1// SGI's rope class implementation -*- C++ -*-
2
3// Copyright (C) 2001-2014 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
51namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
52{
53_GLIBCXX_BEGIN_NAMESPACE_VERSION
54
55  using std::size_t;
56  using std::printf;
57  using std::basic_ostream;
58  using std::__throw_length_error;
59  using std::_Destroy;
60  using std::__uninitialized_fill_n_a;
61
62  // Set buf_start, buf_end, and buf_ptr appropriately, filling tmp_buf
63  // if necessary.  Assumes _M_path_end[leaf_index] and leaf_pos are correct.
64  // Results in a valid buf_ptr if the iterator can be legitimately
65  // dereferenced.
66  template <class _CharT, class _Alloc>
67    void
68    _Rope_iterator_base<_CharT, _Alloc>::
69    _S_setbuf(_Rope_iterator_base<_CharT, _Alloc>& __x)
70    {
71      const _RopeRep* __leaf = __x._M_path_end[__x._M_leaf_index];
72      size_t __leaf_pos = __x._M_leaf_pos;
73      size_t __pos = __x._M_current_pos;
74
75      switch(__leaf->_M_tag)
76	{
77	case __detail::_S_leaf:
78	  __x._M_buf_start = ((_Rope_RopeLeaf<_CharT, _Alloc>*)__leaf)->_M_data;
79	  __x._M_buf_ptr = __x._M_buf_start + (__pos - __leaf_pos);
80	  __x._M_buf_end = __x._M_buf_start + __leaf->_M_size;
81	  break;
82	case __detail::_S_function:
83	case __detail::_S_substringfn:
84	  {
85	    size_t __len = _S_iterator_buf_len;
86	    size_t __buf_start_pos = __leaf_pos;
87	    size_t __leaf_end = __leaf_pos + __leaf->_M_size;
88	    char_producer<_CharT>* __fn = ((_Rope_RopeFunction<_CharT,
89					    _Alloc>*)__leaf)->_M_fn;
90	    if (__buf_start_pos + __len <= __pos)
91	      {
92		__buf_start_pos = __pos - __len / 4;
93		if (__buf_start_pos + __len > __leaf_end)
94		  __buf_start_pos = __leaf_end - __len;
95	      }
96	    if (__buf_start_pos + __len > __leaf_end)
97	      __len = __leaf_end - __buf_start_pos;
98	    (*__fn)(__buf_start_pos - __leaf_pos, __len, __x._M_tmp_buf);
99	    __x._M_buf_ptr = __x._M_tmp_buf + (__pos - __buf_start_pos);
100	    __x._M_buf_start = __x._M_tmp_buf;
101	    __x._M_buf_end = __x._M_tmp_buf + __len;
102	  }
103	  break;
104	default:
105	  break;
106	}
107    }
108
109  // Set path and buffer inside a rope iterator.  We assume that
110  // pos and root are already set.
111  template <class _CharT, class _Alloc>
112    void
113    _Rope_iterator_base<_CharT, _Alloc>::
114    _S_setcache(_Rope_iterator_base<_CharT, _Alloc>& __x)
115    {
116      const _RopeRep* __path[int(__detail::_S_max_rope_depth) + 1];
117      const _RopeRep* __curr_rope;
118      int __curr_depth = -1;  /* index into path    */
119      size_t __curr_start_pos = 0;
120      size_t __pos = __x._M_current_pos;
121      unsigned char __dirns = 0; // Bit vector marking right turns in the path
122
123      if (__pos >= __x._M_root->_M_size)
124	{
125	  __x._M_buf_ptr = 0;
126	  return;
127	}
128      __curr_rope = __x._M_root;
129      if (0 != __curr_rope->_M_c_string)
130	{
131	  /* Treat the root as a leaf. */
132	  __x._M_buf_start = __curr_rope->_M_c_string;
133	  __x._M_buf_end = __curr_rope->_M_c_string + __curr_rope->_M_size;
134	  __x._M_buf_ptr = __curr_rope->_M_c_string + __pos;
135	  __x._M_path_end[0] = __curr_rope;
136	  __x._M_leaf_index = 0;
137	  __x._M_leaf_pos = 0;
138	  return;
139	}
140      for(;;)
141	{
142	  ++__curr_depth;
143	  __path[__curr_depth] = __curr_rope;
144	  switch(__curr_rope->_M_tag)
145	    {
146	    case __detail::_S_leaf:
147	    case __detail::_S_function:
148	    case __detail::_S_substringfn:
149	      __x._M_leaf_pos = __curr_start_pos;
150	      goto done;
151	    case __detail::_S_concat:
152	      {
153		_Rope_RopeConcatenation<_CharT, _Alloc>* __c =
154		  (_Rope_RopeConcatenation<_CharT, _Alloc>*)__curr_rope;
155		_RopeRep* __left = __c->_M_left;
156		size_t __left_len = __left->_M_size;
157
158		__dirns <<= 1;
159		if (__pos >= __curr_start_pos + __left_len)
160		  {
161		    __dirns |= 1;
162		    __curr_rope = __c->_M_right;
163		    __curr_start_pos += __left_len;
164		  }
165		else
166		  __curr_rope = __left;
167	      }
168	      break;
169	    }
170	}
171    done:
172      // Copy last section of path into _M_path_end.
173      {
174	int __i = -1;
175	int __j = __curr_depth + 1 - int(_S_path_cache_len);
176
177	if (__j < 0) __j = 0;
178	while (__j <= __curr_depth)
179	  __x._M_path_end[++__i] = __path[__j++];
180	__x._M_leaf_index = __i;
181      }
182      __x._M_path_directions = __dirns;
183      _S_setbuf(__x);
184    }
185
186  // Specialized version of the above.  Assumes that
187  // the path cache is valid for the previous position.
188  template <class _CharT, class _Alloc>
189    void
190    _Rope_iterator_base<_CharT, _Alloc>::
191    _S_setcache_for_incr(_Rope_iterator_base<_CharT, _Alloc>& __x)
192    {
193      int __current_index = __x._M_leaf_index;
194      const _RopeRep* __current_node = __x._M_path_end[__current_index];
195      size_t __len = __current_node->_M_size;
196      size_t __node_start_pos = __x._M_leaf_pos;
197      unsigned char __dirns = __x._M_path_directions;
198      _Rope_RopeConcatenation<_CharT, _Alloc>* __c;
199
200      if (__x._M_current_pos - __node_start_pos < __len)
201	{
202	  /* More stuff in this leaf, we just didn't cache it. */
203	  _S_setbuf(__x);
204	  return;
205	}
206      //  node_start_pos is starting position of last_node.
207      while (--__current_index >= 0)
208	{
209	  if (!(__dirns & 1) /* Path turned left */)
210	    break;
211	  __current_node = __x._M_path_end[__current_index];
212	  __c = (_Rope_RopeConcatenation<_CharT, _Alloc>*)__current_node;
213	  // Otherwise we were in the right child.  Thus we should pop
214	  // the concatenation node.
215	  __node_start_pos -= __c->_M_left->_M_size;
216	  __dirns >>= 1;
217	}
218      if (__current_index < 0)
219	{
220	  // We underflowed the cache. Punt.
221	  _S_setcache(__x);
222	  return;
223	}
224      __current_node = __x._M_path_end[__current_index];
225      __c = (_Rope_RopeConcatenation<_CharT, _Alloc>*)__current_node;
226      // current_node is a concatenation node.  We are positioned on the first
227      // character in its right child.
228      // node_start_pos is starting position of current_node.
229      __node_start_pos += __c->_M_left->_M_size;
230      __current_node = __c->_M_right;
231      __x._M_path_end[++__current_index] = __current_node;
232      __dirns |= 1;
233      while (__detail::_S_concat == __current_node->_M_tag)
234	{
235	  ++__current_index;
236	  if (int(_S_path_cache_len) == __current_index)
237	    {
238	      int __i;
239	      for (__i = 0; __i < int(_S_path_cache_len) - 1; __i++)
240		__x._M_path_end[__i] = __x._M_path_end[__i+1];
241	      --__current_index;
242	    }
243	  __current_node =
244	    ((_Rope_RopeConcatenation<_CharT, _Alloc>*)__current_node)->_M_left;
245	  __x._M_path_end[__current_index] = __current_node;
246	  __dirns <<= 1;
247	  // node_start_pos is unchanged.
248	}
249      __x._M_leaf_index = __current_index;
250      __x._M_leaf_pos = __node_start_pos;
251      __x._M_path_directions = __dirns;
252      _S_setbuf(__x);
253    }
254
255  template <class _CharT, class _Alloc>
256    void
257    _Rope_iterator_base<_CharT, _Alloc>::
258    _M_incr(size_t __n)
259    {
260      _M_current_pos += __n;
261      if (0 != _M_buf_ptr)
262	{
263	  size_t __chars_left = _M_buf_end - _M_buf_ptr;
264	  if (__chars_left > __n)
265	    _M_buf_ptr += __n;
266	  else if (__chars_left == __n)
267	    {
268	      _M_buf_ptr += __n;
269	      _S_setcache_for_incr(*this);
270	    }
271	  else
272	    _M_buf_ptr = 0;
273	}
274    }
275
276  template <class _CharT, class _Alloc>
277    void
278    _Rope_iterator_base<_CharT, _Alloc>::
279    _M_decr(size_t __n)
280    {
281      if (0 != _M_buf_ptr)
282	{
283	  size_t __chars_left = _M_buf_ptr - _M_buf_start;
284	  if (__chars_left >= __n)
285	    _M_buf_ptr -= __n;
286	  else
287	    _M_buf_ptr = 0;
288	}
289      _M_current_pos -= __n;
290    }
291
292  template <class _CharT, class _Alloc>
293    void
294    _Rope_iterator<_CharT, _Alloc>::
295    _M_check()
296    {
297      if (_M_root_rope->_M_tree_ptr != this->_M_root)
298	{
299	  // _Rope was modified.  Get things fixed up.
300	  _RopeRep::_S_unref(this->_M_root);
301	  this->_M_root = _M_root_rope->_M_tree_ptr;
302	  _RopeRep::_S_ref(this->_M_root);
303	  this->_M_buf_ptr = 0;
304	}
305    }
306
307  template <class _CharT, class _Alloc>
308    inline
309    _Rope_const_iterator<_CharT, _Alloc>::
310    _Rope_const_iterator(const _Rope_iterator<_CharT, _Alloc>& __x)
311    : _Rope_iterator_base<_CharT, _Alloc>(__x)
312    { }
313
314  template <class _CharT, class _Alloc>
315    inline
316    _Rope_iterator<_CharT, _Alloc>::
317    _Rope_iterator(rope<_CharT, _Alloc>& __r, size_t __pos)
318    : _Rope_iterator_base<_CharT,_Alloc>(__r._M_tree_ptr, __pos),
319      _M_root_rope(&__r)
320    { _RopeRep::_S_ref(this->_M_root); }
321
322  template <class _CharT, class _Alloc>
323    inline size_t
324    rope<_CharT, _Alloc>::
325    _S_char_ptr_len(const _CharT* __s)
326    {
327      const _CharT* __p = __s;
328
329      while (!_S_is0(*__p))
330	++__p;
331      return (__p - __s);
332    }
333
334
335#ifndef __GC
336
337  template <class _CharT, class _Alloc>
338    inline void
339    _Rope_RopeRep<_CharT, _Alloc>::
340    _M_free_c_string()
341    {
342      _CharT* __cstr = _M_c_string;
343      if (0 != __cstr)
344	{
345	  size_t __size = this->_M_size + 1;
346	  _Destroy(__cstr, __cstr + __size, _M_get_allocator());
347	  this->_Data_deallocate(__cstr, __size);
348	}
349    }
350
351  template <class _CharT, class _Alloc>
352    inline void
353    _Rope_RopeRep<_CharT, _Alloc>::
354    _S_free_string(_CharT* __s, size_t __n, allocator_type& __a)
355    {
356      if (!_S_is_basic_char_type((_CharT*)0))
357	_Destroy(__s, __s + __n, __a);
358
359      //  This has to be a static member, so this gets a bit messy
360      __a.deallocate(__s,
361		     _Rope_RopeLeaf<_CharT, _Alloc>::_S_rounded_up_size(__n));
362    }
363
364  //  There are several reasons for not doing this with virtual destructors
365  //  and a class specific delete operator:
366  //  - A class specific delete operator can't easily get access to
367  //    allocator instances if we need them.
368  //  - Any virtual function would need a 4 or byte vtable pointer;
369  //    this only requires a one byte tag per object.
370  template <class _CharT, class _Alloc>
371    void
372    _Rope_RopeRep<_CharT, _Alloc>::
373    _M_free_tree()
374    {
375      switch(_M_tag)
376	{
377	case __detail::_S_leaf:
378	  {
379	    _Rope_RopeLeaf<_CharT, _Alloc>* __l
380	      = (_Rope_RopeLeaf<_CharT, _Alloc>*)this;
381	    __l->_Rope_RopeLeaf<_CharT, _Alloc>::~_Rope_RopeLeaf();
382	    this->_L_deallocate(__l, 1);
383	    break;
384	  }
385	case __detail::_S_concat:
386	  {
387	    _Rope_RopeConcatenation<_CharT,_Alloc>* __c
388	      = (_Rope_RopeConcatenation<_CharT, _Alloc>*)this;
389	    __c->_Rope_RopeConcatenation<_CharT, _Alloc>::
390	      ~_Rope_RopeConcatenation();
391	    this->_C_deallocate(__c, 1);
392	    break;
393	  }
394	case __detail::_S_function:
395	  {
396	    _Rope_RopeFunction<_CharT, _Alloc>* __f
397	      = (_Rope_RopeFunction<_CharT, _Alloc>*)this;
398	    __f->_Rope_RopeFunction<_CharT, _Alloc>::~_Rope_RopeFunction();
399	    this->_F_deallocate(__f, 1);
400	    break;
401	  }
402	case __detail::_S_substringfn:
403	  {
404	    _Rope_RopeSubstring<_CharT, _Alloc>* __ss =
405	      (_Rope_RopeSubstring<_CharT, _Alloc>*)this;
406	    __ss->_Rope_RopeSubstring<_CharT, _Alloc>::
407	      ~_Rope_RopeSubstring();
408	    this->_S_deallocate(__ss, 1);
409	    break;
410	  }
411	}
412    }
413#else
414
415  template <class _CharT, class _Alloc>
416    inline void
417    _Rope_RopeRep<_CharT, _Alloc>::
418    _S_free_string(const _CharT*, size_t, allocator_type)
419    { }
420
421#endif
422
423  // Concatenate a C string onto a leaf rope by copying the rope data.
424  // Used for short ropes.
425  template <class _CharT, class _Alloc>
426    typename rope<_CharT, _Alloc>::_RopeLeaf*
427    rope<_CharT, _Alloc>::
428    _S_leaf_concat_char_iter(_RopeLeaf* __r, const _CharT* __iter, size_t __len)
429    {
430      size_t __old_len = __r->_M_size;
431      _CharT* __new_data = (_CharT*)
432	rope::_Data_allocate(_S_rounded_up_size(__old_len + __len));
433      _RopeLeaf* __result;
434
435      uninitialized_copy_n(__r->_M_data, __old_len, __new_data);
436      uninitialized_copy_n(__iter, __len, __new_data + __old_len);
437      _S_cond_store_eos(__new_data[__old_len + __len]);
438      __try
439	{
440	  __result = _S_new_RopeLeaf(__new_data, __old_len + __len,
441				     __r->_M_get_allocator());
442	}
443      __catch(...)
444	{
445	  _RopeRep::__STL_FREE_STRING(__new_data, __old_len + __len,
446				      __r->_M_get_allocator());
447	  __throw_exception_again;
448	}
449      return __result;
450    }
451
452#ifndef __GC
453  // As above, but it's OK to clobber original if refcount is 1
454  template <class _CharT, class _Alloc>
455    typename rope<_CharT,_Alloc>::_RopeLeaf*
456    rope<_CharT, _Alloc>::
457    _S_destr_leaf_concat_char_iter(_RopeLeaf* __r, const _CharT* __iter,
458				   size_t __len)
459    {
460      if (__r->_M_ref_count > 1)
461	return _S_leaf_concat_char_iter(__r, __iter, __len);
462      size_t __old_len = __r->_M_size;
463      if (_S_allocated_capacity(__old_len) >= __old_len + __len)
464	{
465	  // The space has been partially initialized for the standard
466	  // character types.  But that doesn't matter for those types.
467	  uninitialized_copy_n(__iter, __len, __r->_M_data + __old_len);
468	  if (_S_is_basic_char_type((_CharT*)0))
469	    _S_cond_store_eos(__r->_M_data[__old_len + __len]);
470	  else if (__r->_M_c_string != __r->_M_data && 0 != __r->_M_c_string)
471	    {
472	      __r->_M_free_c_string();
473	      __r->_M_c_string = 0;
474	    }
475	  __r->_M_size = __old_len + __len;
476	  __r->_M_ref_count = 2;
477	  return __r;
478	}
479      else
480	{
481	  _RopeLeaf* __result = _S_leaf_concat_char_iter(__r, __iter, __len);
482	  return __result;
483	}
484    }
485#endif
486
487  // Assumes left and right are not 0.
488  // Does not increment (nor decrement on exception) child reference counts.
489  // Result has ref count 1.
490  template <class _CharT, class _Alloc>
491    typename rope<_CharT, _Alloc>::_RopeRep*
492    rope<_CharT, _Alloc>::
493    _S_tree_concat(_RopeRep* __left, _RopeRep* __right)
494    {
495      _RopeConcatenation* __result = _S_new_RopeConcatenation(__left, __right,
496							      __left->
497							      _M_get_allocator());
498      size_t __depth = __result->_M_depth;
499
500      if (__depth > 20
501	  && (__result->_M_size < 1000
502	      || __depth > size_t(__detail::_S_max_rope_depth)))
503	{
504	  _RopeRep* __balanced;
505
506	  __try
507	    {
508	      __balanced = _S_balance(__result);
509	      __result->_M_unref_nonnil();
510	    }
511	  __catch(...)
512	    {
513	      rope::_C_deallocate(__result,1);
514	      __throw_exception_again;
515	    }
516	  // In case of exception, we need to deallocate
517	  // otherwise dangling result node.  But caller
518	  // still owns its children.  Thus unref is
519	  // inappropriate.
520	  return __balanced;
521	}
522      else
523	return __result;
524    }
525
526  template <class _CharT, class _Alloc>
527    typename rope<_CharT, _Alloc>::_RopeRep*
528    rope<_CharT, _Alloc>::
529    _S_concat_char_iter(_RopeRep* __r, const _CharT*__s, size_t __slen)
530    {
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,
539						__r->_M_get_allocator());
540      if (__r->_M_tag == __detail::_S_leaf
541	  && __r->_M_size + __slen <= size_t(_S_copy_max))
542	{
543	  __result = _S_leaf_concat_char_iter((_RopeLeaf*)__r, __s, __slen);
544	  return __result;
545	}
546      if (__detail::_S_concat == __r->_M_tag
547	  && __detail::_S_leaf == ((_RopeConcatenation*) __r)->_M_right->_M_tag)
548	{
549	  _RopeLeaf* __right =
550	    (_RopeLeaf* )(((_RopeConcatenation* )__r)->_M_right);
551	  if (__right->_M_size + __slen <= size_t(_S_copy_max))
552	    {
553	      _RopeRep* __left = ((_RopeConcatenation*)__r)->_M_left;
554	      _RopeRep* __nright =
555		_S_leaf_concat_char_iter((_RopeLeaf*)__right, __s, __slen);
556	      __left->_M_ref_nonnil();
557	      __try
558		{ __result = _S_tree_concat(__left, __nright); }
559	      __catch(...)
560		{
561		  _S_unref(__left);
562		  _S_unref(__nright);
563		  __throw_exception_again;
564		}
565	      return __result;
566	    }
567	}
568      _RopeRep* __nright =
569	__STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen, __r->_M_get_allocator());
570      __try
571	{
572	  __r->_M_ref_nonnil();
573	  __result = _S_tree_concat(__r, __nright);
574	}
575      __catch(...)
576	{
577	  _S_unref(__r);
578	  _S_unref(__nright);
579	  __throw_exception_again;
580	}
581      return __result;
582    }
583
584#ifndef __GC
585  template <class _CharT, class _Alloc>
586    typename rope<_CharT,_Alloc>::_RopeRep*
587    rope<_CharT,_Alloc>::
588    _S_destr_concat_char_iter(_RopeRep* __r, const _CharT* __s, size_t __slen)
589    {
590      _RopeRep* __result;
591      if (0 == __r)
592	return __STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen,
593						__r->_M_get_allocator());
594      size_t __count = __r->_M_ref_count;
595      size_t __orig_size = __r->_M_size;
596      if (__count > 1)
597	return _S_concat_char_iter(__r, __s, __slen);
598      if (0 == __slen)
599	{
600	  __r->_M_ref_count = 2;      // One more than before
601	  return __r;
602	}
603      if (__orig_size + __slen <= size_t(_S_copy_max)
604	  && __detail::_S_leaf == __r->_M_tag)
605	{
606	  __result = _S_destr_leaf_concat_char_iter((_RopeLeaf*)__r, __s,
607						    __slen);
608	  return __result;
609	}
610      if (__detail::_S_concat == __r->_M_tag)
611	{
612	  _RopeLeaf* __right = (_RopeLeaf*)(((_RopeConcatenation*)
613					     __r)->_M_right);
614	  if (__detail::_S_leaf == __right->_M_tag
615	      && __right->_M_size + __slen <= size_t(_S_copy_max))
616	    {
617	      _RopeRep* __new_right =
618		_S_destr_leaf_concat_char_iter(__right, __s, __slen);
619	      if (__right == __new_right)
620		__new_right->_M_ref_count = 1;
621	      else
622		__right->_M_unref_nonnil();
623	      __r->_M_ref_count = 2;    // One more than before.
624	      ((_RopeConcatenation*)__r)->_M_right = __new_right;
625	      __r->_M_size = __orig_size + __slen;
626	      if (0 != __r->_M_c_string)
627		{
628		  __r->_M_free_c_string();
629		  __r->_M_c_string = 0;
630		}
631	      return __r;
632	    }
633	}
634      _RopeRep* __right =
635	__STL_ROPE_FROM_UNOWNED_CHAR_PTR(__s, __slen, __r->_M_get_allocator());
636      __r->_M_ref_nonnil();
637      __try
638	{ __result = _S_tree_concat(__r, __right); }
639      __catch(...)
640	{
641	  _S_unref(__r);
642	  _S_unref(__right);
643	  __throw_exception_again;
644	}
645      return __result;
646    }
647#endif /* !__GC */
648
649  template <class _CharT, class _Alloc>
650    typename rope<_CharT, _Alloc>::_RopeRep*
651    rope<_CharT, _Alloc>::
652    _S_concat(_RopeRep* __left, _RopeRep* __right)
653    {
654      if (0 == __left)
655	{
656	  _S_ref(__right);
657	  return __right;
658	}
659      if (0 == __right)
660	{
661	  __left->_M_ref_nonnil();
662	  return __left;
663	}
664      if (__detail::_S_leaf == __right->_M_tag)
665	{
666	  if (__detail::_S_leaf == __left->_M_tag)
667	    {
668	      if (__right->_M_size + __left->_M_size <= size_t(_S_copy_max))
669		return _S_leaf_concat_char_iter((_RopeLeaf*)__left,
670						((_RopeLeaf*)__right)->_M_data,
671						__right->_M_size);
672	    }
673	  else if (__detail::_S_concat == __left->_M_tag
674		   && __detail::_S_leaf == ((_RopeConcatenation*)
675						   __left)->_M_right->_M_tag)
676	    {
677	      _RopeLeaf* __leftright =
678		(_RopeLeaf*)(((_RopeConcatenation*)__left)->_M_right);
679	      if (__leftright->_M_size
680		  + __right->_M_size <= size_t(_S_copy_max))
681		{
682		  _RopeRep* __leftleft = ((_RopeConcatenation*)__left)->_M_left;
683		  _RopeRep* __rest = _S_leaf_concat_char_iter(__leftright,
684							      ((_RopeLeaf*)
685							       __right)->
686							      _M_data,
687							      __right->_M_size);
688		  __leftleft->_M_ref_nonnil();
689		  __try
690		    { return(_S_tree_concat(__leftleft, __rest)); }
691		  __catch(...)
692		    {
693		      _S_unref(__leftleft);
694		      _S_unref(__rest);
695		      __throw_exception_again;
696		    }
697		}
698	    }
699	}
700      __left->_M_ref_nonnil();
701      __right->_M_ref_nonnil();
702      __try
703	{ return(_S_tree_concat(__left, __right)); }
704      __catch(...)
705	{
706	  _S_unref(__left);
707	  _S_unref(__right);
708	  __throw_exception_again;
709	}
710    }
711
712  template <class _CharT, class _Alloc>
713    typename rope<_CharT, _Alloc>::_RopeRep*
714    rope<_CharT, _Alloc>::
715    _S_substring(_RopeRep* __base, size_t __start, size_t __endp1)
716    {
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, 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      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, size_t __n)
876      {
877	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 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, 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, size_t __n)
911    {
912      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,
923		       const _RopeRep* __r, size_t __begin, size_t __end)
924    {
925      if (0 == __r)
926	return true;
927      switch(__r->_M_tag)
928	{
929	case __detail::_S_concat:
930	  {
931	    _RopeConcatenation* __conc = (_RopeConcatenation*)__r;
932	    _RopeRep* __left =  __conc->_M_left;
933	    size_t __left_len = __left->_M_size;
934	    if (__begin < __left_len)
935	      {
936		size_t __left_end = std::min(__left_len, __end);
937		if (!_S_apply_to_pieces(__c, __left, __begin, __left_end))
938		  return false;
939	      }
940	    if (__end > __left_len)
941	      {
942		_RopeRep* __right =  __conc->_M_right;
943		size_t __right_start = std::max(__left_len, __begin);
944		if (!_S_apply_to_pieces(__c, __right,
945					__right_start - __left_len,
946					__end - __left_len))
947		  return false;
948	      }
949	  }
950	  return true;
951	case __detail::_S_leaf:
952	  {
953	    _RopeLeaf* __l = (_RopeLeaf*)__r;
954	    return __c(__l->_M_data + __begin, __end - __begin);
955	  }
956	case __detail::_S_function:
957	case __detail::_S_substringfn:
958	    {
959	      _RopeFunction* __f = (_RopeFunction*)__r;
960	      size_t __len = __end - __begin;
961	      bool __result;
962	      _CharT* __buffer =
963		(_CharT*)_Alloc().allocate(__len * sizeof(_CharT));
964	      __try
965		{
966		  (*(__f->_M_fn))(__begin, __len, __buffer);
967		  __result = __c(__buffer, __len);
968                  _Alloc().deallocate(__buffer, __len * sizeof(_CharT));
969                }
970	      __catch(...)
971		{
972		  _Alloc().deallocate(__buffer, __len * sizeof(_CharT));
973		  __throw_exception_again;
974		}
975	      return __result;
976	    }
977	default:
978	  return false;
979	}
980    }
981
982  template<class _CharT, class _Traits>
983    inline void
984    _Rope_fill(basic_ostream<_CharT, _Traits>& __o, size_t __n)
985    {
986      char __f = __o.fill();
987      size_t __i;
988
989      for (__i = 0; __i < __n; __i++)
990	__o.put(__f);
991    }
992
993
994  template <class _CharT>
995    inline bool
996    _Rope_is_simple(_CharT*)
997    { return false; }
998
999  inline bool
1000  _Rope_is_simple(char*)
1001  { return true; }
1002
1003  inline bool
1004  _Rope_is_simple(wchar_t*)
1005  { return true; }
1006
1007  template<class _CharT, class _Traits, class _Alloc>
1008    basic_ostream<_CharT, _Traits>&
1009    operator<<(basic_ostream<_CharT, _Traits>& __o,
1010	       const rope<_CharT, _Alloc>& __r)
1011    {
1012      size_t __w = __o.width();
1013      bool __left = bool(__o.flags() & std::ios::left);
1014      size_t __pad_len;
1015      size_t __rope_len = __r.size();
1016      _Rope_insert_char_consumer<_CharT, _Traits> __c(__o);
1017      bool __is_simple = _Rope_is_simple((_CharT*)0);
1018
1019      if (__rope_len < __w)
1020	__pad_len = __w - __rope_len;
1021      else
1022	__pad_len = 0;
1023
1024      if (!__is_simple)
1025	__o.width(__w / __rope_len);
1026      __try
1027	{
1028	  if (__is_simple && !__left && __pad_len > 0)
1029	    _Rope_fill(__o, __pad_len);
1030	  __r.apply_to_pieces(0, __r.size(), __c);
1031	  if (__is_simple && __left && __pad_len > 0)
1032	    _Rope_fill(__o, __pad_len);
1033	  if (!__is_simple)
1034	    __o.width(__w);
1035	}
1036      __catch(...)
1037	{
1038	  if (!__is_simple)
1039	    __o.width(__w);
1040	  __throw_exception_again;
1041	}
1042      return __o;
1043    }
1044
1045  template <class _CharT, class _Alloc>
1046    _CharT*
1047    rope<_CharT, _Alloc>::
1048    _S_flatten(_RopeRep* __r, size_t __start, size_t __len,
1049	       _CharT* __buffer)
1050    {
1051      _Rope_flatten_char_consumer<_CharT> __c(__buffer);
1052      _S_apply_to_pieces(__c, __r, __start, __start + __len);
1053      return(__buffer + __len);
1054    }
1055
1056  template <class _CharT, class _Alloc>
1057    size_t
1058    rope<_CharT, _Alloc>::
1059    find(_CharT __pattern, size_t __start) const
1060    {
1061      _Rope_find_char_char_consumer<_CharT> __c(__pattern);
1062      _S_apply_to_pieces(__c, this->_M_tree_ptr, __start, size());
1063      size_type __result_pos = __start + __c._M_count;
1064#ifndef __STL_OLD_ROPE_SEMANTICS
1065      if (__result_pos == size())
1066	__result_pos = npos;
1067#endif
1068      return __result_pos;
1069    }
1070
1071  template <class _CharT, class _Alloc>
1072    _CharT*
1073    rope<_CharT, _Alloc>::
1074    _S_flatten(_RopeRep* __r, _CharT* __buffer)
1075    {
1076      if (0 == __r)
1077	return __buffer;
1078      switch(__r->_M_tag)
1079	{
1080	case __detail::_S_concat:
1081	  {
1082	    _RopeConcatenation* __c = (_RopeConcatenation*)__r;
1083	    _RopeRep* __left = __c->_M_left;
1084	    _RopeRep* __right = __c->_M_right;
1085	    _CharT* __rest = _S_flatten(__left, __buffer);
1086	    return _S_flatten(__right, __rest);
1087	  }
1088	case __detail::_S_leaf:
1089	  {
1090	    _RopeLeaf* __l = (_RopeLeaf*)__r;
1091	    return copy_n(__l->_M_data, __l->_M_size, __buffer).second;
1092	  }
1093	case __detail::_S_function:
1094	case __detail::_S_substringfn:
1095	  // We don't yet do anything with substring nodes.
1096	  // This needs to be fixed before ropefiles will work well.
1097	  {
1098	    _RopeFunction* __f = (_RopeFunction*)__r;
1099	    (*(__f->_M_fn))(0, __f->_M_size, __buffer);
1100	    return __buffer + __f->_M_size;
1101	  }
1102	default:
1103	  return 0;
1104	}
1105    }
1106
1107  // This needs work for _CharT != char
1108  template <class _CharT, class _Alloc>
1109    void
1110    rope<_CharT, _Alloc>::
1111    _S_dump(_RopeRep* __r, int __indent)
1112    {
1113      for (int __i = 0; __i < __indent; __i++)
1114	putchar(' ');
1115      if (0 == __r)
1116	{
1117	  printf("NULL\n");
1118	  return;
1119	}
1120      if (_S_concat == __r->_M_tag)
1121	{
1122	  _RopeConcatenation* __c = (_RopeConcatenation*)__r;
1123	  _RopeRep* __left = __c->_M_left;
1124	  _RopeRep* __right = __c->_M_right;
1125
1126#ifdef __GC
1127	  printf("Concatenation %p (depth = %d, len = %ld, %s balanced)\n",
1128		 __r, __r->_M_depth, __r->_M_size,
1129		 __r->_M_is_balanced? "" : "not");
1130#else
1131	  printf("Concatenation %p (rc = %ld, depth = %d, "
1132		 "len = %ld, %s balanced)\n",
1133		 __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size,
1134		 __r->_M_is_balanced? "" : "not");
1135#endif
1136	  _S_dump(__left, __indent + 2);
1137	  _S_dump(__right, __indent + 2);
1138	  return;
1139	}
1140      else
1141	{
1142	  char* __kind;
1143
1144	  switch (__r->_M_tag)
1145	    {
1146	    case __detail::_S_leaf:
1147	      __kind = "Leaf";
1148	      break;
1149	    case __detail::_S_function:
1150	      __kind = "Function";
1151	      break;
1152	    case __detail::_S_substringfn:
1153	      __kind = "Function representing substring";
1154	      break;
1155	    default:
1156	      __kind = "(corrupted kind field!)";
1157	    }
1158#ifdef __GC
1159	  printf("%s %p (depth = %d, len = %ld) ",
1160		 __kind, __r, __r->_M_depth, __r->_M_size);
1161#else
1162	  printf("%s %p (rc = %ld, depth = %d, len = %ld) ",
1163		 __kind, __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size);
1164#endif
1165	  if (_S_is_one_byte_char_type((_CharT*)0))
1166	    {
1167	      const int __max_len = 40;
1168	      _Self_destruct_ptr __prefix(_S_substring(__r, 0, __max_len));
1169	      _CharT __buffer[__max_len + 1];
1170	      bool __too_big = __r->_M_size > __prefix->_M_size;
1171
1172	      _S_flatten(__prefix, __buffer);
1173	      __buffer[__prefix->_M_size] = _S_eos((_CharT*)0);
1174	      printf("%s%s\n", (char*)__buffer,
1175		     __too_big? "...\n" : "\n");
1176	    }
1177	  else
1178	    printf("\n");
1179	}
1180    }
1181
1182  template <class _CharT, class _Alloc>
1183    const unsigned long
1184    rope<_CharT, _Alloc>::
1185    _S_min_len[int(__detail::_S_max_rope_depth) + 1] = {
1186      /* 0 */1, /* 1 */2, /* 2 */3, /* 3 */5, /* 4 */8, /* 5 */13, /* 6 */21,
1187      /* 7 */34, /* 8 */55, /* 9 */89, /* 10 */144, /* 11 */233, /* 12 */377,
1188      /* 13 */610, /* 14 */987, /* 15 */1597, /* 16 */2584, /* 17 */4181,
1189      /* 18 */6765, /* 19 */10946, /* 20 */17711, /* 21 */28657, /* 22 */46368,
1190      /* 23 */75025, /* 24 */121393, /* 25 */196418, /* 26 */317811,
1191      /* 27 */514229, /* 28 */832040, /* 29 */1346269, /* 30 */2178309,
1192      /* 31 */3524578, /* 32 */5702887, /* 33 */9227465, /* 34 */14930352,
1193      /* 35 */24157817, /* 36 */39088169, /* 37 */63245986, /* 38 */102334155,
1194      /* 39 */165580141, /* 40 */267914296, /* 41 */433494437,
1195      /* 42 */701408733, /* 43 */1134903170, /* 44 */1836311903,
1196      /* 45 */2971215073u };
1197  // These are Fibonacci numbers < 2**32.
1198
1199  template <class _CharT, class _Alloc>
1200    typename rope<_CharT, _Alloc>::_RopeRep*
1201    rope<_CharT, _Alloc>::
1202    _S_balance(_RopeRep* __r)
1203    {
1204      _RopeRep* __forest[int(__detail::_S_max_rope_depth) + 1];
1205      _RopeRep* __result = 0;
1206      int __i;
1207      // Invariant:
1208      // The concatenation of forest in descending order is equal to __r.
1209      // __forest[__i]._M_size >= _S_min_len[__i]
1210      // __forest[__i]._M_depth = __i
1211      // References from forest are included in refcount.
1212
1213      for (__i = 0; __i <= int(__detail::_S_max_rope_depth); ++__i)
1214	__forest[__i] = 0;
1215      __try
1216	{
1217	  _S_add_to_forest(__r, __forest);
1218	  for (__i = 0; __i <= int(__detail::_S_max_rope_depth); ++__i)
1219	    if (0 != __forest[__i])
1220	      {
1221#ifndef __GC
1222		_Self_destruct_ptr __old(__result);
1223#endif
1224		__result = _S_concat(__forest[__i], __result);
1225		__forest[__i]->_M_unref_nonnil();
1226#if !defined(__GC) && defined(__EXCEPTIONS)
1227		__forest[__i] = 0;
1228#endif
1229	      }
1230	}
1231      __catch(...)
1232	{
1233	  for(__i = 0; __i <= int(__detail::_S_max_rope_depth); __i++)
1234	    _S_unref(__forest[__i]);
1235	  __throw_exception_again;
1236	}
1237
1238      if (__result->_M_depth > int(__detail::_S_max_rope_depth))
1239	__throw_length_error(__N("rope::_S_balance"));
1240      return(__result);
1241    }
1242
1243  template <class _CharT, class _Alloc>
1244    void
1245    rope<_CharT, _Alloc>::
1246    _S_add_to_forest(_RopeRep* __r, _RopeRep** __forest)
1247    {
1248      if (__r->_M_is_balanced)
1249	{
1250	  _S_add_leaf_to_forest(__r, __forest);
1251	  return;
1252	}
1253
1254      {
1255	_RopeConcatenation* __c = (_RopeConcatenation*)__r;
1256
1257	_S_add_to_forest(__c->_M_left, __forest);
1258	_S_add_to_forest(__c->_M_right, __forest);
1259      }
1260    }
1261
1262
1263  template <class _CharT, class _Alloc>
1264    void
1265    rope<_CharT, _Alloc>::
1266    _S_add_leaf_to_forest(_RopeRep* __r, _RopeRep** __forest)
1267    {
1268      _RopeRep* __insertee;		// included in refcount
1269      _RopeRep* __too_tiny = 0;		// included in refcount
1270      int __i;				// forest[0..__i-1] is empty
1271      size_t __s = __r->_M_size;
1272
1273      for (__i = 0; __s >= _S_min_len[__i+1]/* not this bucket */; ++__i)
1274	{
1275	  if (0 != __forest[__i])
1276	    {
1277#ifndef __GC
1278	      _Self_destruct_ptr __old(__too_tiny);
1279#endif
1280	      __too_tiny = _S_concat_and_set_balanced(__forest[__i],
1281						      __too_tiny);
1282	      __forest[__i]->_M_unref_nonnil();
1283	      __forest[__i] = 0;
1284	    }
1285	}
1286      {
1287#ifndef __GC
1288	_Self_destruct_ptr __old(__too_tiny);
1289#endif
1290	__insertee = _S_concat_and_set_balanced(__too_tiny, __r);
1291      }
1292      // Too_tiny dead, and no longer included in refcount.
1293      // Insertee is live and included.
1294      for (;; ++__i)
1295	{
1296	  if (0 != __forest[__i])
1297	    {
1298#ifndef __GC
1299	      _Self_destruct_ptr __old(__insertee);
1300#endif
1301	      __insertee = _S_concat_and_set_balanced(__forest[__i],
1302						      __insertee);
1303	      __forest[__i]->_M_unref_nonnil();
1304	      __forest[__i] = 0;
1305	    }
1306	  if (__i == int(__detail::_S_max_rope_depth)
1307	      || __insertee->_M_size < _S_min_len[__i+1])
1308	    {
1309	      __forest[__i] = __insertee;
1310	      // refcount is OK since __insertee is now dead.
1311	      return;
1312	    }
1313	}
1314    }
1315
1316  template <class _CharT, class _Alloc>
1317    _CharT
1318    rope<_CharT, _Alloc>::
1319    _S_fetch(_RopeRep* __r, size_type __i)
1320    {
1321      __GC_CONST _CharT* __cstr = __r->_M_c_string;
1322
1323      if (0 != __cstr)
1324	return __cstr[__i];
1325      for(;;)
1326	{
1327	  switch(__r->_M_tag)
1328	    {
1329	    case __detail::_S_concat:
1330	      {
1331		_RopeConcatenation* __c = (_RopeConcatenation*)__r;
1332		_RopeRep* __left = __c->_M_left;
1333		size_t __left_len = __left->_M_size;
1334
1335		if (__i >= __left_len)
1336		  {
1337		    __i -= __left_len;
1338		    __r = __c->_M_right;
1339		  }
1340		else
1341		  __r = __left;
1342	      }
1343	      break;
1344	    case __detail::_S_leaf:
1345	      {
1346		_RopeLeaf* __l = (_RopeLeaf*)__r;
1347		return __l->_M_data[__i];
1348	      }
1349	    case __detail::_S_function:
1350	    case __detail::_S_substringfn:
1351	      {
1352		_RopeFunction* __f = (_RopeFunction*)__r;
1353		_CharT __result;
1354
1355		(*(__f->_M_fn))(__i, 1, &__result);
1356		return __result;
1357	      }
1358	    }
1359	}
1360    }
1361
1362#ifndef __GC
1363  // Return a uniquely referenced character slot for the given
1364  // position, or 0 if that's not possible.
1365  template <class _CharT, class _Alloc>
1366    _CharT*
1367    rope<_CharT, _Alloc>::
1368    _S_fetch_ptr(_RopeRep* __r, size_type __i)
1369    {
1370      _RopeRep* __clrstack[__detail::_S_max_rope_depth];
1371      size_t __csptr = 0;
1372
1373      for(;;)
1374	{
1375	  if (__r->_M_ref_count > 1)
1376	    return 0;
1377	  switch(__r->_M_tag)
1378	    {
1379	    case __detail::_S_concat:
1380	      {
1381		_RopeConcatenation* __c = (_RopeConcatenation*)__r;
1382		_RopeRep* __left = __c->_M_left;
1383		size_t __left_len = __left->_M_size;
1384
1385		if (__c->_M_c_string != 0)
1386		  __clrstack[__csptr++] = __c;
1387		if (__i >= __left_len)
1388		  {
1389		    __i -= __left_len;
1390		    __r = __c->_M_right;
1391		  }
1392		else
1393		  __r = __left;
1394	      }
1395	      break;
1396	    case __detail::_S_leaf:
1397	      {
1398		_RopeLeaf* __l = (_RopeLeaf*)__r;
1399		if (__l->_M_c_string != __l->_M_data && __l->_M_c_string != 0)
1400		  __clrstack[__csptr++] = __l;
1401		while (__csptr > 0)
1402		  {
1403		    -- __csptr;
1404		    _RopeRep* __d = __clrstack[__csptr];
1405		    __d->_M_free_c_string();
1406		    __d->_M_c_string = 0;
1407		  }
1408		return __l->_M_data + __i;
1409	      }
1410	    case __detail::_S_function:
1411	    case __detail::_S_substringfn:
1412	      return 0;
1413	    }
1414	}
1415    }
1416#endif /* __GC */
1417
1418  // The following could be implemented trivially using
1419  // lexicographical_compare_3way.
1420  // We do a little more work to avoid dealing with rope iterators for
1421  // flat strings.
1422  template <class _CharT, class _Alloc>
1423    int
1424    rope<_CharT, _Alloc>::
1425    _S_compare (const _RopeRep* __left, const _RopeRep* __right)
1426    {
1427      size_t __left_len;
1428      size_t __right_len;
1429
1430      if (0 == __right)
1431	return 0 != __left;
1432      if (0 == __left)
1433	return -1;
1434      __left_len = __left->_M_size;
1435      __right_len = __right->_M_size;
1436      if (__detail::_S_leaf == __left->_M_tag)
1437	{
1438	  _RopeLeaf* __l = (_RopeLeaf*) __left;
1439	  if (__detail::_S_leaf == __right->_M_tag)
1440	    {
1441	      _RopeLeaf* __r = (_RopeLeaf*) __right;
1442	      return lexicographical_compare_3way(__l->_M_data,
1443						  __l->_M_data + __left_len,
1444						  __r->_M_data, __r->_M_data
1445						  + __right_len);
1446	    }
1447	  else
1448	    {
1449	      const_iterator __rstart(__right, 0);
1450	      const_iterator __rend(__right, __right_len);
1451	      return lexicographical_compare_3way(__l->_M_data, __l->_M_data
1452						  + __left_len,
1453						  __rstart, __rend);
1454	    }
1455	}
1456      else
1457	{
1458	  const_iterator __lstart(__left, 0);
1459	  const_iterator __lend(__left, __left_len);
1460	  if (__detail::_S_leaf == __right->_M_tag)
1461	    {
1462	      _RopeLeaf* __r = (_RopeLeaf*) __right;
1463	      return lexicographical_compare_3way(__lstart, __lend,
1464						  __r->_M_data, __r->_M_data
1465						  + __right_len);
1466	    }
1467	  else
1468	    {
1469	      const_iterator __rstart(__right, 0);
1470	      const_iterator __rend(__right, __right_len);
1471	      return lexicographical_compare_3way(__lstart, __lend,
1472						  __rstart, __rend);
1473	    }
1474	}
1475    }
1476
1477  // Assignment to reference proxies.
1478  template <class _CharT, class _Alloc>
1479    _Rope_char_ref_proxy<_CharT, _Alloc>&
1480    _Rope_char_ref_proxy<_CharT, _Alloc>::
1481    operator=(_CharT __c)
1482    {
1483      _RopeRep* __old = _M_root->_M_tree_ptr;
1484#ifndef __GC
1485      // First check for the case in which everything is uniquely
1486      // referenced.  In that case we can do this destructively.
1487      _CharT* __ptr = _My_rope::_S_fetch_ptr(__old, _M_pos);
1488      if (0 != __ptr)
1489	{
1490	  *__ptr = __c;
1491	  return *this;
1492	}
1493#endif
1494      _Self_destruct_ptr __left(_My_rope::_S_substring(__old, 0, _M_pos));
1495      _Self_destruct_ptr __right(_My_rope::_S_substring(__old, _M_pos + 1,
1496							__old->_M_size));
1497      _Self_destruct_ptr __result_left(_My_rope::
1498				       _S_destr_concat_char_iter(__left,
1499								 &__c, 1));
1500
1501      _RopeRep* __result = _My_rope::_S_concat(__result_left, __right);
1502#ifndef __GC
1503      _RopeRep::_S_unref(__old);
1504#endif
1505      _M_root->_M_tree_ptr = __result;
1506      return *this;
1507    }
1508
1509  template <class _CharT, class _Alloc>
1510    inline _Rope_char_ref_proxy<_CharT, _Alloc>::
1511    operator _CharT() const
1512    {
1513      if (_M_current_valid)
1514	return _M_current;
1515      else
1516	return _My_rope::_S_fetch(_M_root->_M_tree_ptr, _M_pos);
1517    }
1518
1519  template <class _CharT, class _Alloc>
1520    _Rope_char_ptr_proxy<_CharT, _Alloc>
1521    _Rope_char_ref_proxy<_CharT, _Alloc>::
1522    operator&() const
1523    { return _Rope_char_ptr_proxy<_CharT, _Alloc>(*this); }
1524
1525  template <class _CharT, class _Alloc>
1526    rope<_CharT, _Alloc>::
1527    rope(size_t __n, _CharT __c, const allocator_type& __a)
1528    : _Base(__a)
1529    {
1530      rope<_CharT,_Alloc> __result;
1531      const size_t __exponentiate_threshold = 32;
1532      size_t __exponent;
1533      size_t __rest;
1534      _CharT* __rest_buffer;
1535      _RopeRep* __remainder;
1536      rope<_CharT, _Alloc> __remainder_rope;
1537
1538      if (0 == __n)
1539	return;
1540
1541      __exponent = __n / __exponentiate_threshold;
1542      __rest = __n % __exponentiate_threshold;
1543      if (0 == __rest)
1544	__remainder = 0;
1545      else
1546	{
1547	  __rest_buffer = this->_Data_allocate(_S_rounded_up_size(__rest));
1548	  __uninitialized_fill_n_a(__rest_buffer, __rest, __c,
1549				   _M_get_allocator());
1550	  _S_cond_store_eos(__rest_buffer[__rest]);
1551	  __try
1552	    { __remainder = _S_new_RopeLeaf(__rest_buffer, __rest,
1553					    _M_get_allocator()); }
1554	  __catch(...)
1555	    {
1556	      _RopeRep::__STL_FREE_STRING(__rest_buffer, __rest,
1557					  _M_get_allocator());
1558	      __throw_exception_again;
1559	    }
1560	}
1561      __remainder_rope._M_tree_ptr = __remainder;
1562      if (__exponent != 0)
1563	{
1564	  _CharT* __base_buffer =
1565	    this->_Data_allocate(_S_rounded_up_size(__exponentiate_threshold));
1566	  _RopeLeaf* __base_leaf;
1567	  rope __base_rope;
1568	  __uninitialized_fill_n_a(__base_buffer, __exponentiate_threshold, __c,
1569				   _M_get_allocator());
1570	  _S_cond_store_eos(__base_buffer[__exponentiate_threshold]);
1571	  __try
1572	    {
1573	      __base_leaf = _S_new_RopeLeaf(__base_buffer,
1574					    __exponentiate_threshold,
1575					    _M_get_allocator());
1576	    }
1577	  __catch(...)
1578	    {
1579	      _RopeRep::__STL_FREE_STRING(__base_buffer,
1580					  __exponentiate_threshold,
1581					  _M_get_allocator());
1582	      __throw_exception_again;
1583	    }
1584	  __base_rope._M_tree_ptr = __base_leaf;
1585	  if (1 == __exponent)
1586	    __result = __base_rope;
1587	  else
1588	    __result = power(__base_rope, __exponent,
1589			     _Rope_Concat_fn<_CharT, _Alloc>());
1590
1591	  if (0 != __remainder)
1592	    __result += __remainder_rope;
1593	}
1594      else
1595	__result = __remainder_rope;
1596
1597      this->_M_tree_ptr = __result._M_tree_ptr;
1598      this->_M_tree_ptr->_M_ref_nonnil();
1599    }
1600
1601  template<class _CharT, class _Alloc>
1602    _CharT
1603    rope<_CharT, _Alloc>::_S_empty_c_str[1];
1604
1605  template<class _CharT, class _Alloc>
1606    const _CharT*
1607    rope<_CharT, _Alloc>::
1608    c_str() const
1609    {
1610      if (0 == this->_M_tree_ptr)
1611	{
1612	  _S_empty_c_str[0] = _S_eos((_CharT*)0);  // Possibly redundant,
1613	                                           // but probably fast.
1614	  return _S_empty_c_str;
1615	}
1616      __gthread_mutex_lock (&this->_M_tree_ptr->_M_c_string_lock);
1617      __GC_CONST _CharT* __result = this->_M_tree_ptr->_M_c_string;
1618      if (0 == __result)
1619	{
1620	  size_t __s = size();
1621	  __result = this->_Data_allocate(__s + 1);
1622	  _S_flatten(this->_M_tree_ptr, __result);
1623	  __result[__s] = _S_eos((_CharT*)0);
1624	  this->_M_tree_ptr->_M_c_string = __result;
1625	}
1626      __gthread_mutex_unlock (&this->_M_tree_ptr->_M_c_string_lock);
1627      return(__result);
1628    }
1629
1630  template<class _CharT, class _Alloc>
1631    const _CharT* rope<_CharT, _Alloc>::
1632    replace_with_c_str()
1633    {
1634      if (0 == this->_M_tree_ptr)
1635	{
1636	  _S_empty_c_str[0] = _S_eos((_CharT*)0);
1637	  return _S_empty_c_str;
1638	}
1639      __GC_CONST _CharT* __old_c_string = this->_M_tree_ptr->_M_c_string;
1640      if (__detail::_S_leaf == this->_M_tree_ptr->_M_tag
1641	  && 0 != __old_c_string)
1642	return(__old_c_string);
1643      size_t __s = size();
1644      _CharT* __result = this->_Data_allocate(_S_rounded_up_size(__s));
1645      _S_flatten(this->_M_tree_ptr, __result);
1646      __result[__s] = _S_eos((_CharT*)0);
1647      this->_M_tree_ptr->_M_unref_nonnil();
1648      this->_M_tree_ptr = _S_new_RopeLeaf(__result, __s,
1649					  this->_M_get_allocator());
1650      return(__result);
1651    }
1652
1653  // Algorithm specializations.  More should be added.
1654
1655  template<class _Rope_iterator>  // was templated on CharT and Alloc
1656    void		          // VC++ workaround
1657    _Rope_rotate(_Rope_iterator __first,
1658		 _Rope_iterator __middle,
1659		 _Rope_iterator __last)
1660    {
1661      typedef typename _Rope_iterator::value_type _CharT;
1662      typedef typename _Rope_iterator::_allocator_type _Alloc;
1663
1664      rope<_CharT, _Alloc>& __r(__first.container());
1665      rope<_CharT, _Alloc> __prefix = __r.substr(0, __first.index());
1666      rope<_CharT, _Alloc> __suffix =
1667	__r.substr(__last.index(), __r.size() - __last.index());
1668      rope<_CharT, _Alloc> __part1 =
1669	__r.substr(__middle.index(), __last.index() - __middle.index());
1670      rope<_CharT, _Alloc> __part2 =
1671	__r.substr(__first.index(), __middle.index() - __first.index());
1672      __r = __prefix;
1673      __r += __part1;
1674      __r += __part2;
1675      __r += __suffix;
1676    }
1677
1678#if !defined(__GNUC__)
1679  // Appears to confuse g++
1680  inline void
1681  rotate(_Rope_iterator<char, __STL_DEFAULT_ALLOCATOR(char)> __first,
1682	 _Rope_iterator<char, __STL_DEFAULT_ALLOCATOR(char)> __middle,
1683	 _Rope_iterator<char, __STL_DEFAULT_ALLOCATOR(char)> __last)
1684  { _Rope_rotate(__first, __middle, __last); }
1685#endif
1686
1687# if 0
1688  // Probably not useful for several reasons:
1689  // - for SGIs 7.1 compiler and probably some others,
1690  //   this forces lots of rope<wchar_t, ...> instantiations, creating a
1691  //   code bloat and compile time problem.  (Fixed in 7.2.)
1692  // - wchar_t is 4 bytes wide on most UNIX platforms, making it
1693  //   unattractive for unicode strings.  Unsigned short may be a better
1694  //   character type.
1695  inline void
1696  rotate(_Rope_iterator<wchar_t, __STL_DEFAULT_ALLOCATOR(char)> __first,
1697	 _Rope_iterator<wchar_t, __STL_DEFAULT_ALLOCATOR(char)> __middle,
1698	 _Rope_iterator<wchar_t, __STL_DEFAULT_ALLOCATOR(char)> __last)
1699  { _Rope_rotate(__first, __middle, __last); }
1700# endif
1701
1702_GLIBCXX_END_NAMESPACE_VERSION
1703} // namespace
1704