/*

  * © Portions copyright (c) 2006-2007 Nokia Corporation.  All rights reserved.

  * Copyright (c) 1996,1997

  * Silicon Graphics Computer Systems, Inc.

  *

  * Copyright (c) 1997

  * Moscow Center for SPARC Technology

  *

  * Copyright (c) 1999 

  * Boris Fomitchev

  *

  * This material is provided "as is", with absolutely no warranty expressed

  * or implied. Any use is at your own risk.

  *

  * Permission to use or copy this software for any purpose is hereby granted 

  * without fee, provided the above notices are retained on all copies.

  * Permission to modify the code and to distribute modified code is granted,

  * provided the above notices are retained, and a notice that the code was

  * modified is included with the above copyright notice.

  *

  */

 /* NOTE: This is an internal header file, included by other STL headers.

  *   You should not attempt to use it directly.

  */

 // rope<_CharT,_Alloc> is a sequence of _CharT.

 // Ropes appear to be mutable, but update operations

 // really copy enough of the data structure to leave the original

 // valid.  Thus ropes can be logically copied by just copying

 // a pointer value.

 #ifndef _STLP_INTERNAL_ROPE_H

 # define _STLP_INTERNAL_ROPE_H

 # ifndef _STLP_INTERNAL_ALGOBASE_H

 #  include <stl/_algobase.h>

 # endif

 # ifndef _STLP_IOSFWD

 #  include <iosfwd>

 # endif

 # ifndef _STLP_INTERNAL_ALLOC_H

 #  include <stl/_alloc.h>

 # endif

 # ifndef _STLP_INTERNAL_ITERATOR_H

 #  include <stl/_iterator.h>

 # endif

 # ifndef _STLP_INTERNAL_ALGO_H

 #  include <stl/_algo.h>

 # endif

 # ifndef _STLP_INTERNAL_FUNCTION_H

 #  include <stl/_function.h>

 # endif

 # ifndef _STLP_INTERNAL_NUMERIC_H

 #  include <stl/_numeric.h>

 # endif

 # ifndef _STLP_INTERNAL_HASH_FUN_H

 #  include <stl/_hash_fun.h>

 # endif

 # ifdef __GC

 #   define __GC_CONST const

 # else

 # include <stl/_threads.h>

 #   define __GC_CONST   // constant except for deallocation

 # endif

 # ifdef _STLP_SGI_THREADS

 #    include <mutex.h>

 # endif

 #ifdef _STLP_USE_NESTED_TCLASS_THROUGHT_TPARAM 

 #  define _STLP_CREATE_ALLOCATOR(__atype,__a, _Tp) (_Alloc_traits<_Tp,__atype>::create_allocator(__a)) 

 #elif defined(__MRC__)||defined(__SC__) 

 #  define _STLP_CREATE_ALLOCATOR(__atype,__a, _Tp) __stl_alloc_create<_Tp,__atype>(__a,(_Tp*)0) 

 #else 

 #  define _STLP_CREATE_ALLOCATOR(__atype,__a, _Tp) __stl_alloc_create(__a,(_Tp*)0) 

 #endif 

 _STLP_BEGIN_NAMESPACE

 // First a lot of forward declarations.  The standard seems to require

 // much stricter "declaration before use" than many of the implementations

 // that preceded it.

 template<class _CharT, _STLP_DEFAULT_ALLOCATOR_SELECT(_CharT) > class rope;

 template<class _CharT, class _Alloc> struct _Rope_RopeConcatenation;

 template<class _CharT, class _Alloc> struct _Rope_RopeRep;

 template<class _CharT, class _Alloc> struct _Rope_RopeLeaf;

 template<class _CharT, class _Alloc> struct _Rope_RopeFunction;

 template<class _CharT, class _Alloc> struct _Rope_RopeSubstring;

 template<class _CharT, class _Alloc> class _Rope_iterator;

 template<class _CharT, class _Alloc> class _Rope_const_iterator;

 template<class _CharT, class _Alloc> class _Rope_char_ref_proxy;

 template<class _CharT, class _Alloc> class _Rope_char_ptr_proxy;

 // Some helpers, so we can use power on ropes.

 // See below for why this isn't local to the implementation.

 // This uses a nonstandard refcount convention.

 // The result has refcount 0.

 template<class _CharT, class _Alloc>

 struct _Rope_Concat_fn

   : public binary_function<rope<_CharT,_Alloc>, rope<_CharT,_Alloc>,

   rope<_CharT,_Alloc> > {

   rope<_CharT,_Alloc> operator() (const rope<_CharT,_Alloc>& __x,

                                   const rope<_CharT,_Alloc>& __y) {

     return __x + __y;

   }

 };

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>

 __identity_element(_Rope_Concat_fn<_CharT, _Alloc>)

 {

   return rope<_CharT,_Alloc>();

 }

 // The _S_eos function is used for those functions that

 // convert to/from C-like strings to detect the end of the string.

 // The end-of-C-string character.

 // This is what the draft standard says it should be.

 template <class _CharT>

 inline _CharT _S_eos(_CharT*) { return _CharT(); }

 // fbp : some compilers fail to zero-initialize builtins ;(

 inline const char _S_eos(const char*) { return 0; }

 # ifdef _STLP_HAS_WCHAR_T

 inline const wchar_t _S_eos(const wchar_t*) { return 0; }

 # endif

 // Test for basic character types.

 // For basic character types leaves having a trailing eos.

 template <class _CharT>

 inline bool _S_is_basic_char_type(_CharT*) { return false; }

 template <class _CharT>

 inline bool _S_is_one_byte_char_type(_CharT*) { return false; }

 inline bool _S_is_basic_char_type(char*) { return true; }

 inline bool _S_is_one_byte_char_type(char*) { return true; }

 # ifdef _STLP_HAS_WCHAR_T

 inline bool _S_is_basic_char_type(wchar_t*) { return true; }

 # endif

 // Store an eos iff _CharT is a basic character type.

 // Do not reference _S_eos if it isn't.

 template <class _CharT>

 inline void _S_cond_store_eos(_CharT&) {}

 inline void _S_cond_store_eos(char& __c) { __c = 0; }

 # ifdef _STLP_HAS_WCHAR_T

 inline void _S_cond_store_eos(wchar_t& __c) { __c = 0; }

 # endif

 // char_producers are logically functions that generate a section of

 // a string.  These can be convereted to ropes.  The resulting rope

 // invokes the char_producer on demand.  This allows, for example,

 // files to be viewed as ropes without reading the entire file.

 template <class _CharT>

 class char_producer {

 public:

   virtual ~char_producer() {};

   virtual void operator()(size_t __start_pos, size_t __len, 

                           _CharT* __buffer) = 0;

   // Buffer should really be an arbitrary output iterator.

   // That way we could flatten directly into an ostream, etc.

   // This is thoroughly impossible, since iterator types don't

   // have runtime descriptions.

 };

 // Sequence buffers:

 //

 // Sequence must provide an append operation that appends an

 // array to the sequence.  Sequence buffers are useful only if

 // appending an entire array is cheaper than appending element by element.

 // This is true for many string representations.

 // This should  perhaps inherit from ostream<sequence::value_type>

 // and be implemented correspondingly, so that they can be used

 // for formatted.  For the sake of portability, we don't do this yet.

 //

 // For now, sequence buffers behave as output iterators.  But they also

 // behave a little like basic_ostringstream<sequence::value_type> and a

 // little like containers.

 template<class _Sequence

 # if !(defined (_STLP_NON_TYPE_TMPL_PARAM_BUG) || \

        defined ( _STLP_NO_DEFAULT_NON_TYPE_PARAM ))

 , size_t _Buf_sz = 100

 #   if defined(__sgi) && !defined(__GNUC__)

 #	 define __TYPEDEF_WORKAROUND

 ,class _V = typename _Sequence::value_type

 #   endif /* __sgi */

 # endif /* _STLP_NON_TYPE_TMPL_PARAM_BUG */

 >

 // The 3rd parameter works around a common compiler bug.

 class sequence_buffer : public iterator <output_iterator_tag, void, void, void, void> {

 public:

 #       ifndef __TYPEDEF_WORKAROUND

   typedef typename _Sequence::value_type value_type;

   typedef sequence_buffer<_Sequence

 # if !(defined (_STLP_NON_TYPE_TMPL_PARAM_BUG) || \

        defined ( _STLP_NO_DEFAULT_NON_TYPE_PARAM ))

   , _Buf_sz

   > _Self;

 # else /* _STLP_NON_TYPE_TMPL_PARAM_BUG */

   > _Self;

   enum { _Buf_sz = 100}; 

 # endif /* _STLP_NON_TYPE_TMPL_PARAM_BUG */

   // # endif

 #	else /* __TYPEDEF_WORKAROUND */

   typedef _V value_type;

   typedef sequence_buffer<_Sequence, _Buf_sz, _V> _Self;

 #	endif /* __TYPEDEF_WORKAROUND */

 protected:

   _Sequence* _M_prefix;

   value_type _M_buffer[_Buf_sz];

   size_t     _M_buf_count;

 public:

   void flush() {

     _M_prefix->append(_M_buffer, _M_buffer + _M_buf_count);

     _M_buf_count = 0;

   }

   ~sequence_buffer() { flush(); }

   sequence_buffer() : _M_prefix(0), _M_buf_count(0) {}

   sequence_buffer(const _Self& __x) {

     _M_prefix = __x._M_prefix;

     _M_buf_count = __x._M_buf_count;

     copy(__x._M_buffer, __x._M_buffer + __x._M_buf_count, _M_buffer);

   }

   sequence_buffer(_Self& __x) {

     __x.flush();

     _M_prefix = __x._M_prefix;

     _M_buf_count = 0;

   }

   sequence_buffer(_Sequence& __s) : _M_prefix(&__s), _M_buf_count(0) {}

   _Self& operator= (_Self& __x) {

     __x.flush();

     _M_prefix = __x._M_prefix;

     _M_buf_count = 0;

     return *this;

   }

   _Self& operator= (const _Self& __x) {

     _M_prefix = __x._M_prefix;

     _M_buf_count = __x._M_buf_count;

     copy(__x._M_buffer, __x._M_buffer + __x._M_buf_count, _M_buffer);

     return *this;

   }

   void push_back(value_type __x)

   {

     if (_M_buf_count < _Buf_sz) {

       _M_buffer[_M_buf_count] = __x;

       ++_M_buf_count;

     } else {

       flush();

       _M_buffer[0] = __x;

       _M_buf_count = 1;

     }

   }

   void append(value_type* __s, size_t __len)

   {

     if (__len + _M_buf_count <= _Buf_sz) {

       size_t __i = _M_buf_count;

       size_t __j = 0;

       for (; __j < __len; __i++, __j++) {

         _M_buffer[__i] = __s[__j];

       }

       _M_buf_count += __len;

     } else if (0 == _M_buf_count) {

       _M_prefix->append(__s, __s + __len);

     } else {

       flush();

       append(__s, __len);

     }

   }

   _Self& write(value_type* __s, size_t __len)

   {

     append(__s, __len);

     return *this;

   }

   _Self& put(value_type __x)

   {

     push_back(__x);

     return *this;

   }

   _Self& operator=(const value_type& __rhs)

   {

     push_back(__rhs);

     return *this;

   }

   _Self& operator*() { return *this; }

   _Self& operator++() { return *this; }

   _Self& operator++(int) { return *this; }

 };

 // The following should be treated as private, at least for now.

 template<class _CharT>

 class _Rope_char_consumer {

 public:

   // If we had member templates, these should not be virtual.

   // For now we need to use run-time parametrization where

   // compile-time would do.  _Hence this should all be private

   // for now.

   // The symmetry with char_producer is accidental and temporary.

   virtual ~_Rope_char_consumer() {};

   virtual bool operator()(const _CharT* __buffer, size_t __len) = 0;

 };

 //

 // What follows should really be local to rope.  Unfortunately,

 // that doesn't work, since it makes it impossible to define generic

 // equality on rope iterators.  According to the draft standard, the

 // template parameters for such an equality operator cannot be inferred

 // from the occurence of a member class as a parameter.

 // (SGI compilers in fact allow this, but the __result wouldn't be

 // portable.)

 // Similarly, some of the static member functions are member functions

 // only to avoid polluting the global namespace, and to circumvent

 // restrictions on type inference for template functions.

 //

 //

 // The internal data structure for representing a rope.  This is

 // private to the implementation.  A rope is really just a pointer

 // to one of these.

 //

 // A few basic functions for manipulating this data structure

 // are members of _RopeRep.  Most of the more complex algorithms

 // are implemented as rope members.

 //

 // Some of the static member functions of _RopeRep have identically

 // named functions in rope that simply invoke the _RopeRep versions.

 //

 // A macro to introduce various allocation and deallocation functions

 // These need to be defined differently depending on whether or not

 // we are using standard conforming allocators, and whether the allocator

 // instances have real state.  Thus this macro is invoked repeatedly

 // with different definitions of __ROPE_DEFINE_ALLOC.

 #if defined (_STLP_MEMBER_TEMPLATE_CLASSES)

 # define __ROPE_DEFINE_ALLOC(_Tp, __name, _M_proxy) \

         typedef typename \

           _Alloc_traits<_Tp,_Alloc>::allocator_type __name##Allocator;

 #define __ROPE_DEFINE_ALLOCS(__a, _M_proxy) \

         __ROPE_DEFINE_ALLOC(_CharT,_Data, _M_proxy) /* character data */ \

         typedef _Rope_RopeConcatenation<_CharT,__a> __C; \

         __ROPE_DEFINE_ALLOC(__C,_C, _M_proxy) \

         typedef _Rope_RopeLeaf<_CharT,__a> __L; \

         __ROPE_DEFINE_ALLOC(__L,_L, _M_proxy) \

         typedef _Rope_RopeFunction<_CharT,__a> __F; \

         __ROPE_DEFINE_ALLOC(__F,_F, _M_proxy) \

         typedef _Rope_RopeSubstring<_CharT,__a> __S; \

         __ROPE_DEFINE_ALLOC(__S,_S,_M_proxy)

 #else

 #define __ROPE_DEFINE_ALLOC(_Tp, __name, _M_proxy) 

 #define __ROPE_DEFINE_ALLOCS(__a, _M_proxy)

 #endif

 template<class _CharT, class _Alloc>

 struct _Rope_RopeRep

 # ifndef __GC

   : public _Refcount_Base

 # endif

 {

   typedef _Rope_RopeRep<_CharT, _Alloc> _Self;

 public:

 #  define __ROPE_MAX_DEPTH  45

 #  define __ROPE_DEPTH_SIZE 46

   enum { _S_max_rope_depth = __ROPE_MAX_DEPTH };

   enum _Tag {_S_leaf, _S_concat, _S_substringfn, _S_function};

   // Apparently needed by VC++

   // The data fields of leaves are allocated with some

   // extra space, to accomodate future growth and for basic

   // character types, to hold a trailing eos character.

   enum { _S_alloc_granularity = 8 };

   _Tag _M_tag:8;

   bool _M_is_balanced:8;

   _STLP_FORCE_ALLOCATORS(_CharT, _Alloc)

   typedef typename _Alloc_traits<_CharT,_Alloc>::allocator_type

   allocator_type;

   allocator_type get_allocator() const { return allocator_type(_M_size);  }

   unsigned char _M_depth;

   __GC_CONST _CharT* _M_c_string;

   _STLP_alloc_proxy<size_t, _CharT, allocator_type> _M_size;

 # ifdef _STLP_NO_ARROW_OPERATOR

   _Rope_RopeRep() : _Refcount_Base(1), _M_size(allocator_type(), 0) {}

 # endif

   /* Flattened version of string, if needed.  */

   /* typically 0.                             */

   /* If it's not 0, then the memory is owned  */

   /* by this node.                            */

   /* In the case of a leaf, this may point to */

   /* the same memory as the data field.       */

   _Rope_RopeRep(_Tag __t, int __d, bool __b, size_t _p_size,

                 allocator_type __a) :

 #         ifndef __GC

     _Refcount_Base(1),

 #	  endif

     _M_tag(__t), _M_is_balanced(__b), _M_depth(__d), _M_c_string(0), _M_size(__a, _p_size)

   { }

 #   ifdef __GC

   void _M_incr () {}

 #   endif

   // fbp : moved from RopeLeaf

   static size_t _S_rounded_up_size(size_t __n) {

     size_t __size_with_eos;

     if (_S_is_basic_char_type((_CharT*)0)) {

       __size_with_eos = __n + 1;

     } else {

       __size_with_eos = __n;

     }

 #       ifdef __GC

     return __size_with_eos;

 #       else

     // Allow slop for in-place expansion.

     return (__size_with_eos + _S_alloc_granularity-1)

       &~ (_S_alloc_granularity-1);

 #       endif

   }

   static void _S_free_string(__GC_CONST _CharT* __s, size_t __len,

                              allocator_type __a) {

     if (!_S_is_basic_char_type((_CharT*)0)) {

       _STLP_STD::_Destroy(__s, __s + __len);

     }

     //  This has to be a static member, so this gets a bit messy

 #   ifdef _STLP_USE_NESTED_TCLASS_THROUGHT_TPARAM

     __a.deallocate(__s, _S_rounded_up_size(__len));		//*ty 03/24/2001 - restored not to use __stl_alloc_rebind() since it is not defined under _STLP_MEMBER_TEMPLATE_CLASSES

 #   else

     __stl_alloc_rebind (__a, (_CharT*)0).deallocate(__s, _S_rounded_up_size(__len));

 #   endif

   }

   // Deallocate data section of a leaf.

   // This shouldn't be a member function.

   // But its hard to do anything else at the

   // moment, because it's templatized w.r.t.

   // an allocator.

   // Does nothing if __GC is defined.

 #   ifndef __GC

   void _M_free_c_string();

   void _M_free_tree();

   // Deallocate t. Assumes t is not 0.

   void _M_unref_nonnil()

   {

     _M_decr(); if (!_M_ref_count) _M_free_tree();

   }

   void _M_ref_nonnil()

   {

     _M_incr();

   }

   static void _S_unref(_Self* __t)

   {

     if (0 != __t) {

       __t->_M_unref_nonnil();

     }

   }

   static void _S_ref(_Self* __t)

   {

     if (0 != __t) __t->_M_incr();

   }

   static void _S_free_if_unref(_Self* __t)

   {

     if (0 != __t && 0 == __t->_M_ref_count) __t->_M_free_tree();

   }

 #   else /* __GC */

   void _M_unref_nonnil() {}

   void _M_ref_nonnil() {}

   static void _S_unref(_Self*) {}

   static void _S_ref(_Self*) {}

   static void _S_free_if_unref(_Self*) {}

 #   endif

   __ROPE_DEFINE_ALLOCS(_Alloc, _M_size)

     };

 template<class _CharT, class _Alloc>

 struct _Rope_RopeLeaf : public _Rope_RopeRep<_CharT,_Alloc> {

 public:

   __GC_CONST _CharT* _M_data; /* Not necessarily 0 terminated. */

                                 /* The allocated size is         */

                                 /* _S_rounded_up_size(size), except */

                                 /* in the GC case, in which it   */

                                 /* doesn't matter.               */

   _STLP_FORCE_ALLOCATORS(_CharT, _Alloc)

   typedef typename _Rope_RopeRep<_CharT,_Alloc>::allocator_type allocator_type;

   _Rope_RopeLeaf(__GC_CONST _CharT* __d, size_t _p_size, allocator_type __a)

     : _Rope_RopeRep<_CharT,_Alloc>(_Rope_RopeRep<_CharT,_Alloc>::_S_leaf, 0, true, _p_size, __a), 

     _M_data(__d)

   {

     _STLP_ASSERT(_p_size > 0)

     if (_S_is_basic_char_type((_CharT *)0)) {

       // already eos terminated.

       this->_M_c_string = __d;

     }

   }

 # ifdef _STLP_NO_ARROW_OPERATOR

   _Rope_RopeLeaf() {}

   _Rope_RopeLeaf(const _Rope_RopeLeaf<_CharT, _Alloc>& ) {}

 # endif

 // The constructor assumes that d has been allocated with

   // the proper allocator and the properly padded size.

   // In contrast, the destructor deallocates the data:

 # ifndef __GC

   ~_Rope_RopeLeaf() {

     if (_M_data != this->_M_c_string) {

       this->_M_free_c_string();

     }

     _Rope_RopeRep<_CharT,_Alloc>::_S_free_string(_M_data, this->_M_size._M_data, this->get_allocator());

   }

 # endif

 };

 template<class _CharT, class _Alloc>

 struct _Rope_RopeConcatenation : public _Rope_RopeRep<_CharT,_Alloc> {

 public:

   _Rope_RopeRep<_CharT,_Alloc>* _M_left;

   _Rope_RopeRep<_CharT,_Alloc>* _M_right;

   _STLP_FORCE_ALLOCATORS(_CharT, _Alloc)

   typedef typename _Rope_RopeRep<_CharT,_Alloc>::allocator_type allocator_type;

   _Rope_RopeConcatenation(_Rope_RopeRep<_CharT,_Alloc>* __l,

                           _Rope_RopeRep<_CharT,_Alloc>* __r,

                           allocator_type __a)

     :   _Rope_RopeRep<_CharT,_Alloc>(

                                      _Rope_RopeRep<_CharT,_Alloc>::_S_concat, 

 				     (max)(__l->_M_depth, __r->_M_depth) + 1, false,

                                      __l->_M_size._M_data + __r->_M_size._M_data, __a), _M_left(__l), _M_right(__r)

   {}

 # ifdef _STLP_NO_ARROW_OPERATOR

   _Rope_RopeConcatenation() {}

   _Rope_RopeConcatenation(const _Rope_RopeConcatenation<_CharT, _Alloc>&) {}

 # endif

 # ifndef __GC

   ~_Rope_RopeConcatenation() {

     this->_M_free_c_string();

     _M_left->_M_unref_nonnil();

     _M_right->_M_unref_nonnil();

   }

 # endif

 };

 template<class _CharT, class _Alloc>

 struct _Rope_RopeFunction : public _Rope_RopeRep<_CharT,_Alloc> {

 public:

   char_producer<_CharT>* _M_fn;

 #   ifndef __GC

   bool _M_delete_when_done; // Char_producer is owned by the

                                 // rope and should be explicitly

                                 // deleted when the rope becomes

                                 // inaccessible.

 #   else

   // In the GC case, we either register the rope for

   // finalization, or not.  Thus the field is unnecessary;

   // the information is stored in the collector data structures.

   // We do need a finalization procedure to be invoked by the

   // collector.

   static void _S_fn_finalization_proc(void * __tree, void *) {

     delete ((_Rope_RopeFunction *)__tree) -> _M_fn;

   }

 #   endif

   _STLP_FORCE_ALLOCATORS(_CharT, _Alloc)

   typedef typename _Rope_RopeRep<_CharT,_Alloc>::allocator_type allocator_type;

 # ifdef _STLP_NO_ARROW_OPERATOR

   _Rope_RopeFunction() {}

   _Rope_RopeFunction(const _Rope_RopeFunction<_CharT, _Alloc>& ) {}

 # endif

   _Rope_RopeFunction(char_producer<_CharT>* __f, size_t _p_size,

                      bool __d, allocator_type __a)

     :

     _Rope_RopeRep<_CharT,_Alloc>(_Rope_RopeRep<_CharT,_Alloc>::_S_function, 0, true, _p_size, __a),

     _M_fn(__f)

 #       ifndef __GC

     , _M_delete_when_done(__d)

 #       endif

   {

     _STLP_ASSERT(_p_size > 0)

 #       ifdef __GC

     if (__d) {

       GC_REGISTER_FINALIZER(

                             this, _Rope_RopeFunction::_S_fn_finalization_proc, 0, 0, 0);

     }

 #       endif

   }

 # ifndef __GC

   ~_Rope_RopeFunction() {

     this->_M_free_c_string();

     if (_M_delete_when_done) {

       delete _M_fn;

     }

   }

 # endif

 };

 // Substring results are usually represented using just

 // concatenation nodes.  But in the case of very long flat ropes

 // or ropes with a functional representation that isn't practical.

 // In that case, we represent the __result as a special case of

 // RopeFunction, whose char_producer points back to the rope itself.

 // In all cases except repeated substring operations and

 // deallocation, we treat the __result as a RopeFunction.

 template<class _CharT, class _Alloc>

 # if  ( defined (__IBMCPP__) && (__IBMCPP__ == 500) )  // JFA 10-Aug-2000 for some reason xlC cares about the order

 struct _Rope_RopeSubstring : public char_producer<_CharT> , public _Rope_RopeFunction<_CharT,_Alloc>

 # else

 struct _Rope_RopeSubstring : public _Rope_RopeFunction<_CharT,_Alloc>,

                              public char_producer<_CharT>

 # endif

 {

 public:

   // XXX this whole class should be rewritten.

   typedef _Rope_RopeRep<_CharT,_Alloc> _Base;

   _Rope_RopeRep<_CharT,_Alloc>* _M_base;      // not 0

   size_t _M_start;

   virtual void operator()(size_t __start_pos, size_t __req_len,

                           _CharT* __buffer) {

     switch(_M_base->_M_tag) {

     case _Base::_S_function:

     case _Base::_S_substringfn:

       {

         char_producer<_CharT>* __fn =

           ((_Rope_RopeFunction<_CharT,_Alloc>*)_M_base)->_M_fn;

         _STLP_ASSERT(__start_pos + __req_len <= this->_M_size._M_data)

         _STLP_ASSERT(_M_start + this->_M_size._M_data <= _M_base->_M_size._M_data)

         (*__fn)(__start_pos + _M_start, __req_len, __buffer);

       }

       break;

     case _Base::_S_leaf:

       {

         __GC_CONST _CharT* __s =

           ((_Rope_RopeLeaf<_CharT,_Alloc>*)_M_base)->_M_data;

         uninitialized_copy_n(__s + __start_pos + _M_start, __req_len,

                              __buffer);

       }

       break;

     default:

       _STLP_ASSERT(false)

         ;

     }

   }

   _STLP_FORCE_ALLOCATORS(_CharT, _Alloc)

   typedef typename _Rope_RopeRep<_CharT,_Alloc>::allocator_type allocator_type;

   _Rope_RopeSubstring(_Rope_RopeRep<_CharT,_Alloc>* __b, size_t __s,

                       size_t __l, allocator_type __a)

     : _Rope_RopeFunction<_CharT,_Alloc>(this, __l, false, __a),

 	_M_base(__b),

     _M_start(__s)

   {

     _STLP_ASSERT(__l > 0)

     _STLP_ASSERT(__s + __l <= __b->_M_size._M_data)

 #       ifndef __GC

     _M_base->_M_ref_nonnil();

 #       endif

     this->_M_tag = _Base::_S_substringfn;

   }

   virtual ~_Rope_RopeSubstring()

   { 

 #       ifndef __GC

     _M_base->_M_unref_nonnil();

 #       endif

   }

 };

 // Self-destructing pointers to Rope_rep.

 // These are not conventional smart pointers.  Their

 // only purpose in life is to ensure that unref is called

 // on the pointer either at normal exit or if an exception

 // is raised.  It is the caller's responsibility to

 // adjust reference counts when these pointers are initialized

 // or assigned to.  (This convention significantly reduces

 // the number of potentially expensive reference count

 // updates.)

 #ifndef __GC

 template<class _CharT, class _Alloc>

 struct _Rope_self_destruct_ptr {

   _Rope_RopeRep<_CharT,_Alloc>* _M_ptr;

   ~_Rope_self_destruct_ptr() 

   { _Rope_RopeRep<_CharT,_Alloc>::_S_unref(_M_ptr); }

 #   ifdef _STLP_USE_EXCEPTIONS

   _Rope_self_destruct_ptr() : _M_ptr(0) {};

 #   else

   _Rope_self_destruct_ptr() {};

 #   endif

   _Rope_self_destruct_ptr(_Rope_RopeRep<_CharT,_Alloc>* __p) : _M_ptr(__p) {}

   _Rope_RopeRep<_CharT,_Alloc>& operator*() { return *_M_ptr; }

   _Rope_RopeRep<_CharT,_Alloc>* operator->() { return _M_ptr; }

   operator _Rope_RopeRep<_CharT,_Alloc>*() { return _M_ptr; }

   _Rope_self_destruct_ptr<_CharT, _Alloc>& 

   operator= (_Rope_RopeRep<_CharT,_Alloc>* __x)

   { _M_ptr = __x; return *this; }

 };

 #endif

 // Dereferencing a nonconst iterator has to return something

 // that behaves almost like a reference.  It's not possible to

 // return an actual reference since assignment requires extra

 // work.  And we would get into the same problems as with the

 // CD2 version of basic_string.

 template<class _CharT, class _Alloc>

 class _Rope_char_ref_proxy {

   typedef _Rope_char_ref_proxy<_CharT, _Alloc> _Self;

   friend class rope<_CharT,_Alloc>;

   friend class _Rope_iterator<_CharT,_Alloc>;

   friend class _Rope_char_ptr_proxy<_CharT,_Alloc>;

 #   ifdef __GC

   typedef _Rope_RopeRep<_CharT,_Alloc>* _Self_destruct_ptr;

 #   else

   typedef _Rope_self_destruct_ptr<_CharT,_Alloc> _Self_destruct_ptr;

 #   endif

   typedef _Rope_RopeRep<_CharT,_Alloc> _RopeRep;

   typedef rope<_CharT,_Alloc> _My_rope;

   size_t _M_pos;

   _CharT _M_current;

   bool _M_current_valid;

   _My_rope* _M_root;     // The whole rope.

 public:

   _Rope_char_ref_proxy(_My_rope* __r, size_t __p) :

     _M_pos(__p), _M_current_valid(false), _M_root(__r) {}

   _Rope_char_ref_proxy(const _Self& __x) :

     _M_pos(__x._M_pos), _M_current_valid(false), _M_root(__x._M_root) {}

   // Don't preserve cache if the reference can outlive the

   // expression.  We claim that's not possible without calling

   // a copy constructor or generating reference to a proxy

   // reference.  We declare the latter to have undefined semantics.

   _Rope_char_ref_proxy(_My_rope* __r, size_t __p,

                        _CharT __c) :

     _M_pos(__p), _M_current(__c), _M_current_valid(true), _M_root(__r) {}

   inline operator _CharT () const;

   _Self& operator= (_CharT __c);

   _Rope_char_ptr_proxy<_CharT, _Alloc> operator& () const;

   _Self& operator= (const _Self& __c) {

     return operator=((_CharT)__c); 

   }

 };

 #ifdef _STLP_FUNCTION_TMPL_PARTIAL_ORDER

 template<class _CharT, class __Alloc>

 inline void swap(_Rope_char_ref_proxy <_CharT, __Alloc > __a,

                  _Rope_char_ref_proxy <_CharT, __Alloc > __b) {

   _CharT __tmp = __a;

   __a = __b;

   __b = __tmp;

 }

 #else

 // There is no really acceptable way to handle this.  The default

 // definition of swap doesn't work for proxy references.

 // It can't really be made to work, even with ugly hacks, since

 // the only unusual operation it uses is the copy constructor, which

 // is needed for other purposes.  We provide a macro for

 // full specializations, and instantiate the most common case.

 # define _ROPE_SWAP_SPECIALIZATION(_CharT, __Alloc) \

     inline void swap(_Rope_char_ref_proxy <_CharT, __Alloc > __a, \

                      _Rope_char_ref_proxy <_CharT, __Alloc > __b) { \

         _CharT __tmp = __a; \

         __a = __b; \

         __b = __tmp; \

     }

 _ROPE_SWAP_SPECIALIZATION(char,_STLP_DEFAULT_ALLOCATOR(char) )

 #endif /* !_STLP_FUNCTION_TMPL_PARTIAL_ORDER */

   template<class _CharT, class _Alloc>

 class _Rope_char_ptr_proxy {

   // XXX this class should be rewritten.

 public:

   typedef _Rope_char_ptr_proxy<_CharT, _Alloc> _Self;

   friend class _Rope_char_ref_proxy<_CharT,_Alloc>;

   size_t _M_pos;

   rope<_CharT,_Alloc>* _M_root;     // The whole rope.

   _Rope_char_ptr_proxy(const _Rope_char_ref_proxy<_CharT,_Alloc>& __x) 

     : _M_pos(__x._M_pos), _M_root(__x._M_root) {}

   _Rope_char_ptr_proxy(const _Self& __x)

     : _M_pos(__x._M_pos), _M_root(__x._M_root) {}

   _Rope_char_ptr_proxy() {}

   _Rope_char_ptr_proxy(_CharT* __x) : _M_pos(0), _M_root(0) {

     _STLP_ASSERT(0 == __x)

   }

   _Self& 

   operator= (const _Self& __x) {

     _M_pos = __x._M_pos;

     _M_root = __x._M_root;

     return *this;

   }

   _Rope_char_ref_proxy<_CharT,_Alloc> operator*() const {

     return _Rope_char_ref_proxy<_CharT,_Alloc>(_M_root, _M_pos);

   }

 };

 // Rope iterators:

 // Unlike in the C version, we cache only part of the stack

 // for rope iterators, since they must be efficiently copyable.

 // When we run out of cache, we have to reconstruct the iterator

 // value.

 // Pointers from iterators are not included in reference counts.

 // Iterators are assumed to be thread private.  Ropes can

 // be shared.

 template<class _CharT, class _Alloc>

 class _Rope_iterator_base

 /*   : public random_access_iterator<_CharT, ptrdiff_t>  */

 {

   friend class rope<_CharT,_Alloc>;

   typedef _Rope_iterator_base<_CharT, _Alloc> _Self;

 public:

   typedef _Rope_RopeRep<_CharT,_Alloc> _RopeRep;

   // Borland doesnt want this to be protected.

   //  protected:

   enum { _S_path_cache_len = 4 }; // Must be <= 9.

   enum { _S_iterator_buf_len = 15 };

   size_t _M_current_pos;

   _RopeRep* _M_root;     // The whole rope.

   size_t _M_leaf_pos;    // Starting position for current leaf

   __GC_CONST _CharT* _M_buf_start;

   // Buffer possibly

   // containing current char.

   __GC_CONST _CharT* _M_buf_ptr;

   // Pointer to current char in buffer.

   // != 0 ==> buffer valid.

   __GC_CONST _CharT* _M_buf_end;

   // One past __last valid char in buffer.

   // What follows is the path cache.  We go out of our

   // way to make this compact.

   // Path_end contains the bottom section of the path from

   // the root to the current leaf.

   const _RopeRep* _M_path_end[_S_path_cache_len];

   int _M_leaf_index;     // Last valid __pos in path_end;

   // _M_path_end[0] ... _M_path_end[leaf_index-1]

   // point to concatenation nodes.

   unsigned char _M_path_directions;

   // (path_directions >> __i) & 1 is 1

   // iff we got from _M_path_end[leaf_index - __i - 1]

   // to _M_path_end[leaf_index - __i] by going to the

   // __right. Assumes path_cache_len <= 9.

   _CharT _M_tmp_buf[_S_iterator_buf_len];

   // Short buffer for surrounding chars.

   // This is useful primarily for 

   // RopeFunctions.  We put the buffer

   // here to avoid locking in the

   // multithreaded case.

   // The cached path is generally assumed to be valid

   // only if the buffer is valid.

   static void _S_setbuf(_Rope_iterator_base<_CharT, _Alloc>& __x);

   // Set buffer contents given

   // path cache.

   static void _S_setcache(_Rope_iterator_base<_CharT, _Alloc>& __x);

   // Set buffer contents and

   // path cache.

   static void _S_setcache_for_incr(_Rope_iterator_base<_CharT, _Alloc>& __x);

   // As above, but assumes path

   // cache is valid for previous posn.

   _Rope_iterator_base() {}

   _Rope_iterator_base(_RopeRep* __root, size_t __pos)

     : _M_current_pos(__pos),_M_root(__root),  _M_buf_ptr(0) {}

   void _M_incr(size_t __n);

   void _M_decr(size_t __n);

 public:

   size_t index() const { return _M_current_pos; }

   _Rope_iterator_base(const _Self& __x) {

     if (0 != __x._M_buf_ptr) {

       *this = __x;

     } else {

       _M_current_pos = __x._M_current_pos;

       _M_root = __x._M_root;

       _M_buf_ptr = 0;

     }

   }

 };

 template<class _CharT, class _Alloc> class _Rope_iterator;

 template<class _CharT, class _Alloc>

 class _Rope_const_iterator : public _Rope_iterator_base<_CharT,_Alloc> {

   friend class rope<_CharT,_Alloc>;

   typedef  _Rope_const_iterator<_CharT, _Alloc> _Self;

   typedef _Rope_iterator_base<_CharT,_Alloc> _Base;

   //  protected:

 public:

 #   ifndef _STLP_HAS_NO_NAMESPACES

   typedef _Rope_RopeRep<_CharT,_Alloc> _RopeRep;

   // The one from the base class may not be directly visible.

 #   endif

   _Rope_const_iterator(const _RopeRep* __root, size_t __pos):

     _Rope_iterator_base<_CharT,_Alloc>(

                                        __CONST_CAST(_RopeRep*,__root), __pos)

     // Only nonconst iterators modify root ref count

   {}

 public:

   typedef _CharT reference;   // Really a value.  Returning a reference

                                 // Would be a mess, since it would have

                                 // to be included in refcount.

   typedef const _CharT* pointer;

   typedef _CharT value_type;

   typedef ptrdiff_t difference_type;

   typedef random_access_iterator_tag iterator_category;

 public:

   _Rope_const_iterator() {};

   _Rope_const_iterator(const _Self& __x) :

     _Rope_iterator_base<_CharT,_Alloc>(__x) { }

   _Rope_const_iterator(const _Rope_iterator<_CharT,_Alloc>& __x): 

     _Rope_iterator_base<_CharT,_Alloc>(__x) {}

   _Rope_const_iterator(const rope<_CharT,_Alloc>& __r, size_t __pos) :

     _Rope_iterator_base<_CharT,_Alloc>(__r._M_tree_ptr._M_data, __pos) {}

   _Self& operator= (const _Self& __x) {

     if (0 != __x._M_buf_ptr) {

       *(__STATIC_CAST(_Base*,this)) = __x;

     } else {

       this->_M_current_pos = __x._M_current_pos;

       this->_M_root = __x._M_root;

       this->_M_buf_ptr = 0;

     }

     return(*this);

   }

   reference operator*() {

     if (0 == this->_M_buf_ptr) _S_setcache(*this);

     return *(this->_M_buf_ptr);

   }

   _Self& operator++() {

     __GC_CONST _CharT* __next;

     if (0 != this->_M_buf_ptr && (__next = this->_M_buf_ptr + 1) < this->_M_buf_end) {

       this->_M_buf_ptr = __next;

       ++this->_M_current_pos;

     } else {

       this->_M_incr(1);

     }

     return *this;

   }

   _Self& operator+=(ptrdiff_t __n) {

     if (__n >= 0) {

       this->_M_incr(__n);

     } else {

       this->_M_decr(-__n);

     }

     return *this;

   }

   _Self& operator--() {

     this->_M_decr(1);

     return *this;

   }

   _Self& operator-=(ptrdiff_t __n) {

     if (__n >= 0) {

       this->_M_decr(__n);

     } else {

       this->_M_incr(-__n);

     }

     return *this;

   }

   _Self operator++(int) {

     size_t __old_pos = this->_M_current_pos;

     this->_M_incr(1);

     return _Rope_const_iterator<_CharT,_Alloc>(this->_M_root, __old_pos);

     // This makes a subsequent dereference expensive.

     // Perhaps we should instead copy the iterator

     // if it has a valid cache?

   }

   _Self operator--(int) {

     size_t __old_pos = this->_M_current_pos;

     this->_M_decr(1);

     return _Rope_const_iterator<_CharT,_Alloc>(this->_M_root, __old_pos);

   }

   inline reference operator[](size_t __n);

 };

 template<class _CharT, class _Alloc>

 class _Rope_iterator : public _Rope_iterator_base<_CharT,_Alloc> {

   friend class rope<_CharT,_Alloc>;

   typedef _Rope_iterator<_CharT, _Alloc> _Self;

   typedef _Rope_iterator_base<_CharT,_Alloc> _Base;

   typedef _Rope_RopeRep<_CharT,_Alloc> _RopeRep;

   //  protected:

 public:

   rope<_CharT,_Alloc>* _M_root_rope;

   // root is treated as a cached version of this,

   // and is used to detect changes to the underlying

   // rope.

   // Root is included in the reference count.

   // This is necessary so that we can detect changes reliably.

   // Unfortunately, it requires careful bookkeeping for the

   // nonGC case.

   _Rope_iterator(rope<_CharT,_Alloc>* __r, size_t __pos);

   void _M_check();

 public:

   typedef _Rope_char_ref_proxy<_CharT,_Alloc>  reference;

   typedef _Rope_char_ref_proxy<_CharT,_Alloc>* pointer;

   typedef _CharT value_type;

   typedef ptrdiff_t difference_type;

   typedef random_access_iterator_tag iterator_category;

 public:

   ~_Rope_iterator() 		//*TY 5/6/00 - added dtor to balance reference count

   {

     _RopeRep::_S_unref(this->_M_root);

   }

   rope<_CharT,_Alloc>& container() { return *_M_root_rope; }

   _Rope_iterator() {

     this->_M_root = 0;  // Needed for reference counting.

   };

   _Rope_iterator(const  _Self& __x) :

     _Rope_iterator_base<_CharT,_Alloc>(__x) {

     _M_root_rope = __x._M_root_rope;

     _RopeRep::_S_ref(this->_M_root);

   }

   _Rope_iterator(rope<_CharT,_Alloc>& __r, size_t __pos);

   _Self& operator= (const  _Self& __x) {

     _RopeRep* __old = this->_M_root;

     _RopeRep::_S_ref(__x._M_root);

     if (0 != __x._M_buf_ptr) {

       _M_root_rope = __x._M_root_rope;

       *(__STATIC_CAST(_Base*,this)) = __x;

     } else {

       this->_M_current_pos = __x._M_current_pos;

       this->_M_root = __x._M_root;

       _M_root_rope = __x._M_root_rope;

       this->_M_buf_ptr = 0;

     }

     _RopeRep::_S_unref(__old);

     return(*this);

   }

   reference operator*() {

     _M_check();

     if (0 == this->_M_buf_ptr) {

       return _Rope_char_ref_proxy<_CharT,_Alloc>(

                                                  _M_root_rope, this->_M_current_pos);

     } else {

       return _Rope_char_ref_proxy<_CharT,_Alloc>(

                                                  _M_root_rope, this->_M_current_pos, *(this->_M_buf_ptr));

     }

   }

   _Self& operator++() {

     this->_M_incr(1);

     return *this;

   }

   _Self& operator+=(ptrdiff_t __n) {

     if (__n >= 0) {

       this->_M_incr(__n);

     } else {

       this->_M_decr(-__n);

     }

     return *this;

   }

   _Self& operator--() {

     this->_M_decr(1);

     return *this;

   }

   _Self& operator-=(ptrdiff_t __n) {

     if (__n >= 0) {

       this->_M_decr(__n);

     } else {

       this->_M_incr(-__n);

     }

     return *this;

   }

   _Self operator++(int) {

     size_t __old_pos = this->_M_current_pos;

     this->_M_incr(1);

     return _Rope_iterator<_CharT,_Alloc>(_M_root_rope, __old_pos);

   }

   _Self operator--(int) {

     size_t __old_pos = this->_M_current_pos;

     this->_M_decr(1);

     return _Rope_iterator<_CharT,_Alloc>(_M_root_rope, __old_pos);

   }

   reference operator[](ptrdiff_t __n) {

     return _Rope_char_ref_proxy<_CharT,_Alloc>(

                                                _M_root_rope, this->_M_current_pos + __n);

   }

 };

 # ifdef _STLP_USE_OLD_HP_ITERATOR_QUERIES

 template <class _CharT, class _Alloc>

 inline random_access_iterator_tag

 iterator_category(const _Rope_iterator<_CharT,_Alloc>&) {  return random_access_iterator_tag();}

 template <class _CharT, class _Alloc>

 inline _CharT* value_type(const _Rope_iterator<_CharT,_Alloc>&) { return 0; }

 template <class _CharT, class _Alloc>

 inline ptrdiff_t* distance_type(const _Rope_iterator<_CharT,_Alloc>&) { return 0; }

 template <class _CharT, class _Alloc>

 inline random_access_iterator_tag

 iterator_category(const _Rope_const_iterator<_CharT,_Alloc>&) { return random_access_iterator_tag(); }

 template <class _CharT, class _Alloc>

 inline _CharT* value_type(const _Rope_const_iterator<_CharT,_Alloc>&) { return 0; }

 template <class _CharT, class _Alloc>

 inline ptrdiff_t* distance_type(const _Rope_const_iterator<_CharT,_Alloc>&) { return 0; }

 #endif

 template <class _CharT, class _Alloc>

 class rope {

   typedef rope<_CharT,_Alloc> _Self;

 public:

   typedef _CharT value_type;

   typedef ptrdiff_t difference_type;

   typedef size_t size_type;

   typedef _CharT const_reference;

   typedef const _CharT* const_pointer;

   typedef _Rope_iterator<_CharT,_Alloc> iterator;

   typedef _Rope_const_iterator<_CharT,_Alloc> const_iterator;

   typedef _Rope_char_ref_proxy<_CharT,_Alloc> reference;

   typedef _Rope_char_ptr_proxy<_CharT,_Alloc> pointer;

   friend class _Rope_iterator<_CharT,_Alloc>;

   friend class _Rope_const_iterator<_CharT,_Alloc>;

   friend struct _Rope_RopeRep<_CharT,_Alloc>;

   friend class _Rope_iterator_base<_CharT,_Alloc>;

   friend class _Rope_char_ptr_proxy<_CharT,_Alloc>;

   friend class _Rope_char_ref_proxy<_CharT,_Alloc>;

   friend struct _Rope_RopeSubstring<_CharT,_Alloc>;

   _STLP_DECLARE_RANDOM_ACCESS_REVERSE_ITERATORS;

 protected:

   typedef __GC_CONST _CharT* _Cstrptr;

   static _CharT _S_empty_c_str[1];

   static bool _S_is0(_CharT __c) { return __c == _S_eos((_CharT*)0); }

   enum { _S_copy_max = 23 };

   // For strings shorter than _S_copy_max, we copy to

   // concatenate.

 public:

   typedef _Rope_RopeRep<_CharT, _Alloc> _RopeRep;

   _STLP_FORCE_ALLOCATORS(_CharT, _Alloc)

   typedef typename _Alloc_traits<_CharT,_Alloc>::allocator_type  allocator_type;

   allocator_type get_allocator() const { return allocator_type(_M_tree_ptr); }

 public:

   // The only data member of a rope:

   _STLP_alloc_proxy<_RopeRep*, _CharT, allocator_type> _M_tree_ptr;

   typedef _Rope_RopeConcatenation<_CharT,_Alloc> _RopeConcatenation;

   typedef _Rope_RopeLeaf<_CharT,_Alloc> _RopeLeaf;

   typedef _Rope_RopeFunction<_CharT,_Alloc> _RopeFunction;

   typedef _Rope_RopeSubstring<_CharT,_Alloc> _RopeSubstring;

   // Retrieve a character at the indicated position.

   static _CharT _S_fetch(_RopeRep* __r, size_type __pos);

 #       ifndef __GC

   // Obtain a pointer to the character at the indicated position.

   // The pointer can be used to change the character.

   // If such a pointer cannot be produced, as is frequently the

   // case, 0 is returned instead.

   // (Returns nonzero only if all nodes in the path have a refcount

   // of 1.)

   static _CharT* _S_fetch_ptr(_RopeRep* __r, size_type __pos);

 #       endif

   static bool _S_apply_to_pieces(

                                 // should be template parameter

                                  _Rope_char_consumer<_CharT>& __c,

                                  const _RopeRep* __r,

                                  size_t __begin, size_t __end);

                                 // begin and end are assumed to be in range.

 #       ifndef __GC

   static void _S_unref(_RopeRep* __t)

   {

     _RopeRep::_S_unref(__t);

   }

   static void _S_ref(_RopeRep* __t)

   {

     _RopeRep::_S_ref(__t);

   }

 #       else /* __GC */

   static void _S_unref(_RopeRep*) {}

   static void _S_ref(_RopeRep*) {}

 #       endif

 #       ifdef __GC

   typedef _Rope_RopeRep<_CharT,_Alloc>* _Self_destruct_ptr;

 #       else

   typedef _Rope_self_destruct_ptr<_CharT,_Alloc> _Self_destruct_ptr;

 #       endif

   // _Result is counted in refcount.

   static _RopeRep* _S_substring(_RopeRep* __base,

                                 size_t __start, size_t __endp1);

   static _RopeRep* _S_concat_char_iter(_RopeRep* __r,

                                        const _CharT* __iter, size_t __slen);

   // Concatenate rope and char ptr, copying __s.

   // Should really take an arbitrary iterator.

   // Result is counted in refcount.

   static _RopeRep* _S_destr_concat_char_iter(_RopeRep* __r,

                                              const _CharT* __iter, size_t __slen)

     // As above, but one reference to __r is about to be

     // destroyed.  Thus the pieces may be recycled if all

     // relevent reference counts are 1.

 #           ifdef __GC

     // We can't really do anything since refcounts are unavailable.

   { return _S_concat_char_iter(__r, __iter, __slen); }

 #           else

   ;

 #           endif

   static _RopeRep* _S_concat_rep(_RopeRep* __left, _RopeRep* __right);

   // General concatenation on _RopeRep.  _Result

   // has refcount of 1.  Adjusts argument refcounts.

 public:

   void apply_to_pieces( size_t __begin, size_t __end,

                         _Rope_char_consumer<_CharT>& __c) const {

     _S_apply_to_pieces(__c, _M_tree_ptr._M_data, __begin, __end);

   }

 protected:

   static size_t _S_rounded_up_size(size_t __n) {

     return _RopeRep::_S_rounded_up_size(__n);

   }

   static size_t _S_allocated_capacity(size_t __n) {

     if (_S_is_basic_char_type((_CharT*)0)) {

       return _S_rounded_up_size(__n) - 1;

     } else {

       return _S_rounded_up_size(__n);

     }

   }

   // Allocate and construct a RopeLeaf using the supplied allocator

   // Takes ownership of s instead of copying.

   static _RopeLeaf* _S_new_RopeLeaf(__GC_CONST _CharT *__s,

                                     size_t _p_size, allocator_type __a)

   {

    _RopeLeaf* __space = _STLP_CREATE_ALLOCATOR(allocator_type,__a, _RopeLeaf).allocate(1,(const void*)0);

     _STLP_TRY {

       _STLP_PLACEMENT_NEW(__space) _RopeLeaf(__s, _p_size, __a);

     }

    _STLP_UNWIND(_STLP_CREATE_ALLOCATOR(allocator_type,__a, 

                                    _RopeLeaf).deallocate(__space, 1))

 	  return __space;

   }

   static _RopeConcatenation* _S_new_RopeConcatenation(

                                                       _RopeRep* __left, _RopeRep* __right,

                                                       allocator_type __a)

   {

    _RopeConcatenation* __space = _STLP_CREATE_ALLOCATOR(allocator_type,__a,

                                                     _RopeConcatenation).allocate(1,(const void*)0);

     return _STLP_PLACEMENT_NEW(__space) _RopeConcatenation(__left, __right, __a);

   }

   static _RopeFunction* _S_new_RopeFunction(char_producer<_CharT>* __f,

                                             size_t _p_size, bool __d, allocator_type __a)

   {

    _RopeFunction* __space = _STLP_CREATE_ALLOCATOR(allocator_type,__a, 

                                                _RopeFunction).allocate(1,(const void*)0);

     return _STLP_PLACEMENT_NEW(__space) _RopeFunction(__f, _p_size, __d, __a);

   }

   static _RopeSubstring* _S_new_RopeSubstring(

                                               _Rope_RopeRep<_CharT,_Alloc>* __b, size_t __s,

                                               size_t __l, allocator_type __a)

   {

    _RopeSubstring* __space = _STLP_CREATE_ALLOCATOR(allocator_type,__a, 

                                                 _RopeSubstring).allocate(1,(const void*)0);

     return _STLP_PLACEMENT_NEW(__space) _RopeSubstring(__b, __s, __l, __a);

   }

 #         define _STLP_ROPE_FROM_UNOWNED_CHAR_PTR(__s, _p_size, __a) \

                 _S_RopeLeaf_from_unowned_char_ptr(__s, _p_size, __a)     

   static

   _RopeLeaf* _S_RopeLeaf_from_unowned_char_ptr(const _CharT *__s,

                                                size_t _p_size, allocator_type __a)

   {

     if (0 == _p_size) return 0;

    _CharT* __buf = _STLP_CREATE_ALLOCATOR(allocator_type,__a, _CharT).allocate(_S_rounded_up_size(_p_size));

     uninitialized_copy_n(__s, _p_size, __buf);

     _S_cond_store_eos(__buf[_p_size]);

     _STLP_TRY {

       return _S_new_RopeLeaf(__buf, _p_size, __a);

     }

     _STLP_UNWIND(_RopeRep::_S_free_string(__buf, _p_size, __a))

 # if defined (_STLP_THROW_RETURN_BUG)

       return 0;

 # endif

   }

   // Concatenation of nonempty strings.

   // Always builds a concatenation node.

   // Rebalances if the result is too deep.

   // Result has refcount 1.

   // Does not increment left and right ref counts even though

   // they are referenced.

   static _RopeRep*

   _S_tree_concat(_RopeRep* __left, _RopeRep* __right);

   // Concatenation helper functions

   static _RopeLeaf*

   _S_leaf_concat_char_iter(_RopeLeaf* __r,

                            const _CharT* __iter, size_t __slen);

   // Concatenate by copying leaf.

   // should take an arbitrary iterator

   // result has refcount 1.

 #       ifndef __GC

   static _RopeLeaf* _S_destr_leaf_concat_char_iter

   (_RopeLeaf* __r, const _CharT* __iter, size_t __slen);

   // A version that potentially clobbers __r if __r->_M_ref_count == 1.

 #       endif

   // A helper function for exponentiating strings.

   // This uses a nonstandard refcount convention.

   // The result has refcount 0.

   friend struct _Rope_Concat_fn<_CharT,_Alloc>;

   typedef _Rope_Concat_fn<_CharT,_Alloc> _Concat_fn;

 public:

   static size_t _S_char_ptr_len(const _CharT* __s) {

     const _CharT* __p = __s;

     while (!_S_is0(*__p)) { ++__p; }

     return (__p - __s);

   }

 public: /* for operators */

   rope(_RopeRep* __t, const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, __t) { }

 private:

   // Copy __r to the _CharT buffer.

   // Returns __buffer + __r->_M_size._M_data.

   // Assumes that buffer is uninitialized.

   static _CharT* _S_flatten(_RopeRep* __r, _CharT* __buffer);

   // Again, with explicit starting position and length.

   // Assumes that buffer is uninitialized.

   static _CharT* _S_flatten(_RopeRep* __r,

                             size_t __start, size_t __len,

                             _CharT* __buffer);

   // fbp : HP aCC prohibits access to protected min_len from within static methods ( ?? )

 public:

   static const unsigned long _S_min_len[46];

 protected:

   static bool _S_is_balanced(_RopeRep* __r)

   { return (__r->_M_size._M_data >= _S_min_len[__r->_M_depth]); }

   static bool _S_is_almost_balanced(_RopeRep* __r)

   { return (__r->_M_depth == 0 ||

             __r->_M_size._M_data >= _S_min_len[__r->_M_depth - 1]); }

   static bool _S_is_roughly_balanced(_RopeRep* __r)

   { return (__r->_M_depth <= 1 ||

             __r->_M_size._M_data >= _S_min_len[__r->_M_depth - 2]); }

   // Assumes the result is not empty.

   static _RopeRep* _S_concat_and_set_balanced(_RopeRep* __left,

                                               _RopeRep* __right)

   {

     _RopeRep* __result = _S_concat_rep(__left, __right);

     if (_S_is_balanced(__result)) __result->_M_is_balanced = true;

     return __result;

   }

   // The basic rebalancing operation.  Logically copies the

   // rope.  The result has refcount of 1.  The client will

   // usually decrement the reference count of __r.

   // The result is within height 2 of balanced by the above

   // definition.

   static _RopeRep* _S_balance(_RopeRep* __r);

   // Add all unbalanced subtrees to the forest of balanceed trees.

   // Used only by balance.

   static void _S_add_to_forest(_RopeRep*__r, _RopeRep** __forest);

   // Add __r to forest, assuming __r is already balanced.

   static void _S_add_leaf_to_forest(_RopeRep* __r, _RopeRep** __forest);

   // Print to stdout, exposing structure

   static void _S_dump(_RopeRep* __r, int __indent = 0);

   // Return -1, 0, or 1 if __x < __y, __x == __y, or __x > __y resp.

   static int _S_compare(const _RopeRep* __x, const _RopeRep* __y);

 public:

   bool empty() const { return 0 == _M_tree_ptr._M_data; }

   // Comparison member function.  This is public only for those

   // clients that need a ternary comparison.  Others

   // should use the comparison operators below.

   int compare(const _Self& __y) const {

     return _S_compare(_M_tree_ptr._M_data, __y._M_tree_ptr._M_data);

   }

   rope(const _CharT* __s, const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, _STLP_ROPE_FROM_UNOWNED_CHAR_PTR(__s, _S_char_ptr_len(__s),__a))

   { }

   rope(const _CharT* __s, size_t __len,

        const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, (_STLP_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __len, __a)))

   { }

   // Should perhaps be templatized with respect to the iterator type

   // and use Sequence_buffer.  (It should perhaps use sequence_buffer

   // even now.)

   rope(const _CharT *__s, const _CharT *__e,

        const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, _STLP_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __e - __s, __a))

   { }

   rope(const const_iterator& __s, const const_iterator& __e,

        const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, _S_substring(__s._M_root, __s._M_current_pos,

                                     __e._M_current_pos))

   { }

   rope(const iterator& __s, const iterator& __e,

        const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, _S_substring(__s._M_root, __s._M_current_pos,

                                     __e._M_current_pos))

   { }

   rope(_CharT __c, const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, (_RopeRep*)0)

   {

     _CharT* __buf = _M_tree_ptr.allocate(_S_rounded_up_size(1));

     _Construct(__buf, __c);

     _STLP_TRY {

       _M_tree_ptr._M_data = _S_new_RopeLeaf(__buf, 1, __a);

     }

     _STLP_UNWIND(_RopeRep::_S_free_string(__buf, 1, __a))

       }

   rope(size_t __n, _CharT __c,     

        const allocator_type& __a = allocator_type()):

     _M_tree_ptr(__a, (_RopeRep*)0) {

     rope<_CharT,_Alloc> __result;

 # define  __exponentiate_threshold size_t(32)

     _RopeRep* __remainder;

     rope<_CharT,_Alloc> __remainder_rope;

     // gcc-2.7.2 bugs

     typedef _Rope_Concat_fn<_CharT,_Alloc> _Concat_fn;

     if (0 == __n)

       return;

     size_t __exponent = __n / __exponentiate_threshold;

     size_t __rest = __n % __exponentiate_threshold;

     if (0 == __rest) {

       __remainder = 0;

     } else {

       _CharT* __rest_buffer = _M_tree_ptr.allocate(_S_rounded_up_size(__rest));

       uninitialized_fill_n(__rest_buffer, __rest, __c);

       _S_cond_store_eos(__rest_buffer[__rest]);

       _STLP_TRY {

 		__remainder = _S_new_RopeLeaf(__rest_buffer, __rest, __a);

       }

       _STLP_UNWIND(_RopeRep::_S_free_string(__rest_buffer, __rest, __a))

 		}

     __remainder_rope._M_tree_ptr._M_data = __remainder;

     if (__exponent != 0) {

       _CharT* __base_buffer =

 		_M_tree_ptr.allocate(_S_rounded_up_size(__exponentiate_threshold));

       _RopeLeaf* __base_leaf;

       rope<_CharT,_Alloc> __base_rope;

       uninitialized_fill_n(__base_buffer, __exponentiate_threshold, __c);

       _S_cond_store_eos(__base_buffer[__exponentiate_threshold]);

       _STLP_TRY {

 		__base_leaf = _S_new_RopeLeaf(__base_buffer,

                                       __exponentiate_threshold, __a);

       }

       _STLP_UNWIND(_RopeRep::_S_free_string(__base_buffer, 

                                             __exponentiate_threshold, __a))

 		__base_rope._M_tree_ptr._M_data = __base_leaf;

       if (1 == __exponent) {

 		__result = __base_rope;

 #         ifndef __GC

 		_STLP_ASSERT(2 == __result._M_tree_ptr._M_data->_M_ref_count)

 		// One each for base_rope and __result

 #         endif

       } else {

 		__result = power(__base_rope, __exponent, _Concat_fn());

       }

       if (0 != __remainder) {

 		__result += __remainder_rope;

       }

     } else {

       __result = __remainder_rope;

     }

     _M_tree_ptr._M_data = __result._M_tree_ptr._M_data;

     _M_tree_ptr._M_data->_M_ref_nonnil();

 # undef __exponentiate_threshold

   }

   rope(const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, (_RopeRep*)0) {}

   // Construct a rope from a function that can compute its members

   rope(char_producer<_CharT> *__fn, size_t __len, bool __delete_fn,

        const allocator_type& __a = allocator_type())

     : _M_tree_ptr(__a, (_RopeRep*)0)

   {

     _M_tree_ptr._M_data = (0 == __len) ?

       0 : _S_new_RopeFunction(__fn, __len, __delete_fn, __a);

   }

   rope(const _Self& __x)

     : _M_tree_ptr(__x.get_allocator(), __x._M_tree_ptr._M_data)

   {

     _S_ref(_M_tree_ptr._M_data);

   }

   ~rope()

   {

     _S_unref(_M_tree_ptr._M_data);

   }

   _Self& operator=(const _Self& __x)

   {

     _RopeRep* __old = _M_tree_ptr._M_data;

     _STLP_ASSERT(get_allocator() == __x.get_allocator())

     _M_tree_ptr._M_data = __x._M_tree_ptr._M_data;

     _S_ref(_M_tree_ptr._M_data);

     _S_unref(__old);

     return(*this);

   }

   void clear()

   {

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = 0;

   }

   void push_back(_CharT __x)

   {

     _RopeRep* __old = _M_tree_ptr._M_data;

     _M_tree_ptr._M_data = _S_destr_concat_char_iter(_M_tree_ptr._M_data, &__x, 1);

     _S_unref(__old);

   }

   void pop_back()

   {

     _RopeRep* __old = _M_tree_ptr._M_data;

     _M_tree_ptr._M_data = 

       _S_substring(_M_tree_ptr._M_data, 0, _M_tree_ptr._M_data->_M_size._M_data - 1);

     _S_unref(__old);

   }

   _CharT back() const

   {

     return _S_fetch(_M_tree_ptr._M_data, _M_tree_ptr._M_data->_M_size._M_data - 1);

   }

   void push_front(_CharT __x)

   {

     _RopeRep* __old = _M_tree_ptr._M_data;

     _RopeRep* __left =

       _STLP_ROPE_FROM_UNOWNED_CHAR_PTR(&__x, 1, get_allocator());

     _STLP_TRY {

       _M_tree_ptr._M_data = _S_concat_rep(__left, _M_tree_ptr._M_data);

       _S_unref(__old);

       _S_unref(__left);

     }

     _STLP_UNWIND(_S_unref(__left))

       }

   void pop_front()

   {

     _RopeRep* __old = _M_tree_ptr._M_data;

     _M_tree_ptr._M_data = _S_substring(_M_tree_ptr._M_data, 1, _M_tree_ptr._M_data->_M_size._M_data);

     _S_unref(__old);

   }

   _CharT front() const

   {

     return _S_fetch(_M_tree_ptr._M_data, 0);

   }

   void balance()

   {

     _RopeRep* __old = _M_tree_ptr._M_data;

     _M_tree_ptr._M_data = _S_balance(_M_tree_ptr._M_data);

     _S_unref(__old);

   }

   void copy(_CharT* __buffer) const {

     _STLP_STD::_Destroy(__buffer, __buffer + size());

     _S_flatten(_M_tree_ptr._M_data, __buffer);

   }

   // This is the copy function from the standard, but

   // with the arguments reordered to make it consistent with the

   // rest of the interface.

   // Note that this guaranteed not to compile if the draft standard

   // order is assumed.

   size_type copy(size_type __pos, size_type __n, _CharT* __buffer) const 

   {

     size_t _p_size = size();

     size_t __len = (__pos + __n > _p_size? _p_size - __pos : __n);

     _STLP_STD::_Destroy(__buffer, __buffer + __len);

     _S_flatten(_M_tree_ptr._M_data, __pos, __len, __buffer);

     return __len;

   }

   // Print to stdout, exposing structure.  May be useful for

   // performance debugging.

   void dump() {

     _S_dump(_M_tree_ptr._M_data);

   }

   // Convert to 0 terminated string in new allocated memory.

   // Embedded 0s in the input do not terminate the copy.

   const _CharT* c_str() const;

   // As above, but lso use the flattened representation as the

   // the new rope representation.

   const _CharT* replace_with_c_str();

   // Reclaim memory for the c_str generated flattened string.

   // Intentionally undocumented, since it's hard to say when this

   // is safe for multiple threads.

   void delete_c_str () {

     if (0 == _M_tree_ptr._M_data) return;

     if (_RopeRep::_S_leaf == _M_tree_ptr._M_data->_M_tag && 

         ((_RopeLeaf*)_M_tree_ptr._M_data)->_M_data == 

         _M_tree_ptr._M_data->_M_c_string) {

       // Representation shared

       return;

     }

 #           ifndef __GC

     _M_tree_ptr._M_data->_M_free_c_string();

 #           endif

     _M_tree_ptr._M_data->_M_c_string = 0;

   }

   _CharT operator[] (size_type __pos) const {

     return _S_fetch(_M_tree_ptr._M_data, __pos);

   }

   _CharT at(size_type __pos) const {

     // if (__pos >= size()) throw out_of_range;  // XXX

     return (*this)[__pos];

   }

   const_iterator begin() const {

     return(const_iterator(_M_tree_ptr._M_data, 0));

   }

   // An easy way to get a const iterator from a non-const container.

   const_iterator const_begin() const {

     return(const_iterator(_M_tree_ptr._M_data, 0));

   }

   const_iterator end() const {

     return(const_iterator(_M_tree_ptr._M_data, size()));

   }

   const_iterator const_end() const {

     return(const_iterator(_M_tree_ptr._M_data, size()));

   }

   size_type size() const { 

     return(0 == _M_tree_ptr._M_data? 0 : _M_tree_ptr._M_data->_M_size._M_data);

   }

   size_type length() const {

     return size();

   }

   size_type max_size() const {

     return _S_min_len[__ROPE_MAX_DEPTH-1] - 1;

     //  Guarantees that the result can be sufficirntly

     //  balanced.  Longer ropes will probably still work,

     //  but it's harder to make guarantees.

   }

   const_reverse_iterator rbegin() const {

     return const_reverse_iterator(end());

   }

   const_reverse_iterator const_rbegin() const {

     return const_reverse_iterator(end());

   }

   const_reverse_iterator rend() const {

     return const_reverse_iterator(begin());

   }

   const_reverse_iterator const_rend() const {

     return const_reverse_iterator(begin());

   }

   // The symmetric cases are intentionally omitted, since they're presumed

   // to be less common, and we don't handle them as well.

   // The following should really be templatized.

   // The first argument should be an input iterator or

   // forward iterator with value_type _CharT.

   _Self& append(const _CharT* __iter, size_t __n) {

     _RopeRep* __result = 

       _S_destr_concat_char_iter(_M_tree_ptr._M_data, __iter, __n);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

     return *this;

   }

   _Self& append(const _CharT* __c_string) {

     size_t __len = _S_char_ptr_len(__c_string);

     append(__c_string, __len);

     return(*this);

   }

   _Self& append(const _CharT* __s, const _CharT* __e) {

     _RopeRep* __result =

       _S_destr_concat_char_iter(_M_tree_ptr._M_data, __s, __e - __s);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

     return *this;

   }

   _Self& append(const_iterator __s, const_iterator __e) {

     _STLP_ASSERT(__s._M_root == __e._M_root)

     _STLP_ASSERT(get_allocator() == __s._M_root->get_allocator())

     _Self_destruct_ptr __appendee(_S_substring(

                                                __s._M_root, __s._M_current_pos, __e._M_current_pos));

     _RopeRep* __result = 

       _S_concat_rep(_M_tree_ptr._M_data, (_RopeRep*)__appendee);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

     return *this;

   }

   _Self& append(_CharT __c) {

     _RopeRep* __result = 

       _S_destr_concat_char_iter(_M_tree_ptr._M_data, &__c, 1);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

     return *this;

   }

   _Self& append() { return append(_CharT()); }  // XXX why?

   _Self& append(const _Self& __y) {

     _STLP_ASSERT(__y.get_allocator() == get_allocator())

     _RopeRep* __result = _S_concat_rep(_M_tree_ptr._M_data, __y._M_tree_ptr._M_data);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

     return *this;

   }

   _Self& append(size_t __n, _CharT __c) {

     rope<_CharT,_Alloc> __last(__n, __c);

     return append(__last);

   }

   void swap(_Self& __b) {

     _STLP_ASSERT(get_allocator() == __b.get_allocator())

     _RopeRep* __tmp = _M_tree_ptr._M_data;

     _M_tree_ptr._M_data = __b._M_tree_ptr._M_data;

     __b._M_tree_ptr._M_data = __tmp;

   }

 protected:

   // Result is included in refcount.

   static _RopeRep* replace(_RopeRep* __old, size_t __pos1,

                            size_t __pos2, _RopeRep* __r) {

     if (0 == __old) { _S_ref(__r); return __r; }

     _Self_destruct_ptr __left(

                               _S_substring(__old, 0, __pos1));

     _Self_destruct_ptr __right(

                                _S_substring(__old, __pos2, __old->_M_size._M_data));

 	_STLP_MPWFIX_TRY	//*TY 06/01/2000 - 

     _RopeRep* __result;

     if (0 == __r) {

       __result = _S_concat_rep(__left, __right);

     } else {

       _STLP_ASSERT(__old->get_allocator() == __r->get_allocator())

       _Self_destruct_ptr __left_result(_S_concat_rep(__left, __r));

       __result = _S_concat_rep(__left_result, __right);

     }

     return __result;

 	_STLP_MPWFIX_CATCH	//*TY 06/01/2000 - 

   }

 public:

   void insert(size_t __p, const _Self& __r) {

     _RopeRep* __result = 

       replace(_M_tree_ptr._M_data, __p, __p, __r._M_tree_ptr._M_data);

     _STLP_ASSERT(get_allocator() == __r.get_allocator())

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

   }

   void insert(size_t __p, size_t __n, _CharT __c) {

     rope<_CharT,_Alloc> __r(__n,__c);

     insert(__p, __r);

   }

   void insert(size_t __p, const _CharT* __i, size_t __n) {

     _Self_destruct_ptr __left(_S_substring(_M_tree_ptr._M_data, 0, __p));

     _Self_destruct_ptr __right(_S_substring(_M_tree_ptr._M_data, __p, size()));

     _Self_destruct_ptr __left_result(

                                      _S_concat_char_iter(__left, __i, __n));

     // _S_ destr_concat_char_iter should be safe here.

     // But as it stands it's probably not a win, since __left

     // is likely to have additional references.

     _RopeRep* __result = _S_concat_rep(__left_result, __right);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

   }

   void insert(size_t __p, const _CharT* __c_string) {

     insert(__p, __c_string, _S_char_ptr_len(__c_string));

   }

   void insert(size_t __p, _CharT __c) {

     insert(__p, &__c, 1);

   }

   void insert(size_t __p) {

     _CharT __c = _CharT();

     insert(__p, &__c, 1);

   }

   void insert(size_t __p, const _CharT* __i, const _CharT* __j) {

     _Self __r(__i, __j);

     insert(__p, __r);

   }

   void insert(size_t __p, const const_iterator& __i,

               const const_iterator& __j) {

     _Self __r(__i, __j);

     insert(__p, __r);

   }

   void insert(size_t __p, const iterator& __i,

               const iterator& __j) {

     _Self __r(__i, __j);

     insert(__p, __r);

   }

   // (position, length) versions of replace operations:

   void replace(size_t __p, size_t __n, const _Self& __r) {

     _RopeRep* __result = 

       replace(_M_tree_ptr._M_data, __p, __p + __n, __r._M_tree_ptr._M_data);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

   }

   void replace(size_t __p, size_t __n, 

                const _CharT* __i, size_t __i_len) {

     _Self __r(__i, __i_len);

     replace(__p, __n, __r);

   }

   void replace(size_t __p, size_t __n, _CharT __c) {

     _Self __r(__c);

     replace(__p, __n, __r);

   }

   void replace(size_t __p, size_t __n, const _CharT* __c_string) {

     _Self __r(__c_string);

     replace(__p, __n, __r);

   }

   void replace(size_t __p, size_t __n, 

                const _CharT* __i, const _CharT* __j) {

     _Self __r(__i, __j);

     replace(__p, __n, __r);

   }

   void replace(size_t __p, size_t __n,

                const const_iterator& __i, const const_iterator& __j) {

     _Self __r(__i, __j);

     replace(__p, __n, __r);

   }

   void replace(size_t __p, size_t __n,

                const iterator& __i, const iterator& __j) {

     _Self __r(__i, __j);

     replace(__p, __n, __r);

   }

   // Single character variants:

   void replace(size_t __p, _CharT __c) {

     iterator __i(this, __p);

     *__i = __c;

   }

   void replace(size_t __p, const _Self& __r) {

     replace(__p, 1, __r);

   }

   void replace(size_t __p, const _CharT* __i, size_t __i_len) {

     replace(__p, 1, __i, __i_len);

   }

   void replace(size_t __p, const _CharT* __c_string) {

     replace(__p, 1, __c_string);

   }

   void replace(size_t __p, const _CharT* __i, const _CharT* __j) {

     replace(__p, 1, __i, __j);

   }

   void replace(size_t __p, const const_iterator& __i,

                const const_iterator& __j) {

     replace(__p, 1, __i, __j);

   }

   void replace(size_t __p, const iterator& __i,

                const iterator& __j) {

     replace(__p, 1, __i, __j);

   }

   // Erase, (position, size) variant.

   void erase(size_t __p, size_t __n) {

     _RopeRep* __result = replace(_M_tree_ptr._M_data, __p, __p + __n, 0);

     _S_unref(_M_tree_ptr._M_data);

     _M_tree_ptr._M_data = __result;

   }

   // Erase, single character

   void erase(size_t __p) {

     erase(__p, __p + 1);

   }

   // Insert, iterator variants.  

   iterator insert(const iterator& __p, const _Self& __r)

   { insert(__p.index(), __r); return __p; }

   iterator insert(const iterator& __p, size_t __n, _CharT __c)

   { insert(__p.index(), __n, __c); return __p; }

   iterator insert(const iterator& __p, _CharT __c) 

   { insert(__p.index(), __c); return __p; }

   iterator insert(const iterator& __p ) 

   { insert(__p.index()); return __p; }

   iterator insert(const iterator& __p, const _CharT* c_string) 

   { insert(__p.index(), c_string); return __p; }

   iterator insert(const iterator& __p, const _CharT* __i, size_t __n)

   { insert(__p.index(), __i, __n); return __p; }

   iterator insert(const iterator& __p, const _CharT* __i, 

                   const _CharT* __j)

   { insert(__p.index(), __i, __j);  return __p; }

   iterator insert(const iterator& __p,

                   const const_iterator& __i, const const_iterator& __j)

   { insert(__p.index(), __i, __j); return __p; }

   iterator insert(const iterator& __p,

                   const iterator& __i, const iterator& __j)

   { insert(__p.index(), __i, __j); return __p; }

   // Replace, range variants.

   void replace(const iterator& __p, const iterator& __q,

                const _Self& __r)

   { replace(__p.index(), __q.index() - __p.index(), __r); }

   void replace(const iterator& __p, const iterator& __q, _CharT __c)

   { replace(__p.index(), __q.index() - __p.index(), __c); }

   void replace(const iterator& __p, const iterator& __q,

                const _CharT* __c_string)

   { replace(__p.index(), __q.index() - __p.index(), __c_string); }

   void replace(const iterator& __p, const iterator& __q,

                const _CharT* __i, size_t __n)

   { replace(__p.index(), __q.index() - __p.index(), __i, __n); }

   void replace(const iterator& __p, const iterator& __q,

                const _CharT* __i, const _CharT* __j)

   { replace(__p.index(), __q.index() - __p.index(), __i, __j); }

   void replace(const iterator& __p, const iterator& __q,

                const const_iterator& __i, const const_iterator& __j)

   { replace(__p.index(), __q.index() - __p.index(), __i, __j); }

   void replace(const iterator& __p, const iterator& __q,

                const iterator& __i, const iterator& __j)

   { replace(__p.index(), __q.index() - __p.index(), __i, __j); }

   // Replace, iterator variants.

   void replace(const iterator& __p, const _Self& __r)

   { replace(__p.index(), __r); }

   void replace(const iterator& __p, _CharT __c)

   { replace(__p.index(), __c); }

   void replace(const iterator& __p, const _CharT* __c_string)

   { replace(__p.index(), __c_string); }

   void replace(const iterator& __p, const _CharT* __i, size_t __n)

   { replace(__p.index(), __i, __n); }

   void replace(const iterator& __p, const _CharT* __i, const _CharT* __j)

   { replace(__p.index(), __i, __j); }

   void replace(const iterator& __p, const_iterator __i, 

                const_iterator __j)

   { replace(__p.index(), __i, __j); }

   void replace(const iterator& __p, iterator __i, iterator __j)

   { replace(__p.index(), __i, __j); }

   // Iterator and range variants of erase

   iterator erase(const iterator& __p, const iterator& __q) {

     size_t __p_index = __p.index();

     erase(__p_index, __q.index() - __p_index);

     return iterator(this, __p_index);

   }

   iterator erase(const iterator& __p) {

     size_t __p_index = __p.index();

     erase(__p_index, 1);

     return iterator(this, __p_index);

   }

   _Self substr(size_t __start, size_t __len = 1) const {

     return rope<_CharT,_Alloc>(

                                _S_substring(_M_tree_ptr._M_data, __start, __start + __len));

   }

   _Self substr(iterator __start, iterator __end) const {

     return rope<_CharT,_Alloc>(

                                _S_substring(_M_tree_ptr._M_data, __start.index(), __end.index()));

   }

   _Self substr(iterator __start) const {

     size_t __pos = __start.index();

     return rope<_CharT,_Alloc>(

                                _S_substring(_M_tree_ptr._M_data, __pos, __pos + 1));

   }

   _Self substr(const_iterator __start, const_iterator __end) const {

     // This might eventually take advantage of the cache in the

     // iterator.

     return rope<_CharT,_Alloc>(

                                _S_substring(_M_tree_ptr._M_data, __start.index(), __end.index()));

   }

   rope<_CharT,_Alloc> substr(const_iterator __start) {

     size_t __pos = __start.index();

     return rope<_CharT,_Alloc>(

                                _S_substring(_M_tree_ptr._M_data, __pos, __pos + 1));

   }

   enum { npos = -1 };

   //         static const size_type npos;

   size_type find(_CharT __c, size_type __pos = 0) const;

   size_type find(const _CharT* __s, size_type __pos = 0) const {

     size_type __result_pos;

     const_iterator __result = search(const_begin() + (ptrdiff_t)__pos, const_end(),

                                      __s, __s + _S_char_ptr_len(__s));

     __result_pos = __result.index();

 #           ifndef _STLP_OLD_ROPE_SEMANTICS

     if (__result_pos == size()) __result_pos = npos;

 #           endif

     return __result_pos;

   }

   iterator mutable_begin() {

     return(iterator(this, 0));

   }

   iterator mutable_end() {

     return(iterator(this, size()));

   }

   reverse_iterator mutable_rbegin() {

     return reverse_iterator(mutable_end());

   }

   reverse_iterator mutable_rend() {

     return reverse_iterator(mutable_begin());

   }

   reference mutable_reference_at(size_type __pos) {

     return reference(this, __pos);

   }

 #       ifdef __STD_STUFF

   reference operator[] (size_type __pos) {

     return reference(this, __pos);

   }

   reference at(size_type __pos) {

     // if (__pos >= size()) throw out_of_range;  // XXX

     return (*this)[__pos];

   }

   void resize(size_type, _CharT) {}

   void resize(size_type) {}

   void reserve(size_type = 0) {}

   size_type capacity() const {

     return max_size();

   }

   // Stuff below this line is dangerous because it's error prone.

   // I would really like to get rid of it.

   // copy function with funny arg ordering.

   size_type copy(_CharT* __buffer, size_type __n, 

                  size_type __pos = 0) const {

     return copy(__pos, __n, __buffer);

   }

   iterator end() { return mutable_end(); }

   iterator begin() { return mutable_begin(); }

   reverse_iterator rend() { return mutable_rend(); }

   reverse_iterator rbegin() { return mutable_rbegin(); }

 #       else

   const_iterator end() { return const_end(); }

   const_iterator begin() { return const_begin(); }

   const_reverse_iterator rend() { return const_rend(); }

   const_reverse_iterator rbegin() { return const_rbegin(); }

 #	endif

   __ROPE_DEFINE_ALLOCS(_Alloc, _M_tree_ptr)

     };

 # undef __ROPE_DEFINE_ALLOC

 # undef __ROPE_DEFINE_ALLOCS

 template <class _CharT, class _Alloc>

 inline _CharT 

 _Rope_const_iterator< _CharT, _Alloc>::operator[](size_t __n)

 {

   return rope<_CharT,_Alloc>::_S_fetch(this->_M_root, this->_M_current_pos + __n);

 }

 template <class _CharT, class _Alloc>

 inline bool operator== (const _Rope_const_iterator<_CharT,_Alloc>& __x,

                         const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return (__x._M_current_pos == __y._M_current_pos && 

           __x._M_root == __y._M_root);

 }

 template <class _CharT, class _Alloc>

 inline bool operator< (const _Rope_const_iterator<_CharT,_Alloc>& __x,

                        const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return (__x._M_current_pos < __y._M_current_pos);

 }

 #ifdef _STLP_USE_SEPARATE_RELOPS_NAMESPACE

 template <class _CharT, class _Alloc>

 inline bool operator!= (const _Rope_const_iterator<_CharT,_Alloc>& __x,

                         const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return !(__x == __y);

 }

 template <class _CharT, class _Alloc>

 inline bool operator> (const _Rope_const_iterator<_CharT,_Alloc>& __x,

                        const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return __y < __x;

 }

 template <class _CharT, class _Alloc>

 inline bool operator<= (const _Rope_const_iterator<_CharT,_Alloc>& __x,

                         const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return !(__y < __x);

 }

 template <class _CharT, class _Alloc>

 inline bool operator>= (const _Rope_const_iterator<_CharT,_Alloc>& __x,

                         const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return !(__x < __y);

 }

 #endif /* _STLP_USE_SEPARATE_RELOPS_NAMESPACE */

 template <class _CharT, class _Alloc>

 inline ptrdiff_t operator-(const _Rope_const_iterator<_CharT,_Alloc>& __x,

                            const _Rope_const_iterator<_CharT,_Alloc>& __y) {

   return (ptrdiff_t)__x._M_current_pos - (ptrdiff_t)__y._M_current_pos;

 }

 #if !defined( __MWERKS__ ) || __MWERKS__ >= 0x2000		// dwa 8/21/97  - "ambiguous access to overloaded function" bug.

 template <class _CharT, class _Alloc>

 inline _Rope_const_iterator<_CharT,_Alloc>

 operator-(const _Rope_const_iterator<_CharT,_Alloc>& __x, ptrdiff_t __n) {

   return _Rope_const_iterator<_CharT,_Alloc>(

                                              __x._M_root, __x._M_current_pos - __n);

 }

 # endif

 template <class _CharT, class _Alloc>

 inline _Rope_const_iterator<_CharT,_Alloc>

 operator+(const _Rope_const_iterator<_CharT,_Alloc>& __x, ptrdiff_t __n) {

   return _Rope_const_iterator<_CharT,_Alloc>(

                                              __x._M_root, __x._M_current_pos + __n);

 }

 template <class _CharT, class _Alloc>

 inline _Rope_const_iterator<_CharT,_Alloc>

 operator+(ptrdiff_t __n, const _Rope_const_iterator<_CharT,_Alloc>& __x) {

   return _Rope_const_iterator<_CharT,_Alloc>(

                                              __x._M_root, __x._M_current_pos + __n);

 }

 template <class _CharT, class _Alloc>

 inline bool operator== (const _Rope_iterator<_CharT,_Alloc>& __x,

                         const _Rope_iterator<_CharT,_Alloc>& __y) {

   return (__x._M_current_pos == __y._M_current_pos && 

           __x._M_root_rope == __y._M_root_rope);

 }

 template <class _CharT, class _Alloc>

 inline bool operator< (const _Rope_iterator<_CharT,_Alloc>& __x,

                        const _Rope_iterator<_CharT,_Alloc>& __y) {

   return (__x._M_current_pos < __y._M_current_pos);

 }

 #ifdef _STLP_USE_SEPARATE_RELOPS_NAMESPACE

 template <class _CharT, class _Alloc>

 inline bool operator!= (const _Rope_iterator<_CharT,_Alloc>& __x,

                         const _Rope_iterator<_CharT,_Alloc>& __y) {

   return !(__x == __y);

 }

 template <class _CharT, class _Alloc>

 inline bool operator> (const _Rope_iterator<_CharT,_Alloc>& __x,

                        const _Rope_iterator<_CharT,_Alloc>& __y) {

   return __y < __x;

 }

 template <class _CharT, class _Alloc>

 inline bool operator<= (const _Rope_iterator<_CharT,_Alloc>& __x,

                         const _Rope_iterator<_CharT,_Alloc>& __y) {

   return !(__y < __x);

 }

 template <class _CharT, class _Alloc>

 inline bool operator>= (const _Rope_iterator<_CharT,_Alloc>& __x,

                         const _Rope_iterator<_CharT,_Alloc>& __y) {

   return !(__x < __y);

 }

 #endif /* _STLP_USE_SEPARATE_RELOPS_NAMESPACE */

 template <class _CharT, class _Alloc>

 inline ptrdiff_t operator-(const _Rope_iterator<_CharT,_Alloc>& __x,

                            const _Rope_iterator<_CharT,_Alloc>& __y) {

   return (ptrdiff_t)__x._M_current_pos - (ptrdiff_t)__y._M_current_pos;

 }

 #if !defined( __MWERKS__ ) || __MWERKS__ >= 0x2000		// dwa 8/21/97  - "ambiguous access to overloaded function" bug.

 template <class _CharT, class _Alloc>

 inline _Rope_iterator<_CharT,_Alloc>

 operator-(const _Rope_iterator<_CharT,_Alloc>& __x,

           ptrdiff_t __n) {

   return _Rope_iterator<_CharT,_Alloc>(

                                        __x._M_root_rope, __x._M_current_pos - __n);

 }

 # endif

 template <class _CharT, class _Alloc>

 inline _Rope_iterator<_CharT,_Alloc>

 operator+(const _Rope_iterator<_CharT,_Alloc>& __x,

           ptrdiff_t __n) {

   return _Rope_iterator<_CharT,_Alloc>(

                                        __x._M_root_rope, __x._M_current_pos + __n);

 }

 template <class _CharT, class _Alloc>

 inline _Rope_iterator<_CharT,_Alloc>

 operator+(ptrdiff_t __n, const _Rope_iterator<_CharT,_Alloc>& __x) {

   return _Rope_iterator<_CharT,_Alloc>(

                                        __x._M_root_rope, __x._M_current_pos + __n);

 }

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>

 operator+ (const rope<_CharT,_Alloc>& __left,

            const rope<_CharT,_Alloc>& __right)

 {

   _STLP_ASSERT(__left.get_allocator() == __right.get_allocator())

   return rope<_CharT,_Alloc>(rope<_CharT,_Alloc>::_S_concat_rep(__left._M_tree_ptr._M_data, __right._M_tree_ptr._M_data));

   // Inlining this should make it possible to keep __left and

   // __right in registers.

 }

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>&

 operator+= (rope<_CharT,_Alloc>& __left, 

             const rope<_CharT,_Alloc>& __right)

 {

   __left.append(__right);

   return __left;

 }

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>

 operator+ (const rope<_CharT,_Alloc>& __left,

            const _CharT* __right) {

   size_t __rlen = rope<_CharT,_Alloc>::_S_char_ptr_len(__right);

   return rope<_CharT,_Alloc>(

                              rope<_CharT,_Alloc>::_S_concat_char_iter(

                                                                       __left._M_tree_ptr._M_data, __right, __rlen)); 

 }

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>&

 operator+= (rope<_CharT,_Alloc>& __left,

             const _CharT* __right) {

   __left.append(__right);

   return __left;

 }

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>

 operator+ (const rope<_CharT,_Alloc>& __left, _STLP_SIMPLE_TYPE(_CharT) __right) {

   return rope<_CharT,_Alloc>(

                              rope<_CharT,_Alloc>::_S_concat_char_iter(

                                                                       __left._M_tree_ptr._M_data, &__right, 1));

 }

 template <class _CharT, class _Alloc>

 inline

 rope<_CharT,_Alloc>&

 operator+= (rope<_CharT,_Alloc>& __left, _STLP_SIMPLE_TYPE(_CharT) __right) {

   __left.append(__right);

   return __left;

 }

 template <class _CharT, class _Alloc>

 inline bool

 operator< (const rope<_CharT,_Alloc>& __left, 

            const rope<_CharT,_Alloc>& __right) {

   return __left.compare(__right) < 0;

 }

 template <class _CharT, class _Alloc>

 inline bool

 operator== (const rope<_CharT,_Alloc>& __left, 

             const rope<_CharT,_Alloc>& __right) {

   return __left.compare(__right) == 0;

 }

 #ifdef _STLP_USE_SEPARATE_RELOPS_NAMESPACE

 template <class _CharT, class _Alloc>

 inline bool

 operator!= (const rope<_CharT,_Alloc>& __x, const rope<_CharT,_Alloc>& __y) {

   return !(__x == __y);

 }

 template <class _CharT, class _Alloc>

 inline bool

 operator> (const rope<_CharT,_Alloc>& __x, const rope<_CharT,_Alloc>& __y) {

   return __y < __x;

 }

 template <class _CharT, class _Alloc>

 inline bool

 operator<= (const rope<_CharT,_Alloc>& __x, const rope<_CharT,_Alloc>& __y) {

   return !(__y < __x);

 }

 template <class _CharT, class _Alloc>

 inline bool

 operator>= (const rope<_CharT,_Alloc>& __x, const rope<_CharT,_Alloc>& __y) {

   return !(__x < __y);

 }

 template <class _CharT, class _Alloc>

 inline bool operator!= (const _Rope_char_ptr_proxy<_CharT,_Alloc>& __x,

                         const _Rope_char_ptr_proxy<_CharT,_Alloc>& __y) {

   return !(__x == __y);

 }

 #endif /* _STLP_USE_SEPARATE_RELOPS_NAMESPACE */

 template <class _CharT, class _Alloc>

 inline bool operator== (const _Rope_char_ptr_proxy<_CharT,_Alloc>& __x,

                         const _Rope_char_ptr_proxy<_CharT,_Alloc>& __y) {

   return (__x._M_pos == __y._M_pos && __x._M_root == __y._M_root);

 }

 #ifdef _STLP_USE_NEW_IOSTREAMS

 template<class _CharT, class _Traits, class _Alloc>

 basic_ostream<_CharT, _Traits>& operator<< (

                                             basic_ostream<_CharT, _Traits>& __o,

                                             const rope<_CharT, _Alloc>& __r);

 #elif ! defined (_STLP_USE_NO_IOSTREAMS)

 template<class _CharT, class _Alloc>

 ostream& operator<< (ostream& __o, const rope<_CharT,_Alloc>& __r);        

 #endif

 typedef rope<char, _STLP_DEFAULT_ALLOCATOR(char) > crope;

 # ifdef _STLP_HAS_WCHAR_T

 typedef rope<wchar_t, _STLP_DEFAULT_ALLOCATOR(wchar_t) > wrope;

 # endif

 inline crope::reference __mutable_reference_at(crope& __c, size_t __i)

 {

   return __c.mutable_reference_at(__i);

 }

 # ifdef _STLP_HAS_WCHAR_T

 inline wrope::reference __mutable_reference_at(wrope& __c, size_t __i)

 {

   return __c.mutable_reference_at(__i);

 }

 # endif

 #ifdef _STLP_FUNCTION_TMPL_PARTIAL_ORDER

 template <class _CharT, class _Alloc>

 inline void swap(rope<_CharT,_Alloc>& __x, rope<_CharT,_Alloc>& __y) {

   __x.swap(__y);

 }

 #else

 inline void swap(crope& __x, crope& __y) { __x.swap(__y); }

 # ifdef _STLP_HAS_WCHAR_T	// dwa 8/21/97

 inline void swap(wrope& __x, wrope& __y) { __x.swap(__y); }

 # endif

 #endif /* _STLP_FUNCTION_TMPL_PARTIAL_ORDER */

 // Hash functions should probably be revisited later:

 _STLP_TEMPLATE_NULL struct hash<crope>

 {

   size_t operator()(const crope& __str) const

   {

     size_t _p_size = __str.size();

     if (0 == _p_size) return 0;

     return 13*__str[0] + 5*__str[_p_size - 1] + _p_size;

   }

 };

 # ifdef _STLP_HAS_WCHAR_T	// dwa 8/21/97

 _STLP_TEMPLATE_NULL struct hash<wrope>

 {

   size_t operator()(const wrope& __str) const

   {

     size_t _p_size = __str.size();

     if (0 == _p_size) return 0;

     return 13*__str[0] + 5*__str[_p_size - 1] + _p_size;

   }

 };

 #endif

 #ifndef _STLP_MSVC

 // I couldn't get this to work with VC++

 template<class _CharT,class _Alloc>

 void

 _Rope_rotate(_Rope_iterator<_CharT,_Alloc> __first,

              _Rope_iterator<_CharT,_Alloc> __middle,

              _Rope_iterator<_CharT,_Alloc> __last);

 #if !defined(__GNUC__)

 // Appears to confuse g++

 inline void rotate(_Rope_iterator<char,_STLP_DEFAULT_ALLOCATOR(char) > __first,

                    _Rope_iterator<char,_STLP_DEFAULT_ALLOCATOR(char) > __middle,

                    _Rope_iterator<char,_STLP_DEFAULT_ALLOCATOR(char) > __last) {

   _Rope_rotate(__first, __middle, __last);

 }

 #endif

 #endif

 template <class _CharT, class _Alloc>

 inline _Rope_char_ref_proxy<_CharT, _Alloc>::operator _CharT () const

 {

   if (_M_current_valid) {

 	return _M_current;

   } else {

     return _My_rope::_S_fetch(_M_root->_M_tree_ptr._M_data, _M_pos);

   }

 }

 _STLP_END_NAMESPACE

 # if !defined (_STLP_LINK_TIME_INSTANTIATION)

 #  include <stl/_rope.c>

 # endif

 # endif /* _STLP_INTERNAL_ROPE_H */

 // Local Variables:

 // mode:C++

 // End: