST_ASSERT(Data().size() > 0);
+        return Data().c_str() + 1;
+    }
+
+    const E* data() const
+    { 
+        BOOST_ASSERT(Data().size() > 0);
+        return Data().data() + 1;
+    }
+    
+    allocator_type get_allocator() const
+    { 
+        return Data().get_allocator();
+    }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// class template flex_string
+// a std::basic_string compatible implementation 
+// Uses a Storage policy 
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename E,
+    class T = std::char_traits<E>,
+    class A = std::allocator<E>,
+    class Storage = AllocatorStringStorage<E, A> >
+class flex_string : private Storage
+{
+#if defined(BOOST_WAVE_FLEXSTRING_THROW_ON_ENFORCE)
+    template <typename Exception>
+    static void Enforce(bool condition, Exception*, const char* msg)
+    { if (!condition) boost::throw_exception(Exception(msg)); }
+#else
+    template <typename Exception>
+    static inline void Enforce(bool condition, Exception*, const char* msg)
+    { BOOST_ASSERT(condition && msg); }
+#endif // defined(BOOST_WAVE_FLEXSTRING_THROW_ON_ENFORCE)
+
+#ifndef NDEBUG
+    bool Sane() const
+    {
+        return
+            begin() <= end() &&
+            empty() == (size() == 0) &&
+            empty() == (begin() == end()) &&
+            size() <= max_size() &&
+            capacity() <= max_size() &&
+            size() <= capacity();
+    }
+
+    struct Invariant;
+    friend struct Invariant;
+    struct Invariant
+    {
+        Invariant(const flex_string& s) : s_(s)
+        {
+            BOOST_ASSERT(s_.Sane());
+        }
+        ~Invariant()
+        {
+            BOOST_ASSERT(s_.Sane());
+        }
+    private:
+        const flex_string& s_;
+        Invariant& operator=(const Invariant&);
+    };
+#endif
+
+public:
+    // types
+    typedef T traits_type;
+    typedef typename traits_type::char_type value_type;
+    typedef A allocator_type;
+    typedef typename A::size_type size_type;
+    typedef typename A::difference_type difference_type;
+    
+    typedef typename A::reference reference;
+    typedef typename A::const_reference const_reference;
+    typedef typename A::pointer pointer;
+    typedef typename A::const_pointer const_pointer;
+    
+    typedef typename Storage::iterator iterator;
+    typedef typename Storage::const_iterator const_iterator;
+
+    typedef boost::reverse_iterator<iterator> reverse_iterator;
+    typedef boost::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    static const size_type npos;    // = size_type(-1)
+
+private:
+    static size_type Min(size_type lhs, size_type rhs)
+    { return lhs < rhs ? lhs : rhs; }
+    static void Procust(size_type& n, size_type nmax)
+    { if (n > nmax) n = nmax; }
+    
+public:    
+    // 21.3.1 construct/copy/destroy
+    explicit flex_string(const A& a = A())
+    : Storage(a) 
+    {}
+    
+    flex_string(const flex_string& str)
+    : Storage(str) 
+    {
+    }
+    
+    flex_string(const flex_string& str, size_type pos, 
+        size_type n = npos, const A& a = A())
+    : Storage(a) 
+    {
+        Enforce(pos <= str.size(), (std::out_of_range*)0, "");
+        assign(str, pos, n);
+    }
+    
+    flex_string(const value_type* s, const A& a = A())
+    : Storage(s, traits_type::length(s), a)
+    {}
+    
+    flex_string(const value_type* s, size_type n, const A& a = A())
+    : Storage(s, n, a)
+    {}
+    
+    flex_string(size_type n, value_type c, const A& a = A())
+    : Storage(n, c, a)
+    {}
+
+    template <class InputIterator>
+    flex_string(InputIterator begin, InputIterator end, const A& a = A())
+    : Storage(a)
+    {
+        assign(begin, end);
+    }
+
+    ~flex_string()
+    {}
+    
+    flex_string& operator=(const flex_string& str)
+    {
+        if (this != &str) {
+            Storage& s = *this;
+            s = str;
+        }
+        return *this;
+    }   
+    
+    flex_string& operator=(const value_type* s)
+    {
+        assign(s);
+        return *this;
+    }
+
+    flex_string& operator=(value_type c)
+    {
+        assign(1, c);
+        return *this;
+    }
+    
+    // 21.3.2 iterators:
+    iterator begin()
+    { return Storage::begin(); }
+    
+    const_iterator begin() const
+    { return Storage::begin(); }
+    
+    iterator end()
+    { return Storage::end(); }
+    
+    const_iterator end() const
+    { return Storage::end(); }
+
+    reverse_iterator rbegin()
+    { return reverse_iterator(end()); }
+    
+    const_reverse_iterator rbegin() const
+    { return const_reverse_iterator(end()); }
+    
+    reverse_iterator rend()
+    { return reverse_iterator(begin()); }
+    
+    const_reverse_iterator rend() const
+    { return const_reverse_iterator(begin()); }
+
+#if BOOST_WAVE_FLEX_STRING_SERIALIZATION_HACK != 0
+    //  temporary hack to make it easier to serialize flex_string's using
+    //  the Boost.Serialization library 
+    value_type & back() { return *(begin()+size()-1); }
+    value_type const& back() const { return *(begin()+size()-1); }
+#endif
+
+    // 21.3.3 capacity:
+    size_type size() const
+    { return Storage::size(); }
+    
+    size_type length() const
+    { return size(); }
+    
+    size_type max_size() const
+    { return Storage::max_size(); }
+
+    void resize(size_type n, value_type c)
+    { Storage::resize(n, c); }
+    
+    void resize(size_type n)
+    { resize(n, value_type()); }
+    
+    size_type capacity() const
+    { return Storage::capacity(); }
+    
+    void reserve(size_type res_arg = 0)
+    {
+        Enforce(res_arg <= max_size(), (std::length_error*)0, "");
+        Storage::reserve(res_arg);
+    }
+    
+    void clear()
+    { resize(0); } 
+    
+    bool empty() const
+    { return size() == 0; }
+    
+    // 21.3.4 element access:
+    const_reference operator[](size_type pos) const
+    { return *(begin() + pos); }
+    
+    reference operator[](size_type pos)
+    { return *(begin() + pos); }
+
+    const_reference at(size_type n) const
+    {
+        Enforce(n < size(), (std::out_of_range*)0, "");
+        return (*this)[n];
+    }
+    
+    reference at(size_type n)
+    {
+        Enforce(n < size(), (std::out_of_range*)0, "");
+        return (*this)[n];
+    }
+    
+    // 21.3.5 modifiers:
+    flex_string& operator+=(const flex_string& str)
+    { return append(str); }
+    
+    flex_string& operator+=(const value_type* s)
+    { return append(s); }
+
+    flex_string& operator+=(value_type c)
+    { 
+        push_back(c);
+        return *this;
+    }
+    
+    flex_string& append(const flex_string& str)
+    { return append(str, 0, npos); }
+    
+    flex_string& append(const flex_string& str, const size_type pos,
+        size_type n)
+    { 
+        const size_type sz = str.size();
+        Enforce(pos <= sz, (std::out_of_range*)0, "");
+        Procust(n, sz - pos);
+        return append(str.c_str() + pos, n); 
+    }
+    
+    flex_string& append(const value_type* s, const size_type n)
+    { 
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        if (IsAliasedRange(s, s + n))
+        {
+            const size_type offset = s - &*begin();
+            Storage::reserve(size() + n);
+            s = &*begin() + offset;
+        }
+        Storage::append(s, s+ n); 
+        return *this;
+    }
+    
+    flex_string& append(const value_type* s)
+    { return append(s, traits_type::length(s)); }
+    
+    flex_string& append(size_type n, value_type c)
+    { 
+        resize(size() + n, c);
+        return *this;
+    }
+
+    template<class InputIterator>
+    flex_string& append(InputIterator first, InputIterator last)
+    {
+        insert(end(), first, last);
+        return *this;
+    }
+
+    void push_back(value_type c)
+    { 
+        const size_type cap = capacity();
+        if (size() == cap)
+        {
+            reserve(cap << 1u);
+        }
+        Storage::append(&c, &c + 1);
+    }
+
+    flex_string& assign(const flex_string& str)
+    { 
+        if (&str == this) return *this;
+        return assign(str.data(), str.size());
+    }
+    
+    flex_string& assign(const flex_string& str, size_type pos,
+        size_type n)
+    { 
+        const size_type sz = str.size();
+        Enforce(pos <= str.size(), (std::out_of_range*)0, "");
+        Procust(n, sz - pos);
+        return assign(str.data() + pos, n);
+    }
+    
+    flex_string& assign(const value_type* s, size_type n)
+    {
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        if (size() >= n)
+        {
+            std::copy(s, s + n, begin());
+            resize(n);
+        }
+        else
+        {
+            const value_type *const s2 = s + size();
+            std::copy(s, s2, begin());
+            append(s2, n - size());
+        }
+        return *this;
+    }
+    
+    flex_string& assign(const value_type* s)
+    { return assign(s, traits_type::length(s)); }
+    
+    template <class ItOrLength, class ItOrChar>
+    flex_string& assign(ItOrLength first_or_n, ItOrChar last_or_c)
+    { return replace(begin(), end(), first_or_n, last_or_c); }
+    
+    flex_string& insert(size_type pos1, const flex_string& str)
+    { return insert(pos1, str.data(), str.size()); }
+    
+    flex_string& insert(size_type pos1, const flex_string& str,
+        size_type pos2, size_type n)
+    { 
+        Enforce(pos2 <= str.length(), (std::out_of_range*)0, "");
+        Procust(n, str.length() - pos2);
+        return insert(pos1, str.data() + pos2, n); 
+    }
+    
+    flex_string& insert(size_type pos, const value_type* s, size_type n)
+    { 
+        Enforce(pos <= length(), (std::out_of_range*)0, "");
+        insert(begin() + pos, s, s + n); 
+        return *this;
+    }
+    
+    flex_string& insert(size_type pos, const value_type* s)
+    { return insert(pos, s, traits_type::length(s)); }
+    
+    flex_string& insert(size_type pos, size_type n, value_type c)
+    { 
+        Enforce(pos <= length(), (std::out_of_range*)0, "");
+        insert(begin() + pos, n, c);
+        return *this;
+    }
+    
+    iterator insert(iterator p, value_type c = value_type()) 
+    {
+        const size_type pos = p - begin();
+        insert(pos, &c, 1);
+        return begin() + pos;
+    }
+    
+private:
+    // Care must be taken when dereferencing some iterator types.
+    //
+    // Users can implement this function in their namespace if their storage 
+    // uses a special iterator type, the function will be found through ADL.
+    template<class Iterator>
+    const typename std::iterator_traits<Iterator>::value_type* 
+    DereferenceValidIterator(Iterator it) const
+    {
+        return &*it;
+    }
+
+    // Care must be taken when dereferencing a reverse iterators, hence this 
+    // special case. This isn't in the std namespace so as not to pollute it or 
+    // create name clashes.
+    template<typename Iterator>
+    const typename std::iterator_traits<Iterator>::value_type* 
+    DereferenceValidIterator(std::reverse_iterator<Iterator> it) const
+    {
+        return &*--it;
+    }
+
+    // Determine if the range aliases the current string.
+    //
+    // This method cannot be const because calling begin/end on copy-on-write 
+    // implementations must have side effects.
+    // A const version wouldn't make the string unique through this call.
+    template<class Iterator>
+    bool IsAliasedRange(Iterator beginIterator, Iterator endIterator)
+    {
+        if(!empty() && beginIterator != endIterator)
+        {
+            typedef const typename std::iterator_traits<Iterator>::value_type * 
+                pointer;
+
+            pointer myBegin(&*begin());
+            pointer myEnd(&*begin() + size());
+            pointer rangeBegin(DereferenceValidIterator(beginIterator));
+
+            const std::less_equal<pointer> less_equal = std::less_equal<pointer>();
+            if(less_equal(myBegin, rangeBegin) && less_equal(rangeBegin, myEnd))
+                return true;
+        }
+        return false;
+    }
+
+    template <int i> class Selector {};
+
+    flex_string& InsertImplDiscr(iterator p, 
+        size_type n, value_type c, Selector<1>)
+    { 
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        BOOST_ASSERT(begin() <= p && p <= end());
+        const size_type insertOffset(p - begin());
+        const size_type originalSize(size());
+        if(n < originalSize - insertOffset)
+        {
+            // The new characters fit within the original string.
+            // The characters that are pushed back need to be moved because 
+            // they're aliased.
+            // The appended characters will all be overwritten by the move.
+            append(n, value_type(0));
+            value_type* begin(&*begin());
+            flex_string_details::pod_move(begin + insertOffset, 
+                begin + originalSize, begin + insertOffset + n);
+            std::fill(begin + insertOffset, begin + insertOffset + n, c);
+        }
+        else
+        {
+            // The new characters exceed the original string.
+            // The characters that are pushed back can simply be copied since 
+            // they aren't aliased.
+            // The appended characters will partly be overwritten by the copy.
+            append(n, c);
+            value_type* begin(&*begin());
+            flex_string_details::pod_copy(begin + insertOffset, 
+                begin + originalSize, begin + insertOffset + n);
+            std::fill(begin + insertOffset, begin + originalSize, c);
+        }
+        return *this;
+    }
+
+    template<class InputIterator>
+    flex_string& InsertImplDiscr(iterator i,
+        InputIterator b, InputIterator e, Selector<0>)
+    { 
+        InsertImpl(i, b, e, 
+            typename std::iterator_traits<InputIterator>::iterator_category());
+        return *this;
+    }
+
+    template <class FwdIterator>
+    void InsertImpl(iterator i,
+        FwdIterator s1, FwdIterator s2, std::forward_iterator_tag)
+    { 
+        if(s1 == s2)
+        {
+            // Insert an empty range.
+            return;
+        }
+
+        if(IsAliasedRange(s1, s2))
+        {
+            // The source range is contained in the current string, copy it 
+            // and recurse.
+            const flex_string temporary(s1, s2);
+            InsertImpl(i, temporary.begin(), temporary.end(),
+                typename std::iterator_traits<FwdIterator>::iterator_category());
+            return;
+        }
+
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        const size_type pos = i - begin();
+        const typename std::iterator_traits<FwdIterator>::difference_type n2 = 
+            std::distance(s1, s2);
+
+        BOOST_ASSERT(n2 >= 0);
+        using namespace flex_string_details;
+        BOOST_ASSERT(pos <= size());
+
+        const typename std::iterator_traits<FwdIterator>::difference_type maxn2 = 
+            capacity() - size();
+        if (maxn2 < n2)
+        {
+            // Reallocate the string.
+            BOOST_ASSERT(!IsAliasedRange(s1, s2));
+            reserve(size() + n2);
+            i = begin() + pos;
+        }
+        if (pos + n2 <= size())
+        {
+            const iterator tailBegin = end() - n2;
+            Storage::append(tailBegin, tailBegin + n2);
+            std::copy(reverse_iterator(tailBegin), reverse_iterator(i), 
+                reverse_iterator(tailBegin + n2));
+            std::copy(s1, s2, i);
+        }
+        else
+        {
+            FwdIterator t = s1;
+            const size_type old_size = size();
+            std::advance(t, old_size - pos);
+            BOOST_ASSERT(std::distance(t, s2) >= 0);
+            Storage::append(t, s2);
+            Storage::append(data() + pos, data() + old_size);
+            std::copy(s1, t, i);
+        }
+    }
+
+    template <class InputIterator>
+    void InsertImpl(iterator insertPosition,
+        InputIterator inputBegin, InputIterator inputEnd, 
+        std::input_iterator_tag)
+    {
+        flex_string temporary(begin(), insertPosition);
+        for (; inputBegin != inputEnd; ++inputBegin)
+        {
+            temporary.push_back(*inputBegin);
+        }
+        temporary.append(insertPosition, end());
+        swap(temporary);
+    }
+
+public:
+    template <class ItOrLength, class ItOrChar>
+    void insert(iterator p, ItOrLength first_or_n, ItOrChar last_or_c)
+    { 
+        Selector<std::numeric_limits<ItOrLength>::is_specialized> sel;
+        InsertImplDiscr(p, first_or_n, last_or_c, sel);
+    }
+    
+    flex_string& erase(size_type pos = 0, size_type n = npos)
+    { 
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        Enforce(pos <= length(), (std::out_of_range*)0, "");
+        Procust(n, length() - pos);
+        std::copy(begin() + pos + n, end(), begin() + pos);
+        resize(length() - n);
+        return *this;
+    }
+    
+    iterator erase(iterator position)
+    {
+        const size_type pos(position - begin());
+        erase(pos, 1);
+        return begin() + pos;
+    }
+    
+    iterator erase(iterator first, iterator last)
+    {
+        const size_type pos(first - begin());
+        erase(pos, last - first);
+        return begin() + pos;
+    }
+
+    // Replaces at most n1 chars of *this, starting with pos1 with the content of str
+    flex_string& replace(size_type pos1, size_type n1, const flex_string& str)
+    { return replace(pos1, n1, str, 0, npos); }
+    
+    // Replaces at most n1 chars of *this, starting with pos1,
+    // with at most n2 chars of str starting with pos2
+    flex_string& replace(size_type pos1, size_type n1, const flex_string& str,
+        size_type pos2, size_type n2)
+    {
+        Enforce(pos2 <= str.length(), (std::out_of_range*)0, "");
+        return replace(pos1, n1, str.data() + pos2, 
+            Min(n2, str.size() - pos2));
+    }
+    
+    // Replaces at most n1 chars of *this, starting with pos, with chars from s
+    flex_string& replace(size_type pos, size_type n1, const value_type* s)
+    { return replace(pos, n1, s, traits_type::length(s)); }
+    
+    // Replaces at most n1 chars of *this, starting with pos, with n2 occurences of c
+    // consolidated with
+    // Replaces at most n1 chars of *this, starting with pos,
+    // with at most n2 chars of str.
+    // str must have at least n2 chars.
+    template <class StrOrLength, class NumOrChar>
+    flex_string& replace(size_type pos, size_type n1, 
+        StrOrLength s_or_n2, NumOrChar n_or_c)
+    {
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        Enforce(pos <= size(), (std::out_of_range*)0, "");
+        Procust(n1, length() - pos);
+        const iterator b = begin() + pos;
+        return replace(b, b + n1, s_or_n2, n_or_c);
+    }
+
+    flex_string& replace(iterator i1, iterator i2, const flex_string& str)
+    { return replace(i1, i2, str.c_str(), str.length()); }
+    
+    flex_string& replace(iterator i1, iterator i2, const value_type* s)
+    { return replace(i1, i2, s, traits_type::length(s)); }
+
+private:
+    flex_string& ReplaceImplDiscr(iterator i1, iterator i2, 
+        const value_type* s, size_type n, Selector<2>)
+    { 
+        BOOST_ASSERT(i1 <= i2);
+        BOOST_ASSERT(begin() <= i1 && i1 <= end());
+        BOOST_ASSERT(begin() <= i2 && i2 <= end());
+        return replace(i1, i2, s, s + n); 
+    }
+    
+    flex_string& ReplaceImplDiscr(iterator i1, iterator i2,
+        size_type n2, value_type c, Selector<1>)
+    { 
+        const size_type n1 = i2 - i1;
+        if (n1 > n2)
+        {
+            std::fill(i1, i1 + n2, c);
+            erase(i1 + n2, i2);
+        }
+        else
+        {
+            std::fill(i1, i2, c);
+            insert(i2, n2 - n1, c);
+        }
+        return *this;
+    }
+
+    template <class InputIterator>
+    flex_string& ReplaceImplDiscr(iterator i1, iterator i2,
+        InputIterator b, InputIterator e, Selector<0>)
+    { 
+        ReplaceImpl(i1, i2, b, e, 
+            typename std::iterator_traits<InputIterator>::iterator_category());
+        return *this;
+    }
+
+    template <class FwdIterator>
+    void ReplaceImpl(iterator i1, iterator i2,
+        FwdIterator s1, FwdIterator s2, std::forward_iterator_tag)
+    { 
+#ifndef NDEBUG
+        Invariant checker(*this); 
+#endif
+        const typename std::iterator_traits<iterator>::difference_type n1 = 
+            i2 - i1;
+        BOOST_ASSERT(n1 >= 0);
+        const typename std::iterator_traits<FwdIterator>::difference_type n2 = 
+        std::distance(s1, s2);
+        BOOST_ASSERT(n2 >= 0);
+
+        if (IsAliasedRange(s1, s2))
+        {
+            // Aliased replace, copy to new string.
+            flex_string temporary;
+            temporary.reserve(size() - n1 + n2);
+            temporary.append(begin(), i1).append(s1, s2).append(i2, end());
+            swap(temporary);
+            return;
+        }
+
+        if (n1 > n2)
+        {
+            // Shrinks
+            std::copy(s1, s2, i1);
+            erase(i1 + n2, i2);
+        }
+        else
+        {
+            // Grows
+            flex_string_details::copy_n(s1, n1, i1);
+            std::advance(s1, n1);
+            insert(i2, s1, s2);
+        }
+    }
+
+    template <class InputIterator>
+    void ReplaceImpl(iterator i1, iterator i2,
+        InputIterator b, InputIterator e, std::input_iterator_tag)
+    {
+        flex_string temp(begin(), i1);
+        temp.append(b, e).append(i2, end());
+        swap(temp);
+    }
+
+public:
+    template <class T1, class T2>
+    flex_string& replace(iterator i1, iterator i2,
+        T1 first_or_n_or_s, T2 last_or_c_or_n)
+    { 
+        const bool 
+            num1 = std::numeric_limits<T1>::is_specialized,
+            num2 = std::numeric_limits<T2>::is_specialized;
+        return ReplaceImplDiscr(i1, i2, first_or_n_or_s, last_or_c_or_n, 
+            Selector<num1 ? (num2 ? 1 : -1) : (num2 ? 2 : 0)>()); 
+    }
+       
+    size_type copy(value_type* s, size_type n, size_type pos = 0) const
+    {
+        Enforce(pos <= size(), (std::out_of_range*)0, "");
+        n = Min(n, size() - pos);
+        
+        flex_string_details::pod_copy(
+            &*begin() + pos,
+            &*begin() + pos + n,
+            s);
+        return n;
+    }
+    
+    void swap(flex_string& rhs)
+    {
+        Storage& srhs = rhs;
+        this->Storage::swap(srhs);
+    }
+    
+    // 21.3.6 string operations:
+    const value_type* c_str() const
+    { return Storage::c_str(); }
+    
+    const value_type* data() const
+    { return Storage::data(); }
+    
+    allocator_type get_allocator() const
+    { return Storage::get_allocator(); }
+    
+    size_type find(const flex_string& str, size_type pos = 0) const
+    { return find(str.data(), pos, str.length()); }
+
+    size_type find (const value_type* s, size_type pos, size_type n) const
+    {
+        const size_type size_(size());
+        if (n + pos > size_) 
+            return npos; 
+        for (; pos < size_; ++pos)
+        {
+            if (traits_type::compare(&*begin() + pos, s, n) == 0)
+            {
+                return pos;
+            }
+        }
+        return npos;
+    }
+    
+    size_type find (const value_type* s, size_type pos = 0) const
+    { return find(s, pos, traits_type::length(s)); }
+
+    size_type find (value_type c, size_type pos = 0) const
+    { return find(&c, pos, 1); }
+    
+    size_type rfind(const flex_string& str, size_type pos = npos) const
+    { return rfind(str.c_str(), pos, str.length()); }
+    
+    size_type rfind(const value_type* s, size_type pos, size_type n) const
+    {
+        if (n > length()) return npos;
+        pos = Min(pos, length() - n);
+        if (n == 0) return pos;
+
+        const_iterator i(begin() + pos);
+        for (; ; --i)
+        {
+            if (traits_type::eq(*i, *s) 
+                && traits_type::compare(&*i, s, n) == 0)
+            {
+                return i - begin();
+            }
+            if (i == begin()) break;
+        }
+        return npos;
+    }
+
+    size_type rfind(const value_type* s, size_type pos = npos) const
+    { return rfind(s, pos, traits_type::length(s)); }
+
+    size_type rfind(value_type c, size_type pos = npos) const
+    { return rfind(&c, pos, 1); }
+    
+    size_type find_first_of(const flex_string& str, size_type pos = 0) const
+    { return find_first_of(str.c_str(), pos, str.length()); }
+    
+    size_type find_first_of(const value_type* s, 
+        size_type pos, size_type n) const
+    {
+        if (pos > length() || n == 0) return npos;
+        const_iterator i(begin() + pos),
+            finish(end());
+        for (; i != finish; ++i)
+        {
+            if (traits_type::find(s, n, *i) != 0)
+            {
+                return i - begin();
+            }
+        }
+        return npos;
+    }
+        
+    size_type find_first_of(const value_type* s, size_type pos = 0) const
+    { return find_first_of(s, pos, traits_type::length(s)); }
+    
+    size_type find_first_of(value_type c, size_type pos = 0) const
+    { return find_first_of(&c, pos, 1); }
+    
+    size_type find_last_of (const flex_string& str,
+        size_type pos = npos) const
+    { return find_last_of(str.c_str(), pos, str.length()); }
+    
+    size_type find_last_of (const value_type* s, size_type pos, 
+        size_type n) const
+    {
+        if (!empty() && n > 0)
+        {
+            pos = Min(pos, length() - 1);
+            const_iterator i(begin() + pos);
+            for (;; --i)
+            {
+                if (traits_type::find(s, n, *i) != 0)
+                {
+                    return i - begin();
+                }
+                if (i == begin()) break;
+            }
+        }
+        return npos;
+    }
+
+    size_type find_last_of (const value_type* s, 
+        size_type pos = npos) const
+    { return find_last_of(s, pos, traits_type::length(s)); }
+
+    size_type find_last_of (value_type c, size_type pos = npos) const
+    { return find_last_of(&c, pos, 1); }
+    
+    size_type find_first_not_of(const flex_string& str,
+        size_type pos = 0) const
+    { return find_first_not_of(str.data(), pos, str.size()); }
+    
+    size_type find_first_not_of(const value_type* s, size_type pos,
+        size_type n) const
+    {
+        if (pos < length())
+        {
+            const_iterator 
+                i(begin() + pos),
+                finish(end());
+            for (; i != finish; ++i)
+            {
+                if (traits_type::find(s, n, *i) == 0)
+                {
+                    return i - begin();
+                }
+            }
+        }
+        return npos;
+    }
+    
+    size_type find_first_not_of(const value_type* s, 
+        size_type pos = 0) const
+    { return find_first_not_of(s, pos, traits_type::length(s)); }
+        
+    size_type find_first_not_of(value_type c, size_type pos = 0) const
+    { return find_first_not_of(&c, pos, 1); }
+    
+    size_type find_last_not_of(const flex_string& str,
+        size_type pos = npos) const
+    { return find_last_not_of(str.c_str(), pos, str.length()); }
+    
+    size_type find_last_not_of(const value_type* s, size_type pos,
+        size_type n) const
+    {
+        if (!empty())
+        {
+            pos = Min(pos, size() - 1);
+            const_iterator i(begin() + pos);
+            for (;; --i)
+            {
+                if (traits_type::find(s, n, *i) == 0)
+                {
+                    return i - begin();
+                }
+                if (i == begin()) break;
+            }
+        }
+        return npos;
+    }
+
+    size_type find_last_not_of(const value_type* s, 
+        size_type pos = npos) const
+    { return find_last_not_of(s, pos, traits_type::length(s)); }
+    
+    size_type find_last_not_of (value_type c, size_type pos = npos) const
+    { return find_last_not_of(&c, pos, 1); }
+    
+    flex_string substr(size_type pos = 0, size_type n = npos) const
+    {
+        Enforce(pos <= size(), (std::out_of_range*)0, "");
+        return flex_string(data() + pos, Min(n, size() - pos));
+    }
+
+    std::ptrdiff_t compare(const flex_string& str) const
+    { 
+        // FIX due to Goncalo N M de Carvalho July 18, 2005
+        return compare(0, size(), str);
+    }
+    
+    std::ptrdiff_t compare(size_type pos1, size_type n1,
+        const flex_string& str) const
+    { return compare(pos1, n1, str.data(), str.size()); }
+    
+    // FIX to compare: added the TC 
+    // (http://www.comeaucomputing.com/iso/lwg-defects.html number 5)
+    // Thanks to Caleb Epstein for the fix
+    std::ptrdiff_t compare(size_type pos1, size_type n1,
+        const value_type* s) const
+    {
+        return compare(pos1, n1, s, traits_type::length(s));
+    }
+    
+    std::ptrdiff_t compare(size_type pos1, size_type n1,
+        const value_type* s, size_type n2) const
+    {
+        Enforce(pos1 <= size(), (std::out_of_range*)0, "");
+        Procust(n1, size() - pos1);
+        const int r = traits_type::compare(pos1 + data(), s, Min(n1, n2));
+        return r != 0 ? r : n1 > n2 ? 1 : n1 < n2 ? -1 : 0;
+    }
+
+    std::ptrdiff_t compare(size_type pos1, size_type n1,
+        const flex_string& str,
+        size_type pos2, size_type n2) const
+    {
+        Enforce(pos2 <= str.size(), (std::out_of_range*)0, "");
+        return compare(pos1, n1, str.data() + pos2, Min(n2, str.size() - pos2));
+    }
+
+    std::ptrdiff_t compare(const value_type* s) const
+    { 
+        // Could forward to compare(0, size(), s, traits_type::length(s)) 
+        // but that does two extra checks 
+        const size_type n1(size()), n2(traits_type::length(s)); 
+        const int r = traits_type::compare(data(), s, Min(n1, n2)); 
+        return r != 0 ? r : n1 > n2 ? 1 : n1 < n2 ? -1 : 0; 
+    }
+};
+
+// non-member functions
+template <typename E, class T, class A, class S>
+flex_string<E, T, A, S> operator+(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{
+    flex_string<E, T, A, S> result;
+    result.reserve(lhs.size() + rhs.size());
+    result.append(lhs).append(rhs);
+    return result;
+}
+
+template <typename E, class T, class A, class S>
+flex_string<E, T, A, S> operator+(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{
+    flex_string<E, T, A, S> result;
+    const typename flex_string<E, T, A, S>::size_type len = 
+        flex_string<E, T, A, S>::traits_type::length(lhs);
+    result.reserve(len + rhs.size());
+    result.append(lhs, len).append(rhs);
+    return result;
+}
+
+template <typename E, class T, class A, class S>
+flex_string<E, T, A, S> operator+(
+    typename flex_string<E, T, A, S>::value_type lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{
+    flex_string<E, T, A, S> result;
+    result.reserve(1 + rhs.size());
+    result.push_back(lhs);
+    result.append(rhs);
+    return result;
+}
+
+template <typename E, class T, class A, class S>
+flex_string<E, T, A, S> operator+(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{
+    typedef typename flex_string<E, T, A, S>::size_type size_type;
+    typedef typename flex_string<E, T, A, S>::traits_type traits_type;
+
+    flex_string<E, T, A, S> result;
+    const size_type len = traits_type::length(rhs);
+    result.reserve(lhs.size() + len);
+    result.append(lhs).append(rhs, len);
+    return result;
+}
+
+template <typename E, class T, class A, class S>
+flex_string<E, T, A, S> operator+(const flex_string<E, T, A, S>& lhs, 
+    typename flex_string<E, T, A, S>::value_type rhs)
+{
+    flex_string<E, T, A, S> result;
+    result.reserve(lhs.size() + 1);
+    result.append(lhs);
+    result.push_back(rhs);
+    return result;
+}
+
+template <typename E, class T, class A, class S>
+inline bool operator==(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return lhs.compare(rhs) == 0; }
+
+template <typename E, class T, class A, class S>
+inline bool operator==(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return rhs == lhs; }
+
+template <typename E, class T, class A, class S>
+inline bool operator==(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{ return lhs.compare(rhs) == 0; }
+
+template <typename E, class T, class A, class S>
+inline bool operator!=(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return !(lhs == rhs); }
+
+template <typename E, class T, class A, class S>
+inline bool operator!=(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return !(lhs == rhs); }
+
+template <typename E, class T, class A, class S>
+inline bool operator!=(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{ return !(lhs == rhs); }
+
+template <typename E, class T, class A, class S>
+inline bool operator<(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return lhs.compare(rhs) < 0; }
+
+template <typename E, class T, class A, class S>
+inline bool operator<(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{ return lhs.compare(rhs) < 0; }
+
+template <typename E, class T, class A, class S>
+inline bool operator<(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return rhs.compare(lhs) > 0; }
+
+template <typename E, class T, class A, class S>
+inline bool operator>(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return rhs < lhs; }
+
+template <typename E, class T, class A, class S>
+inline bool operator>(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{ return rhs < lhs; }
+
+template <typename E, class T, class A, class S>
+bool operator>(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return rhs < lhs; }
+
+template <typename E, class T, class A, class S>
+inline bool operator<=(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return !(rhs < lhs); }
+
+template <typename E, class T, class A, class S>
+inline bool operator<=(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{ return !(rhs < lhs); }
+
+template <typename E, class T, class A, class S>
+bool operator<=(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return !(rhs < lhs); }
+
+template <typename E, class T, class A, class S>
+bool operator>=(const flex_string<E, T, A, S>& lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return !(lhs < rhs); }
+
+template <typename E, class T, class A, class S>
+bool operator>=(const flex_string<E, T, A, S>& lhs, 
+    const typename flex_string<E, T, A, S>::value_type* rhs)
+{ return !(lhs < rhs); }
+
+template <typename E, class T, class A, class S>
+inline bool operator>=(const typename flex_string<E, T, A, S>::value_type* lhs, 
+    const flex_string<E, T, A, S>& rhs)
+{ return !(lhs < rhs); }
+
+template <typename E, class T, class A, class S>
+void swap(flex_string<E, T, A, S>& lhs, flex_string<E, T, A, S>& rhs)
+{
+    // subclause 21.3.7.8:
+    lhs.swap(rhs);
+}
+
+template <typename E, class T, class A, class S>
+inline std::basic_istream<typename flex_string<E, T, A, S>::value_type, 
+    typename flex_string<E, T, A, S>::traits_type>&
+operator>>(
+    std::basic_istream<typename flex_string<E, T, A, S>::value_type, 
+    typename flex_string<E, T, A, S>::traits_type>& is,
+    flex_string<E, T, A, S>& str);
+
+template <typename E, class T, class A, class S>
+std::basic_ostream<typename flex_string<E, T, A, S>::value_type,
+    typename flex_string<E, T, A, S>::traits_type>&
+operator<<(
+    std::basic_ostream<typename flex_string<E, T, A, S>::value_type, 
+    typename flex_string<E, T, A, S>::traits_type>& os,
+    const flex_string<E, T, A, S>& str)
+{ return os << str.c_str(); }
+
+template <typename E1, class T, class A, class S>
+const typename flex_string<E1, T, A, S>::size_type
+flex_string<E1, T, A, S>::npos = (typename flex_string<E1, T, A, S>::size_type)(-1);
+
+///////////////////////////////////////////////////////////////////////////////
+}   // namespace util
+}   // namespace wave
+}   // namespace boost
+
+#if BOOST_WAVE_SERIALIZATION != 0
+///////////////////////////////////////////////////////////////////////////////
+namespace boost { namespace serialization {
+
+#if !defined(BOOST_WAVE_FLEX_STRING_SERIALIZATION_HACK)
+
+// FIXME: This doesn't work because of the missing flex_string::operator>>()
+template <typename E, class T, class A, class S>
+struct implementation_level<boost::wave::util::flex_string<E, T, A, S> >
+{
+    typedef mpl::integral_c_tag tag;
+    typedef mpl::int_<boost::serialization::primitive_type> type;
+    BOOST_STATIC_CONSTANT(
+        int,
+        value = implementation_level::type::value
+    );
+};
+
+#else
+
+//  We serialize flex_strings as vectors of char's for now
+template<class Archive, typename E, class T, class A, class S>
+inline void save(Archive & ar, 
+    boost::wave::util::flex_string<E, T, A, S> const &t,
+    const unsigned int file_version)
+{
+    boost::serialization::stl::save_collection<
+        Archive, wave::util::flex_string<E, T, A, S> >(ar, t);
+}
+
+template<class Archive, typename E, class T, class A, class S>
+inline void load(Archive & ar, boost::wave::util::flex_string<E, T, A, S> &t,
+    const unsigned int file_version)
+{
+    boost::serialization::stl::load_collection<
+        Archive, boost::wave::util::flex_string<E, T, A, S>,
+        boost::serialization::stl::archive_input_seq<
+            Archive, boost::wave::util::flex_string<E, T, A, S> >,
+        boost::serialization::stl::reserve_imp<
+            boost::wave::util::flex_string<E, T, A, S> >
+    >(ar, t);
+}
+
+// split non-intrusive serialization function member into separate
+// non intrusive save/load member functions
+template<class Archive, typename E, class T, class A, class S>
+inline void serialize(Archive & ar, boost::wave::util::flex_string<E, T, A, S> &t,
+    const unsigned int file_version)
+{
+    boost::serialization::split_free(ar, t, file_version);
+}
+
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+}} // boost::serialization
+#endif
+
+// the suffix header occurs after all of the code
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // FLEX_STRING_INC_