/*

  * Copyright (c) 1996,1997

  * Silicon Graphics Computer Systems, Inc.

  *

  * 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.

  */

 // Set buf_start, buf_end, and buf_ptr appropriately, filling tmp_buf

 // if necessary.  Assumes path_end[leaf_index] and leaf_pos are correct.

 // Results in a valid buf_ptr if the iterator can be legitimately

 // dereferenced.

 #ifndef _STLP_ROPEIMPL_H

 #define _STLP_ROPEIMPL_H

 #ifndef _STLP_INTERNAL_ROPE_H

 #  include <stl/_rope.h>

 #endif

 #ifndef _STLP_INTERNAL_CSTDIO

 #  include <stl/_cstdio.h>

 #endif

 #if !defined (_STLP_USE_NO_IOSTREAMS)

 #  ifndef _STLP_IOSTREAM

 #    include <iostream>

 #  endif

 #endif

 #include <stl/_range_errors.h>

 _STLP_BEGIN_NAMESPACE

 # if defined ( _STLP_NESTED_TYPE_PARAM_BUG )

 # define __allocator__ _Alloc

 # else

 # define __allocator__ allocator_type

 # endif

 template<class _CharT, class _Alloc>

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

   : _Rope_iterator_base<_CharT,_Alloc>(__r->_M_tree_ptr._M_data, __pos),

   _M_root_rope(__r) { _RopeRep::_S_ref(this->_M_root); }

 template<class _CharT, class _Alloc>

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

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

   _M_root_rope(&__r) {

 #if !defined (__DMC__)

   _RopeRep::_S_ref(this->_M_root); if (!(__r.empty()))_S_setcache(*this);

 #else

   _Rope_iterator_base<_CharT, _Alloc>* __x = this;

   _RopeRep::_S_ref(this->_M_root); if (!(__r.empty()))_S_setcache(*__x);

 #endif

 }

 template<class _CharT, class _Alloc>

 void _Rope_RopeRep<_CharT, _Alloc>::_M_free_c_string() {

   _CharT* __cstr = _M_c_string;

   if (0 != __cstr) {

     size_t _p_size = _M_size._M_data + 1;

     _STLP_STD::_Destroy_Range(__cstr, __cstr + _p_size);

     _M_size.deallocate(__cstr, _p_size);

   }

 }

 // Set buf_start, buf_end, and buf_ptr appropriately, filling tmp_buf

 // if necessary.  Assumes _M_path_end[leaf_index] and leaf_pos are correct.

 // Results in a valid buf_ptr if the iterator can be legitimately

 // dereferenced.

 template <class _CharT, class _Alloc>

 void _Rope_iterator_base<_CharT,_Alloc>::_S_setbuf(

   _Rope_iterator_base<_CharT,_Alloc>& __x) {

   const _RopeRep* __leaf = __x._M_path_end._M_data[__x._M_leaf_index];

   size_t __leaf_pos = __x._M_leaf_pos;

   size_t __pos = __x._M_current_pos;

   switch(__leaf->_M_tag) {

   case _RopeRep::_S_leaf:

     typedef _Rope_RopeLeaf<_CharT, _Alloc> _RopeLeaf;

     __x._M_buf_start = __STATIC_CAST(const _RopeLeaf*, __leaf)->_M_data;

     __x._M_buf_ptr = __x._M_buf_start + (__pos - __leaf_pos);

     __x._M_buf_end = __x._M_buf_start + __leaf->_M_size._M_data;

     break;

   case _RopeRep::_S_function:

   case _RopeRep::_S_substringfn:

     {

       size_t __len = _S_iterator_buf_len;

       size_t __buf_start_pos = __leaf_pos;

       size_t __leaf_end = __leaf_pos + __leaf->_M_size._M_data;

       typedef _Rope_RopeFunction<_CharT, _Alloc> _RopeFunction;

       char_producer<_CharT>* __fn = __STATIC_CAST(const _RopeFunction*, __leaf)->_M_fn;

       if (__buf_start_pos + __len <= __pos) {

         __buf_start_pos = __pos - __len/4;

         if (__buf_start_pos + __len > __leaf_end) {

           __buf_start_pos = __leaf_end - __len;

         }

       }

       if (__buf_start_pos + __len > __leaf_end) {

         __len = __leaf_end - __buf_start_pos;

       }

       (*__fn)(__buf_start_pos - __leaf_pos, __len, __x._M_tmp_buf._M_data);

       __x._M_buf_ptr = __x._M_tmp_buf._M_data + (__pos - __buf_start_pos);

       __x._M_buf_start = __x._M_tmp_buf._M_data;

       __x._M_buf_end = __x._M_tmp_buf._M_data + __len;

     }

     break;

   default:

       _STLP_ASSERT(0)

       ;

   }

 }

 // Set path and buffer inside a rope iterator.  We assume that

 // pos and root are already set.

 template <class _CharT, class _Alloc>

 void _Rope_iterator_base<_CharT,_Alloc>::_S_setcache(

   _Rope_iterator_base<_CharT,_Alloc>& __x) {

   const _RopeRep* __path[_RopeRep::_S_max_rope_depth+1];

   const _RopeRep* __curr_rope;

   int __curr_depth = -1;  /* index into path    */

   size_t __curr_start_pos = 0;

   size_t __pos = __x._M_current_pos;

   unsigned char __dirns = 0; // Bit vector marking right turns in the path

   _STLP_ASSERT(__pos <= __x._M_root->_M_size._M_data)

   if (__pos >= __x._M_root->_M_size._M_data) {

     __x._M_buf_ptr = 0;

     return;

   }

   __curr_rope = __x._M_root;

   if (0 != __curr_rope->_M_c_string) {

     /* Treat the root as a leaf. */

     __x._M_buf_start = __curr_rope->_M_c_string;

     __x._M_buf_end = __curr_rope->_M_c_string + __curr_rope->_M_size._M_data;

     __x._M_buf_ptr = __curr_rope->_M_c_string + __pos;

     __x._M_path_end._M_data[0] = __curr_rope;

     __x._M_leaf_index = 0;

     __x._M_leaf_pos = 0;

     return;

   }

   for(;;) {

     ++__curr_depth;

     _STLP_ASSERT(__curr_depth <= _RopeRep::_S_max_rope_depth)

     __path[__curr_depth] = __curr_rope;

     switch(__curr_rope->_M_tag) {

     case _RopeRep::_S_leaf:

     case _RopeRep::_S_function:

     case _RopeRep::_S_substringfn:

       __x._M_leaf_pos = __curr_start_pos;

       goto done;

     case _RopeRep::_S_concat:

       {

         const _RopeConcat* __c = __STATIC_CAST(const _RopeConcat*, __curr_rope);

         _RopeRep* __left = __c->_M_left;

         size_t __left_len = __left->_M_size._M_data;

         __dirns <<= 1;

         if (__pos >= __curr_start_pos + __left_len) {

           __dirns |= 1;

           __curr_rope = __c->_M_right;

           __curr_start_pos += __left_len;

         } else {

           __curr_rope = __left;

         }

       }

       break;

     }

   }

 done:

     // Copy last section of path into _M_path_end.

   {

     int __i = -1;

     int __j = __curr_depth + 1 - _S_path_cache_len;

     if (__j < 0) __j = 0;

     while (__j <= __curr_depth) {

       __x._M_path_end._M_data[++__i] = __path[__j++];

     }

     __x._M_leaf_index = __i;

   }

   __x._M_path_directions = __dirns;

   _S_setbuf(__x);

 }

 // Specialized version of the above.  Assumes that

 // the path cache is valid for the previous position.

 template <class _CharT, class _Alloc>

 void _Rope_iterator_base<_CharT,_Alloc>::_S_setcache_for_incr(

 _Rope_iterator_base<_CharT,_Alloc>& __x) {

   int __current_index = __x._M_leaf_index;

   const _RopeRep* __current_node = __x._M_path_end._M_data[__current_index];

   size_t __len = __current_node->_M_size._M_data;

   size_t __node_start_pos = __x._M_leaf_pos;

   unsigned char __dirns = __x._M_path_directions;

   const _RopeConcat* __c;

   _STLP_ASSERT(__x._M_current_pos <= __x._M_root->_M_size._M_data)

   if (__x._M_current_pos - __node_start_pos < __len) {

     /* More stuff in this leaf, we just didn't cache it. */

     _S_setbuf(__x);

     return;

   }

   _STLP_ASSERT(__node_start_pos + __len == __x._M_current_pos)

     //  node_start_pos is starting position of last_node.

   while (--__current_index >= 0) {

     if (!(__dirns & 1) /* Path turned left */)

       break;

     __current_node = __x._M_path_end._M_data[__current_index];

     __c = __STATIC_CAST(const _RopeConcat*, __current_node);

     // Otherwise we were in the right child.  Thus we should pop

     // the concatenation node.

     __node_start_pos -= __c->_M_left->_M_size._M_data;

     __dirns >>= 1;

   }

   if (__current_index < 0) {

     // We underflowed the cache. Punt.

     _S_setcache(__x);

     return;

   }

   __current_node = __x._M_path_end._M_data[__current_index];

   __c = __STATIC_CAST(const _RopeConcat*, __current_node);

   // current_node is a concatenation node.  We are positioned on the first

   // character in its right child.

   // node_start_pos is starting position of current_node.

   __node_start_pos += __c->_M_left->_M_size._M_data;

   __current_node = __c->_M_right;

   __x._M_path_end._M_data[++__current_index] = __current_node;

   __dirns |= 1;

   while (_RopeRep::_S_concat == __current_node->_M_tag) {

     ++__current_index;

     if (_S_path_cache_len == __current_index) {

       int __i;

       for (__i = 0; __i < _S_path_cache_len-1; ++__i) {

         __x._M_path_end._M_data[__i] = __x._M_path_end._M_data[__i+1];

       }

       --__current_index;

     }

     __current_node = __STATIC_CAST(const _RopeConcat*, __current_node)->_M_left;

     __x._M_path_end._M_data[__current_index] = __current_node;

     __dirns <<= 1;

     // node_start_pos is unchanged.

   }

   __x._M_leaf_index = __current_index;

   __x._M_leaf_pos = __node_start_pos;

   __x._M_path_directions = __dirns;

   _S_setbuf(__x);

 }

 template <class _CharT, class _Alloc>

 void _Rope_iterator_base<_CharT,_Alloc>::_M_incr(size_t __n) {

   _M_current_pos += __n;

   if (0 != _M_buf_ptr) {

     size_t __chars_left = _M_buf_end - _M_buf_ptr;

     if (__chars_left > __n) {

       _M_buf_ptr += __n;

     } else if (__chars_left == __n) {

       _M_buf_ptr += __n;

       _S_setcache_for_incr(*this);

     } else {

       _M_buf_ptr = 0;

     }

   }

 }

 template <class _CharT, class _Alloc>

 void _Rope_iterator_base<_CharT,_Alloc>::_M_decr(size_t __n) {

   if (0 != _M_buf_ptr) {

     size_t __chars_left = _M_buf_ptr - _M_buf_start;

     if (__chars_left >= __n) {

       _M_buf_ptr -= __n;

     } else {

       _M_buf_ptr = 0;

     }

   }

   _M_current_pos -= __n;

 }

 template <class _CharT, class _Alloc>

 void _Rope_iterator<_CharT,_Alloc>::_M_check() {

   if (_M_root_rope->_M_tree_ptr._M_data != this->_M_root) {

     // _Rope was modified.  Get things fixed up.

     _RopeRep::_S_unref(this->_M_root);

     this->_M_root = _M_root_rope->_M_tree_ptr._M_data;

     _RopeRep::_S_ref(this->_M_root);

     this->_M_buf_ptr = 0;

   }

 }

 //  There are several reasons for not doing this with virtual destructors

 //  and a class specific delete operator:

 //  - A class specific delete operator can't easily get access to

 //    allocator instances if we need them.

 //  - Any virtual function would need a 4 or byte vtable pointer;

 //    this only requires a one byte tag per object.

 template <class _CharT, class _Alloc>

 void _Rope_RopeRep<_CharT,_Alloc>::_M_free_tree() {

   switch (_M_tag) {

   case _S_leaf:

     {

       typedef _Rope_RopeLeaf<_CharT, _Alloc> _RopeLeaf;

       _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, this);

       _STLP_STD::_Destroy(__l); // ->_Rope_RopeLeaf<_CharT,_Alloc>::~_Rope_RopeLeaf();

       _STLP_CREATE_ALLOCATOR(allocator_type,(const allocator_type&)_M_size,

                              _RopeLeaf).deallocate(__l, 1);

       break;

     }

   case _S_concat:

     {

       typedef _Rope_RopeConcatenation<_CharT, _Alloc> _RopeConcatenation;

       _RopeConcatenation* __c  = __STATIC_CAST(_RopeConcatenation*, this);

       _STLP_STD::_Destroy(__c);

       _STLP_CREATE_ALLOCATOR(allocator_type,(const allocator_type&)_M_size,

                              _RopeConcatenation).deallocate(__c, 1);

       break;

     }

   case _S_function:

     {

       typedef _Rope_RopeFunction<_CharT, _Alloc> _RopeFunction;

       _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, this);

       _STLP_STD::_Destroy(__f);

       _STLP_CREATE_ALLOCATOR(allocator_type, (const allocator_type&)_M_size,

                              _RopeFunction).deallocate(__f, 1);

       break;

     }

   case _S_substringfn:

     {

       typedef _Rope_RopeSubstring<_CharT, _Alloc> _RopeSubstring;

       _RopeSubstring* __rss = __STATIC_CAST(_RopeSubstring*, this);

       _STLP_STD::_Destroy(__rss);

       _STLP_CREATE_ALLOCATOR(allocator_type, (const allocator_type&)_M_size,

                              _RopeSubstring).deallocate(__rss, 1);

       break;

     }

   }

 }

 # if defined ( _STLP_NESTED_TYPE_PARAM_BUG )

 #   define __RopeLeaf__ _Rope_RopeLeaf<_CharT,_Alloc>

 #   define __RopeRep__ _Rope_RopeRep<_CharT,_Alloc>

 #   define _RopeLeaf _Rope_RopeLeaf<_CharT,_Alloc>

 #   define _RopeRep _Rope_RopeRep<_CharT,_Alloc>

 #   define size_type size_t

 # else

 #   define __RopeLeaf__ _STLP_TYPENAME_ON_RETURN_TYPE rope<_CharT,_Alloc>::_RopeLeaf

 #   define __RopeRep__ _STLP_TYPENAME_ON_RETURN_TYPE rope<_CharT,_Alloc>::_RopeRep

 # endif

 template <class _CharT, class _Alloc>

 void rope<_CharT, _Alloc>::_M_throw_out_of_range() const {

   __stl_throw_out_of_range("rope");

 }

 // Concatenate a C string onto a leaf rope by copying the rope data.

 // Used for short ropes.

 template <class _CharT, class _Alloc>

 __RopeLeaf__*

 rope<_CharT,_Alloc>::_S_leaf_concat_char_iter (

   _RopeLeaf* __r, const _CharT* __iter, size_t __len) {

   size_t __old_len = __r->_M_size._M_data;

   _CharT* __new_data = __r->_M_size.allocate(_S_rounded_up_size(__old_len + __len));

   _RopeLeaf* __result;

   _STLP_PRIV __ucopy_n(__r->_M_data, __old_len, __new_data);

   _STLP_PRIV __ucopy_n(__iter, __len, __new_data + __old_len);

   _S_construct_null(__new_data + __old_len + __len);

   _STLP_TRY {

     __result = _S_new_RopeLeaf(__new_data, __old_len + __len, __r->get_allocator());

   }

   _STLP_UNWIND(_RopeRep::_S_free_string(__new_data, __old_len + __len,

                                         __r->get_allocator()))

   return __result;

 }

 template <class _CharT, class _Alloc>

 void _Terminate_RopeLeaf(_Rope_RopeLeaf<_CharT,_Alloc> *__r,

                          size_t __size, const __true_type& /*basic char type*/) {

   _S_construct_null(__r->_M_data + __size);

   _STLP_ASSERT(__r->_M_c_string == __r->_M_data)

 }

 template <class _CharT, class _Alloc>

 void _Terminate_RopeLeaf(_Rope_RopeLeaf<_CharT,_Alloc> *__r,

                          size_t, const __false_type& /*basic char type*/) {

   if (__r->_M_c_string != __r->_M_data && 0 != __r->_M_c_string) {

     __r->_M_free_c_string();

     __r->_M_c_string = 0;

   }

 }

 // As above, but it's OK to clobber original if refcount is 1

 template <class _CharT, class _Alloc>

 __RopeLeaf__*

 rope<_CharT,_Alloc>::_S_destr_leaf_concat_char_iter (_RopeLeaf* __r, const _CharT* __iter, size_t __len) {

   //_STLP_ASSERT(__r->_M_ref_count >= 1)

   if ( /* __r->_M_ref_count > 1 */  __r->_M_incr() > 2 ) { // - ptr

     __r->_M_decr(); // - ptr

     return _S_leaf_concat_char_iter(__r, __iter, __len);

   }

   __r->_M_decr(); // - ptr, __r->_M_ref_count == 1 or 0

   size_t __old_len = __r->_M_size._M_data;

   if (_S_rounded_up_size(__old_len) == _S_rounded_up_size(__old_len + __len)) {

     // The space has been partially initialized for the standard

     // character types.  But that doesn't matter for those types.

     _STLP_PRIV __ucopy_n(__iter, __len, __r->_M_data + __old_len);

     _Terminate_RopeLeaf(__r, __old_len + __len, _IsBasicCharType());

     __r->_M_size._M_data = __old_len + __len;

     // _STLP_ASSERT(__r->_M_ref_count == 1)

     // __r->_M_ref_count = 2;

     __r->_M_incr(); // i.e.  __r->_M_ref_count = 2

     return __r;

   } else {

     _RopeLeaf* __result = _S_leaf_concat_char_iter(__r, __iter, __len);

     //_STLP_ASSERT(__result->_M_ref_count == 1)

     return __result;

   }

 }

 // Assumes left and right are not 0.

 // Does not increment (nor decrement on exception) child reference counts.

 // Result has ref count 1.

 template <class _CharT, class _Alloc>

 __RopeRep__*

 rope<_CharT,_Alloc>::_S_tree_concat (_RopeRep* __left, _RopeRep* __right) {

   _RopeConcatenation* __result =

     _S_new_RopeConcatenation(__left, __right, __left->get_allocator());

   size_t __depth = __result->_M_depth;

   _STLP_ASSERT(__left->get_allocator() == __right->get_allocator())

   if (__depth > 20 && (__result->_M_size._M_data < 1000 ||

       __depth > _RopeRep::_S_max_rope_depth)) {

     _RopeRep* __balanced;

     _STLP_TRY {

       __balanced = _S_balance(__result);

      // _STLP_ASSERT(__result == __balanced ||

      //              1 == __result->_M_ref_count &&

      //              1 == __balanced->_M_ref_count)

       __result->_M_unref_nonnil();

     }

     _STLP_UNWIND((_STLP_CREATE_ALLOCATOR(allocator_type,(allocator_type&)__left->_M_size,

                                          _RopeConcatenation).deallocate(__result,1)))

     // In case of exception, we need to deallocate

     // otherwise dangling result node.  But caller

     // still owns its children.  Thus unref is

     // inappropriate.

     return __balanced;

   } else {

     return __result;

   }

 }

 template <class _CharT, class _Alloc>

 __RopeRep__*

 rope<_CharT,_Alloc>::_S_concat_char_iter (_RopeRep* __r,

                                           const _CharT*__s, size_t __slen) {

   _RopeRep* __result;

   if (0 == __slen) {

     _S_ref(__r);

     return __r;

   }

   if (0 == __r)

     return _S_RopeLeaf_from_unowned_char_ptr(__s, __slen, __r->get_allocator());

   if (_RopeRep::_S_leaf == __r->_M_tag &&

       __r->_M_size._M_data + __slen <= _S_copy_max) {

     __result = _S_leaf_concat_char_iter((_RopeLeaf*)__r, __s, __slen);

     // _STLP_ASSERT(1 == __result->_M_ref_count)

     return __result;

   }

   if (_RopeRep::_S_concat == __r->_M_tag &&

       _RopeRep::_S_leaf == ((_RopeConcatenation*)__r)->_M_right->_M_tag) {

     _RopeLeaf* __right = (_RopeLeaf* )(((_RopeConcatenation* )__r)->_M_right);

     if (__right->_M_size._M_data + __slen <= _S_copy_max) {

       _RopeRep* __left = ((_RopeConcatenation*)__r)->_M_left;

       _RopeRep* __nright = _S_leaf_concat_char_iter((_RopeLeaf*)__right, __s, __slen);

       __left->_M_ref_nonnil();

       _STLP_TRY {

         __result = _S_tree_concat(__left, __nright);

       }

       _STLP_UNWIND(_S_unref(__left); _S_unref(__nright))

       // _STLP_ASSERT(1 == __result->_M_ref_count)

       return __result;

     }

   }

   _RopeRep* __nright =

     _S_RopeLeaf_from_unowned_char_ptr(__s, __slen, __r->get_allocator());

   _STLP_TRY {

     __r->_M_ref_nonnil();

     __result = _S_tree_concat(__r, __nright);

   }

   _STLP_UNWIND(_S_unref(__r); _S_unref(__nright))

   // _STLP_ASSERT(1 == __result->_M_ref_count)

   return __result;

 }

 template <class _CharT, class _Alloc>

 __RopeRep__*

 rope<_CharT,_Alloc>::_S_destr_concat_char_iter(

   _RopeRep* __r, const _CharT* __s, size_t __slen) {

   _RopeRep* __result;

   if (0 == __r)

     return _S_RopeLeaf_from_unowned_char_ptr(__s, __slen,

                                              __r->get_allocator());

   // size_t __count = __r->_M_ref_count;

   size_t __orig_size = __r->_M_size._M_data;

   // _STLP_ASSERT(__count >= 1)

   if ( /* __count > 1 */ __r->_M_incr() > 2 ) {

     __r->_M_decr();

     return _S_concat_char_iter(__r, __s, __slen);

   }

   if (0 == __slen) {

     return __r;

   }

   __r->_M_decr();

   if (__orig_size + __slen <= _S_copy_max && _RopeRep::_S_leaf == __r->_M_tag) {

     return _S_destr_leaf_concat_char_iter((_RopeLeaf*)__r, __s, __slen);

   }

   if (_RopeRep::_S_concat == __r->_M_tag) {

     _RopeLeaf* __right = __STATIC_CAST(_RopeLeaf*, __STATIC_CAST(_RopeConcatenation*, __r)->_M_right);

     if (_RopeRep::_S_leaf == __right->_M_tag &&

         __right->_M_size._M_data + __slen <= _S_copy_max) {

       _RopeRep* __new_right = _S_destr_leaf_concat_char_iter(__right, __s, __slen);

       if (__right == __new_right) {

         // _STLP_ASSERT(__new_right->_M_ref_count == 2)

         // __new_right->_M_ref_count = 1;

         __new_right->_M_decr();

       } else {

         // _STLP_ASSERT(__new_right->_M_ref_count >= 1)

         __right->_M_unref_nonnil();

       }

       // _STLP_ASSERT(__r->_M_ref_count == 1)

       // __r->_M_ref_count = 2;    // One more than before.

       __r->_M_incr();

       __STATIC_CAST(_RopeConcatenation*, __r)->_M_right = __new_right;

       // E.Musser : moved below

       //    __r->_M_size._M_data = __orig_size + __slen;

       if (0 != __r->_M_c_string) {

         __r->_M_free_c_string();

         __r->_M_c_string = 0;

       }

       __r->_M_size._M_data = __orig_size + __slen;

       return __r;

     }

   }

   _RopeRep* __right =

     _S_RopeLeaf_from_unowned_char_ptr(__s, __slen, __r->get_allocator());

   __r->_M_ref_nonnil();

   _STLP_TRY {

     __result = _S_tree_concat(__r, __right);

   }

   _STLP_UNWIND(_S_unref(__r); _S_unref(__right))

     // _STLP_ASSERT(1 == __result->_M_ref_count)

   return __result;

 }

 template <class _CharT, class _Alloc>

 __RopeRep__*

 rope<_CharT,_Alloc>::_S_concat_rep(_RopeRep* __left, _RopeRep* __right) {

   if (0 == __left) {

     _S_ref(__right);

     return __right;

   }

   if (0 == __right) {

     __left->_M_ref_nonnil();

     return __left;

   }

   if (_RopeRep::_S_leaf == __right->_M_tag) {

     if (_RopeRep::_S_leaf == __left->_M_tag) {

       if (__right->_M_size._M_data + __left->_M_size._M_data <= _S_copy_max) {

         return _S_leaf_concat_char_iter(__STATIC_CAST(_RopeLeaf*, __left),

                                         __STATIC_CAST(_RopeLeaf*, __right)->_M_data,

                                         __right->_M_size._M_data);

       }

     } else if (_RopeRep::_S_concat == __left->_M_tag &&

                _RopeRep::_S_leaf == __STATIC_CAST(_RopeConcatenation*, __left)->_M_right->_M_tag) {

       _RopeLeaf* __leftright =

         __STATIC_CAST(_RopeLeaf*, __STATIC_CAST(_RopeConcatenation*, __left)->_M_right);

       if (__leftright->_M_size._M_data + __right->_M_size._M_data <= _S_copy_max) {

         _RopeRep* __leftleft = __STATIC_CAST(_RopeConcatenation*, __left)->_M_left;

         _RopeRep* __rest = _S_leaf_concat_char_iter(__leftright,

                                                     __STATIC_CAST(_RopeLeaf*, __right)->_M_data,

                                                     __right->_M_size._M_data);

         __leftleft->_M_ref_nonnil();

         _STLP_TRY {

           return _S_tree_concat(__leftleft, __rest);

         }

         _STLP_UNWIND(_S_unref(__leftleft); _S_unref(__rest))

       }

     }

   }

   __left->_M_ref_nonnil();

   __right->_M_ref_nonnil();

   _STLP_TRY {

     return _S_tree_concat(__left, __right);

   }

   _STLP_UNWIND(_S_unref(__left); _S_unref(__right))

   _STLP_RET_AFTER_THROW(0)

 }

 template <class _CharT, class _Alloc>

 __RopeRep__*

 rope<_CharT,_Alloc>::_S_substring(_RopeRep* __base,

                                   size_t __start, size_t __endp1) {

   if (0 == __base) return 0;

   size_t __len = __base->_M_size._M_data;

   size_t __adj_endp1;

   const size_t __lazy_threshold = 128;

   if (__endp1 >= __len) {

     if (0 == __start) {

       __base->_M_ref_nonnil();

       return __base;

     } else {

       __adj_endp1 = __len;

     }

   } else {

     __adj_endp1 = __endp1;

   }

   switch(__base->_M_tag) {

   case _RopeRep::_S_concat:

   {

     _RopeConcatenation* __c = __STATIC_CAST(_RopeConcatenation*, __base);

     _RopeRep* __left = __c->_M_left;

     _RopeRep* __right = __c->_M_right;

     size_t __left_len = __left->_M_size._M_data;

     _RopeRep* __result;

     if (__adj_endp1 <= __left_len) {

       return _S_substring(__left, __start, __endp1);

     } else if (__start >= __left_len) {

       return _S_substring(__right, __start - __left_len,

                           __adj_endp1 - __left_len);

     }

     _Self_destruct_ptr __left_result(_S_substring(__left, __start, __left_len));

     _Self_destruct_ptr __right_result(_S_substring(__right, 0, __endp1 - __left_len));

     _STLP_MPWFIX_TRY    //*TY 06/01/2000 - mpw forgets to call dtor on __left_result and __right_result without this try block

     __result = _S_concat_rep(__left_result, __right_result);

     // _STLP_ASSERT(1 == __result->_M_ref_count)

     return __result;

     _STLP_MPWFIX_CATCH    //*TY 06/01/2000 -

   }

   case _RopeRep::_S_leaf:

   {

     _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, __base);

     _RopeLeaf* __result;

     size_t __result_len;

     if (__start >= __adj_endp1) return 0;

     __result_len = __adj_endp1 - __start;

     if (__result_len > __lazy_threshold) goto lazy;

     const _CharT* __section = __l->_M_data + __start;

     // We should sometimes create substring node instead.

     __result = _S_RopeLeaf_from_unowned_char_ptr(__section, __result_len,

                                                  __base->get_allocator());

     return __result;

   }

   case _RopeRep::_S_substringfn:

   // Avoid introducing multiple layers of substring nodes.

   {

     _RopeSubstring* __old = __STATIC_CAST(_RopeSubstring*, __base);

     size_t __result_len;

     if (__start >= __adj_endp1) return 0;

     __result_len = __adj_endp1 - __start;

     if (__result_len > __lazy_threshold) {

       _RopeSubstring* __result = _S_new_RopeSubstring(__old->_M_base,

                                                       __start + __old->_M_start,

                                                       __adj_endp1 - __start,

                                                       __base->get_allocator());

       return __result;

     } // *** else fall through: ***

   }

   case _RopeRep::_S_function:

   {

     _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, __base);

     if (__start >= __adj_endp1) return 0;

     size_t __result_len = __adj_endp1 - __start;

     if (__result_len > __lazy_threshold) goto lazy;

     _CharT* __section = __base->_M_size.allocate(_S_rounded_up_size(__result_len));

     _STLP_TRY {

       (*(__f->_M_fn))(__start, __result_len, __section);

     }

     _STLP_UNWIND(_RopeRep::_S_free_string(__section,

                                           __result_len, __base->get_allocator()))

     _S_construct_null(__section + __result_len);

     return _S_new_RopeLeaf(__section, __result_len,

                            __base->get_allocator());

   }

   }

   /*NOTREACHED*/

   _STLP_ASSERT(false)

   lazy:

   {

     // Create substring node.

     return _S_new_RopeSubstring(__base, __start, __adj_endp1 - __start,

                                 __base->get_allocator());

   }

 }

 template<class _CharT>

 class _Rope_flatten_char_consumer : public _Rope_char_consumer<_CharT> {

 private:

   _CharT* _M_buf_ptr;

 public:

   _Rope_flatten_char_consumer(_CharT* __buffer) {

     _M_buf_ptr = __buffer;

   }

   ~_Rope_flatten_char_consumer() {}

   bool operator() (const _CharT* __leaf, size_t __n) {

     _STLP_PRIV __ucopy_n(__leaf, __n, _M_buf_ptr);

     _M_buf_ptr += __n;

     return true;

   }

 };

 template<class _CharT>

 class _Rope_find_char_char_consumer : public _Rope_char_consumer<_CharT> {

 private:

   _CharT _M_pattern;

 public:

   size_t _M_count;  // Number of nonmatching characters

   _Rope_find_char_char_consumer(_CharT __p)

     : _M_pattern(__p), _M_count(0) {}

   ~_Rope_find_char_char_consumer() {}

   bool operator() (const _CharT* __leaf, size_t __n) {

     size_t __i;

     for (__i = 0; __i < __n; ++__i) {

       if (__leaf[__i] == _M_pattern) {

         _M_count += __i; return false;

       }

     }

     _M_count += __n; return true;

   }

 };

 #if !defined (_STLP_USE_NO_IOSTREAMS)

 template<class _CharT, class _Traits>

 // Here _CharT is both the stream and rope character type.

 class _Rope_insert_char_consumer : public _Rope_char_consumer<_CharT> {

 private:

   typedef basic_ostream<_CharT,_Traits> _Insert_ostream;

   typedef _Rope_insert_char_consumer<_CharT,_Traits> _Self;

   _Insert_ostream& _M_o;

   //explicitely defined as private to avoid warnings:

   _Self& operator = (_Self const&);

 public:

   _Rope_insert_char_consumer(_Insert_ostream& __writer)

     : _M_o(__writer) {}

 #  if defined(__MRC__) || (defined(__SC__) && !defined(__DMC__))  //*TY 05/23/2000 - added support for mpw compiler's trigger function approach to generate vtable

   ~_Rope_insert_char_consumer();    //*TY 05/23/2000 -

 #  else    //*TY 05/23/2000 -

   ~_Rope_insert_char_consumer() {}

 #  endif    //*TY 05/23/2000 -

   // Caller is presumed to own the ostream

   bool operator() (const _CharT* __leaf, size_t __n);

   // Returns true to continue traversal.

 };

 #  if defined (__MRC__) || (defined (__SC__) && !defined (__DMC__))    //*TY 05/23/2000 - added support for mpw compiler's trigger function approach to generate vtable

 template<class _CharT, class _Traits>

 _Rope_insert_char_consumer<_CharT, _Traits>::  ~_Rope_insert_char_consumer() {}

 #  endif    //*TY 05/23/2000 -

 template<class _CharT, class _Traits>

 bool _Rope_insert_char_consumer<_CharT, _Traits>::operator()

   (const _CharT* __leaf, size_t __n) {

   size_t __i;

   //  We assume that formatting is set up correctly for each element.

   for (__i = 0; __i < __n; ++__i) _M_o.put(__leaf[__i]);

   return true;

 }

 #endif /* !_STLP_USE_NO_IOSTREAMS */

 template <class _CharT, class _Alloc, class _CharConsumer>

 bool _S_apply_to_pieces(_CharConsumer& __c,

                         _Rope_RopeRep<_CharT, _Alloc> * __r,

                         size_t __begin, size_t __end) {

   typedef _Rope_RopeRep<_CharT, _Alloc> _RopeRep;

   typedef _Rope_RopeConcatenation<_CharT,_Alloc> _RopeConcatenation;

   typedef _Rope_RopeLeaf<_CharT,_Alloc> _RopeLeaf;

   typedef _Rope_RopeFunction<_CharT,_Alloc> _RopeFunction;

   if (0 == __r) return true;

   switch(__r->_M_tag) {

   case _RopeRep::_S_concat:

   {

     _RopeConcatenation* __conc = __STATIC_CAST(_RopeConcatenation*, __r);

     _RopeRep* __left =  __conc->_M_left;

     size_t __left_len = __left->_M_size._M_data;

     if (__begin < __left_len) {

       size_t __left_end = (min) (__left_len, __end);

       if (!_S_apply_to_pieces(__c, __left, __begin, __left_end))

         return false;

     }

     if (__end > __left_len) {

       _RopeRep* __right =  __conc->_M_right;

       size_t __right_start = (max)(__left_len, __begin);

       if (!_S_apply_to_pieces(__c, __right,

                               __right_start - __left_len,

                               __end - __left_len)) {

         return false;

       }

     }

   }

   return true;

   case _RopeRep::_S_leaf:

   {

     _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, __r);

     return __c(__l->_M_data + __begin, __end - __begin);

   }

   case _RopeRep::_S_function:

   case _RopeRep::_S_substringfn:

   {

     _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, __r);

     size_t __len = __end - __begin;

     bool __result;

     _CharT* __buffer = __r->get_allocator().allocate(__len);

     _STLP_TRY {

       (*(__f->_M_fn))(__begin, __len, __buffer);

       __result = __c(__buffer, __len);

       __r->get_allocator().deallocate(__buffer, __len);

     }

     _STLP_UNWIND((__r->get_allocator().deallocate(__buffer, __len)))

     return __result;

   }

   default:

     _STLP_ASSERT(false)

     /*NOTREACHED*/

     return false;

   }

 }

 #if !defined (_STLP_USE_NO_IOSTREAMS)

 template<class _CharT, class _Traits>

 inline void _Rope_fill(basic_ostream<_CharT, _Traits>& __o, streamsize __n) {

   char __f = __o.fill();

   for (streamsize __i = 0; __i < __n; ++__i) __o.put(__f);

 }

 template<class _CharT, class _Traits, class _Alloc>

 basic_ostream<_CharT, _Traits>& _S_io_get(basic_ostream<_CharT, _Traits>& __o,

                                           const rope<_CharT, _Alloc>& __r, const __true_type& /*_IsBasicCharType*/) {

   streamsize __w = __o.width();

   const bool __left = (__o.flags() & ios::left) != 0;

   size_t __rope_len = __r.size();

   _Rope_insert_char_consumer<_CharT, _Traits> __c(__o);

   const bool __need_pad = (((sizeof(streamsize) > sizeof(size_t)) && (__STATIC_CAST(streamsize, __rope_len) < __w)) ||

                            ((sizeof(streamsize) <= sizeof(size_t)) && (__rope_len < __STATIC_CAST(size_t, __w))));

   streamsize __pad_len = __need_pad ? __w - __rope_len : 0;

   if (!__left && __pad_len > 0) {

     _Rope_fill(__o, __pad_len);

   }

   __r.apply_to_pieces(0, __rope_len, __c);

   if (__left && __pad_len > 0) {

     _Rope_fill(__o, __pad_len);

   }

   return __o;

 }

 template<class _CharT, class _Traits, class _Alloc>

 basic_ostream<_CharT, _Traits>& _S_io_get(basic_ostream<_CharT, _Traits>& __o,

                                          const rope<_CharT, _Alloc>& __r, const __false_type& /*_IsBasicCharType*/) {

   streamsize __w = __o.width();

   size_t __rope_len = __r.size();

   _Rope_insert_char_consumer<_CharT, _Traits> __c(__o);

   __o.width(__w /__rope_len);

   _STLP_TRY {

     __r.apply_to_pieces(0, __rope_len, __c);

     __o.width(__w);

   }

   _STLP_UNWIND(__o.width(__w))

   return __o;

 }

 template<class _CharT, class _Traits, class _Alloc>

 basic_ostream<_CharT, _Traits>& operator<<(basic_ostream<_CharT, _Traits>& __o,

                                            const rope<_CharT, _Alloc>& __r) {

   typedef typename _IsIntegral<_CharT>::_Ret _Char_Is_Integral;

   return _S_io_get(__o, __r, _Char_Is_Integral());

 }

 #endif /* NO_IOSTREAMS */

 template <class _CharT, class _Alloc>

 _CharT* rope<_CharT,_Alloc>::_S_flatten(_RopeRep* __r,

                                         size_t __start, size_t __len,

                                         _CharT* __buffer) {

   _Rope_flatten_char_consumer<_CharT> __c(__buffer);

   _S_apply_to_pieces(__c, __r, __start, __start + __len);

   return(__buffer + __len);

 }

 template <class _CharT, class _Alloc>

 size_t rope<_CharT,_Alloc>::find(_CharT __pattern, size_t __start) const {

   _Rope_find_char_char_consumer<_CharT> __c(__pattern);

   _S_apply_to_pieces(__c, _M_tree_ptr._M_data, __start, size());

   size_type __result_pos = __start + __c._M_count;

 #ifndef _STLP_OLD_ROPE_SEMANTICS

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

 #endif

   return __result_pos;

 }

 template <class _CharT, class _Alloc>

 _CharT*

 rope<_CharT,_Alloc>::_S_flatten(_Rope_RopeRep<_CharT, _Alloc>* __r, _CharT* __buffer) {

   if (0 == __r) return __buffer;

   switch(__r->_M_tag) {

   case _RopeRep::_S_concat:

   {

     _RopeConcatenation* __c = __STATIC_CAST(_RopeConcatenation*, __r);

     _RopeRep* __left = __c->_M_left;

     _RopeRep* __right = __c->_M_right;

     _CharT* __rest = _S_flatten(__left, __buffer);

     return _S_flatten(__right, __rest);

   }

   case _RopeRep::_S_leaf:

   {

     _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, __r);

     return _STLP_PRIV __ucopy_n(__l->_M_data, __l->_M_size._M_data, __buffer).second;

   }

   case _RopeRep::_S_function:

   case _RopeRep::_S_substringfn:

   // We dont yet do anything with substring nodes.

   // This needs to be fixed before ropefiles will work well.

   {

     _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, __r);

     (*(__f->_M_fn))(0, __f->_M_size._M_data, __buffer);

     return __buffer + __f->_M_size._M_data;

   }

   default:

     _STLP_ASSERT(false)

     /*NOTREACHED*/

     return 0;

   }

 }

 #ifdef _STLP_DEBUG

 // This needs work for _CharT != char

 template <class _CharT, class _Alloc>

 void rope<_CharT,_Alloc>::_S_dump(_RopeRep* __r, int __indent) {

   for (int __i = 0; __i < __indent; ++__i) putchar(' ');

   if (0 == __r) {

     printf("NULL\n"); return;

   }

   if (_RopeRep::_S_concat == __r->_M_tag) {

     _RopeConcatenation* __c = __STATIC_CAST(_RopeConcatenation*, __r);

     _RopeRep* __left = __c->_M_left;

     _RopeRep* __right = __c->_M_right;

     printf("Concatenation %p (rc = %ld, depth = %d, len = %ld, %s balanced)\n",

       __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size._M_data,

       __r->_M_is_balanced? "" : "not");

     _S_dump(__left, __indent + 2);

     _S_dump(__right, __indent + 2);

     return;

   }

   else {

     const char* __kind;

     switch (__r->_M_tag) {

       case _RopeRep::_S_leaf:

         __kind = "Leaf";

         break;

       case _RopeRep::_S_function:

         __kind = "Function";

         break;

       case _RopeRep::_S_substringfn:

         __kind = "Function representing substring";

         break;

       default:

         __kind = "(corrupted kind field!)";

     }

     printf("%s %p (rc = %ld, depth = %d, len = %ld) ",

      __kind, __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size._M_data);

     if (sizeof(_CharT) == 1) {

       const int __max_len = 40;

       _Self_destruct_ptr __prefix(_S_substring(__r, 0, __max_len));

       _CharT __buffer[__max_len + 1];

       bool __too_big = __r->_M_size._M_data > __prefix->_M_size._M_data;

       _S_flatten(__prefix, __buffer);

       __buffer[__prefix->_M_size._M_data] = _STLP_DEFAULT_CONSTRUCTED(_CharT);

       printf("%s%s\n", (char*)__buffer, __too_big? "...\n" : "\n");

     } else {

       printf("\n");

     }

   }

 }

 #endif /* _STLP_DEBUG */

 # define __ROPE_TABLE_BODY  = { \

 /* 0 */1, /* 1 */2, /* 2 */3, /* 3 */5, /* 4 */8, /* 5 */13, /* 6 */21,         \

 /* 7 */34, /* 8 */55, /* 9 */89, /* 10 */144, /* 11 */233, /* 12 */377,         \

 /* 13 */610, /* 14 */987, /* 15 */1597, /* 16 */2584, /* 17 */4181,             \

 /* 18 */6765ul, /* 19 */10946ul, /* 20 */17711ul, /* 21 */28657ul, /* 22 */46368ul,   \

 /* 23 */75025ul, /* 24 */121393ul, /* 25 */196418ul, /* 26 */317811ul,                \

 /* 27 */514229ul, /* 28 */832040ul, /* 29 */1346269ul, /* 30 */2178309ul,             \

 /* 31 */3524578ul, /* 32 */5702887ul, /* 33 */9227465ul, /* 34 */14930352ul,          \

 /* 35 */24157817ul, /* 36 */39088169ul, /* 37 */63245986ul, /* 38 */102334155ul,      \

 /* 39 */165580141ul, /* 40 */267914296ul, /* 41 */433494437ul,                        \

 /* 42 */701408733ul, /* 43 */1134903170ul, /* 44 */1836311903ul,                      \

 /* 45 */2971215073ul }

 # if ( _STLP_STATIC_TEMPLATE_DATA > 0 )

 template <class _CharT, class _Alloc>

 const unsigned long

 rope<_CharT,_Alloc>::_S_min_len[__ROPE_DEPTH_SIZE] __ROPE_TABLE_BODY;

 # else

 __DECLARE_INSTANCE(const unsigned long,

                    crope::_S_min_len[__ROPE_DEPTH_SIZE],

                    __ROPE_TABLE_BODY);

 #  ifndef _STLP_NO_WCHAR_T

 __DECLARE_INSTANCE(const unsigned long,

                    wrope::_S_min_len[__ROPE_DEPTH_SIZE],

                    __ROPE_TABLE_BODY);

 #  endif

 # endif

 # undef __ROPE_DEPTH_SIZE

 # undef __ROPE_MAX_DEPTH

 # undef __ROPE_TABLE_BODY

 // These are Fibonacci numbers < 2**32.

 template <class _CharT, class _Alloc>

 __RopeRep__* rope<_CharT,_Alloc>::_S_balance(_RopeRep* __r) {

   _RopeRep* __forest[_RopeRep::_S_max_rope_depth + 1] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

                                                          0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

                                                          0,0,0,0,0,0};

   _RopeRep* __result = 0;

   int __i;

   // Invariant:

   // The concatenation of forest in descending order is equal to __r.

   // __forest[__i]._M_size._M_data >= _S_min_len[__i]

   // __forest[__i]._M_depth = __i

   // References from forest are included in refcount.

   _STLP_TRY {

     _S_add_to_forest(__r, __forest);

     for (__i = 0; __i <= _RopeRep::_S_max_rope_depth; ++__i)

       if (0 != __forest[__i]) {

         _Self_destruct_ptr __old(__result);

         __result = _S_concat_rep(__forest[__i], __result);

         __forest[__i]->_M_unref_nonnil();

 # ifdef _STLP_USE_EXCEPTIONS

         __forest[__i] = 0;

 # endif

       }

     }

     _STLP_UNWIND(for(__i = 0; __i <= _RopeRep::_S_max_rope_depth; ++__i)

     _S_unref(__forest[__i]))

     if (__result->_M_depth > _RopeRep::_S_max_rope_depth) {

       __stl_throw_range_error("rope too long");

     }

     return(__result);

 }

 template <class _CharT, class _Alloc>

 void

 rope<_CharT,_Alloc>::_S_add_to_forest(_RopeRep* __r, _RopeRep** __forest)

 {

     if (__r -> _M_is_balanced) {

       _S_add_leaf_to_forest(__r, __forest);

       return;

     }

     _STLP_ASSERT(__r->_M_tag == _RopeRep::_S_concat)

     {

       _RopeConcatenation* __c = (_RopeConcatenation*)__r;

       _S_add_to_forest(__c->_M_left, __forest);

       _S_add_to_forest(__c->_M_right, __forest);

     }

 }

 template <class _CharT, class _Alloc>

 void

 rope<_CharT,_Alloc>::_S_add_leaf_to_forest(_RopeRep* __r, _RopeRep** __forest)

 {

     _RopeRep* __insertee;       // included in refcount

     _RopeRep* __too_tiny = 0;      // included in refcount

     int __i;          // forest[0..__i-1] is empty

     size_t __s = __r->_M_size._M_data;

     for (__i = 0; __s >= _S_min_len[__i+1]/* not this bucket */; ++__i) {

   if (0 != __forest[__i]) {

         _Self_destruct_ptr __old(__too_tiny);

       __too_tiny = _S_concat_and_set_balanced(__forest[__i], __too_tiny);

       __forest[__i]->_M_unref_nonnil();

       __forest[__i] = 0;

   }

     }

     {

     _Self_destruct_ptr __old(__too_tiny);

   __insertee = _S_concat_and_set_balanced(__too_tiny, __r);

     }

     // Too_tiny dead, and no longer included in refcount.

     // Insertee is live and included.

     _STLP_ASSERT(_S_is_almost_balanced(__insertee))

     _STLP_ASSERT(__insertee->_M_depth <= __r->_M_depth + 1)

     for (;; ++__i) {

       if (0 != __forest[__i]) {

         _Self_destruct_ptr __old(__insertee);

       __insertee = _S_concat_and_set_balanced(__forest[__i], __insertee);

       __forest[__i]->_M_unref_nonnil();

       __forest[__i] = 0;

       _STLP_ASSERT(_S_is_almost_balanced(__insertee))

   }

   _STLP_ASSERT(_S_min_len[__i] <= __insertee->_M_size._M_data)

   _STLP_ASSERT(__forest[__i] == 0)

   if (__i == _RopeRep::_S_max_rope_depth ||

         __insertee->_M_size._M_data < _S_min_len[__i+1]) {

       __forest[__i] = __insertee;

       // refcount is OK since __insertee is now dead.

       return;

   }

     }

 }

 template <class _CharT, class _Alloc>

 _CharT

 rope<_CharT,_Alloc>::_S_fetch(_RopeRep* __r, size_type __i)

 {

     _CharT* __cstr = __r->_M_c_string;

     _STLP_ASSERT(__i < __r->_M_size._M_data)

     if (0 != __cstr) return __cstr[__i];

     for(;;) {

       switch(__r->_M_tag) {

   case _RopeRep::_S_concat:

       {

     _RopeConcatenation* __c = (_RopeConcatenation*)__r;

     _RopeRep* __left = __c->_M_left;

     size_t __left_len = __left->_M_size._M_data;

     if (__i >= __left_len) {

         __i -= __left_len;

         __r = __c->_M_right;

     } else {

         __r = __left;

     }

       }

       break;

   case _RopeRep::_S_leaf:

       {

     _RopeLeaf* __l = (_RopeLeaf*)__r;

     return __l->_M_data[__i];

       }

   case _RopeRep::_S_function:

   case _RopeRep::_S_substringfn:

       {

     _RopeFunction* __f = (_RopeFunction*)__r;

     _CharT __result;

     (*(__f->_M_fn))(__i, 1, &__result);

     return __result;

       }

       }

     }

 #if defined(_STLP_NEED_UNREACHABLE_RETURN)

     return 0;

 #endif

 }

 // Return a uniquely referenced character slot for the given

 // position, or 0 if that's not possible.

 template <class _CharT, class _Alloc>

 _CharT*

 rope<_CharT,_Alloc>::_S_fetch_ptr(_RopeRep* __r, size_type __i)

 {

     _RopeRep* __clrstack[_RopeRep::_S_max_rope_depth];

     size_t __csptr = 0;

     for(;;) {

       // if (__r->_M_ref_count > 1) return 0;

       if ( __r->_M_incr() > 2 ) {

         __r->_M_decr();

         return 0;

       }

       switch(__r->_M_tag) {

   case _RopeRep::_S_concat:

       {

     _RopeConcatenation* __c = (_RopeConcatenation*)__r;

     _RopeRep* __left = __c->_M_left;

     size_t __left_len = __left->_M_size._M_data;

     if (__c->_M_c_string != 0) __clrstack[__csptr++] = __c;

     if (__i >= __left_len) {

         __i -= __left_len;

         __r = __c->_M_right;

     } else {

         __r = __left;

     }

       }

       break;

   case _RopeRep::_S_leaf:

       {

     _RopeLeaf* __l = (_RopeLeaf*)__r;

     if (__l->_M_c_string != __l->_M_data && __l->_M_c_string != 0)

         __clrstack[__csptr++] = __l;

     while (__csptr > 0) {

         -- __csptr;

         _RopeRep* __d = __clrstack[__csptr];

         __d->_M_free_c_string();

         __d->_M_c_string = 0;

     }

     return __l->_M_data + __i;

       }

   case _RopeRep::_S_function:

   case _RopeRep::_S_substringfn:

       return 0;

       }

     }

 #if defined(_STLP_NEED_UNREACHABLE_RETURN)

     return 0;

 #endif

 }

 // The following could be implemented trivially using

 // lexicographical_compare_3way.

 // We do a little more work to avoid dealing with rope iterators for

 // flat strings.

 template <class _CharT, class _Alloc>

 int

 rope<_CharT,_Alloc>::_S_compare (const _RopeRep* __left,

                                  const _RopeRep* __right) {

   size_t __left_len;

   size_t __right_len;

   if (0 == __right) return 0 != __left;

   if (0 == __left) return -1;

   __left_len = __left->_M_size._M_data;

   __right_len = __right->_M_size._M_data;

   if (_RopeRep::_S_leaf == __left->_M_tag) {

     const _RopeLeaf* __l = __STATIC_CAST(const _RopeLeaf*, __left);

     if (_RopeRep::_S_leaf == __right->_M_tag) {

       const _RopeLeaf* __r = __STATIC_CAST(const _RopeLeaf*, __right);

       return _STLP_PRIV __lexicographical_compare_3way(__l->_M_data, __l->_M_data + __left_len,

                                                        __r->_M_data, __r->_M_data + __right_len);

     }

     else {

       const_iterator __rstart(__right, 0);

       const_iterator __rend(__right, __right_len);

       return _STLP_PRIV __lexicographical_compare_3way(__l->_M_data, __l->_M_data + __left_len,

                                                        __rstart, __rend);

     }

   }

   else {

     const_iterator __lstart(__left, 0);

     const_iterator __lend(__left, __left_len);

     if (_RopeRep::_S_leaf == __right->_M_tag) {

       const _RopeLeaf* __r = __STATIC_CAST(const _RopeLeaf*, __right);

       return _STLP_PRIV __lexicographical_compare_3way(__lstart, __lend,

                                                        __r->_M_data, __r->_M_data + __right_len);

     }

     else {

       const_iterator __rstart(__right, 0);

       const_iterator __rend(__right, __right_len);

       return _STLP_PRIV __lexicographical_compare_3way(__lstart, __lend, __rstart, __rend);

     }

   }

 }

 // Assignment to reference proxies.

 template <class _CharT, class _Alloc>

 _Rope_char_ref_proxy<_CharT, _Alloc>&

 _Rope_char_ref_proxy<_CharT, _Alloc>::operator= (_CharT __c) {

     _RopeRep* __old = _M_root->_M_tree_ptr._M_data;

   // First check for the case in which everything is uniquely

   // referenced.  In that case we can do this destructively.

   _CharT* __ptr = _My_rope::_S_fetch_ptr(__old, _M_pos);

   if (0 != __ptr) {

       *__ptr = __c;

       return *this;

   }

     _Self_destruct_ptr __left(

       _My_rope::_S_substring(__old, 0, _M_pos));

     _Self_destruct_ptr __right(

       _My_rope::_S_substring(__old, _M_pos+1, __old->_M_size._M_data));

     _Self_destruct_ptr __result_left(

       _My_rope::_S_destr_concat_char_iter(__left, &__c, 1));

     // _STLP_ASSERT(__left == __result_left || 1 == __result_left->_M_ref_count)

     _RopeRep* __result =

       _My_rope::_S_concat_rep(__result_left, __right);

     // _STLP_ASSERT(1 <= __result->_M_ref_count)

     _RopeRep::_S_unref(__old);

     _M_root->_M_tree_ptr._M_data = __result;

     return *this;

 }

 template <class _CharT, class _Alloc>

 _Rope_char_ptr_proxy<_CharT, _Alloc>

 _Rope_char_ref_proxy<_CharT, _Alloc>::operator& () const {

     return _Rope_char_ptr_proxy<_CharT, _Alloc>(*this);

 }

 # if ( _STLP_STATIC_TEMPLATE_DATA > 0 )

 template<class _CharT, class _Alloc>

 _CharT rope<_CharT,_Alloc>::_S_empty_c_str[1] = { _CharT() };

 # else

 __DECLARE_INSTANCE(char, crope::_S_empty_c_str[1], ={0});

 # ifdef _STLP_HAS_WCHAR_T

 __DECLARE_INSTANCE(wchar_t, wrope::_S_empty_c_str[1], ={0});

 # endif /* _STLP_HAS_WCHAR_T */

 # endif /* _STLP_STATIC_TEMPLATE_DATA */

 // # endif

 #if !defined (_STLP_STATIC_CONST_INIT_BUG)

 #  if !defined (__GNUC__) || (__GNUC__ != 2) || (__GNUC_MINOR__ != 96)

 template <class _CharT, class _Alloc>

 const size_t rope<_CharT, _Alloc>::npos;

 #  endif

 #endif

 template<class _CharT, class _Alloc>

 const _CharT* rope<_CharT,_Alloc>::c_str() const {

   if (0 == _M_tree_ptr._M_data) {

     // Possibly redundant, but probably fast.

     _S_empty_c_str[0] = _STLP_DEFAULT_CONSTRUCTED(_CharT);

     return _S_empty_c_str;

   }

   _CharT* __old_c_string = _M_tree_ptr._M_data->_M_c_string;

   if (0 != __old_c_string) return __old_c_string;

   size_t __s = size();

   _CharT* __result = _STLP_CREATE_ALLOCATOR(allocator_type,(const allocator_type&)_M_tree_ptr, _CharT).allocate(__s + 1);

   _S_flatten(_M_tree_ptr._M_data, __result);

   _S_construct_null(__result + __s);

   __old_c_string = __STATIC_CAST(_CharT*, _Atomic_swap_ptr(__REINTERPRET_CAST(void* _STLP_VOLATILE*, &(_M_tree_ptr._M_data->_M_c_string)),

                                                            __result));

   if (0 != __old_c_string) {

     // It must have been added in the interim.  Hence it had to have been

     // separately allocated.  Deallocate the old copy, since we just

     // replaced it.

     _STLP_STD::_Destroy_Range(__old_c_string, __old_c_string + __s + 1);

     _STLP_CREATE_ALLOCATOR(allocator_type,(const allocator_type&)_M_tree_ptr, _CharT).deallocate(__old_c_string, __s + 1);

   }

   return __result;

 }

 template<class _CharT, class _Alloc>

 const _CharT* rope<_CharT,_Alloc>::replace_with_c_str() {

   if (0 == _M_tree_ptr._M_data) {

     _S_empty_c_str[0] = _STLP_DEFAULT_CONSTRUCTED(_CharT);

     return _S_empty_c_str;

   }

   _CharT* __old_c_string = _M_tree_ptr._M_data->_M_c_string;

   if (_RopeRep::_S_leaf == _M_tree_ptr._M_data->_M_tag && 0 != __old_c_string) {

     return __old_c_string;

   }

   size_t __s = size();

   _CharT* __result = _M_tree_ptr.allocate(_S_rounded_up_size(__s));

   _S_flatten(_M_tree_ptr._M_data, __result);

   _S_construct_null(__result + __s);

   _M_tree_ptr._M_data->_M_unref_nonnil();

   _M_tree_ptr._M_data = _S_new_RopeLeaf(__result, __s, _M_tree_ptr);

   return __result;

 }

 // Algorithm specializations.  More should be added.

 #if (!defined (_STLP_MSVC) || (_STLP_MSVC >= 1310)) && \

     (!defined (__DMC__) || defined (__PUT_STATIC_DATA_MEMBERS_HERE))

 // 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) {

   _STLP_ASSERT(__first.container() == __middle.container() &&

                __middle.container() == __last.container())

   rope<_CharT,_Alloc>& __r(__first.container());

   rope<_CharT,_Alloc> __prefix = __r.substr(0, __first.index());

   rope<_CharT,_Alloc> __suffix =

     __r.substr(__last.index(), __r.size() - __last.index());

   rope<_CharT,_Alloc> __part1 =

     __r.substr(__middle.index(), __last.index() - __middle.index());

   rope<_CharT,_Alloc> __part2 =

     __r.substr(__first.index(), __middle.index() - __first.index());

   __r = __prefix;

   __r += __part1;

   __r += __part2;

   __r += __suffix;

 }

 # if 0

 // Probably not useful for several reasons:

 // - for SGIs 7.1 compiler and probably some others,

 //   this forces lots of rope<wchar_t, ...> instantiations, creating a

 //   code bloat and compile time problem.  (Fixed in 7.2.)

 // - wchar_t is 4 bytes wide on most UNIX platforms, making it unattractive

 //   for unicode strings.  Unsigned short may be a better character

 //   type.

 inline void rotate(

     _Rope_iterator<wchar_t,_STLP_DEFAULT_ALLOCATOR(char) > __first,

                 _Rope_iterator<wchar_t,_STLP_DEFAULT_ALLOCATOR(char) > __middle,

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

     _Rope_rotate(__first, __middle, __last);

 }

 # endif

 #endif /* _STLP_MSVC */

 #   undef __RopeLeaf__

 #   undef __RopeRep__

 #   undef __RopeLeaf

 #   undef __RopeRep

 #   undef size_type

 _STLP_END_NAMESPACE

 # endif /* ROPEIMPL_H */

 // Local Variables:

 // mode:C++

 // End: