basic_string.tcc revision 132720
1// Components for manipulating sequences of characters -*- C++ -*-
2
3// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
4// Free Software Foundation, Inc.
5//
6// This file is part of the GNU ISO C++ Library.  This library is free
7// software; you can redistribute it and/or modify it under the
8// terms of the GNU General Public License as published by the
9// Free Software Foundation; either version 2, or (at your option)
10// any later version.
11
12// This library is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15// GNU General Public License for more details.
16
17// You should have received a copy of the GNU General Public License along
18// with this library; see the file COPYING.  If not, write to the Free
19// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
20// USA.
21
22// As a special exception, you may use this file as part of a free software
23// library without restriction.  Specifically, if other files instantiate
24// templates or use macros or inline functions from this file, or you compile
25// this file and link it with other files to produce an executable, this
26// file does not by itself cause the resulting executable to be covered by
27// the GNU General Public License.  This exception does not however
28// invalidate any other reasons why the executable file might be covered by
29// the GNU General Public License.
30
31//
32// ISO C++ 14882: 21  Strings library
33//
34
35// This file is included by <string>.  It is not meant to be included
36// separately.
37
38// Written by Jason Merrill based upon the specification by Takanori Adachi
39// in ANSI X3J16/94-0013R2.  Rewritten by Nathan Myers to ISO-14882.
40
41#ifndef _BASIC_STRING_TCC
42#define _BASIC_STRING_TCC 1
43
44#pragma GCC system_header
45
46namespace std
47{
48  template<typename _Type>
49    inline bool
50    __is_null_pointer(_Type* __ptr)
51    { return __ptr == 0; }
52
53  template<typename _Type>
54    inline bool
55    __is_null_pointer(_Type)
56    { return false; }
57
58  template<typename _CharT, typename _Traits, typename _Alloc>
59    const typename basic_string<_CharT, _Traits, _Alloc>::size_type
60    basic_string<_CharT, _Traits, _Alloc>::
61    _Rep::_S_max_size = (((npos - sizeof(_Rep_base))/sizeof(_CharT)) - 1) / 4;
62
63  template<typename _CharT, typename _Traits, typename _Alloc>
64    const _CharT
65    basic_string<_CharT, _Traits, _Alloc>::
66    _Rep::_S_terminal = _CharT();
67
68  template<typename _CharT, typename _Traits, typename _Alloc>
69    const typename basic_string<_CharT, _Traits, _Alloc>::size_type
70    basic_string<_CharT, _Traits, _Alloc>::npos;
71
72  // Linker sets _S_empty_rep_storage to all 0s (one reference, empty string)
73  // at static init time (before static ctors are run).
74  template<typename _CharT, typename _Traits, typename _Alloc>
75    typename basic_string<_CharT, _Traits, _Alloc>::size_type
76    basic_string<_CharT, _Traits, _Alloc>::_Rep::_S_empty_rep_storage[
77    (sizeof(_Rep_base) + sizeof(_CharT) + sizeof(size_type) - 1) /
78      sizeof(size_type)];
79
80  // NB: This is the special case for Input Iterators, used in
81  // istreambuf_iterators, etc.
82  // Input Iterators have a cost structure very different from
83  // pointers, calling for a different coding style.
84  template<typename _CharT, typename _Traits, typename _Alloc>
85    template<typename _InIterator>
86      _CharT*
87      basic_string<_CharT, _Traits, _Alloc>::
88      _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
89		   input_iterator_tag)
90      {
91	if (__beg == __end && __a == _Alloc())
92	  return _S_empty_rep()._M_refdata();
93	// Avoid reallocation for common case.
94	_CharT __buf[128];
95	size_type __len = 0;
96	while (__beg != __end && __len < sizeof(__buf) / sizeof(_CharT))
97	  {
98	    __buf[__len++] = *__beg;
99	    ++__beg;
100	  }
101	_Rep* __r = _Rep::_S_create(__len, size_type(0), __a);
102	traits_type::copy(__r->_M_refdata(), __buf, __len);
103	try
104	  {
105	    while (__beg != __end)
106	      {
107		if (__len == __r->_M_capacity)
108		  {
109		    // Allocate more space.
110		    _Rep* __another = _Rep::_S_create(__len + 1, __len, __a);
111		    traits_type::copy(__another->_M_refdata(),
112				      __r->_M_refdata(), __len);
113		    __r->_M_destroy(__a);
114		    __r = __another;
115		  }
116		__r->_M_refdata()[__len++] = *__beg;
117		++__beg;
118	      }
119	  }
120	catch(...)
121	  {
122	    __r->_M_destroy(__a);
123	    __throw_exception_again;
124	  }
125	__r->_M_length = __len;
126	__r->_M_refdata()[__len] = _Rep::_S_terminal;       // grrr.
127	return __r->_M_refdata();
128      }
129
130  template<typename _CharT, typename _Traits, typename _Alloc>
131    template <typename _InIterator>
132      _CharT*
133      basic_string<_CharT, _Traits, _Alloc>::
134      _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
135		   forward_iterator_tag)
136      {
137	if (__beg == __end && __a == _Alloc())
138	  return _S_empty_rep()._M_refdata();
139
140	// NB: Not required, but considered best practice.
141	if (__builtin_expect(__is_null_pointer(__beg), 0))
142	  __throw_logic_error(__N("basic_string::_S_construct NULL not valid"));
143
144	const size_type __dnew = static_cast<size_type>(std::distance(__beg,
145								      __end));
146	// Check for out_of_range and length_error exceptions.
147	_Rep* __r = _Rep::_S_create(__dnew, size_type(0), __a);
148	try
149	  { _S_copy_chars(__r->_M_refdata(), __beg, __end); }
150	catch(...)
151	  {
152	    __r->_M_destroy(__a);
153	    __throw_exception_again;
154	  }
155	__r->_M_length = __dnew;
156	__r->_M_refdata()[__dnew] = _Rep::_S_terminal;  // grrr.
157	return __r->_M_refdata();
158      }
159
160  template<typename _CharT, typename _Traits, typename _Alloc>
161    _CharT*
162    basic_string<_CharT, _Traits, _Alloc>::
163    _S_construct(size_type __n, _CharT __c, const _Alloc& __a)
164    {
165      if (__n == 0 && __a == _Alloc())
166	return _S_empty_rep()._M_refdata();
167
168      // Check for out_of_range and length_error exceptions.
169      _Rep* __r = _Rep::_S_create(__n, size_type(0), __a);
170      if (__n)
171	traits_type::assign(__r->_M_refdata(), __n, __c);
172
173      __r->_M_length = __n;
174      __r->_M_refdata()[__n] = _Rep::_S_terminal;  // grrr
175      return __r->_M_refdata();
176    }
177
178  template<typename _CharT, typename _Traits, typename _Alloc>
179    basic_string<_CharT, _Traits, _Alloc>::
180    basic_string(const basic_string& __str)
181    : _M_dataplus(__str._M_rep()->_M_grab(_Alloc(__str.get_allocator()),
182					  __str.get_allocator()),
183		  __str.get_allocator())
184    { }
185
186  template<typename _CharT, typename _Traits, typename _Alloc>
187    basic_string<_CharT, _Traits, _Alloc>::
188    basic_string(const _Alloc& __a)
189    : _M_dataplus(_S_construct(size_type(), _CharT(), __a), __a)
190    { }
191
192  template<typename _CharT, typename _Traits, typename _Alloc>
193    basic_string<_CharT, _Traits, _Alloc>::
194    basic_string(const basic_string& __str, size_type __pos, size_type __n)
195    : _M_dataplus(_S_construct(__str._M_data()
196			       + __str._M_check(__pos,
197						"basic_string::basic_string"),
198			       __str._M_data() + __str._M_limit(__pos, __n)
199			       + __pos, _Alloc()), _Alloc())
200    { }
201
202  template<typename _CharT, typename _Traits, typename _Alloc>
203    basic_string<_CharT, _Traits, _Alloc>::
204    basic_string(const basic_string& __str, size_type __pos,
205		 size_type __n, const _Alloc& __a)
206    : _M_dataplus(_S_construct(__str._M_data()
207			       + __str._M_check(__pos,
208						"basic_string::basic_string"),
209			       __str._M_data() + __str._M_limit(__pos, __n)
210			       + __pos, __a), __a)
211    { }
212
213  // TBD: DPG annotate
214  template<typename _CharT, typename _Traits, typename _Alloc>
215    basic_string<_CharT, _Traits, _Alloc>::
216    basic_string(const _CharT* __s, size_type __n, const _Alloc& __a)
217    : _M_dataplus(_S_construct(__s, __s + __n, __a), __a)
218    { }
219
220  // TBD: DPG annotate
221  template<typename _CharT, typename _Traits, typename _Alloc>
222    basic_string<_CharT, _Traits, _Alloc>::
223    basic_string(const _CharT* __s, const _Alloc& __a)
224    : _M_dataplus(_S_construct(__s, __s ? __s + traits_type::length(__s) :
225			       __s + npos, __a), __a)
226    { }
227
228  template<typename _CharT, typename _Traits, typename _Alloc>
229    basic_string<_CharT, _Traits, _Alloc>::
230    basic_string(size_type __n, _CharT __c, const _Alloc& __a)
231    : _M_dataplus(_S_construct(__n, __c, __a), __a)
232    { }
233
234  // TBD: DPG annotate
235  template<typename _CharT, typename _Traits, typename _Alloc>
236    template<typename _InputIterator>
237    basic_string<_CharT, _Traits, _Alloc>::
238    basic_string(_InputIterator __beg, _InputIterator __end, const _Alloc& __a)
239    : _M_dataplus(_S_construct(__beg, __end, __a), __a)
240    { }
241
242  template<typename _CharT, typename _Traits, typename _Alloc>
243    basic_string<_CharT, _Traits, _Alloc>&
244    basic_string<_CharT, _Traits, _Alloc>::
245    assign(const basic_string& __str)
246    {
247      if (_M_rep() != __str._M_rep())
248	{
249	  // XXX MT
250	  const allocator_type __a = this->get_allocator();
251	  _CharT* __tmp = __str._M_rep()->_M_grab(__a, __str.get_allocator());
252	  _M_rep()->_M_dispose(__a);
253	  _M_data(__tmp);
254	}
255      return *this;
256    }
257
258   template<typename _CharT, typename _Traits, typename _Alloc>
259     basic_string<_CharT, _Traits, _Alloc>&
260     basic_string<_CharT, _Traits, _Alloc>::
261     assign(const _CharT* __s, size_type __n)
262     {
263       __glibcxx_requires_string_len(__s, __n);
264       if (__n > this->max_size())
265	 __throw_length_error(__N("basic_string::assign"));
266       if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
267	   || less<const _CharT*>()(_M_data() + this->size(), __s))
268	 return _M_replace_safe(size_type(0), this->size(), __s, __n);
269       else
270	 {
271	   // Work in-place
272	   const size_type __pos = __s - _M_data();
273	   if (__pos >= __n)
274	     traits_type::copy(_M_data(), __s, __n);
275	   else if (__pos)
276	     traits_type::move(_M_data(), __s, __n);
277	   _M_rep()->_M_set_sharable();
278	   _M_rep()->_M_length = __n;
279	   _M_data()[__n] = _Rep::_S_terminal;  // grr.
280	   return *this;
281	 }
282     }
283
284   template<typename _CharT, typename _Traits, typename _Alloc>
285     basic_string<_CharT, _Traits, _Alloc>&
286     basic_string<_CharT, _Traits, _Alloc>::
287     insert(size_type __pos, const _CharT* __s, size_type __n)
288     {
289       __glibcxx_requires_string_len(__s, __n);
290       _M_check(__pos, "basic_string::insert");
291       if (this->max_size() - this->size() < __n)
292	 __throw_length_error(__N("basic_string::insert"));
293       if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
294           || less<const _CharT*>()(_M_data() + this->size(), __s))
295         return _M_replace_safe(__pos, size_type(0), __s, __n);
296       else
297         {
298           // Work in-place. If _M_mutate reallocates the string, __s
299           // does not point anymore to valid data, therefore we save its
300           // offset, then we restore it.
301           const size_type __off = __s - _M_data();
302           _M_mutate(__pos, 0, __n);
303           __s = _M_data() + __off;
304           _CharT* __p = _M_data() + __pos;
305           if (__s  + __n <= __p)
306             traits_type::copy(__p, __s, __n);
307           else if (__s >= __p)
308             traits_type::copy(__p, __s + __n, __n);
309           else
310             {
311	       const size_type __nleft = __p - __s;
312               traits_type::copy(__p, __s, __nleft);
313               traits_type::copy(__p + __nleft, __p + __n, __n - __nleft);
314             }
315           return *this;
316         }
317     }
318
319   template<typename _CharT, typename _Traits, typename _Alloc>
320     basic_string<_CharT, _Traits, _Alloc>&
321     basic_string<_CharT, _Traits, _Alloc>::
322     replace(size_type __pos, size_type __n1, const _CharT* __s,
323	     size_type __n2)
324     {
325       __glibcxx_requires_string_len(__s, __n2);
326       _M_check(__pos, "basic_string::replace");
327       __n1 = _M_limit(__pos, __n1);
328       if (this->max_size() - (this->size() - __n1) < __n2)
329         __throw_length_error(__N("basic_string::replace"));
330       bool __left;
331       if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
332	   || less<const _CharT*>()(_M_data() + this->size(), __s))
333         return _M_replace_safe(__pos, __n1, __s, __n2);
334       else if ((__left = __s + __n2 <= _M_data() + __pos)
335		|| _M_data() + __pos + __n1 <= __s)
336	 {
337	   // Work in-place: non-overlapping case.
338	   const size_type __off = __s - _M_data();
339	   _M_mutate(__pos, __n1, __n2);
340	   if (__left)
341	     traits_type::copy(_M_data() + __pos,
342			       _M_data() + __off, __n2);
343	   else
344	     traits_type::copy(_M_data() + __pos,
345			       _M_data() + __off + __n2 - __n1, __n2);
346	   return *this;
347	 }
348       else
349	 {
350	   // Todo: overlapping case.
351	   const basic_string __tmp(__s, __n2);
352	   return _M_replace_safe(__pos, __n1, __tmp._M_data(), __n2);
353	 }
354     }
355
356  template<typename _CharT, typename _Traits, typename _Alloc>
357    void
358    basic_string<_CharT, _Traits, _Alloc>::_Rep::
359    _M_destroy(const _Alloc& __a) throw ()
360    {
361      if (this == &_S_empty_rep())
362        return;
363      const size_type __size = sizeof(_Rep_base) +
364	                       (this->_M_capacity + 1) * sizeof(_CharT);
365      _Raw_bytes_alloc(__a).deallocate(reinterpret_cast<char*>(this), __size);
366    }
367
368  template<typename _CharT, typename _Traits, typename _Alloc>
369    void
370    basic_string<_CharT, _Traits, _Alloc>::_M_leak_hard()
371    {
372      if (_M_rep() == &_S_empty_rep())
373        return;
374      if (_M_rep()->_M_is_shared())
375	_M_mutate(0, 0, 0);
376      _M_rep()->_M_set_leaked();
377    }
378
379  template<typename _CharT, typename _Traits, typename _Alloc>
380    void
381    basic_string<_CharT, _Traits, _Alloc>::
382    _M_mutate(size_type __pos, size_type __len1, size_type __len2)
383    {
384      const size_type __old_size = this->size();
385      const size_type __new_size = __old_size + __len2 - __len1;
386      const size_type __how_much = __old_size - __pos - __len1;
387
388      if (_M_rep() == &_S_empty_rep()
389	  || _M_rep()->_M_is_shared() || __new_size > capacity())
390	{
391	  // Must reallocate.
392	  const allocator_type __a = get_allocator();
393	  _Rep* __r = _Rep::_S_create(__new_size, capacity(), __a);
394
395	  if (__pos)
396	    traits_type::copy(__r->_M_refdata(), _M_data(), __pos);
397	  if (__how_much)
398	    traits_type::copy(__r->_M_refdata() + __pos + __len2,
399			      _M_data() + __pos + __len1, __how_much);
400
401	  _M_rep()->_M_dispose(__a);
402	  _M_data(__r->_M_refdata());
403	}
404      else if (__how_much && __len1 != __len2)
405	{
406	  // Work in-place
407	  traits_type::move(_M_data() + __pos + __len2,
408			    _M_data() + __pos + __len1, __how_much);
409	}
410      _M_rep()->_M_set_sharable();
411      _M_rep()->_M_length = __new_size;
412      _M_data()[__new_size] = _Rep::_S_terminal; // grrr. (per 21.3.4)
413      // You cannot leave those LWG people alone for a second.
414    }
415
416  template<typename _CharT, typename _Traits, typename _Alloc>
417    void
418    basic_string<_CharT, _Traits, _Alloc>::reserve(size_type __res)
419    {
420      if (__res != this->capacity() || _M_rep()->_M_is_shared())
421        {
422	  if (__res > this->max_size())
423	    __throw_length_error(__N("basic_string::reserve"));
424	  // Make sure we don't shrink below the current size
425	  if (__res < this->size())
426	    __res = this->size();
427	  const allocator_type __a = get_allocator();
428	  _CharT* __tmp = _M_rep()->_M_clone(__a, __res - this->size());
429	  _M_rep()->_M_dispose(__a);
430	  _M_data(__tmp);
431        }
432    }
433
434  template<typename _CharT, typename _Traits, typename _Alloc>
435    void basic_string<_CharT, _Traits, _Alloc>::swap(basic_string& __s)
436    {
437      if (_M_rep()->_M_is_leaked())
438	_M_rep()->_M_set_sharable();
439      if (__s._M_rep()->_M_is_leaked())
440	__s._M_rep()->_M_set_sharable();
441      if (this->get_allocator() == __s.get_allocator())
442	{
443	  _CharT* __tmp = _M_data();
444	  _M_data(__s._M_data());
445	  __s._M_data(__tmp);
446	}
447      // The code below can usually be optimized away.
448      else
449	{
450	  const basic_string __tmp1(_M_ibegin(), _M_iend(),
451				    __s.get_allocator());
452	  const basic_string __tmp2(__s._M_ibegin(), __s._M_iend(),
453				    this->get_allocator());
454	  *this = __tmp2;
455	  __s = __tmp1;
456	}
457    }
458
459  template<typename _CharT, typename _Traits, typename _Alloc>
460    typename basic_string<_CharT, _Traits, _Alloc>::_Rep*
461    basic_string<_CharT, _Traits, _Alloc>::_Rep::
462    _S_create(size_type __capacity, size_type __old_capacity,
463	      const _Alloc& __alloc)
464    {
465      typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
466      // _GLIBCXX_RESOLVE_LIB_DEFECTS
467      // 83.  String::npos vs. string::max_size()
468      if (__capacity > _S_max_size)
469	__throw_length_error(__N("basic_string::_S_create"));
470
471      // The standard places no restriction on allocating more memory
472      // than is strictly needed within this layer at the moment or as
473      // requested by an explicit application call to reserve().
474
475      // Many malloc implementations perform quite poorly when an
476      // application attempts to allocate memory in a stepwise fashion
477      // growing each allocation size by only 1 char.  Additionally,
478      // it makes little sense to allocate less linear memory than the
479      // natural blocking size of the malloc implementation.
480      // Unfortunately, we would need a somewhat low-level calculation
481      // with tuned parameters to get this perfect for any particular
482      // malloc implementation.  Fortunately, generalizations about
483      // common features seen among implementations seems to suffice.
484
485      // __pagesize need not match the actual VM page size for good
486      // results in practice, thus we pick a common value on the low
487      // side.  __malloc_header_size is an estimate of the amount of
488      // overhead per memory allocation (in practice seen N * sizeof
489      // (void*) where N is 0, 2 or 4).  According to folklore,
490      // picking this value on the high side is better than
491      // low-balling it (especially when this algorithm is used with
492      // malloc implementations that allocate memory blocks rounded up
493      // to a size which is a power of 2).
494      const size_type __pagesize = 4096; // must be 2^i * __subpagesize
495      const size_type __subpagesize = 128; // should be >> __malloc_header_size
496      const size_type __malloc_header_size = 4 * sizeof (void*);
497
498      // The below implements an exponential growth policy, necessary to
499      // meet amortized linear time requirements of the library: see
500      // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
501      // It's active for allocations requiring an amount of memory above
502      // system pagesize. This is consistent with the requirements of the
503      // standard: http://gcc.gnu.org/ml/libstdc++/2001-07/msg00130.html
504
505      // The biggest string which fits in a memory page
506      const size_type __page_capacity = ((__pagesize - __malloc_header_size
507					  - sizeof(_Rep) - sizeof(_CharT))
508					 / sizeof(_CharT));
509
510      if (__capacity > __old_capacity && __capacity < 2 * __old_capacity
511	  && __capacity > __page_capacity)
512	__capacity = 2 * __old_capacity;
513
514      // NB: Need an array of char_type[__capacity], plus a terminating
515      // null char_type() element, plus enough for the _Rep data structure.
516      // Whew. Seemingly so needy, yet so elemental.
517      size_type __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
518
519      const size_type __adj_size = __size + __malloc_header_size;
520      if (__adj_size > __pagesize)
521	{
522	  const size_type __extra = __pagesize - __adj_size % __pagesize;
523	  __capacity += __extra / sizeof(_CharT);
524	  // Never allocate a string bigger than _S_max_size.
525	  if (__capacity > _S_max_size)
526	    __capacity = _S_max_size;
527	  __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
528	}
529      else if (__size > __subpagesize)
530	{
531	  const size_type __extra = __subpagesize - __adj_size % __subpagesize;
532	  __capacity += __extra / sizeof(_CharT);
533	  __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
534	}
535
536      // NB: Might throw, but no worries about a leak, mate: _Rep()
537      // does not throw.
538      void* __place = _Raw_bytes_alloc(__alloc).allocate(__size);
539      _Rep *__p = new (__place) _Rep;
540      __p->_M_capacity = __capacity;
541      __p->_M_set_sharable();  // One reference.
542      __p->_M_length = 0;
543      return __p;
544    }
545
546  template<typename _CharT, typename _Traits, typename _Alloc>
547    _CharT*
548    basic_string<_CharT, _Traits, _Alloc>::_Rep::
549    _M_clone(const _Alloc& __alloc, size_type __res)
550    {
551      // Requested capacity of the clone.
552      const size_type __requested_cap = this->_M_length + __res;
553      _Rep* __r = _Rep::_S_create(__requested_cap, this->_M_capacity,
554				  __alloc);
555      if (this->_M_length)
556	traits_type::copy(__r->_M_refdata(), _M_refdata(),
557			  this->_M_length);
558
559      __r->_M_length = this->_M_length;
560      __r->_M_refdata()[this->_M_length] = _Rep::_S_terminal;
561      return __r->_M_refdata();
562    }
563
564  template<typename _CharT, typename _Traits, typename _Alloc>
565    void
566    basic_string<_CharT, _Traits, _Alloc>::resize(size_type __n, _CharT __c)
567    {
568      if (__n > max_size())
569	__throw_length_error(__N("basic_string::resize"));
570      const size_type __size = this->size();
571      if (__size < __n)
572	this->append(__n - __size, __c);
573      else if (__n < __size)
574	this->erase(__n);
575      // else nothing (in particular, avoid calling _M_mutate() unnecessarily.)
576    }
577
578  template<typename _CharT, typename _Traits, typename _Alloc>
579    template<typename _InputIterator>
580      basic_string<_CharT, _Traits, _Alloc>&
581      basic_string<_CharT, _Traits, _Alloc>::
582      _M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
583			  _InputIterator __k2, __false_type)
584      {
585	const basic_string __s(__k1, __k2);
586	const size_type __n1 = __i2 - __i1;
587	if (this->max_size() - (this->size() - __n1) < __s.size())
588	  __throw_length_error(__N("basic_string::_M_replace_dispatch"));
589	return _M_replace_safe(__i1 - _M_ibegin(), __n1, __s._M_data(),
590			       __s.size());
591      }
592
593  template<typename _CharT, typename _Traits, typename _Alloc>
594    basic_string<_CharT, _Traits, _Alloc>&
595    basic_string<_CharT, _Traits, _Alloc>::
596    append(const basic_string& __str)
597    {
598      // Iff appending itself, string needs to pre-reserve the
599      // correct size so that _M_mutate does not clobber the
600      // pointer __str._M_data() formed here.
601      const size_type __size = __str.size();
602      const size_type __len = __size + this->size();
603      if (__len > this->capacity())
604	this->reserve(__len);
605      return _M_replace_safe(this->size(), size_type(0), __str._M_data(),
606			     __str.size());
607    }
608
609  template<typename _CharT, typename _Traits, typename _Alloc>
610    basic_string<_CharT, _Traits, _Alloc>&
611    basic_string<_CharT, _Traits, _Alloc>::
612    append(const basic_string& __str, size_type __pos, size_type __n)
613    {
614      // Iff appending itself, string needs to pre-reserve the
615      // correct size so that _M_mutate does not clobber the
616      // pointer __str._M_data() formed here.
617      __str._M_check(__pos, "basic_string::append");
618      __n = __str._M_limit(__pos, __n);
619      const size_type __len = __n + this->size();
620      if (__len > this->capacity())
621	this->reserve(__len);
622      return _M_replace_safe(this->size(), size_type(0), __str._M_data()
623			     + __pos, __n);
624    }
625
626  template<typename _CharT, typename _Traits, typename _Alloc>
627    basic_string<_CharT, _Traits, _Alloc>&
628    basic_string<_CharT, _Traits, _Alloc>::
629    append(const _CharT* __s, size_type __n)
630    {
631      __glibcxx_requires_string_len(__s, __n);
632      const size_type __len = __n + this->size();
633      if (__len > this->capacity())
634	this->reserve(__len);
635      return _M_replace_safe(this->size(), size_type(0), __s, __n);
636    }
637
638  template<typename _CharT, typename _Traits, typename _Alloc>
639    basic_string<_CharT, _Traits, _Alloc>
640    operator+(const _CharT* __lhs,
641	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
642    {
643      __glibcxx_requires_string(__lhs);
644      typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
645      typedef typename __string_type::size_type	  __size_type;
646      const __size_type __len = _Traits::length(__lhs);
647      __string_type __str;
648      __str.reserve(__len + __rhs.size());
649      __str.append(__lhs, __len);
650      __str.append(__rhs);
651      return __str;
652    }
653
654  template<typename _CharT, typename _Traits, typename _Alloc>
655    basic_string<_CharT, _Traits, _Alloc>
656    operator+(_CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs)
657    {
658      typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
659      typedef typename __string_type::size_type	  __size_type;
660      __string_type __str;
661      const __size_type __len = __rhs.size();
662      __str.reserve(__len + 1);
663      __str.append(__size_type(1), __lhs);
664      __str.append(__rhs);
665      return __str;
666    }
667
668  template<typename _CharT, typename _Traits, typename _Alloc>
669    typename basic_string<_CharT, _Traits, _Alloc>::size_type
670    basic_string<_CharT, _Traits, _Alloc>::
671    copy(_CharT* __s, size_type __n, size_type __pos) const
672    {
673      _M_check(__pos, "basic_string::copy");
674      __n = _M_limit(__pos, __n);
675      __glibcxx_requires_string_len(__s, __n);
676      if (__n)
677	traits_type::copy(__s, _M_data() + __pos, __n);
678      // 21.3.5.7 par 3: do not append null.  (good.)
679      return __n;
680    }
681
682  template<typename _CharT, typename _Traits, typename _Alloc>
683    typename basic_string<_CharT, _Traits, _Alloc>::size_type
684    basic_string<_CharT, _Traits, _Alloc>::
685    find(const _CharT* __s, size_type __pos, size_type __n) const
686    {
687      __glibcxx_requires_string_len(__s, __n);
688      const size_type __size = this->size();
689      const _CharT* __data = _M_data();
690      for (; __pos + __n <= __size; ++__pos)
691	if (traits_type::compare(__data + __pos, __s, __n) == 0)
692	  return __pos;
693      return npos;
694    }
695
696  template<typename _CharT, typename _Traits, typename _Alloc>
697    typename basic_string<_CharT, _Traits, _Alloc>::size_type
698    basic_string<_CharT, _Traits, _Alloc>::
699    find(_CharT __c, size_type __pos) const
700    {
701      const size_type __size = this->size();
702      size_type __ret = npos;
703      if (__pos < __size)
704	{
705	  const _CharT* __data = _M_data();
706	  const size_type __n = __size - __pos;
707	  const _CharT* __p = traits_type::find(__data + __pos, __n, __c);
708	  if (__p)
709	    __ret = __p - __data;
710	}
711      return __ret;
712    }
713
714  template<typename _CharT, typename _Traits, typename _Alloc>
715    typename basic_string<_CharT, _Traits, _Alloc>::size_type
716    basic_string<_CharT, _Traits, _Alloc>::
717    rfind(const _CharT* __s, size_type __pos, size_type __n) const
718    {
719      __glibcxx_requires_string_len(__s, __n);
720      const size_type __size = this->size();
721      if (__n <= __size)
722	{
723	  __pos = std::min(size_type(__size - __n), __pos);
724	  const _CharT* __data = _M_data();
725	  do
726	    {
727	      if (traits_type::compare(__data + __pos, __s, __n) == 0)
728		return __pos;
729	    }
730	  while (__pos-- > 0);
731	}
732      return npos;
733    }
734
735  template<typename _CharT, typename _Traits, typename _Alloc>
736    typename basic_string<_CharT, _Traits, _Alloc>::size_type
737    basic_string<_CharT, _Traits, _Alloc>::
738    rfind(_CharT __c, size_type __pos) const
739    {
740      size_type __size = this->size();
741      if (__size)
742	{
743	  if (--__size > __pos)
744	    __size = __pos;
745	  for (++__size; __size-- > 0; )
746	    if (traits_type::eq(_M_data()[__size], __c))
747	      return __size;
748	}
749      return npos;
750    }
751
752  template<typename _CharT, typename _Traits, typename _Alloc>
753    typename basic_string<_CharT, _Traits, _Alloc>::size_type
754    basic_string<_CharT, _Traits, _Alloc>::
755    find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
756    {
757      __glibcxx_requires_string_len(__s, __n);
758      for (; __n && __pos < this->size(); ++__pos)
759	{
760	  const _CharT* __p = traits_type::find(__s, __n, _M_data()[__pos]);
761	  if (__p)
762	    return __pos;
763	}
764      return npos;
765    }
766
767  template<typename _CharT, typename _Traits, typename _Alloc>
768    typename basic_string<_CharT, _Traits, _Alloc>::size_type
769    basic_string<_CharT, _Traits, _Alloc>::
770    find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
771    {
772      __glibcxx_requires_string_len(__s, __n);
773      size_type __size = this->size();
774      if (__size && __n)
775	{
776	  if (--__size > __pos)
777	    __size = __pos;
778	  do
779	    {
780	      if (traits_type::find(__s, __n, _M_data()[__size]))
781		return __size;
782	    }
783	  while (__size-- != 0);
784	}
785      return npos;
786    }
787
788  template<typename _CharT, typename _Traits, typename _Alloc>
789    typename basic_string<_CharT, _Traits, _Alloc>::size_type
790    basic_string<_CharT, _Traits, _Alloc>::
791    find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const
792    {
793      __glibcxx_requires_string_len(__s, __n);
794      for (; __pos < this->size(); ++__pos)
795	if (!traits_type::find(__s, __n, _M_data()[__pos]))
796	  return __pos;
797      return npos;
798    }
799
800  template<typename _CharT, typename _Traits, typename _Alloc>
801    typename basic_string<_CharT, _Traits, _Alloc>::size_type
802    basic_string<_CharT, _Traits, _Alloc>::
803    find_first_not_of(_CharT __c, size_type __pos) const
804    {
805      for (; __pos < this->size(); ++__pos)
806	if (!traits_type::eq(_M_data()[__pos], __c))
807	  return __pos;
808      return npos;
809    }
810
811  template<typename _CharT, typename _Traits, typename _Alloc>
812    typename basic_string<_CharT, _Traits, _Alloc>::size_type
813    basic_string<_CharT, _Traits, _Alloc>::
814    find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const
815    {
816      __glibcxx_requires_string_len(__s, __n);
817      size_type __size = this->size();
818      if (__size)
819	{
820	  if (--__size > __pos)
821	    __size = __pos;
822	  do
823	    {
824	      if (!traits_type::find(__s, __n, _M_data()[__size]))
825		return __size;
826	    }
827	  while (__size--);
828	}
829      return npos;
830    }
831
832  template<typename _CharT, typename _Traits, typename _Alloc>
833    typename basic_string<_CharT, _Traits, _Alloc>::size_type
834    basic_string<_CharT, _Traits, _Alloc>::
835    find_last_not_of(_CharT __c, size_type __pos) const
836    {
837      size_type __size = this->size();
838      if (__size)
839	{
840	  if (--__size > __pos)
841	    __size = __pos;
842	  do
843	    {
844	      if (!traits_type::eq(_M_data()[__size], __c))
845		return __size;
846	    }
847	  while (__size--);
848	}
849      return npos;
850    }
851
852  template<typename _CharT, typename _Traits, typename _Alloc>
853    int
854    basic_string<_CharT, _Traits, _Alloc>::
855    compare(size_type __pos, size_type __n, const basic_string& __str) const
856    {
857      _M_check(__pos, "basic_string::compare");
858      __n = _M_limit(__pos, __n);
859      const size_type __osize = __str.size();
860      const size_type __len = std::min(__n, __osize);
861      int __r = traits_type::compare(_M_data() + __pos, __str.data(), __len);
862      if (!__r)
863	__r = __n - __osize;
864      return __r;
865    }
866
867  template<typename _CharT, typename _Traits, typename _Alloc>
868    int
869    basic_string<_CharT, _Traits, _Alloc>::
870    compare(size_type __pos1, size_type __n1, const basic_string& __str,
871	    size_type __pos2, size_type __n2) const
872    {
873      _M_check(__pos1, "basic_string::compare");
874      __str._M_check(__pos2, "basic_string::compare");
875      __n1 = _M_limit(__pos1, __n1);
876      __n2 = __str._M_limit(__pos2, __n2);
877      const size_type __len = std::min(__n1, __n2);
878      int __r = traits_type::compare(_M_data() + __pos1,
879				     __str.data() + __pos2, __len);
880      if (!__r)
881	__r = __n1 - __n2;
882      return __r;
883    }
884
885  template<typename _CharT, typename _Traits, typename _Alloc>
886    int
887    basic_string<_CharT, _Traits, _Alloc>::
888    compare(const _CharT* __s) const
889    {
890      __glibcxx_requires_string(__s);
891      const size_type __size = this->size();
892      const size_type __osize = traits_type::length(__s);
893      const size_type __len = std::min(__size, __osize);
894      int __r = traits_type::compare(_M_data(), __s, __len);
895      if (!__r)
896	__r = __size - __osize;
897      return __r;
898    }
899
900  template<typename _CharT, typename _Traits, typename _Alloc>
901    int
902    basic_string <_CharT, _Traits, _Alloc>::
903    compare(size_type __pos, size_type __n1, const _CharT* __s) const
904    {
905      __glibcxx_requires_string(__s);
906      _M_check(__pos, "basic_string::compare");
907      __n1 = _M_limit(__pos, __n1);
908      const size_type __osize = traits_type::length(__s);
909      const size_type __len = std::min(__n1, __osize);
910      int __r = traits_type::compare(_M_data() + __pos, __s, __len);
911      if (!__r)
912	__r = __n1 - __osize;
913      return __r;
914    }
915
916  template<typename _CharT, typename _Traits, typename _Alloc>
917    int
918    basic_string <_CharT, _Traits, _Alloc>::
919    compare(size_type __pos, size_type __n1, const _CharT* __s,
920	    size_type __n2) const
921    {
922      __glibcxx_requires_string_len(__s, __n2);
923      _M_check(__pos, "basic_string::compare");
924      __n1 = _M_limit(__pos, __n1);
925      const size_type __len = std::min(__n1, __n2);
926      int __r = traits_type::compare(_M_data() + __pos, __s, __len);
927      if (!__r)
928	__r = __n1 - __n2;
929      return __r;
930    }
931
932  // Inhibit implicit instantiations for required instantiations,
933  // which are defined via explicit instantiations elsewhere.
934  // NB: This syntax is a GNU extension.
935#if _GLIBCXX_EXTERN_TEMPLATE
936  extern template class basic_string<char>;
937  extern template
938    basic_istream<char>&
939    operator>>(basic_istream<char>&, string&);
940  extern template
941    basic_ostream<char>&
942    operator<<(basic_ostream<char>&, const string&);
943  extern template
944    basic_istream<char>&
945    getline(basic_istream<char>&, string&, char);
946  extern template
947    basic_istream<char>&
948    getline(basic_istream<char>&, string&);
949
950#ifdef _GLIBCXX_USE_WCHAR_T
951  extern template class basic_string<wchar_t>;
952  extern template
953    basic_istream<wchar_t>&
954    operator>>(basic_istream<wchar_t>&, wstring&);
955  extern template
956    basic_ostream<wchar_t>&
957    operator<<(basic_ostream<wchar_t>&, const wstring&);
958  extern template
959    basic_istream<wchar_t>&
960    getline(basic_istream<wchar_t>&, wstring&, wchar_t);
961  extern template
962    basic_istream<wchar_t>&
963    getline(basic_istream<wchar_t>&, wstring&);
964#endif
965#endif
966} // namespace std
967
968#endif
969