1 // SGI's rope class implementation -*- C++ -*-
2 
3 // Copyright (C) 2001-2021 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /*
26  * Copyright (c) 1997
27  * Silicon Graphics Computer Systems, Inc.
28  *
29  * Permission to use, copy, modify, distribute and sell this software
30  * and its documentation for any purpose is hereby granted without fee,
31  * provided that the above copyright notice appear in all copies and
32  * that both that copyright notice and this permission notice appear
33  * in supporting documentation.  Silicon Graphics makes no
34  * representations about the suitability of this software for any
35  * purpose.  It is provided "as is" without express or implied warranty.
36  */
37 
38 /** @file ropeimpl.h
39  *  This is an internal header file, included by other library headers.
40  *  Do not attempt to use it directly. @headername{ext/rope}
41  */
42 
43 #include <cstdio>
44 #include <ostream>
45 #include <bits/functexcept.h>
46 
47 #include <ext/algorithm> // For copy_n and lexicographical_compare_3way
48 #include <ext/memory> // For uninitialized_copy_n
49 #include <ext/numeric> // For power
50 
_GLIBCXX_VISIBILITY(default)51 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
52 {
53 _GLIBCXX_BEGIN_NAMESPACE_VERSION
54 
55   // Set buf_start, buf_end, and buf_ptr appropriately, filling tmp_buf
56   // if necessary.  Assumes _M_path_end[leaf_index] and leaf_pos are correct.
57   // Results in a valid buf_ptr if the iterator can be legitimately
58   // dereferenced.
59   template <class _CharT, class _Alloc>
60     void
61     _Rope_iterator_base<_CharT, _Alloc>::
62     _S_setbuf(_Rope_iterator_base<_CharT, _Alloc>& __x)
63     {
64       using std::size_t;
65       const _RopeRep* __leaf = __x._M_path_end[__x._M_leaf_index];
66       size_t __leaf_pos = __x._M_leaf_pos;
67       size_t __pos = __x._M_current_pos;
68 
69       switch(__leaf->_M_tag)
70 	{
71 	case __detail::_S_leaf:
72 	  __x._M_buf_start = ((_Rope_RopeLeaf<_CharT, _Alloc>*)__leaf)->_M_data;
73 	  __x._M_buf_ptr = __x._M_buf_start + (__pos - __leaf_pos);
74 	  __x._M_buf_end = __x._M_buf_start + __leaf->_M_size;
75 	  break;
76 	case __detail::_S_function:
77 	case __detail::_S_substringfn:
78 	  {
79 	    size_t __len = _S_iterator_buf_len;
80 	    size_t __buf_start_pos = __leaf_pos;
81 	    size_t __leaf_end = __leaf_pos + __leaf->_M_size;
82 	    char_producer<_CharT>* __fn = ((_Rope_RopeFunction<_CharT,
83 					    _Alloc>*)__leaf)->_M_fn;
84 	    if (__buf_start_pos + __len <= __pos)
85 	      {
86 		__buf_start_pos = __pos - __len / 4;
87 		if (__buf_start_pos + __len > __leaf_end)
88 		  __buf_start_pos = __leaf_end - __len;
89 	      }
90 	    if (__buf_start_pos + __len > __leaf_end)
91 	      __len = __leaf_end - __buf_start_pos;
92 	    (*__fn)(__buf_start_pos - __leaf_pos, __len, __x._M_tmp_buf);
93 	    __x._M_buf_ptr = __x._M_tmp_buf + (__pos - __buf_start_pos);
94 	    __x._M_buf_start = __x._M_tmp_buf;
95 	    __x._M_buf_end = __x._M_tmp_buf + __len;
96 	  }
97 	  break;
98 	default:
99 	  break;
100 	}
101     }
102 
103   // Set path and buffer inside a rope iterator.  We assume that
104   // pos and root are already set.
105   template <class _CharT, class _Alloc>
106     void
107     _Rope_iterator_base<_CharT, _Alloc>::
108     _S_setcache(_Rope_iterator_base<_CharT, _Alloc>& __x)
109     {
110       using std::size_t;
111       const _RopeRep* __path[int(__detail::_S_max_rope_depth) + 1];
112       const _RopeRep* __curr_rope;
113       int __curr_depth = -1;  /* index into path    */
114       size_t __curr_start_pos = 0;
115       size_t __pos = __x._M_current_pos;
116       unsigned char __dirns = 0; // Bit vector marking right turns in the path
117 
118       if (__pos >= __x._M_root->_M_size)
119 	{
120 	  __x._M_buf_ptr = 0;
121 	  return;
122 	}
123       __curr_rope = __x._M_root;
124       if (0 != __curr_rope->_M_c_string)
125 	{
126 	  /* Treat the root as a leaf. */
127 	  __x._M_buf_start = __curr_rope->_M_c_string;
128 	  __x._M_buf_end = __curr_rope->_M_c_string + __curr_rope->_M_size;
129 	  __x._M_buf_ptr = __curr_rope->_M_c_string + __pos;
130 	  __x._M_path_end[0] = __curr_rope;
131 	  __x._M_leaf_index = 0;
132 	  __x._M_leaf_pos = 0;
133 	  return;
134 	}
135       for(;;)
136 	{
137 	  ++__curr_depth;
138 	  __path[__curr_depth] = __curr_rope;
139 	  switch(__curr_rope->_M_tag)
140 	    {
141 	    case __detail::_S_leaf:
142 	    case __detail::_S_function:
143 	    case __detail::_S_substringfn:
144 	      __x._M_leaf_pos = __curr_start_pos;
145 	      goto done;
146 	    case __detail::_S_concat:
147 	      {
148 		_Rope_RopeConcatenation<_CharT, _Alloc>* __c =
149 		  (_Rope_RopeConcatenation<_CharT, _Alloc>*)__curr_rope;
150 		_RopeRep* __left = __c->_M_left;
151 		size_t __left_len = __left->_M_size;
152 
153 		__dirns <<= 1;
154 		if (__pos >= __curr_start_pos + __left_len)
155 		  {
156 		    __dirns |= 1;
157 		    __curr_rope = __c->_M_right;
158 		    __curr_start_pos += __left_len;
159 		  }
160 		else
161 		  __curr_rope = __left;
162 	      }
163 	      break;
164 	    }
165 	}
166     done:
167       // Copy last section of path into _M_path_end.
168       {
169 	int __i = -1;
170 	int __j = __curr_depth + 1 - int(_S_path_cache_len);
171 
172 	if (__j < 0) __j = 0;
173 	while (__j <= __curr_depth)
174 	  __x._M_path_end[++__i] = __path[__j++];
175 	__x._M_leaf_index = __i;
176       }
177       __x._M_path_directions = __dirns;
178       _S_setbuf(__x);
179     }
180 
181   // Specialized version of the above.  Assumes that
182   // the path cache is valid for the previous position.
183   template <class _CharT, class _Alloc>
184     void
185     _Rope_iterator_base<_CharT, _Alloc>::
186     _S_setcache_for_incr(_Rope_iterator_base<_CharT, _Alloc>& __x)
187     {
188       using std::size_t;
189       int __current_index = __x._M_leaf_index;
190       const _RopeRep* __current_node = __x._M_path_end[__current_index];
191       size_t __len = __current_node->_M_size;
192       size_t __node_start_pos = __x._M_leaf_pos;
193       unsigned char __dirns = __x._M_path_directions;
194       _Rope_RopeConcatenation<_CharT, _Alloc>* __c;
195 
196       if (__x._M_current_pos - __node_start_pos < __len)
197 	{
198 	  /* More stuff in this leaf, we just didn't cache it. */
199 	  _S_setbuf(__x);
200 	  return;
201 	}
202       //  node_start_pos is starting position of last_node.
203       while (--__current_index >= 0)
204 	{
205 	  if (!(__dirns & 1) /* Path turned left */)
206 	    break;
207 	  __current_node = __x._M_path_end[__current_index];
208 	  __c = (_Rope_RopeConcatenation<_CharT, _Alloc>*)__current_node;
209 	  // Otherwise we were in the right child.  Thus we should pop
210 	  // the concatenation node.
211 	  __node_start_pos -= __c->_M_left->_M_size;
212 	  __dirns >>= 1;
213 	}
214       if (__current_index < 0)
215 	{
216 	  // We underflowed the cache. Punt.
217 	  _S_setcache(__x);
218 	  return;
219 	}
220       __current_node = __x._M_path_end[__current_index];
221       __c = (_Rope_RopeConcatenation<_CharT, _Alloc>*)__current_node;
222       // current_node is a concatenation node.  We are positioned on the first
223       // character in its right child.
224       // node_start_pos is starting position of current_node.
225       __node_start_pos += __c->_M_left->_M_size;
226       __current_node = __c->_M_right;
227       __x._M_path_end[++__current_index] = __current_node;
228       __dirns |= 1;
229       while (__detail::_S_concat == __current_node->_M_tag)
230 	{
231 	  ++__current_index;
232 	  if (int(_S_path_cache_len) == __current_index)
233 	    {
234 	      int __i;
235 	      for (__i = 0; __i < int(_S_path_cache_len) - 1; __i++)
236 		__x._M_path_end[__i] = __x._M_path_end[__i+1];
237 	      --__current_index;
238 	    }
239 	  __current_node =
240 	    ((_Rope_RopeConcatenation<_CharT, _Alloc>*)__current_node)->_M_left;
241 	  __x._M_path_end[__current_index] = __current_node;
242 	  __dirns <<= 1;
243 	  // node_start_pos is unchanged.
244 	}
245       __x._M_leaf_index = __current_index;
246       __x._M_leaf_pos = __node_start_pos;
247       __x._M_path_directions = __dirns;
248       _S_setbuf(__x);
249     }
250 
251   template <class _CharT, class _Alloc>
252     void
253     _Rope_iterator_base<_CharT, _Alloc>::
254     _M_incr(std::size_t __n)
255     {
256       _M_current_pos += __n;
257       if (0 != _M_buf_ptr)
258 	{
259 	  std::size_t __chars_left = _M_buf_end - _M_buf_ptr;
260 	  if (__chars_left > __n)
261 	    _M_buf_ptr += __n;
262 	  else if (__chars_left == __n)
263 	    {
264 	      _M_buf_ptr += __n;
265 	      _S_setcache_for_incr(*this);
266 	    }
267 	  else
268 	    _M_buf_ptr = 0;
269 	}
270     }
271 
272   template <class _CharT, class _Alloc>
273     void
274     _Rope_iterator_base<_CharT, _Alloc>::
275     _M_decr(std::size_t __n)
276     {
277       if (0 != _M_buf_ptr)
278 	{
279 	  std::size_t __chars_left = _M_buf_ptr - _M_buf_start;
280 	  if (__chars_left >= __n)
281 	    _M_buf_ptr -= __n;
282 	  else
283 	    _M_buf_ptr = 0;
284 	}
285       _M_current_pos -= __n;
286     }
287 
288   template <class _CharT, class _Alloc>
289     void
290     _Rope_iterator<_CharT, _Alloc>::
291     _M_check()
292     {
293       if (_M_root_rope->_M_tree_ptr != this->_M_root)
294 	{
295 	  // _Rope was modified.  Get things fixed up.
296 	  _RopeRep::_S_unref(this->_M_root);
297 	  this->_M_root = _M_root_rope->_M_tree_ptr;
298 	  _RopeRep::_S_ref(this->_M_root);
299 	  this->_M_buf_ptr = 0;
300 	}
301     }
302 
303   template <class _CharT, class _Alloc>
304     inline
305     _Rope_const_iterator<_CharT, _Alloc>::
306     _Rope_const_iterator(const _Rope_iterator<_CharT, _Alloc>& __x)
307     : _Rope_iterator_base<_CharT, _Alloc>(__x)
308     { }
309 
310   template <class _CharT, class _Alloc>
311     inline
312     _Rope_iterator<_CharT, _Alloc>::
313     _Rope_iterator(rope<_CharT, _Alloc>& __r, std::size_t __pos)
314     : _Rope_iterator_base<_CharT,_Alloc>(__r._M_tree_ptr, __pos),
315       _M_root_rope(&__r)
316     { _RopeRep::_S_ref(this->_M_root); }
317 
318   template <class _CharT, class _Alloc>
319     inline std::size_t
320     rope<_CharT, _Alloc>::
321     _S_char_ptr_len(const _CharT* __s)
322     {
323       const _CharT* __p = __s;
324 
325       while (!_S_is0(*__p))
326 	++__p;
327       return (__p - __s);
328     }
329 
330 
331 #ifndef __GC
332 
333   template <class _CharT, class _Alloc>
334     inline void
335     _Rope_RopeRep<_CharT, _Alloc>::
336     _M_free_c_string()
337     {
338       _CharT* __cstr = _M_c_string;
339       if (0 != __cstr)
340 	{
341 	  std::size_t __size = this->_M_size + 1;
342 	  std::_Destroy(__cstr, __cstr + __size, _M_get_allocator());
343 	  this->_Data_deallocate(__cstr, __size);
344 	}
345     }
346 
347   template <class _CharT, class _Alloc>
348     inline void
349     _Rope_RopeRep<_CharT, _Alloc>::
350     _S_free_string(_CharT* __s, std::size_t __n, allocator_type& __a)
351     {
352       if (!_S_is_basic_char_type((_CharT*)0))
353 	std::_Destroy(__s, __s + __n, __a);
354 
355       //  This has to be a static member, so this gets a bit messy
356       __a.deallocate(__s,
357 		     _Rope_RopeLeaf<_CharT, _Alloc>::_S_rounded_up_size(__n));
358     }
359 
360   //  There are several reasons for not doing this with virtual destructors
361   //  and a class specific delete operator:
362   //  - A class specific delete operator can't easily get access to
363   //    allocator instances if we need them.
364   //  - Any virtual function would need a 4 or byte vtable pointer;
365   //    this only requires a one byte tag per object.
366   template <class _CharT, class _Alloc>
367     void
368     _Rope_RopeRep<_CharT, _Alloc>::
369     _M_free_tree()
370     {
371       switch(_M_tag)
372 	{
373 	case __detail::_S_leaf:
374 	  {
375 	    _Rope_RopeLeaf<_CharT, _Alloc>* __l
376 	      = (_Rope_RopeLeaf<_CharT, _Alloc>*)this;
377 	    __l->_Rope_RopeLeaf<_CharT, _Alloc>::~_Rope_RopeLeaf();
378 	    this->_L_deallocate(__l, 1);
379 	    break;
380 	  }
381 	case __detail::_S_concat:
382 	  {
383 	    _Rope_RopeConcatenation<_CharT,_Alloc>* __c
384 	      = (_Rope_RopeConcatenation<_CharT, _Alloc>*)this;
385 	    __c->_Rope_RopeConcatenation<_CharT, _Alloc>::
386 	      ~_Rope_RopeConcatenation();
387 	    this->_C_deallocate(__c, 1);
388 	    break;
389 	  }
390 	case __detail::_S_function:
391 	  {
392 	    _Rope_RopeFunction<_CharT, _Alloc>* __f
393 	      = (_Rope_RopeFunction<_CharT, _Alloc>*)this;
394 	    __f->_Rope_RopeFunction<_CharT, _Alloc>::~_Rope_RopeFunction();
395 	    this->_F_deallocate(__f, 1);
396 	    break;
397 	  }
398 	case __detail::_S_substringfn:
399 	  {
400 	    _Rope_RopeSubstring<_CharT, _Alloc>* __ss =
401 	      (_Rope_RopeSubstring<_CharT, _Alloc>*)this;
402 	    __ss->_Rope_RopeSubstring<_CharT, _Alloc>::
403 	      ~_Rope_RopeSubstring();
404 	    this->_S_deallocate(__ss, 1);
405 	    break;
406 	  }
407 	}
408     }
409 #else
410 
411   template <class _CharT, class _Alloc>
412     inline void
413     _Rope_RopeRep<_CharT, _Alloc>::
414     _S_free_string(const _CharT*, std::size_t, allocator_type)
415     { }
416 
417 #endif
418 
419   // Concatenate a C string onto a leaf rope by copying the rope data.
420   // Used for short ropes.
421   template <class _CharT, class _Alloc>
422     typename rope<_CharT, _Alloc>::_RopeLeaf*
423     rope<_CharT, _Alloc>::
424     _S_leaf_concat_char_iter(_RopeLeaf* __r, const _CharT* __iter,
425 			     std::size_t __len)
426     {
427       std::size_t __old_len = __r->_M_size;
428       _CharT* __new_data = (_CharT*)
429 	rope::_Data_allocate(_S_rounded_up_size(__old_len + __len));
430       _RopeLeaf* __result;
431 
432       uninitialized_copy_n(__r->_M_data, __old_len, __new_data);
433       uninitialized_copy_n(__iter, __len, __new_data + __old_len);
434       _S_cond_store_eos(__new_data[__old_len + __len]);
435       __try
436 	{
437 	  __result = _S_new_RopeLeaf(__new_data, __old_len + __len,
438 				     __r->_M_get_allocator());
439 	}
440       __catch(...)
441 	{
442 	  _RopeRep::__STL_FREE_STRING(__new_data, __old_len + __len,
443 				      __r->_M_get_allocator());
444 	  __throw_exception_again;
445 	}
446       return __result;
447     }
448 
449 #ifndef __GC
450   // As above, but it's OK to clobber original if refcount is 1
451   template <class _CharT, class _Alloc>
452     typename rope<_CharT,_Alloc>::_RopeLeaf*
453     rope<_CharT, _Alloc>::
454     _S_destr_leaf_concat_char_iter(_RopeLeaf* __r, const _CharT* __iter,
455 				   std::size_t __len)
456     {
457       if (__r->_M_ref_count > 1)
458 	return _S_leaf_concat_char_iter(__r, __iter, __len);
459       std::size_t __old_len = __r->_M_size;
460       if (_S_allocated_capacity(__old_len) >= __old_len + __len)
461 	{
462 	  // The space has been partially initialized for the standard
463 	  // character types.  But that doesn't matter for those types.
464 	  uninitialized_copy_n(__iter, __len, __r->_M_data + __old_len);
465 	  if (_S_is_basic_char_type((_CharT*)0))
466 	    _S_cond_store_eos(__r->_M_data[__old_len + __len]);
467 	  else if (__r->_M_c_string != __r->_M_data && 0 != __r->_M_c_string)
468 	    {
469 	      __r->_M_free_c_string();
470 	      __r->_M_c_string = 0;
471 	    }
472 	  __r->_M_size = __old_len + __len;
473 	  __r->_M_ref_count = 2;
474 	  return __r;
475 	}
476       else
477 	{
478 	  _RopeLeaf* __result = _S_leaf_concat_char_iter(__r, __iter, __len);
479 	  return __result;
480 	}
481     }
482 #endif
483 
484   // Assumes left and right are not 0.
485   // Does not increment (nor decrement on exception) child reference counts.
486   // Result has ref count 1.
487   template <class _CharT, class _Alloc>
488     typename rope<_CharT, _Alloc>::_RopeRep*
489     rope<_CharT, _Alloc>::
490     _S_tree_concat(_RopeRep* __left, _RopeRep* __right)
491     {
492       using std::size_t;
493       _RopeConcatenation* __result = _S_new_RopeConcatenation(__left, __right,
494 							      __left->
495 							      _M_get_allocator());
496       size_t __depth = __result->_M_depth;
497 
498       if (__depth > 20
499 	  && (__result->_M_size < 1000
500 	      || __depth > size_t(__detail::_S_max_rope_depth)))
501 	{
502 	  _RopeRep* __balanced;
503 
504 	  __try
505 	    {
506 	      __balanced = _S_balance(__result);
507 	      __result->_M_unref_nonnil();
508 	    }
509 	  __catch(...)
510 	    {
511 	      rope::_C_deallocate(__result,1);
512 	      __throw_exception_again;
513 	    }
514 	  // In case of exception, we need to deallocate
515 	  // otherwise dangling result node.  But caller
516 	  // still owns its children.  Thus unref is
517 	  // inappropriate.
518 	  return __balanced;
519 	}
520       else
521 	return __result;
522     }
523 
524   template <class _CharT, class _Alloc>
525     typename rope<_CharT, _Alloc>::_RopeRep*
526     rope<_CharT, _Alloc>::
527     _S_concat_char_iter(_RopeRep* __r, const _CharT*__s, std::size_t __slen,
528 			allocator_type& __a)
529     {
530       using std::size_t;
531       _RopeRep* __result;
532       if (0 == __slen)
533 	{
534 	  _S_ref(__r);
535 	  return __r;
536 	}
537       if (0 == __r)
538 	return __STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen, __a);
539       if (__r->_M_tag == __detail::_S_leaf
540 	  && __r->_M_size + __slen <= size_t(_S_copy_max))
541 	{
542 	  __result = _S_leaf_concat_char_iter((_RopeLeaf*)__r, __s, __slen);
543 	  return __result;
544 	}
545       if (__detail::_S_concat == __r->_M_tag
546 	  && __detail::_S_leaf == ((_RopeConcatenation*) __r)->_M_right->_M_tag)
547 	{
548 	  _RopeLeaf* __right =
549 	    (_RopeLeaf* )(((_RopeConcatenation* )__r)->_M_right);
550 	  if (__right->_M_size + __slen <= size_t(_S_copy_max))
551 	    {
552 	      _RopeRep* __left = ((_RopeConcatenation*)__r)->_M_left;
553 	      _RopeRep* __nright =
554 		_S_leaf_concat_char_iter((_RopeLeaf*)__right, __s, __slen);
555 	      __left->_M_ref_nonnil();
556 	      __try
557 		{ __result = _S_tree_concat(__left, __nright); }
558 	      __catch(...)
559 		{
560 		  _S_unref(__left);
561 		  _S_unref(__nright);
562 		  __throw_exception_again;
563 		}
564 	      return __result;
565 	    }
566 	}
567       _RopeRep* __nright = __STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen, __a);
568       __try
569 	{
570 	  __r->_M_ref_nonnil();
571 	  __result = _S_tree_concat(__r, __nright);
572 	}
573       __catch(...)
574 	{
575 	  _S_unref(__r);
576 	  _S_unref(__nright);
577 	  __throw_exception_again;
578 	}
579       return __result;
580     }
581 
582 #ifndef __GC
583   template <class _CharT, class _Alloc>
584     typename rope<_CharT,_Alloc>::_RopeRep*
585     rope<_CharT,_Alloc>::
586     _S_destr_concat_char_iter(_RopeRep* __r, const _CharT* __s,
587 			      std::size_t __slen, allocator_type& __a)
588     {
589       using std::size_t;
590       _RopeRep* __result;
591       if (0 == __r)
592 	return __STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen, __a);
593       size_t __count = __r->_M_ref_count;
594       size_t __orig_size = __r->_M_size;
595       if (__count > 1)
596 	return _S_concat_char_iter(__r, __s, __slen, __a);
597       if (0 == __slen)
598 	{
599 	  __r->_M_ref_count = 2;      // One more than before
600 	  return __r;
601 	}
602       if (__orig_size + __slen <= size_t(_S_copy_max)
603 	  && __detail::_S_leaf == __r->_M_tag)
604 	{
605 	  __result = _S_destr_leaf_concat_char_iter((_RopeLeaf*)__r, __s,
606 						    __slen);
607 	  return __result;
608 	}
609       if (__detail::_S_concat == __r->_M_tag)
610 	{
611 	  _RopeLeaf* __right = (_RopeLeaf*)(((_RopeConcatenation*)
612 					     __r)->_M_right);
613 	  if (__detail::_S_leaf == __right->_M_tag
614 	      && __right->_M_size + __slen <= size_t(_S_copy_max))
615 	    {
616 	      _RopeRep* __new_right =
617 		_S_destr_leaf_concat_char_iter(__right, __s, __slen);
618 	      if (__right == __new_right)
619 		__new_right->_M_ref_count = 1;
620 	      else
621 		__right->_M_unref_nonnil();
622 	      __r->_M_ref_count = 2;    // One more than before.
623 	      ((_RopeConcatenation*)__r)->_M_right = __new_right;
624 	      __r->_M_size = __orig_size + __slen;
625 	      if (0 != __r->_M_c_string)
626 		{
627 		  __r->_M_free_c_string();
628 		  __r->_M_c_string = 0;
629 		}
630 	      return __r;
631 	    }
632 	}
633       _RopeRep* __right = __STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen, __a);
634       __r->_M_ref_nonnil();
635       __try
636 	{ __result = _S_tree_concat(__r, __right); }
637       __catch(...)
638 	{
639 	  _S_unref(__r);
640 	  _S_unref(__right);
641 	  __throw_exception_again;
642 	}
643       return __result;
644     }
645 #endif /* !__GC */
646 
647   template <class _CharT, class _Alloc>
648     typename rope<_CharT, _Alloc>::_RopeRep*
649     rope<_CharT, _Alloc>::
650     _S_concat(_RopeRep* __left, _RopeRep* __right)
651     {
652       using std::size_t;
653       if (0 == __left)
654 	{
655 	  _S_ref(__right);
656 	  return __right;
657 	}
658       if (0 == __right)
659 	{
660 	  __left->_M_ref_nonnil();
661 	  return __left;
662 	}
663       if (__detail::_S_leaf == __right->_M_tag)
664 	{
665 	  if (__detail::_S_leaf == __left->_M_tag)
666 	    {
667 	      if (__right->_M_size + __left->_M_size <= size_t(_S_copy_max))
668 		return _S_leaf_concat_char_iter((_RopeLeaf*)__left,
669 						((_RopeLeaf*)__right)->_M_data,
670 						__right->_M_size);
671 	    }
672 	  else if (__detail::_S_concat == __left->_M_tag
673 		   && __detail::_S_leaf == ((_RopeConcatenation*)
674 						   __left)->_M_right->_M_tag)
675 	    {
676 	      _RopeLeaf* __leftright =
677 		(_RopeLeaf*)(((_RopeConcatenation*)__left)->_M_right);
678 	      if (__leftright->_M_size
679 		  + __right->_M_size <= size_t(_S_copy_max))
680 		{
681 		  _RopeRep* __leftleft = ((_RopeConcatenation*)__left)->_M_left;
682 		  _RopeRep* __rest = _S_leaf_concat_char_iter(__leftright,
683 							      ((_RopeLeaf*)
684 							       __right)->
685 							      _M_data,
686 							      __right->_M_size);
687 		  __leftleft->_M_ref_nonnil();
688 		  __try
689 		    { return(_S_tree_concat(__leftleft, __rest)); }
690 		  __catch(...)
691 		    {
692 		      _S_unref(__leftleft);
693 		      _S_unref(__rest);
694 		      __throw_exception_again;
695 		    }
696 		}
697 	    }
698 	}
699       __left->_M_ref_nonnil();
700       __right->_M_ref_nonnil();
701       __try
702 	{ return(_S_tree_concat(__left, __right)); }
703       __catch(...)
704 	{
705 	  _S_unref(__left);
706 	  _S_unref(__right);
707 	  __throw_exception_again;
708 	}
709     }
710 
711   template <class _CharT, class _Alloc>
712     typename rope<_CharT, _Alloc>::_RopeRep*
713     rope<_CharT, _Alloc>::
714     _S_substring(_RopeRep* __base, std::size_t __start, std::size_t __endp1)
715     {
716       using std::size_t;
717       if (0 == __base)
718 	return 0;
719       size_t __len = __base->_M_size;
720       size_t __adj_endp1;
721       const size_t __lazy_threshold = 128;
722 
723       if (__endp1 >= __len)
724 	{
725 	  if (0 == __start)
726 	    {
727 	      __base->_M_ref_nonnil();
728 	      return __base;
729 	    }
730 	  else
731 	    __adj_endp1 = __len;
732 
733 	}
734       else
735 	__adj_endp1 = __endp1;
736 
737       switch(__base->_M_tag)
738 	{
739 	case __detail::_S_concat:
740 	    {
741 	      _RopeConcatenation* __c = (_RopeConcatenation*)__base;
742 	      _RopeRep* __left = __c->_M_left;
743 	      _RopeRep* __right = __c->_M_right;
744 	      size_t __left_len = __left->_M_size;
745 	      _RopeRep* __result;
746 
747 	      if (__adj_endp1 <= __left_len)
748 		return _S_substring(__left, __start, __endp1);
749 	      else if (__start >= __left_len)
750 		return _S_substring(__right, __start - __left_len,
751 				    __adj_endp1 - __left_len);
752 	      _Self_destruct_ptr __left_result(_S_substring(__left,
753 							    __start,
754 							    __left_len));
755 	      _Self_destruct_ptr __right_result(_S_substring(__right, 0,
756 							     __endp1
757 							     - __left_len));
758 	      __result = _S_concat(__left_result, __right_result);
759 	      return __result;
760 	    }
761 	case __detail::_S_leaf:
762 	  {
763 	    _RopeLeaf* __l = (_RopeLeaf*)__base;
764 	    _RopeLeaf* __result;
765 	    size_t __result_len;
766 	    if (__start >= __adj_endp1)
767 	      return 0;
768 	    __result_len = __adj_endp1 - __start;
769 	    if (__result_len > __lazy_threshold)
770 	      goto lazy;
771 #ifdef __GC
772 	    const _CharT* __section = __l->_M_data + __start;
773 	    __result = _S_new_RopeLeaf(__section, __result_len,
774 				       __base->_M_get_allocator());
775 	    __result->_M_c_string = 0;  // Not eos terminated.
776 #else
777 	    // We should sometimes create substring node instead.
778 	    __result = __STL_ROPE_FROM_UNOWNED_CHAR_PTR(__l->_M_data + __start,
779 							__result_len,
780 							__base->
781 							_M_get_allocator());
782 #endif
783 	    return __result;
784 	  }
785 	case __detail::_S_substringfn:
786 	  // Avoid introducing multiple layers of substring nodes.
787 	  {
788 	    _RopeSubstring* __old = (_RopeSubstring*)__base;
789 	    size_t __result_len;
790 	    if (__start >= __adj_endp1)
791 	      return 0;
792 	    __result_len = __adj_endp1 - __start;
793 	    if (__result_len > __lazy_threshold)
794 	      {
795 		_RopeSubstring* __result =
796 		  _S_new_RopeSubstring(__old->_M_base,
797 				       __start + __old->_M_start,
798 				       __adj_endp1 - __start,
799 				       __base->_M_get_allocator());
800 		return __result;
801 
802 	      } // *** else fall through: ***
803 	  }
804 	case __detail::_S_function:
805 	  {
806 	    _RopeFunction* __f = (_RopeFunction*)__base;
807 	    _CharT* __section;
808 	    size_t __result_len;
809 	    if (__start >= __adj_endp1)
810 	      return 0;
811 	    __result_len = __adj_endp1 - __start;
812 
813 	    if (__result_len > __lazy_threshold)
814 	      goto lazy;
815 	    __section = (_CharT*)
816 	      rope::_Data_allocate(_S_rounded_up_size(__result_len));
817 	    __try
818 	      {	(*(__f->_M_fn))(__start, __result_len, __section); }
819 	    __catch(...)
820 	      {
821 		_RopeRep::__STL_FREE_STRING(__section, __result_len,
822 					    __base->_M_get_allocator());
823 		__throw_exception_again;
824 	      }
825 	    _S_cond_store_eos(__section[__result_len]);
826 	    return _S_new_RopeLeaf(__section, __result_len,
827 				   __base->_M_get_allocator());
828 	  }
829 	}
830     lazy:
831       {
832 	// Create substring node.
833 	return _S_new_RopeSubstring(__base, __start, __adj_endp1 - __start,
834 				    __base->_M_get_allocator());
835       }
836     }
837 
838   template<class _CharT>
839     class _Rope_flatten_char_consumer
840     : public _Rope_char_consumer<_CharT>
841     {
842     private:
843       _CharT* _M_buf_ptr;
844     public:
845 
846       _Rope_flatten_char_consumer(_CharT* __buffer)
847       { _M_buf_ptr = __buffer; }
848 
849       ~_Rope_flatten_char_consumer() {}
850 
851       bool
852       operator()(const _CharT* __leaf, std::size_t __n)
853       {
854 	uninitialized_copy_n(__leaf, __n, _M_buf_ptr);
855 	_M_buf_ptr += __n;
856 	return true;
857       }
858     };
859 
860   template<class _CharT>
861     class _Rope_find_char_char_consumer
862     : public _Rope_char_consumer<_CharT>
863     {
864     private:
865       _CharT _M_pattern;
866     public:
867       std::size_t _M_count;  // Number of nonmatching characters
868 
869       _Rope_find_char_char_consumer(_CharT __p)
870       : _M_pattern(__p), _M_count(0) {}
871 
872       ~_Rope_find_char_char_consumer() {}
873 
874       bool
875       operator()(const _CharT* __leaf, std::size_t __n)
876       {
877 	std::size_t __i;
878 	for (__i = 0; __i < __n; __i++)
879 	  {
880 	    if (__leaf[__i] == _M_pattern)
881 	      {
882 		_M_count += __i;
883 		return false;
884 	      }
885 	  }
886 	_M_count += __n; return true;
887       }
888     };
889 
890   template<class _CharT, class _Traits>
891   // Here _CharT is both the stream and rope character type.
892     class _Rope_insert_char_consumer
893     : public _Rope_char_consumer<_CharT>
894     {
895     private:
896       typedef std::basic_ostream<_CharT,_Traits> _Insert_ostream;
897       _Insert_ostream& _M_o;
898     public:
899       _Rope_insert_char_consumer(_Insert_ostream& __writer)
900 	: _M_o(__writer) {}
901       ~_Rope_insert_char_consumer() { }
902       // Caller is presumed to own the ostream
903       bool operator() (const _CharT* __leaf, std::size_t __n);
904       // Returns true to continue traversal.
905     };
906 
907   template<class _CharT, class _Traits>
908     bool
909     _Rope_insert_char_consumer<_CharT, _Traits>::
910     operator()(const _CharT* __leaf, std::size_t __n)
911     {
912       std::size_t __i;
913       //  We assume that formatting is set up correctly for each element.
914       for (__i = 0; __i < __n; __i++)
915 	_M_o.put(__leaf[__i]);
916       return true;
917     }
918 
919   template <class _CharT, class _Alloc>
920     bool
921     rope<_CharT, _Alloc>::
922     _S_apply_to_pieces(_Rope_char_consumer<_CharT>& __c, const _RopeRep* __r,
923 		       std::size_t __begin, std::size_t __end)
924     {
925       using std::size_t;
926       if (0 == __r)
927 	return true;
928       switch(__r->_M_tag)
929 	{
930 	case __detail::_S_concat:
931 	  {
932 	    _RopeConcatenation* __conc = (_RopeConcatenation*)__r;
933 	    _RopeRep* __left =  __conc->_M_left;
934 	    size_t __left_len = __left->_M_size;
935 	    if (__begin < __left_len)
936 	      {
937 		size_t __left_end = std::min(__left_len, __end);
938 		if (!_S_apply_to_pieces(__c, __left, __begin, __left_end))
939 		  return false;
940 	      }
941 	    if (__end > __left_len)
942 	      {
943 		_RopeRep* __right =  __conc->_M_right;
944 		size_t __right_start = std::max(__left_len, __begin);
945 		if (!_S_apply_to_pieces(__c, __right,
946 					__right_start - __left_len,
947 					__end - __left_len))
948 		  return false;
949 	      }
950 	  }
951 	  return true;
952 	case __detail::_S_leaf:
953 	  {
954 	    _RopeLeaf* __l = (_RopeLeaf*)__r;
955 	    return __c(__l->_M_data + __begin, __end - __begin);
956 	  }
957 	case __detail::_S_function:
958 	case __detail::_S_substringfn:
959 	    {
960 	      _RopeFunction* __f = (_RopeFunction*)__r;
961 	      size_t __len = __end - __begin;
962 	      bool __result;
963 	      _CharT* __buffer =
964 		(_CharT*)_Alloc().allocate(__len * sizeof(_CharT));
965 	      __try
966 		{
967 		  (*(__f->_M_fn))(__begin, __len, __buffer);
968 		  __result = __c(__buffer, __len);
969                   _Alloc().deallocate(__buffer, __len * sizeof(_CharT));
970                 }
971 	      __catch(...)
972 		{
973 		  _Alloc().deallocate(__buffer, __len * sizeof(_CharT));
974 		  __throw_exception_again;
975 		}
976 	      return __result;
977 	    }
978 	default:
979 	  return false;
980 	}
981     }
982 
983   template<class _CharT, class _Traits>
984     inline void
985     _Rope_fill(std::basic_ostream<_CharT, _Traits>& __o, std::size_t __n)
986     {
987       char __f = __o.fill();
988       std::size_t __i;
989 
990       for (__i = 0; __i < __n; __i++)
991 	__o.put(__f);
992     }
993 
994 
995   template <class _CharT>
996     inline bool
997     _Rope_is_simple(_CharT*)
998     { return false; }
999 
1000   inline bool
1001   _Rope_is_simple(char*)
1002   { return true; }
1003 
1004   inline bool
1005   _Rope_is_simple(wchar_t*)
1006   { return true; }
1007 
1008   template<class _CharT, class _Traits, class _Alloc>
1009     std::basic_ostream<_CharT, _Traits>&
1010     operator<<(std::basic_ostream<_CharT, _Traits>& __o,
1011 	       const rope<_CharT, _Alloc>& __r)
1012     {
1013       using std::size_t;
1014       size_t __w = __o.width();
1015       bool __left = bool(__o.flags() & std::ios::left);
1016       size_t __pad_len;
1017       size_t __rope_len = __r.size();
1018       _Rope_insert_char_consumer<_CharT, _Traits> __c(__o);
1019       bool __is_simple = _Rope_is_simple((_CharT*)0);
1020 
1021       if (__rope_len < __w)
1022 	__pad_len = __w - __rope_len;
1023       else
1024 	__pad_len = 0;
1025 
1026       if (!__is_simple)
1027 	__o.width(__w / __rope_len);
1028       __try
1029 	{
1030 	  if (__is_simple && !__left && __pad_len > 0)
1031 	    _Rope_fill(__o, __pad_len);
1032 	  __r.apply_to_pieces(0, __r.size(), __c);
1033 	  if (__is_simple && __left && __pad_len > 0)
1034 	    _Rope_fill(__o, __pad_len);
1035 	  if (!__is_simple)
1036 	    __o.width(__w);
1037 	}
1038       __catch(...)
1039 	{
1040 	  if (!__is_simple)
1041 	    __o.width(__w);
1042 	  __throw_exception_again;
1043 	}
1044       return __o;
1045     }
1046 
1047   template <class _CharT, class _Alloc>
1048     _CharT*
1049     rope<_CharT, _Alloc>::
1050     _S_flatten(_RopeRep* __r, std::size_t __start, std::size_t __len,
1051 	       _CharT* __buffer)
1052     {
1053       _Rope_flatten_char_consumer<_CharT> __c(__buffer);
1054       _S_apply_to_pieces(__c, __r, __start, __start + __len);
1055       return(__buffer + __len);
1056     }
1057 
1058   template <class _CharT, class _Alloc>
1059     std::size_t
1060     rope<_CharT, _Alloc>::
1061     find(_CharT __pattern, std::size_t __start) const
1062     {
1063       _Rope_find_char_char_consumer<_CharT> __c(__pattern);
1064       _S_apply_to_pieces(__c, this->_M_tree_ptr, __start, size());
1065       size_type __result_pos = __start + __c._M_count;
1066 #ifndef __STL_OLD_ROPE_SEMANTICS
1067       if (__result_pos == size())
1068 	__result_pos = npos;
1069 #endif
1070       return __result_pos;
1071     }
1072 
1073   template <class _CharT, class _Alloc>
1074     _CharT*
1075     rope<_CharT, _Alloc>::
1076     _S_flatten(_RopeRep* __r, _CharT* __buffer)
1077     {
1078       if (0 == __r)
1079 	return __buffer;
1080       switch(__r->_M_tag)
1081 	{
1082 	case __detail::_S_concat:
1083 	  {
1084 	    _RopeConcatenation* __c = (_RopeConcatenation*)__r;
1085 	    _RopeRep* __left = __c->_M_left;
1086 	    _RopeRep* __right = __c->_M_right;
1087 	    _CharT* __rest = _S_flatten(__left, __buffer);
1088 	    return _S_flatten(__right, __rest);
1089 	  }
1090 	case __detail::_S_leaf:
1091 	  {
1092 	    _RopeLeaf* __l = (_RopeLeaf*)__r;
1093 	    return copy_n(__l->_M_data, __l->_M_size, __buffer).second;
1094 	  }
1095 	case __detail::_S_function:
1096 	case __detail::_S_substringfn:
1097 	  // We don't yet do anything with substring nodes.
1098 	  // This needs to be fixed before ropefiles will work well.
1099 	  {
1100 	    _RopeFunction* __f = (_RopeFunction*)__r;
1101 	    (*(__f->_M_fn))(0, __f->_M_size, __buffer);
1102 	    return __buffer + __f->_M_size;
1103 	  }
1104 	default:
1105 	  return 0;
1106 	}
1107     }
1108 
1109   // This needs work for _CharT != char
1110   template <class _CharT, class _Alloc>
1111     void
1112     rope<_CharT, _Alloc>::
1113     _S_dump(_RopeRep* __r, int __indent)
1114     {
1115       using std::printf;
1116       for (int __i = 0; __i < __indent; __i++)
1117 	putchar(' ');
1118       if (0 == __r)
1119 	{
1120 	  printf("NULL\n");
1121 	  return;
1122 	}
1123       if (__detail::_S_concat == __r->_M_tag)
1124 	{
1125 	  _RopeConcatenation* __c = (_RopeConcatenation*)__r;
1126 	  _RopeRep* __left = __c->_M_left;
1127 	  _RopeRep* __right = __c->_M_right;
1128 
1129 #ifdef __GC
1130 	  printf("Concatenation %p (depth = %d, len = %ld, %s balanced)\n",
1131 		 __r, __r->_M_depth, __r->_M_size,
1132 		 __r->_M_is_balanced? "" : "not");
1133 #else
1134 	  printf("Concatenation %p (rc = %ld, depth = %d, "
1135 		 "len = %ld, %s balanced)\n",
1136 		 __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size,
1137 		 __r->_M_is_balanced? "" : "not");
1138 #endif
1139 	  _S_dump(__left, __indent + 2);
1140 	  _S_dump(__right, __indent + 2);
1141 	  return;
1142 	}
1143       else
1144 	{
1145 	  const char* __kind;
1146 
1147 	  switch (__r->_M_tag)
1148 	    {
1149 	    case __detail::_S_leaf:
1150 	      __kind = "Leaf";
1151 	      break;
1152 	    case __detail::_S_function:
1153 	      __kind = "Function";
1154 	      break;
1155 	    case __detail::_S_substringfn:
1156 	      __kind = "Function representing substring";
1157 	      break;
1158 	    default:
1159 	      __kind = "(corrupted kind field!)";
1160 	    }
1161 #ifdef __GC
1162 	  printf("%s %p (depth = %d, len = %ld) ",
1163 		 __kind, __r, __r->_M_depth, __r->_M_size);
1164 #else
1165 	  printf("%s %p (rc = %ld, depth = %d, len = %ld) ",
1166 		 __kind, __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size);
1167 #endif
1168 	  if (_S_is_one_byte_char_type((_CharT*)0))
1169 	    {
1170 	      const int __max_len = 40;
1171 	      _Self_destruct_ptr __prefix(_S_substring(__r, 0, __max_len));
1172 	      _CharT __buffer[__max_len + 1];
1173 	      bool __too_big = __r->_M_size > __prefix->_M_size;
1174 
1175 	      _S_flatten(__prefix, __buffer);
1176 	      __buffer[__prefix->_M_size] = _S_eos((_CharT*)0);
1177 	      printf("%s%s\n", (char*)__buffer,
1178 		     __too_big? "...\n" : "\n");
1179 	    }
1180 	  else
1181 	    printf("\n");
1182 	}
1183     }
1184 
1185   template <class _CharT, class _Alloc>
1186     const unsigned long
1187     rope<_CharT, _Alloc>::
1188     _S_min_len[int(__detail::_S_max_rope_depth) + 1] = {
1189       /* 0 */1, /* 1 */2, /* 2 */3, /* 3 */5, /* 4 */8, /* 5 */13, /* 6 */21,
1190       /* 7 */34, /* 8 */55, /* 9 */89, /* 10 */144, /* 11 */233, /* 12 */377,
1191       /* 13 */610, /* 14 */987, /* 15 */1597, /* 16 */2584, /* 17 */4181,
1192       /* 18 */6765, /* 19 */10946, /* 20 */17711, /* 21 */28657, /* 22 */46368,
1193       /* 23 */75025, /* 24 */121393, /* 25 */196418, /* 26 */317811,
1194       /* 27 */514229, /* 28 */832040, /* 29 */1346269, /* 30 */2178309,
1195       /* 31 */3524578, /* 32 */5702887, /* 33 */9227465, /* 34 */14930352,
1196       /* 35 */24157817, /* 36 */39088169, /* 37 */63245986, /* 38 */102334155,
1197       /* 39 */165580141, /* 40 */267914296, /* 41 */433494437,
1198       /* 42 */701408733, /* 43 */1134903170, /* 44 */1836311903,
1199       /* 45 */2971215073u };
1200   // These are Fibonacci numbers < 2**32.
1201 
1202   template <class _CharT, class _Alloc>
1203     typename rope<_CharT, _Alloc>::_RopeRep*
1204     rope<_CharT, _Alloc>::
1205     _S_balance(_RopeRep* __r)
1206     {
1207       _RopeRep* __forest[int(__detail::_S_max_rope_depth) + 1];
1208       _RopeRep* __result = 0;
1209       int __i;
1210       // Invariant:
1211       // The concatenation of forest in descending order is equal to __r.
1212       // __forest[__i]._M_size >= _S_min_len[__i]
1213       // __forest[__i]._M_depth = __i
1214       // References from forest are included in refcount.
1215 
1216       for (__i = 0; __i <= int(__detail::_S_max_rope_depth); ++__i)
1217 	__forest[__i] = 0;
1218       __try
1219 	{
1220 	  _S_add_to_forest(__r, __forest);
1221 	  for (__i = 0; __i <= int(__detail::_S_max_rope_depth); ++__i)
1222 	    if (0 != __forest[__i])
1223 	      {
1224 #ifndef __GC
1225 		_Self_destruct_ptr __old(__result);
1226 #endif
1227 		__result = _S_concat(__forest[__i], __result);
1228 		__forest[__i]->_M_unref_nonnil();
1229 #if !defined(__GC) && __cpp_exceptions
1230 		__forest[__i] = 0;
1231 #endif
1232 	      }
1233 	}
1234       __catch(...)
1235 	{
1236 	  for(__i = 0; __i <= int(__detail::_S_max_rope_depth); __i++)
1237 	    _S_unref(__forest[__i]);
1238 	  __throw_exception_again;
1239 	}
1240 
1241       if (__result->_M_depth > int(__detail::_S_max_rope_depth))
1242 	std::__throw_length_error(__N("rope::_S_balance"));
1243       return(__result);
1244     }
1245 
1246   template <class _CharT, class _Alloc>
1247     void
1248     rope<_CharT, _Alloc>::
1249     _S_add_to_forest(_RopeRep* __r, _RopeRep** __forest)
1250     {
1251       if (__r->_M_is_balanced)
1252 	{
1253 	  _S_add_leaf_to_forest(__r, __forest);
1254 	  return;
1255 	}
1256 
1257       {
1258 	_RopeConcatenation* __c = (_RopeConcatenation*)__r;
1259 
1260 	_S_add_to_forest(__c->_M_left, __forest);
1261 	_S_add_to_forest(__c->_M_right, __forest);
1262       }
1263     }
1264 
1265 
1266   template <class _CharT, class _Alloc>
1267     void
1268     rope<_CharT, _Alloc>::
1269     _S_add_leaf_to_forest(_RopeRep* __r, _RopeRep** __forest)
1270     {
1271       _RopeRep* __insertee;		// included in refcount
1272       _RopeRep* __too_tiny = 0;		// included in refcount
1273       int __i;				// forest[0..__i-1] is empty
1274       std::size_t __s = __r->_M_size;
1275 
1276       for (__i = 0; __s >= _S_min_len[__i+1]/* not this bucket */; ++__i)
1277 	{
1278 	  if (0 != __forest[__i])
1279 	    {
1280 #ifndef __GC
1281 	      _Self_destruct_ptr __old(__too_tiny);
1282 #endif
1283 	      __too_tiny = _S_concat_and_set_balanced(__forest[__i],
1284 						      __too_tiny);
1285 	      __forest[__i]->_M_unref_nonnil();
1286 	      __forest[__i] = 0;
1287 	    }
1288 	}
1289       {
1290 #ifndef __GC
1291 	_Self_destruct_ptr __old(__too_tiny);
1292 #endif
1293 	__insertee = _S_concat_and_set_balanced(__too_tiny, __r);
1294       }
1295       // Too_tiny dead, and no longer included in refcount.
1296       // Insertee is live and included.
1297       for (;; ++__i)
1298 	{
1299 	  if (0 != __forest[__i])
1300 	    {
1301 #ifndef __GC
1302 	      _Self_destruct_ptr __old(__insertee);
1303 #endif
1304 	      __insertee = _S_concat_and_set_balanced(__forest[__i],
1305 						      __insertee);
1306 	      __forest[__i]->_M_unref_nonnil();
1307 	      __forest[__i] = 0;
1308 	    }
1309 	  if (__i == int(__detail::_S_max_rope_depth)
1310 	      || __insertee->_M_size < _S_min_len[__i+1])
1311 	    {
1312 	      __forest[__i] = __insertee;
1313 	      // refcount is OK since __insertee is now dead.
1314 	      return;
1315 	    }
1316 	}
1317     }
1318 
1319   template <class _CharT, class _Alloc>
1320     _CharT
1321     rope<_CharT, _Alloc>::
1322     _S_fetch(_RopeRep* __r, size_type __i)
1323     {
1324       __GC_CONST _CharT* __cstr = __r->_M_c_string;
1325 
1326       if (0 != __cstr)
1327 	return __cstr[__i];
1328       for(;;)
1329 	{
1330 	  switch(__r->_M_tag)
1331 	    {
1332 	    case __detail::_S_concat:
1333 	      {
1334 		_RopeConcatenation* __c = (_RopeConcatenation*)__r;
1335 		_RopeRep* __left = __c->_M_left;
1336 		std::size_t __left_len = __left->_M_size;
1337 
1338 		if (__i >= __left_len)
1339 		  {
1340 		    __i -= __left_len;
1341 		    __r = __c->_M_right;
1342 		  }
1343 		else
1344 		  __r = __left;
1345 	      }
1346 	      break;
1347 	    case __detail::_S_leaf:
1348 	      {
1349 		_RopeLeaf* __l = (_RopeLeaf*)__r;
1350 		return __l->_M_data[__i];
1351 	      }
1352 	    case __detail::_S_function:
1353 	    case __detail::_S_substringfn:
1354 	      {
1355 		_RopeFunction* __f = (_RopeFunction*)__r;
1356 		_CharT __result;
1357 
1358 		(*(__f->_M_fn))(__i, 1, &__result);
1359 		return __result;
1360 	      }
1361 	    }
1362 	}
1363     }
1364 
1365 #ifndef __GC
1366   // Return a uniquely referenced character slot for the given
1367   // position, or 0 if that's not possible.
1368   template <class _CharT, class _Alloc>
1369     _CharT*
1370     rope<_CharT, _Alloc>::
1371     _S_fetch_ptr(_RopeRep* __r, size_type __i)
1372     {
1373       _RopeRep* __clrstack[__detail::_S_max_rope_depth];
1374       std::size_t __csptr = 0;
1375 
1376       for(;;)
1377 	{
1378 	  if (__r->_M_ref_count > 1)
1379 	    return 0;
1380 	  switch(__r->_M_tag)
1381 	    {
1382 	    case __detail::_S_concat:
1383 	      {
1384 		_RopeConcatenation* __c = (_RopeConcatenation*)__r;
1385 		_RopeRep* __left = __c->_M_left;
1386 		std::size_t __left_len = __left->_M_size;
1387 
1388 		if (__c->_M_c_string != 0)
1389 		  __clrstack[__csptr++] = __c;
1390 		if (__i >= __left_len)
1391 		  {
1392 		    __i -= __left_len;
1393 		    __r = __c->_M_right;
1394 		  }
1395 		else
1396 		  __r = __left;
1397 	      }
1398 	      break;
1399 	    case __detail::_S_leaf:
1400 	      {
1401 		_RopeLeaf* __l = (_RopeLeaf*)__r;
1402 		if (__l->_M_c_string != __l->_M_data && __l->_M_c_string != 0)
1403 		  __clrstack[__csptr++] = __l;
1404 		while (__csptr > 0)
1405 		  {
1406 		    -- __csptr;
1407 		    _RopeRep* __d = __clrstack[__csptr];
1408 		    __d->_M_free_c_string();
1409 		    __d->_M_c_string = 0;
1410 		  }
1411 		return __l->_M_data + __i;
1412 	      }
1413 	    case __detail::_S_function:
1414 	    case __detail::_S_substringfn:
1415 	      return 0;
1416 	    }
1417 	}
1418     }
1419 #endif /* __GC */
1420 
1421   // The following could be implemented trivially using
1422   // lexicographical_compare_3way.
1423   // We do a little more work to avoid dealing with rope iterators for
1424   // flat strings.
1425   template <class _CharT, class _Alloc>
1426     int
1427     rope<_CharT, _Alloc>::
1428     _S_compare (const _RopeRep* __left, const _RopeRep* __right)
1429     {
1430       std::size_t __left_len;
1431       std::size_t __right_len;
1432 
1433       if (0 == __right)
1434 	return 0 != __left;
1435       if (0 == __left)
1436 	return -1;
1437       __left_len = __left->_M_size;
1438       __right_len = __right->_M_size;
1439       if (__detail::_S_leaf == __left->_M_tag)
1440 	{
1441 	  _RopeLeaf* __l = (_RopeLeaf*) __left;
1442 	  if (__detail::_S_leaf == __right->_M_tag)
1443 	    {
1444 	      _RopeLeaf* __r = (_RopeLeaf*) __right;
1445 	      return lexicographical_compare_3way(__l->_M_data,
1446 						  __l->_M_data + __left_len,
1447 						  __r->_M_data, __r->_M_data
1448 						  + __right_len);
1449 	    }
1450 	  else
1451 	    {
1452 	      const_iterator __rstart(__right, 0);
1453 	      const_iterator __rend(__right, __right_len);
1454 	      return lexicographical_compare_3way(__l->_M_data, __l->_M_data
1455 						  + __left_len,
1456 						  __rstart, __rend);
1457 	    }
1458 	}
1459       else
1460 	{
1461 	  const_iterator __lstart(__left, 0);
1462 	  const_iterator __lend(__left, __left_len);
1463 	  if (__detail::_S_leaf == __right->_M_tag)
1464 	    {
1465 	      _RopeLeaf* __r = (_RopeLeaf*) __right;
1466 	      return lexicographical_compare_3way(__lstart, __lend,
1467 						  __r->_M_data, __r->_M_data
1468 						  + __right_len);
1469 	    }
1470 	  else
1471 	    {
1472 	      const_iterator __rstart(__right, 0);
1473 	      const_iterator __rend(__right, __right_len);
1474 	      return lexicographical_compare_3way(__lstart, __lend,
1475 						  __rstart, __rend);
1476 	    }
1477 	}
1478     }
1479 
1480   // Assignment to reference proxies.
1481   template <class _CharT, class _Alloc>
1482     _Rope_char_ref_proxy<_CharT, _Alloc>&
1483     _Rope_char_ref_proxy<_CharT, _Alloc>::
1484     operator=(_CharT __c)
1485     {
1486       _RopeRep* __old = _M_root->_M_tree_ptr;
1487 #ifndef __GC
1488       // First check for the case in which everything is uniquely
1489       // referenced.  In that case we can do this destructively.
1490       _CharT* __ptr = _My_rope::_S_fetch_ptr(__old, _M_pos);
1491       if (0 != __ptr)
1492 	{
1493 	  *__ptr = __c;
1494 	  return *this;
1495 	}
1496 #endif
1497       _Self_destruct_ptr __left(_My_rope::_S_substring(__old, 0, _M_pos));
1498       _Self_destruct_ptr __right(_My_rope::_S_substring(__old, _M_pos + 1,
1499 							__old->_M_size));
1500       typename _RopeRep::allocator_type __a = _M_root->_M_get_allocator();
1501       _Self_destruct_ptr __result_left(_My_rope::
1502 				       _S_destr_concat_char_iter(__left,
1503 								 &__c, 1,
1504 								 __a));
1505 
1506       _RopeRep* __result = _My_rope::_S_concat(__result_left, __right);
1507 #ifndef __GC
1508       _RopeRep::_S_unref(__old);
1509 #endif
1510       _M_root->_M_tree_ptr = __result;
1511       return *this;
1512     }
1513 
1514   template <class _CharT, class _Alloc>
1515     inline _Rope_char_ref_proxy<_CharT, _Alloc>::
1516     operator _CharT() const
1517     {
1518       if (_M_current_valid)
1519 	return _M_current;
1520       else
1521 	return _My_rope::_S_fetch(_M_root->_M_tree_ptr, _M_pos);
1522     }
1523 
1524   template <class _CharT, class _Alloc>
1525     _Rope_char_ptr_proxy<_CharT, _Alloc>
1526     _Rope_char_ref_proxy<_CharT, _Alloc>::
1527     operator&() const
1528     { return _Rope_char_ptr_proxy<_CharT, _Alloc>(*this); }
1529 
1530   template <class _CharT, class _Alloc>
1531     rope<_CharT, _Alloc>::
1532     rope(std::size_t __n, _CharT __c, const allocator_type& __a)
1533     : _Base(__a)
1534     {
1535       using std::__uninitialized_fill_n_a;
1536 
1537       rope<_CharT,_Alloc> __result;
1538       const std::size_t __exponentiate_threshold = 32;
1539       std::size_t __exponent;
1540       std::size_t __rest;
1541       _CharT* __rest_buffer;
1542       _RopeRep* __remainder;
1543       rope<_CharT, _Alloc> __remainder_rope;
1544 
1545       if (0 == __n)
1546 	return;
1547 
1548       __exponent = __n / __exponentiate_threshold;
1549       __rest = __n % __exponentiate_threshold;
1550       if (0 == __rest)
1551 	__remainder = 0;
1552       else
1553 	{
1554 	  __rest_buffer = this->_Data_allocate(_S_rounded_up_size(__rest));
1555 	  __uninitialized_fill_n_a(__rest_buffer, __rest, __c,
1556 				   _M_get_allocator());
1557 	  _S_cond_store_eos(__rest_buffer[__rest]);
1558 	  __try
1559 	    { __remainder = _S_new_RopeLeaf(__rest_buffer, __rest,
1560 					    _M_get_allocator()); }
1561 	  __catch(...)
1562 	    {
1563 	      _RopeRep::__STL_FREE_STRING(__rest_buffer, __rest,
1564 					  _M_get_allocator());
1565 	      __throw_exception_again;
1566 	    }
1567 	}
1568       __remainder_rope._M_tree_ptr = __remainder;
1569       if (__exponent != 0)
1570 	{
1571 	  _CharT* __base_buffer =
1572 	    this->_Data_allocate(_S_rounded_up_size(__exponentiate_threshold));
1573 	  _RopeLeaf* __base_leaf;
1574 	  rope __base_rope;
1575 	  __uninitialized_fill_n_a(__base_buffer, __exponentiate_threshold, __c,
1576 				   _M_get_allocator());
1577 	  _S_cond_store_eos(__base_buffer[__exponentiate_threshold]);
1578 	  __try
1579 	    {
1580 	      __base_leaf = _S_new_RopeLeaf(__base_buffer,
1581 					    __exponentiate_threshold,
1582 					    _M_get_allocator());
1583 	    }
1584 	  __catch(...)
1585 	    {
1586 	      _RopeRep::__STL_FREE_STRING(__base_buffer,
1587 					  __exponentiate_threshold,
1588 					  _M_get_allocator());
1589 	      __throw_exception_again;
1590 	    }
1591 	  __base_rope._M_tree_ptr = __base_leaf;
1592 	  if (1 == __exponent)
1593 	    __result = __base_rope;
1594 	  else
1595 	    __result = power(__base_rope, __exponent,
1596 			     _Rope_Concat_fn<_CharT, _Alloc>());
1597 
1598 	  if (0 != __remainder)
1599 	    __result += __remainder_rope;
1600 	}
1601       else
1602 	__result = __remainder_rope;
1603 
1604       this->_M_tree_ptr = __result._M_tree_ptr;
1605       this->_M_tree_ptr->_M_ref_nonnil();
1606     }
1607 
1608   template<class _CharT, class _Alloc>
1609     _CharT
1610     rope<_CharT, _Alloc>::_S_empty_c_str[1];
1611 
1612   template<class _CharT, class _Alloc>
1613     const _CharT*
1614     rope<_CharT, _Alloc>::
1615     c_str() const
1616     {
1617       if (0 == this->_M_tree_ptr)
1618 	{
1619 	  _S_empty_c_str[0] = _S_eos((_CharT*)0);  // Possibly redundant,
1620 	                                           // but probably fast.
1621 	  return _S_empty_c_str;
1622 	}
1623       __gthread_mutex_lock (&this->_M_tree_ptr->_M_c_string_lock);
1624       __GC_CONST _CharT* __result = this->_M_tree_ptr->_M_c_string;
1625       if (0 == __result)
1626 	{
1627 	  std::size_t __s = size();
1628 	  __result = this->_Data_allocate(__s + 1);
1629 	  _S_flatten(this->_M_tree_ptr, __result);
1630 	  __result[__s] = _S_eos((_CharT*)0);
1631 	  this->_M_tree_ptr->_M_c_string = __result;
1632 	}
1633       __gthread_mutex_unlock (&this->_M_tree_ptr->_M_c_string_lock);
1634       return(__result);
1635     }
1636 
1637   template<class _CharT, class _Alloc>
1638     const _CharT* rope<_CharT, _Alloc>::
1639     replace_with_c_str()
1640     {
1641       if (0 == this->_M_tree_ptr)
1642 	{
1643 	  _S_empty_c_str[0] = _S_eos((_CharT*)0);
1644 	  return _S_empty_c_str;
1645 	}
1646       __GC_CONST _CharT* __old_c_string = this->_M_tree_ptr->_M_c_string;
1647       if (__detail::_S_leaf == this->_M_tree_ptr->_M_tag
1648 	  && 0 != __old_c_string)
1649 	return(__old_c_string);
1650       std::size_t __s = size();
1651       _CharT* __result = this->_Data_allocate(_S_rounded_up_size(__s));
1652       _S_flatten(this->_M_tree_ptr, __result);
1653       __result[__s] = _S_eos((_CharT*)0);
1654       this->_M_tree_ptr->_M_unref_nonnil();
1655       this->_M_tree_ptr = _S_new_RopeLeaf(__result, __s,
1656 					  this->_M_get_allocator());
1657       return(__result);
1658     }
1659 
1660   // Algorithm specializations.  More should be added.
1661 
1662   template<class _Rope_iterator>  // was templated on CharT and Alloc
1663     void		          // VC++ workaround
1664     _Rope_rotate(_Rope_iterator __first,
1665 		 _Rope_iterator __middle,
1666 		 _Rope_iterator __last)
1667     {
1668       typedef typename _Rope_iterator::value_type _CharT;
1669       typedef typename _Rope_iterator::_allocator_type _Alloc;
1670 
1671       rope<_CharT, _Alloc>& __r(__first.container());
1672       rope<_CharT, _Alloc> __prefix = __r.substr(0, __first.index());
1673       rope<_CharT, _Alloc> __suffix =
1674 	__r.substr(__last.index(), __r.size() - __last.index());
1675       rope<_CharT, _Alloc> __part1 =
1676 	__r.substr(__middle.index(), __last.index() - __middle.index());
1677       rope<_CharT, _Alloc> __part2 =
1678 	__r.substr(__first.index(), __middle.index() - __first.index());
1679       __r = __prefix;
1680       __r += __part1;
1681       __r += __part2;
1682       __r += __suffix;
1683     }
1684 
1685 #if !defined(__GNUC__)
1686   // Appears to confuse g++
1687   inline void
1688   rotate(_Rope_iterator<char, __STL_DEFAULT_ALLOCATOR(char)> __first,
1689 	 _Rope_iterator<char, __STL_DEFAULT_ALLOCATOR(char)> __middle,
1690 	 _Rope_iterator<char, __STL_DEFAULT_ALLOCATOR(char)> __last)
1691   { _Rope_rotate(__first, __middle, __last); }
1692 #endif
1693 
1694 # if 0
1695   // Probably not useful for several reasons:
1696   // - for SGIs 7.1 compiler and probably some others,
1697   //   this forces lots of rope<wchar_t, ...> instantiations, creating a
1698   //   code bloat and compile time problem.  (Fixed in 7.2.)
1699   // - wchar_t is 4 bytes wide on most UNIX platforms, making it
1700   //   unattractive for unicode strings.  Unsigned short may be a better
1701   //   character type.
1702   inline void
1703   rotate(_Rope_iterator<wchar_t, __STL_DEFAULT_ALLOCATOR(char)> __first,
1704 	 _Rope_iterator<wchar_t, __STL_DEFAULT_ALLOCATOR(char)> __middle,
1705 	 _Rope_iterator<wchar_t, __STL_DEFAULT_ALLOCATOR(char)> __last)
1706   { _Rope_rotate(__first, __middle, __last); }
1707 # endif
1708 
1709 _GLIBCXX_END_NAMESPACE_VERSION
1710 } // namespace
1711