libstdc++-v3/include/bits/basic_string.tcc

   1 // Components for manipulating sequences of characters -*- C++ -*-
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   4 // 2006, 2007, 2008, 2009
   5 // Free Software Foundation, Inc.
   6 //
   7 // This file is part of the GNU ISO C++ Library.  This library is free
   8 // software; you can redistribute it and/or modify it under the
   9 // terms of the GNU General Public License as published by the
  10 // Free Software Foundation; either version 3, or (at your option)
  11 // any later version.
  12
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // Under Section 7 of GPL version 3, you are granted additional
  19 // permissions described in the GCC Runtime Library Exception, version
  20 // 3.1, as published by the Free Software Foundation.
  21
  22 // You should have received a copy of the GNU General Public License and
  23 // a copy of the GCC Runtime Library Exception along with this program;
  24 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 // <http://www.gnu.org/licenses/>.
  26
  27 /** @file basic_string.tcc
  28  *  This is an internal header file, included by other library headers.
  29  *  You should not attempt to use it directly.
  30  */
  31
  32 //
  33 // ISO C++ 14882: 21  Strings library
  34 //
  35
  36 // Written by Jason Merrill based upon the specification by Takanori Adachi
  37 // in ANSI X3J16/94-0013R2.  Rewritten by Nathan Myers to ISO-14882.
  38
  39 #ifndef _BASIC_STRING_TCC
  40 #define _BASIC_STRING_TCC 1
  41
  42 #pragma GCC system_header
  43
  44 #include <cxxabi-forced.h>
  45
  46 _GLIBCXX_BEGIN_NAMESPACE(std)
  47
  48   template<typename _CharT, typename _Traits, typename _Alloc>
  49     const typename basic_string<_CharT, _Traits, _Alloc>::size_type
  50     basic_string<_CharT, _Traits, _Alloc>::
  51     _Rep::_S_max_size = (((npos - sizeof(_Rep_base))/sizeof(_CharT)) - 1) / 4;
  52
  53   template<typename _CharT, typename _Traits, typename _Alloc>
  54     const _CharT
  55     basic_string<_CharT, _Traits, _Alloc>::
  56     _Rep::_S_terminal = _CharT();
  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>::npos;
  61
  62   // Linker sets _S_empty_rep_storage to all 0s (one reference, empty string)
  63   // at static init time (before static ctors are run).
  64   template<typename _CharT, typename _Traits, typename _Alloc>
  65     typename basic_string<_CharT, _Traits, _Alloc>::size_type
  66     basic_string<_CharT, _Traits, _Alloc>::_Rep::_S_empty_rep_storage[
  67     (sizeof(_Rep_base) + sizeof(_CharT) + sizeof(size_type) - 1) /
  68       sizeof(size_type)];
  69
  70   // NB: This is the special case for Input Iterators, used in
  71   // istreambuf_iterators, etc.
  72   // Input Iterators have a cost structure very different from
  73   // pointers, calling for a different coding style.
  74   template<typename _CharT, typename _Traits, typename _Alloc>
  75     template<typename _InIterator>
  76       _CharT*
  77       basic_string<_CharT, _Traits, _Alloc>::
  78       _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
  79                    input_iterator_tag)
  80       {
  81 #ifndef _GLIBCXX_FULLY_DYNAMIC_STRING
  82         if (__beg == __end && __a == _Alloc())
  83           return _S_empty_rep()._M_refdata();
  84 #endif
  85         // Avoid reallocation for common case.
  86         _CharT __buf[128];
  87         size_type __len = 0;
  88         while (__beg != __end && __len < sizeof(__buf) / sizeof(_CharT))
  89           {
  90             __buf[__len++] = *__beg;
  91             ++__beg;
  92           }
  93         _Rep* __r = _Rep::_S_create(__len, size_type(0), __a);
  94         _M_copy(__r->_M_refdata(), __buf, __len);
  95         __try
  96           {
  97             while (__beg != __end)
  98               {
  99                 if (__len == __r->_M_capacity)
 100                   {
 101                     // Allocate more space.
 102                     _Rep* __another = _Rep::_S_create(__len + 1, __len, __a);
 103                     _M_copy(__another->_M_refdata(), __r->_M_refdata(), __len);
 104                     __r->_M_destroy(__a);
 105                     __r = __another;
 106                   }
 107                 __r->_M_refdata()[__len++] = *__beg;
 108                 ++__beg;
 109               }
 110           }
 111         __catch(...)
 112           {
 113             __r->_M_destroy(__a);
 114             __throw_exception_again;
 115           }
 116         __r->_M_set_length_and_sharable(__len);
 117         return __r->_M_refdata();
 118       }
 119
 120   template<typename _CharT, typename _Traits, typename _Alloc>
 121     template <typename _FwdIterator>
 122       _CharT*
 123       basic_string<_CharT, _Traits, _Alloc>::
 124       _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a,
 125                    forward_iterator_tag)
 126       {
 127 #ifndef _GLIBCXX_FULLY_DYNAMIC_STRING
 128         if (__beg == __end && __a == _Alloc())
 129           return _S_empty_rep()._M_refdata();
 130 #endif
 131         // NB: Not required, but considered best practice.
 132         if (__gnu_cxx::__is_null_pointer(__beg) && __beg != __end)
 133           __throw_logic_error(__N("basic_string::_S_construct NULL not valid"));
 134
 135         const size_type __dnew = static_cast<size_type>(std::distance(__beg,
 136                                                                       __end));
 137         // Check for out_of_range and length_error exceptions.
 138         _Rep* __r = _Rep::_S_create(__dnew, size_type(0), __a);
 139         __try
 140           { _S_copy_chars(__r->_M_refdata(), __beg, __end); }
 141         __catch(...)
 142           {
 143             __r->_M_destroy(__a);
 144             __throw_exception_again;
 145           }
 146         __r->_M_set_length_and_sharable(__dnew);
 147         return __r->_M_refdata();
 148       }
 149
 150   template<typename _CharT, typename _Traits, typename _Alloc>
 151     _CharT*
 152     basic_string<_CharT, _Traits, _Alloc>::
 153     _S_construct(size_type __n, _CharT __c, const _Alloc& __a)
 154     {
 155 #ifndef _GLIBCXX_FULLY_DYNAMIC_STRING
 156       if (__n == 0 && __a == _Alloc())
 157         return _S_empty_rep()._M_refdata();
 158 #endif
 159       // Check for out_of_range and length_error exceptions.
 160       _Rep* __r = _Rep::_S_create(__n, size_type(0), __a);
 161       if (__n)
 162         _M_assign(__r->_M_refdata(), __n, __c);
 163
 164       __r->_M_set_length_and_sharable(__n);
 165       return __r->_M_refdata();
 166     }
 167
 168   template<typename _CharT, typename _Traits, typename _Alloc>
 169     _CharT*
 170     basic_string<_CharT, _Traits, _Alloc>::
 171     _S_construct(const _CharT* __s, size_type __n, const _Alloc& __a)
 172     {
 173 #ifndef _GLIBCXX_FULLY_DYNAMIC_STRING
 174       if (__n == 0 && __a == _Alloc())
 175         return _S_empty_rep()._M_refdata();
 176 #endif
 177       // NB: Not required, but considered best practice.
 178       if (__gnu_cxx::__is_null_pointer(__s) && __n)
 179         __throw_logic_error(__N("basic_string::_S_construct NULL not valid"));
 180
 181       // Check for out_of_range and length_error exceptions.
 182       _Rep* __r = _Rep::_S_create(__n, size_type(0), __a);
 183       if (__n)
 184         _M_copy(__r->_M_refdata(), __s, __n);
 185
 186       __r->_M_set_length_and_sharable(__n);
 187       return __r->_M_refdata();
 188     }
 189
 190   template<typename _CharT, typename _Traits, typename _Alloc>
 191     basic_string<_CharT, _Traits, _Alloc>::
 192     basic_string(const basic_string& __str)
 193     : _M_dataplus(__str._M_rep()->_M_grab(_Alloc(__str.get_allocator()),
 194                                           __str.get_allocator()),
 195                   __str.get_allocator())
 196     { }
 197
 198   template<typename _CharT, typename _Traits, typename _Alloc>
 199     basic_string<_CharT, _Traits, _Alloc>::
 200     basic_string(const _Alloc& __a)
 201     : _M_dataplus(_S_construct(size_type(), _CharT(), __a), __a)
 202     { }
 203
 204   template<typename _CharT, typename _Traits, typename _Alloc>
 205     basic_string<_CharT, _Traits, _Alloc>::
 206     basic_string(const basic_string& __str, size_type __pos, size_type __n)
 207     : _M_dataplus(_S_construct(__str._M_data()
 208                                + __str._M_check(__pos,
 209                                                 "basic_string::basic_string"),
 210                                __str._M_limit(__pos, __n), _Alloc()), _Alloc())
 211     { }
 212
 213   template<typename _CharT, typename _Traits, typename _Alloc>
 214     basic_string<_CharT, _Traits, _Alloc>::
 215     basic_string(const basic_string& __str, size_type __pos,
 216                  size_type __n, const _Alloc& __a)
 217     : _M_dataplus(_S_construct(__str._M_data()
 218                                + __str._M_check(__pos,
 219                                                 "basic_string::basic_string"),
 220                                __str._M_limit(__pos, __n), __a), __a)
 221     { }
 222
 223   // TBD: DPG annotate
 224   template<typename _CharT, typename _Traits, typename _Alloc>
 225     basic_string<_CharT, _Traits, _Alloc>::
 226     basic_string(const _CharT* __s, size_type __n, const _Alloc& __a)
 227     : _M_dataplus(_S_construct(__s, __n, __a), __a)
 228     { }
 229
 230   // TBD: DPG annotate
 231   template<typename _CharT, typename _Traits, typename _Alloc>
 232     basic_string<_CharT, _Traits, _Alloc>::
 233     basic_string(const _CharT* __s, const _Alloc& __a)
 234     : _M_dataplus(_S_construct(__s, __s ? traits_type::length(__s) : npos,
 235                                __a), __a)
 236     { }
 237
 238   template<typename _CharT, typename _Traits, typename _Alloc>
 239     basic_string<_CharT, _Traits, _Alloc>::
 240     basic_string(size_type __n, _CharT __c, const _Alloc& __a)
 241     : _M_dataplus(_S_construct(__n, __c, __a), __a)
 242     { }
 243
 244   // TBD: DPG annotate
 245   template<typename _CharT, typename _Traits, typename _Alloc>
 246     template<typename _InputIterator>
 247       basic_string<_CharT, _Traits, _Alloc>::
 248       basic_string(_InputIterator __beg, _InputIterator __end,
 249                    const _Alloc& __a)
 250       : _M_dataplus(_S_construct(__beg, __end, __a), __a)
 251       { }
 252
 253 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 254   template<typename _CharT, typename _Traits, typename _Alloc>
 255     basic_string<_CharT, _Traits, _Alloc>::
 256     basic_string(initializer_list<_CharT> __l, const _Alloc& __a)
 257     : _M_dataplus(_S_construct(__l.begin(), __l.size(), __a), __a)
 258     { }
 259 #endif
 260
 261   template<typename _CharT, typename _Traits, typename _Alloc>
 262     basic_string<_CharT, _Traits, _Alloc>&
 263     basic_string<_CharT, _Traits, _Alloc>::
 264     assign(const basic_string& __str)
 265     {
 266       if (_M_rep() != __str._M_rep())
 267         {
 268           // XXX MT
 269           const allocator_type __a = this->get_allocator();
 270           _CharT* __tmp = __str._M_rep()->_M_grab(__a, __str.get_allocator());
 271           _M_rep()->_M_dispose(__a);
 272           _M_data(__tmp);
 273         }
 274       return *this;
 275     }
 276
 277   template<typename _CharT, typename _Traits, typename _Alloc>
 278     basic_string<_CharT, _Traits, _Alloc>&
 279     basic_string<_CharT, _Traits, _Alloc>::
 280     assign(const _CharT* __s, size_type __n)
 281     {
 282       __glibcxx_requires_string_len(__s, __n);
 283       _M_check_length(this->size(), __n, "basic_string::assign");
 284       if (_M_disjunct(__s) || _M_rep()->_M_is_shared())
 285         return _M_replace_safe(size_type(0), this->size(), __s, __n);
 286       else
 287         {
 288           // Work in-place.
 289           const size_type __pos = __s - _M_data();
 290           if (__pos >= __n)
 291             _M_copy(_M_data(), __s, __n);
 292           else if (__pos)
 293             _M_move(_M_data(), __s, __n);
 294           _M_rep()->_M_set_length_and_sharable(__n);
 295           return *this;
 296         }
 297      }
 298
 299   template<typename _CharT, typename _Traits, typename _Alloc>
 300     basic_string<_CharT, _Traits, _Alloc>&
 301     basic_string<_CharT, _Traits, _Alloc>::
 302     append(size_type __n, _CharT __c)
 303     {
 304       if (__n)
 305         {
 306           _M_check_length(size_type(0), __n, "basic_string::append");
 307           const size_type __len = __n + this->size();
 308           if (__len > this->capacity() || _M_rep()->_M_is_shared())
 309             this->reserve(__len);
 310           _M_assign(_M_data() + this->size(), __n, __c);
 311           _M_rep()->_M_set_length_and_sharable(__len);
 312         }
 313       return *this;
 314     }
 315
 316   template<typename _CharT, typename _Traits, typename _Alloc>
 317     basic_string<_CharT, _Traits, _Alloc>&
 318     basic_string<_CharT, _Traits, _Alloc>::
 319     append(const _CharT* __s, size_type __n)
 320     {
 321       __glibcxx_requires_string_len(__s, __n);
 322       if (__n)
 323         {
 324           _M_check_length(size_type(0), __n, "basic_string::append");
 325           const size_type __len = __n + this->size();
 326           if (__len > this->capacity() || _M_rep()->_M_is_shared())
 327             {
 328               if (_M_disjunct(__s))
 329                 this->reserve(__len);
 330               else
 331                 {
 332                   const size_type __off = __s - _M_data();
 333                   this->reserve(__len);
 334                   __s = _M_data() + __off;
 335                 }
 336             }
 337           _M_copy(_M_data() + this->size(), __s, __n);
 338           _M_rep()->_M_set_length_and_sharable(__len);
 339         }
 340       return *this;
 341     }
 342
 343   template<typename _CharT, typename _Traits, typename _Alloc>
 344     basic_string<_CharT, _Traits, _Alloc>&
 345     basic_string<_CharT, _Traits, _Alloc>::
 346     append(const basic_string& __str)
 347     {
 348       const size_type __size = __str.size();
 349       if (__size)
 350         {
 351           const size_type __len = __size + this->size();
 352           if (__len > this->capacity() || _M_rep()->_M_is_shared())
 353             this->reserve(__len);
 354           _M_copy(_M_data() + this->size(), __str._M_data(), __size);
 355           _M_rep()->_M_set_length_and_sharable(__len);
 356         }
 357       return *this;
 358     }
 359
 360   template<typename _CharT, typename _Traits, typename _Alloc>
 361     basic_string<_CharT, _Traits, _Alloc>&
 362     basic_string<_CharT, _Traits, _Alloc>::
 363     append(const basic_string& __str, size_type __pos, size_type __n)
 364     {
 365       __str._M_check(__pos, "basic_string::append");
 366       __n = __str._M_limit(__pos, __n);
 367       if (__n)
 368         {
 369           const size_type __len = __n + this->size();
 370           if (__len > this->capacity() || _M_rep()->_M_is_shared())
 371             this->reserve(__len);
 372           _M_copy(_M_data() + this->size(), __str._M_data() + __pos, __n);
 373           _M_rep()->_M_set_length_and_sharable(__len);
 374         }
 375       return *this;
 376     }
 377
 378    template<typename _CharT, typename _Traits, typename _Alloc>
 379      basic_string<_CharT, _Traits, _Alloc>&
 380      basic_string<_CharT, _Traits, _Alloc>::
 381      insert(size_type __pos, const _CharT* __s, size_type __n)
 382      {
 383        __glibcxx_requires_string_len(__s, __n);
 384        _M_check(__pos, "basic_string::insert");
 385        _M_check_length(size_type(0), __n, "basic_string::insert");
 386        if (_M_disjunct(__s) || _M_rep()->_M_is_shared())
 387          return _M_replace_safe(__pos, size_type(0), __s, __n);
 388        else
 389          {
 390            // Work in-place.
 391            const size_type __off = __s - _M_data();
 392            _M_mutate(__pos, 0, __n);
 393            __s = _M_data() + __off;
 394            _CharT* __p = _M_data() + __pos;
 395            if (__s  + __n <= __p)
 396              _M_copy(__p, __s, __n);
 397            else if (__s >= __p)
 398              _M_copy(__p, __s + __n, __n);
 399            else
 400              {
 401                const size_type __nleft = __p - __s;
 402                _M_copy(__p, __s, __nleft);
 403                _M_copy(__p + __nleft, __p + __n, __n - __nleft);
 404              }
 405            return *this;
 406          }
 407      }
 408
 409    template<typename _CharT, typename _Traits, typename _Alloc>
 410      typename basic_string<_CharT, _Traits, _Alloc>::iterator
 411      basic_string<_CharT, _Traits, _Alloc>::
 412      erase(iterator __first, iterator __last)
 413      {
 414        _GLIBCXX_DEBUG_PEDASSERT(__first >= _M_ibegin() && __first <= __last
 415                                 && __last <= _M_iend());
 416
 417        // NB: This isn't just an optimization (bail out early when
 418        // there is nothing to do, really), it's also a correctness
 419        // issue vs MT, see libstdc++/40518.
 420        const size_type __size = __last - __first;
 421        if (__size)
 422          {
 423            const size_type __pos = __first - _M_ibegin();
 424            _M_mutate(__pos, __size, size_type(0));
 425            _M_rep()->_M_set_leaked();
 426            return iterator(_M_data() + __pos);
 427          }
 428        else
 429          return __first;
 430      }
 431
 432    template<typename _CharT, typename _Traits, typename _Alloc>
 433      basic_string<_CharT, _Traits, _Alloc>&
 434      basic_string<_CharT, _Traits, _Alloc>::
 435      replace(size_type __pos, size_type __n1, const _CharT* __s,
 436              size_type __n2)
 437      {
 438        __glibcxx_requires_string_len(__s, __n2);
 439        _M_check(__pos, "basic_string::replace");
 440        __n1 = _M_limit(__pos, __n1);
 441        _M_check_length(__n1, __n2, "basic_string::replace");
 442        bool __left;
 443        if (_M_disjunct(__s) || _M_rep()->_M_is_shared())
 444          return _M_replace_safe(__pos, __n1, __s, __n2);
 445        else if ((__left = __s + __n2 <= _M_data() + __pos)
 446                 || _M_data() + __pos + __n1 <= __s)
 447          {
 448            // Work in-place: non-overlapping case.
 449            size_type __off = __s - _M_data();
 450            __left ? __off : (__off += __n2 - __n1);
 451            _M_mutate(__pos, __n1, __n2);
 452            _M_copy(_M_data() + __pos, _M_data() + __off, __n2);
 453            return *this;
 454          }
 455        else
 456          {
 457            // Todo: overlapping case.
 458            const basic_string __tmp(__s, __n2);
 459            return _M_replace_safe(__pos, __n1, __tmp._M_data(), __n2);
 460          }
 461      }
 462
 463   template<typename _CharT, typename _Traits, typename _Alloc>
 464     void
 465     basic_string<_CharT, _Traits, _Alloc>::_Rep::
 466     _M_destroy(const _Alloc& __a) throw ()
 467     {
 468       const size_type __size = sizeof(_Rep_base) +
 469                                (this->_M_capacity + 1) * sizeof(_CharT);
 470       _Raw_bytes_alloc(__a).deallocate(reinterpret_cast<char*>(this), __size);
 471     }
 472
 473   template<typename _CharT, typename _Traits, typename _Alloc>
 474     void
 475     basic_string<_CharT, _Traits, _Alloc>::
 476     _M_leak_hard()
 477     {
 478 #ifndef _GLIBCXX_FULLY_DYNAMIC_STRING
 479       if (_M_rep() == &_S_empty_rep())
 480         return;
 481 #endif
 482       if (_M_rep()->_M_is_shared())
 483         _M_mutate(0, 0, 0);
 484       _M_rep()->_M_set_leaked();
 485     }
 486
 487   template<typename _CharT, typename _Traits, typename _Alloc>
 488     void
 489     basic_string<_CharT, _Traits, _Alloc>::
 490     _M_mutate(size_type __pos, size_type __len1, size_type __len2)
 491     {
 492       const size_type __old_size = this->size();
 493       const size_type __new_size = __old_size + __len2 - __len1;
 494       const size_type __how_much = __old_size - __pos - __len1;
 495
 496       if (__new_size > this->capacity() || _M_rep()->_M_is_shared())
 497         {
 498           // Must reallocate.
 499           const allocator_type __a = get_allocator();
 500           _Rep* __r = _Rep::_S_create(__new_size, this->capacity(), __a);
 501
 502           if (__pos)
 503             _M_copy(__r->_M_refdata(), _M_data(), __pos);
 504           if (__how_much)
 505             _M_copy(__r->_M_refdata() + __pos + __len2,
 506                     _M_data() + __pos + __len1, __how_much);
 507
 508           _M_rep()->_M_dispose(__a);
 509           _M_data(__r->_M_refdata());
 510         }
 511       else if (__how_much && __len1 != __len2)
 512         {
 513           // Work in-place.
 514           _M_move(_M_data() + __pos + __len2,
 515                   _M_data() + __pos + __len1, __how_much);
 516         }
 517       _M_rep()->_M_set_length_and_sharable(__new_size);
 518     }
 519
 520   template<typename _CharT, typename _Traits, typename _Alloc>
 521     void
 522     basic_string<_CharT, _Traits, _Alloc>::
 523     reserve(size_type __res)
 524     {
 525       if (__res != this->capacity() || _M_rep()->_M_is_shared())
 526         {
 527           // Make sure we don't shrink below the current size
 528           if (__res < this->size())
 529             __res = this->size();
 530           const allocator_type __a = get_allocator();
 531           _CharT* __tmp = _M_rep()->_M_clone(__a, __res - this->size());
 532           _M_rep()->_M_dispose(__a);
 533           _M_data(__tmp);
 534         }
 535     }
 536
 537   template<typename _CharT, typename _Traits, typename _Alloc>
 538     void
 539     basic_string<_CharT, _Traits, _Alloc>::
 540     swap(basic_string& __s)
 541     {
 542       if (_M_rep()->_M_is_leaked())
 543         _M_rep()->_M_set_sharable();
 544       if (__s._M_rep()->_M_is_leaked())
 545         __s._M_rep()->_M_set_sharable();
 546       if (this->get_allocator() == __s.get_allocator())
 547         {
 548           _CharT* __tmp = _M_data();
 549           _M_data(__s._M_data());
 550           __s._M_data(__tmp);
 551         }
 552       // The code below can usually be optimized away.
 553       else
 554         {
 555           const basic_string __tmp1(_M_ibegin(), _M_iend(),
 556                                     __s.get_allocator());
 557           const basic_string __tmp2(__s._M_ibegin(), __s._M_iend(),
 558                                     this->get_allocator());
 559           *this = __tmp2;
 560           __s = __tmp1;
 561         }
 562     }
 563
 564   template<typename _CharT, typename _Traits, typename _Alloc>
 565     typename basic_string<_CharT, _Traits, _Alloc>::_Rep*
 566     basic_string<_CharT, _Traits, _Alloc>::_Rep::
 567     _S_create(size_type __capacity, size_type __old_capacity,
 568               const _Alloc& __alloc)
 569     {
 570       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 571       // 83.  String::npos vs. string::max_size()
 572       if (__capacity > _S_max_size)
 573         __throw_length_error(__N("basic_string::_S_create"));
 574
 575       // The standard places no restriction on allocating more memory
 576       // than is strictly needed within this layer at the moment or as
 577       // requested by an explicit application call to reserve().
 578
 579       // Many malloc implementations perform quite poorly when an
 580       // application attempts to allocate memory in a stepwise fashion
 581       // growing each allocation size by only 1 char.  Additionally,
 582       // it makes little sense to allocate less linear memory than the
 583       // natural blocking size of the malloc implementation.
 584       // Unfortunately, we would need a somewhat low-level calculation
 585       // with tuned parameters to get this perfect for any particular
 586       // malloc implementation.  Fortunately, generalizations about
 587       // common features seen among implementations seems to suffice.
 588
 589       // __pagesize need not match the actual VM page size for good
 590       // results in practice, thus we pick a common value on the low
 591       // side.  __malloc_header_size is an estimate of the amount of
 592       // overhead per memory allocation (in practice seen N * sizeof
 593       // (void*) where N is 0, 2 or 4).  According to folklore,
 594       // picking this value on the high side is better than
 595       // low-balling it (especially when this algorithm is used with
 596       // malloc implementations that allocate memory blocks rounded up
 597       // to a size which is a power of 2).
 598       const size_type __pagesize = 4096;
 599       const size_type __malloc_header_size = 4 * sizeof(void*);
 600
 601       // The below implements an exponential growth policy, necessary to
 602       // meet amortized linear time requirements of the library: see
 603       // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
 604       // It's active for allocations requiring an amount of memory above
 605       // system pagesize. This is consistent with the requirements of the
 606       // standard: http://gcc.gnu.org/ml/libstdc++/2001-07/msg00130.html
 607       if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
 608         __capacity = 2 * __old_capacity;
 609
 610       // NB: Need an array of char_type[__capacity], plus a terminating
 611       // null char_type() element, plus enough for the _Rep data structure.
 612       // Whew. Seemingly so needy, yet so elemental.
 613       size_type __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
 614
 615       const size_type __adj_size = __size + __malloc_header_size;
 616       if (__adj_size > __pagesize && __capacity > __old_capacity)
 617         {
 618           const size_type __extra = __pagesize - __adj_size % __pagesize;
 619           __capacity += __extra / sizeof(_CharT);
 620           // Never allocate a string bigger than _S_max_size.
 621           if (__capacity > _S_max_size)
 622             __capacity = _S_max_size;
 623           __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
 624         }
 625
 626       // NB: Might throw, but no worries about a leak, mate: _Rep()
 627       // does not throw.
 628       void* __place = _Raw_bytes_alloc(__alloc).allocate(__size);
 629       _Rep *__p = new (__place) _Rep;
 630       __p->_M_capacity = __capacity;
 631       // ABI compatibility - 3.4.x set in _S_create both
 632       // _M_refcount and _M_length.  All callers of _S_create
 633       // in basic_string.tcc then set just _M_length.
 634       // In 4.0.x and later both _M_refcount and _M_length
 635       // are initialized in the callers, unfortunately we can
 636       // have 3.4.x compiled code with _S_create callers inlined
 637       // calling 4.0.x+ _S_create.
 638       __p->_M_set_sharable();
 639       return __p;
 640     }
 641
 642   template<typename _CharT, typename _Traits, typename _Alloc>
 643     _CharT*
 644     basic_string<_CharT, _Traits, _Alloc>::_Rep::
 645     _M_clone(const _Alloc& __alloc, size_type __res)
 646     {
 647       // Requested capacity of the clone.
 648       const size_type __requested_cap = this->_M_length + __res;
 649       _Rep* __r = _Rep::_S_create(__requested_cap, this->_M_capacity,
 650                                   __alloc);
 651       if (this->_M_length)
 652         _M_copy(__r->_M_refdata(), _M_refdata(), this->_M_length);
 653
 654       __r->_M_set_length_and_sharable(this->_M_length);
 655       return __r->_M_refdata();
 656     }
 657
 658   template<typename _CharT, typename _Traits, typename _Alloc>
 659     void
 660     basic_string<_CharT, _Traits, _Alloc>::
 661     resize(size_type __n, _CharT __c)
 662     {
 663       const size_type __size = this->size();
 664       _M_check_length(__size, __n, "basic_string::resize");
 665       if (__size < __n)
 666         this->append(__n - __size, __c);
 667       else if (__n < __size)
 668         this->erase(__n);
 669       // else nothing (in particular, avoid calling _M_mutate() unnecessarily.)
 670     }
 671
 672   template<typename _CharT, typename _Traits, typename _Alloc>
 673     template<typename _InputIterator>
 674       basic_string<_CharT, _Traits, _Alloc>&
 675       basic_string<_CharT, _Traits, _Alloc>::
 676       _M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
 677                           _InputIterator __k2, __false_type)
 678       {
 679         const basic_string __s(__k1, __k2);
 680         const size_type __n1 = __i2 - __i1;
 681         _M_check_length(__n1, __s.size(), "basic_string::_M_replace_dispatch");
 682         return _M_replace_safe(__i1 - _M_ibegin(), __n1, __s._M_data(),
 683                                __s.size());
 684       }
 685
 686   template<typename _CharT, typename _Traits, typename _Alloc>
 687     basic_string<_CharT, _Traits, _Alloc>&
 688     basic_string<_CharT, _Traits, _Alloc>::
 689     _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
 690                    _CharT __c)
 691     {
 692       _M_check_length(__n1, __n2, "basic_string::_M_replace_aux");
 693       _M_mutate(__pos1, __n1, __n2);
 694       if (__n2)
 695         _M_assign(_M_data() + __pos1, __n2, __c);
 696       return *this;
 697     }
 698
 699   template<typename _CharT, typename _Traits, typename _Alloc>
 700     basic_string<_CharT, _Traits, _Alloc>&
 701     basic_string<_CharT, _Traits, _Alloc>::
 702     _M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
 703                     size_type __n2)
 704     {
 705       _M_mutate(__pos1, __n1, __n2);
 706       if (__n2)
 707         _M_copy(_M_data() + __pos1, __s, __n2);
 708       return *this;
 709     }
 710
 711   template<typename _CharT, typename _Traits, typename _Alloc>
 712     basic_string<_CharT, _Traits, _Alloc>
 713     operator+(const _CharT* __lhs,
 714               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
 715     {
 716       __glibcxx_requires_string(__lhs);
 717       typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
 718       typedef typename __string_type::size_type   __size_type;
 719       const __size_type __len = _Traits::length(__lhs);
 720       __string_type __str;
 721       __str.reserve(__len + __rhs.size());
 722       __str.append(__lhs, __len);
 723       __str.append(__rhs);
 724       return __str;
 725     }
 726
 727   template<typename _CharT, typename _Traits, typename _Alloc>
 728     basic_string<_CharT, _Traits, _Alloc>
 729     operator+(_CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs)
 730     {
 731       typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
 732       typedef typename __string_type::size_type   __size_type;
 733       __string_type __str;
 734       const __size_type __len = __rhs.size();
 735       __str.reserve(__len + 1);
 736       __str.append(__size_type(1), __lhs);
 737       __str.append(__rhs);
 738       return __str;
 739     }
 740
 741   template<typename _CharT, typename _Traits, typename _Alloc>
 742     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 743     basic_string<_CharT, _Traits, _Alloc>::
 744     copy(_CharT* __s, size_type __n, size_type __pos) const
 745     {
 746       _M_check(__pos, "basic_string::copy");
 747       __n = _M_limit(__pos, __n);
 748       __glibcxx_requires_string_len(__s, __n);
 749       if (__n)
 750         _M_copy(__s, _M_data() + __pos, __n);
 751       // 21.3.5.7 par 3: do not append null.  (good.)
 752       return __n;
 753     }
 754
 755   template<typename _CharT, typename _Traits, typename _Alloc>
 756     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 757     basic_string<_CharT, _Traits, _Alloc>::
 758     find(const _CharT* __s, size_type __pos, size_type __n) const
 759     {
 760       __glibcxx_requires_string_len(__s, __n);
 761       const size_type __size = this->size();
 762       const _CharT* __data = _M_data();
 763
 764       if (__n == 0)
 765         return __pos <= __size ? __pos : npos;
 766
 767       if (__n <= __size)
 768         {
 769           for (; __pos <= __size - __n; ++__pos)
 770             if (traits_type::eq(__data[__pos], __s[0])
 771                 && traits_type::compare(__data + __pos + 1,
 772                                         __s + 1, __n - 1) == 0)
 773               return __pos;
 774         }
 775       return npos;
 776     }
 777
 778   template<typename _CharT, typename _Traits, typename _Alloc>
 779     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 780     basic_string<_CharT, _Traits, _Alloc>::
 781     find(_CharT __c, size_type __pos) const
 782     {
 783       size_type __ret = npos;
 784       const size_type __size = this->size();
 785       if (__pos < __size)
 786         {
 787           const _CharT* __data = _M_data();
 788           const size_type __n = __size - __pos;
 789           const _CharT* __p = traits_type::find(__data + __pos, __n, __c);
 790           if (__p)
 791             __ret = __p - __data;
 792         }
 793       return __ret;
 794     }
 795
 796   template<typename _CharT, typename _Traits, typename _Alloc>
 797     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 798     basic_string<_CharT, _Traits, _Alloc>::
 799     rfind(const _CharT* __s, size_type __pos, size_type __n) const
 800     {
 801       __glibcxx_requires_string_len(__s, __n);
 802       const size_type __size = this->size();
 803       if (__n <= __size)
 804         {
 805           __pos = std::min(size_type(__size - __n), __pos);
 806           const _CharT* __data = _M_data();
 807           do
 808             {
 809               if (traits_type::compare(__data + __pos, __s, __n) == 0)
 810                 return __pos;
 811             }
 812           while (__pos-- > 0);
 813         }
 814       return npos;
 815     }
 816
 817   template<typename _CharT, typename _Traits, typename _Alloc>
 818     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 819     basic_string<_CharT, _Traits, _Alloc>::
 820     rfind(_CharT __c, size_type __pos) const
 821     {
 822       size_type __size = this->size();
 823       if (__size)
 824         {
 825           if (--__size > __pos)
 826             __size = __pos;
 827           for (++__size; __size-- > 0; )
 828             if (traits_type::eq(_M_data()[__size], __c))
 829               return __size;
 830         }
 831       return npos;
 832     }
 833
 834   template<typename _CharT, typename _Traits, typename _Alloc>
 835     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 836     basic_string<_CharT, _Traits, _Alloc>::
 837     find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
 838     {
 839       __glibcxx_requires_string_len(__s, __n);
 840       for (; __n && __pos < this->size(); ++__pos)
 841         {
 842           const _CharT* __p = traits_type::find(__s, __n, _M_data()[__pos]);
 843           if (__p)
 844             return __pos;
 845         }
 846       return npos;
 847     }
 848
 849   template<typename _CharT, typename _Traits, typename _Alloc>
 850     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 851     basic_string<_CharT, _Traits, _Alloc>::
 852     find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
 853     {
 854       __glibcxx_requires_string_len(__s, __n);
 855       size_type __size = this->size();
 856       if (__size && __n)
 857         {
 858           if (--__size > __pos)
 859             __size = __pos;
 860           do
 861             {
 862               if (traits_type::find(__s, __n, _M_data()[__size]))
 863                 return __size;
 864             }
 865           while (__size-- != 0);
 866         }
 867       return npos;
 868     }
 869
 870   template<typename _CharT, typename _Traits, typename _Alloc>
 871     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 872     basic_string<_CharT, _Traits, _Alloc>::
 873     find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const
 874     {
 875       __glibcxx_requires_string_len(__s, __n);
 876       for (; __pos < this->size(); ++__pos)
 877         if (!traits_type::find(__s, __n, _M_data()[__pos]))
 878           return __pos;
 879       return npos;
 880     }
 881
 882   template<typename _CharT, typename _Traits, typename _Alloc>
 883     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 884     basic_string<_CharT, _Traits, _Alloc>::
 885     find_first_not_of(_CharT __c, size_type __pos) const
 886     {
 887       for (; __pos < this->size(); ++__pos)
 888         if (!traits_type::eq(_M_data()[__pos], __c))
 889           return __pos;
 890       return npos;
 891     }
 892
 893   template<typename _CharT, typename _Traits, typename _Alloc>
 894     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 895     basic_string<_CharT, _Traits, _Alloc>::
 896     find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const
 897     {
 898       __glibcxx_requires_string_len(__s, __n);
 899       size_type __size = this->size();
 900       if (__size)
 901         {
 902           if (--__size > __pos)
 903             __size = __pos;
 904           do
 905             {
 906               if (!traits_type::find(__s, __n, _M_data()[__size]))
 907                 return __size;
 908             }
 909           while (__size--);
 910         }
 911       return npos;
 912     }
 913
 914   template<typename _CharT, typename _Traits, typename _Alloc>
 915     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 916     basic_string<_CharT, _Traits, _Alloc>::
 917     find_last_not_of(_CharT __c, size_type __pos) const
 918     {
 919       size_type __size = this->size();
 920       if (__size)
 921         {
 922           if (--__size > __pos)
 923             __size = __pos;
 924           do
 925             {
 926               if (!traits_type::eq(_M_data()[__size], __c))
 927                 return __size;
 928             }
 929           while (__size--);
 930         }
 931       return npos;
 932     }
 933
 934   template<typename _CharT, typename _Traits, typename _Alloc>
 935     int
 936     basic_string<_CharT, _Traits, _Alloc>::
 937     compare(size_type __pos, size_type __n, const basic_string& __str) const
 938     {
 939       _M_check(__pos, "basic_string::compare");
 940       __n = _M_limit(__pos, __n);
 941       const size_type __osize = __str.size();
 942       const size_type __len = std::min(__n, __osize);
 943       int __r = traits_type::compare(_M_data() + __pos, __str.data(), __len);
 944       if (!__r)
 945         __r = _S_compare(__n, __osize);
 946       return __r;
 947     }
 948
 949   template<typename _CharT, typename _Traits, typename _Alloc>
 950     int
 951     basic_string<_CharT, _Traits, _Alloc>::
 952     compare(size_type __pos1, size_type __n1, const basic_string& __str,
 953             size_type __pos2, size_type __n2) const
 954     {
 955       _M_check(__pos1, "basic_string::compare");
 956       __str._M_check(__pos2, "basic_string::compare");
 957       __n1 = _M_limit(__pos1, __n1);
 958       __n2 = __str._M_limit(__pos2, __n2);
 959       const size_type __len = std::min(__n1, __n2);
 960       int __r = traits_type::compare(_M_data() + __pos1,
 961                                      __str.data() + __pos2, __len);
 962       if (!__r)
 963         __r = _S_compare(__n1, __n2);
 964       return __r;
 965     }
 966
 967   template<typename _CharT, typename _Traits, typename _Alloc>
 968     int
 969     basic_string<_CharT, _Traits, _Alloc>::
 970     compare(const _CharT* __s) const
 971     {
 972       __glibcxx_requires_string(__s);
 973       const size_type __size = this->size();
 974       const size_type __osize = traits_type::length(__s);
 975       const size_type __len = std::min(__size, __osize);
 976       int __r = traits_type::compare(_M_data(), __s, __len);
 977       if (!__r)
 978         __r = _S_compare(__size, __osize);
 979       return __r;
 980     }
 981
 982   template<typename _CharT, typename _Traits, typename _Alloc>
 983     int
 984     basic_string <_CharT, _Traits, _Alloc>::
 985     compare(size_type __pos, size_type __n1, const _CharT* __s) const
 986     {
 987       __glibcxx_requires_string(__s);
 988       _M_check(__pos, "basic_string::compare");
 989       __n1 = _M_limit(__pos, __n1);
 990       const size_type __osize = traits_type::length(__s);
 991       const size_type __len = std::min(__n1, __osize);
 992       int __r = traits_type::compare(_M_data() + __pos, __s, __len);
 993       if (!__r)
 994         __r = _S_compare(__n1, __osize);
 995       return __r;
 996     }
 997
 998   template<typename _CharT, typename _Traits, typename _Alloc>
 999     int
1000     basic_string <_CharT, _Traits, _Alloc>::
1001     compare(size_type __pos, size_type __n1, const _CharT* __s,
1002             size_type __n2) const
1003     {
1004       __glibcxx_requires_string_len(__s, __n2);
1005       _M_check(__pos, "basic_string::compare");
1006       __n1 = _M_limit(__pos, __n1);
1007       const size_type __len = std::min(__n1, __n2);
1008       int __r = traits_type::compare(_M_data() + __pos, __s, __len);
1009       if (!__r)
1010         __r = _S_compare(__n1, __n2);
1011       return __r;
1012     }
1013
1014   // 21.3.7.9 basic_string::getline and operators
1015   template<typename _CharT, typename _Traits, typename _Alloc>
1016     basic_istream<_CharT, _Traits>&
1017     operator>>(basic_istream<_CharT, _Traits>& __in,
1018                basic_string<_CharT, _Traits, _Alloc>& __str)
1019     {
1020       typedef basic_istream<_CharT, _Traits>            __istream_type;
1021       typedef basic_string<_CharT, _Traits, _Alloc>     __string_type;
1022       typedef typename __istream_type::ios_base         __ios_base;
1023       typedef typename __istream_type::int_type         __int_type;
1024       typedef typename __string_type::size_type         __size_type;
1025       typedef ctype<_CharT>                             __ctype_type;
1026       typedef typename __ctype_type::ctype_base         __ctype_base;
1027
1028       __size_type __extracted = 0;
1029       typename __ios_base::iostate __err = __ios_base::goodbit;
1030       typename __istream_type::sentry __cerb(__in, false);
1031       if (__cerb)
1032         {
1033           __try
1034             {
1035               // Avoid reallocation for common case.
1036               __str.erase();
1037               _CharT __buf[128];
1038               __size_type __len = 0;
1039               const streamsize __w = __in.width();
1040               const __size_type __n = __w > 0 ? static_cast<__size_type>(__w)
1041                                               : __str.max_size();
1042               const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
1043               const __int_type __eof = _Traits::eof();
1044               __int_type __c = __in.rdbuf()->sgetc();
1045
1046               while (__extracted < __n
1047                      && !_Traits::eq_int_type(__c, __eof)
1048                      && !__ct.is(__ctype_base::space,
1049                                  _Traits::to_char_type(__c)))
1050                 {
1051                   if (__len == sizeof(__buf) / sizeof(_CharT))
1052                     {
1053                       __str.append(__buf, sizeof(__buf) / sizeof(_CharT));
1054                       __len = 0;
1055                     }
1056                   __buf[__len++] = _Traits::to_char_type(__c);
1057                   ++__extracted;
1058                   __c = __in.rdbuf()->snextc();
1059                 }
1060               __str.append(__buf, __len);
1061
1062               if (_Traits::eq_int_type(__c, __eof))
1063                 __err |= __ios_base::eofbit;
1064               __in.width(0);
1065             }
1066           __catch(__cxxabiv1::__forced_unwind&)
1067             {
1068               __in._M_setstate(__ios_base::badbit);
1069               __throw_exception_again;
1070             }
1071           __catch(...)
1072             {
1073               // _GLIBCXX_RESOLVE_LIB_DEFECTS
1074               // 91. Description of operator>> and getline() for string<>
1075               // might cause endless loop
1076               __in._M_setstate(__ios_base::badbit);
1077             }
1078         }
1079       // 211.  operator>>(istream&, string&) doesn't set failbit
1080       if (!__extracted)
1081         __err |= __ios_base::failbit;
1082       if (__err)
1083         __in.setstate(__err);
1084       return __in;
1085     }
1086
1087   template<typename _CharT, typename _Traits, typename _Alloc>
1088     basic_istream<_CharT, _Traits>&
1089     getline(basic_istream<_CharT, _Traits>& __in,
1090             basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim)
1091     {
1092       typedef basic_istream<_CharT, _Traits>            __istream_type;
1093       typedef basic_string<_CharT, _Traits, _Alloc>     __string_type;
1094       typedef typename __istream_type::ios_base         __ios_base;
1095       typedef typename __istream_type::int_type         __int_type;
1096       typedef typename __string_type::size_type         __size_type;
1097
1098       __size_type __extracted = 0;
1099       const __size_type __n = __str.max_size();
1100       typename __ios_base::iostate __err = __ios_base::goodbit;
1101       typename __istream_type::sentry __cerb(__in, true);
1102       if (__cerb)
1103         {
1104           __try
1105             {
1106               __str.erase();
1107               const __int_type __idelim = _Traits::to_int_type(__delim);
1108               const __int_type __eof = _Traits::eof();
1109               __int_type __c = __in.rdbuf()->sgetc();
1110
1111               while (__extracted < __n
1112                      && !_Traits::eq_int_type(__c, __eof)
1113                      && !_Traits::eq_int_type(__c, __idelim))
1114                 {
1115                   __str += _Traits::to_char_type(__c);
1116                   ++__extracted;
1117                   __c = __in.rdbuf()->snextc();
1118                 }
1119
1120               if (_Traits::eq_int_type(__c, __eof))
1121                 __err |= __ios_base::eofbit;
1122               else if (_Traits::eq_int_type(__c, __idelim))
1123                 {
1124                   ++__extracted;
1125                   __in.rdbuf()->sbumpc();
1126                 }
1127               else
1128                 __err |= __ios_base::failbit;
1129             }
1130           __catch(__cxxabiv1::__forced_unwind&)
1131             {
1132               __in._M_setstate(__ios_base::badbit);
1133               __throw_exception_again;
1134             }
1135           __catch(...)
1136             {
1137               // _GLIBCXX_RESOLVE_LIB_DEFECTS
1138               // 91. Description of operator>> and getline() for string<>
1139               // might cause endless loop
1140               __in._M_setstate(__ios_base::badbit);
1141             }
1142         }
1143       if (!__extracted)
1144         __err |= __ios_base::failbit;
1145       if (__err)
1146         __in.setstate(__err);
1147       return __in;
1148     }
1149
1150   // Inhibit implicit instantiations for required instantiations,
1151   // which are defined via explicit instantiations elsewhere.
1152   // NB: This syntax is a GNU extension.
1153 #if _GLIBCXX_EXTERN_TEMPLATE > 0
1154   extern template class basic_string<char>;
1155   extern template
1156     basic_istream<char>&
1157     operator>>(basic_istream<char>&, string&);
1158   extern template
1159     basic_ostream<char>&
1160     operator<<(basic_ostream<char>&, const string&);
1161   extern template
1162     basic_istream<char>&
1163     getline(basic_istream<char>&, string&, char);
1164   extern template
1165     basic_istream<char>&
1166     getline(basic_istream<char>&, string&);
1167
1168 #ifdef _GLIBCXX_USE_WCHAR_T
1169   extern template class basic_string<wchar_t>;
1170   extern template
1171     basic_istream<wchar_t>&
1172     operator>>(basic_istream<wchar_t>&, wstring&);
1173   extern template
1174     basic_ostream<wchar_t>&
1175     operator<<(basic_ostream<wchar_t>&, const wstring&);
1176   extern template
1177     basic_istream<wchar_t>&
1178     getline(basic_istream<wchar_t>&, wstring&, wchar_t);
1179   extern template
1180     basic_istream<wchar_t>&
1181     getline(basic_istream<wchar_t>&, wstring&);
1182 #endif
1183 #endif
1184
1185 _GLIBCXX_END_NAMESPACE
1186
1187 #endif