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
   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
  46 namespace 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[100];
  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     { }
 184
 185   template<typename _CharT, typename _Traits, typename _Alloc>
 186     basic_string<_CharT, _Traits, _Alloc>::
 187     basic_string(const _Alloc& __a)
 188     : _M_dataplus(_S_construct(size_type(), _CharT(), __a), __a)
 189     { }
 190
 191   template<typename _CharT, typename _Traits, typename _Alloc>
 192     basic_string<_CharT, _Traits, _Alloc>::
 193     basic_string(const basic_string& __str, size_type __pos, size_type __n)
 194     : _M_dataplus(_S_construct(__str._M_data()
 195                                + __str._M_check(__pos,
 196                                                 "basic_string::basic_string"),
 197                                __str._M_data() + __str._M_limit(__pos, __n)
 198                                + __pos, _Alloc()), _Alloc())
 199     { }
 200
 201   template<typename _CharT, typename _Traits, typename _Alloc>
 202     basic_string<_CharT, _Traits, _Alloc>::
 203     basic_string(const basic_string& __str, size_type __pos,
 204                  size_type __n, const _Alloc& __a)
 205     : _M_dataplus(_S_construct(__str._M_data()
 206                                + __str._M_check(__pos,
 207                                                 "basic_string::basic_string"),
 208                                __str._M_data() + __str._M_limit(__pos, __n)
 209                                + __pos, __a), __a)
 210     { }
 211
 212   // TBD: DPG annotate
 213   template<typename _CharT, typename _Traits, typename _Alloc>
 214     basic_string<_CharT, _Traits, _Alloc>::
 215     basic_string(const _CharT* __s, size_type __n, const _Alloc& __a)
 216     : _M_dataplus(_S_construct(__s, __s + __n, __a), __a)
 217     { }
 218
 219   // TBD: DPG annotate
 220   template<typename _CharT, typename _Traits, typename _Alloc>
 221     basic_string<_CharT, _Traits, _Alloc>::
 222     basic_string(const _CharT* __s, const _Alloc& __a)
 223     : _M_dataplus(_S_construct(__s, __s ? __s + traits_type::length(__s) :
 224                                __s + npos, __a), __a)
 225     { }
 226
 227   template<typename _CharT, typename _Traits, typename _Alloc>
 228     basic_string<_CharT, _Traits, _Alloc>::
 229     basic_string(size_type __n, _CharT __c, const _Alloc& __a)
 230     : _M_dataplus(_S_construct(__n, __c, __a), __a)
 231     { }
 232
 233   // TBD: DPG annotate
 234   template<typename _CharT, typename _Traits, typename _Alloc>
 235     template<typename _InputIterator>
 236     basic_string<_CharT, _Traits, _Alloc>::
 237     basic_string(_InputIterator __beg, _InputIterator __end, const _Alloc& __a)
 238     : _M_dataplus(_S_construct(__beg, __end, __a), __a)
 239     { }
 240
 241   template<typename _CharT, typename _Traits, typename _Alloc>
 242     basic_string<_CharT, _Traits, _Alloc>&
 243     basic_string<_CharT, _Traits, _Alloc>::
 244     assign(const basic_string& __str)
 245     {
 246       if (_M_rep() != __str._M_rep())
 247         {
 248           // XXX MT
 249           const allocator_type __a = this->get_allocator();
 250           _CharT* __tmp = __str._M_rep()->_M_grab(__a, __str.get_allocator());
 251           _M_rep()->_M_dispose(__a);
 252           _M_data(__tmp);
 253         }
 254       return *this;
 255     }
 256
 257    template<typename _CharT, typename _Traits, typename _Alloc>
 258      basic_string<_CharT, _Traits, _Alloc>&
 259      basic_string<_CharT, _Traits, _Alloc>::
 260      assign(const _CharT* __s, size_type __n)
 261      {
 262        __glibcxx_requires_string_len(__s, __n);
 263        if (__n > this->max_size())
 264          __throw_length_error(__N("basic_string::assign"));
 265        if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
 266            || less<const _CharT*>()(_M_data() + this->size(), __s))
 267          return _M_replace_safe(size_type(0), this->size(), __s, __n);
 268        else
 269          {
 270            // Work in-place
 271            const size_type __pos = __s - _M_data();
 272            if (__pos >= __n)
 273              traits_type::copy(_M_data(), __s, __n);
 274            else if (__pos)
 275              traits_type::move(_M_data(), __s, __n);
 276            _M_rep()->_M_length = __n;
 277            _M_data()[__n] = _Rep::_S_terminal;  // grr.
 278            return *this;
 279          }
 280      }
 281
 282    template<typename _CharT, typename _Traits, typename _Alloc>
 283      basic_string<_CharT, _Traits, _Alloc>&
 284      basic_string<_CharT, _Traits, _Alloc>::
 285      insert(size_type __pos, const _CharT* __s, size_type __n)
 286      {
 287        __glibcxx_requires_string_len(__s, __n);
 288        _M_check(__pos, "basic_string::insert");
 289        if (this->max_size() - this->size() < __n)
 290          __throw_length_error(__N("basic_string::insert"));
 291        if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
 292            || less<const _CharT*>()(_M_data() + this->size(), __s))
 293          return _M_replace_safe(__pos, size_type(0), __s, __n);
 294        else
 295          {
 296            // Work in-place. If _M_mutate reallocates the string, __s
 297            // does not point anymore to valid data, therefore we save its
 298            // offset, then we restore it.
 299            const size_type __off = __s - _M_data();
 300            _M_mutate(__pos, 0, __n);
 301            __s = _M_data() + __off;
 302            _CharT* __p = _M_data() + __pos;
 303            if (__s  + __n <= __p)
 304              traits_type::copy(__p, __s, __n);
 305            else if (__s >= __p)
 306              traits_type::copy(__p, __s + __n, __n);
 307            else
 308              {
 309                const size_type __nleft = __p - __s;
 310                traits_type::copy(__p, __s, __nleft);
 311                traits_type::copy(__p + __nleft, __p + __n, __n - __nleft);
 312              }
 313            return *this;
 314          }
 315      }
 316
 317    template<typename _CharT, typename _Traits, typename _Alloc>
 318      basic_string<_CharT, _Traits, _Alloc>&
 319      basic_string<_CharT, _Traits, _Alloc>::
 320      replace(size_type __pos, size_type __n1, const _CharT* __s,
 321              size_type __n2)
 322      {
 323        __glibcxx_requires_string_len(__s, __n2);
 324        _M_check(__pos, "basic_string::replace");
 325        __n1 = _M_limit(__pos, __n1);
 326        if (this->max_size() - (this->size() - __n1) < __n2)
 327          __throw_length_error(__N("basic_string::replace"));
 328        bool __left;
 329        if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
 330            || less<const _CharT*>()(_M_data() + this->size(), __s))
 331          return _M_replace_safe(__pos, __n1, __s, __n2);
 332        else if ((__left = __s + __n2 <= _M_data() + __pos)
 333                 || _M_data() + __pos + __n1 <= __s)
 334          {
 335            // Work in-place: non-overlapping case.
 336            const size_type __off = __s - _M_data();
 337            _M_mutate(__pos, __n1, __n2);
 338            if (__left)
 339              traits_type::copy(_M_data() + __pos,
 340                                _M_data() + __off, __n2);
 341            else
 342              traits_type::copy(_M_data() + __pos,
 343                                _M_data() + __off + __n2 - __n1, __n2);
 344            return *this;
 345          }
 346        else
 347          {
 348            // Todo: overlapping case.
 349            const basic_string __tmp(__s, __n2);
 350            return _M_replace_safe(__pos, __n1, __tmp._M_data(), __n2);
 351          }
 352      }
 353
 354   template<typename _CharT, typename _Traits, typename _Alloc>
 355     void
 356     basic_string<_CharT, _Traits, _Alloc>::_Rep::
 357     _M_destroy(const _Alloc& __a) throw ()
 358     {
 359       if (this == &_S_empty_rep())
 360         return;
 361       const size_type __size = sizeof(_Rep_base) +
 362                                (this->_M_capacity + 1) * sizeof(_CharT);
 363       _Raw_bytes_alloc(__a).deallocate(reinterpret_cast<char*>(this), __size);
 364     }
 365
 366   template<typename _CharT, typename _Traits, typename _Alloc>
 367     void
 368     basic_string<_CharT, _Traits, _Alloc>::_M_leak_hard()
 369     {
 370       if (_M_rep() == &_S_empty_rep())
 371         return;
 372       if (_M_rep()->_M_is_shared())
 373         _M_mutate(0, 0, 0);
 374       _M_rep()->_M_set_leaked();
 375     }
 376
 377   template<typename _CharT, typename _Traits, typename _Alloc>
 378     void
 379     basic_string<_CharT, _Traits, _Alloc>::
 380     _M_mutate(size_type __pos, size_type __len1, size_type __len2)
 381     {
 382       const size_type __old_size = this->size();
 383       const size_type __new_size = __old_size + __len2 - __len1;
 384       const _CharT*        __src = _M_data()  + __pos + __len1;
 385       const size_type __how_much = __old_size - __pos - __len1;
 386
 387       if (_M_rep() == &_S_empty_rep()
 388           || _M_rep()->_M_is_shared() || __new_size > capacity())
 389         {
 390           // Must reallocate.
 391           const allocator_type __a = get_allocator();
 392           _Rep* __r = _Rep::_S_create(__new_size, capacity(), __a);
 393
 394           if (__pos)
 395             traits_type::copy(__r->_M_refdata(), _M_data(), __pos);
 396           if (__how_much)
 397             traits_type::copy(__r->_M_refdata() + __pos + __len2,
 398                               __src, __how_much);
 399
 400           _M_rep()->_M_dispose(__a);
 401           _M_data(__r->_M_refdata());
 402         }
 403       else if (__how_much && __len1 != __len2)
 404         {
 405           // Work in-place
 406           traits_type::move(_M_data() + __pos + __len2, __src, __how_much);
 407         }
 408       _M_rep()->_M_set_sharable();
 409       _M_rep()->_M_length = __new_size;
 410       _M_data()[__new_size] = _Rep::_S_terminal; // grrr. (per 21.3.4)
 411       // You cannot leave those LWG people alone for a second.
 412     }
 413
 414   template<typename _CharT, typename _Traits, typename _Alloc>
 415     void
 416     basic_string<_CharT, _Traits, _Alloc>::reserve(size_type __res)
 417     {
 418       if (__res != this->capacity() || _M_rep()->_M_is_shared())
 419         {
 420           if (__res > this->max_size())
 421             __throw_length_error(__N("basic_string::reserve"));
 422           // Make sure we don't shrink below the current size
 423           if (__res < this->size())
 424             __res = this->size();
 425           const allocator_type __a = get_allocator();
 426           _CharT* __tmp = _M_rep()->_M_clone(__a, __res - this->size());
 427           _M_rep()->_M_dispose(__a);
 428           _M_data(__tmp);
 429         }
 430     }
 431
 432   template<typename _CharT, typename _Traits, typename _Alloc>
 433     void basic_string<_CharT, _Traits, _Alloc>::swap(basic_string& __s)
 434     {
 435       if (_M_rep()->_M_is_leaked())
 436         _M_rep()->_M_set_sharable();
 437       if (__s._M_rep()->_M_is_leaked())
 438         __s._M_rep()->_M_set_sharable();
 439       if (this->get_allocator() == __s.get_allocator())
 440         {
 441           _CharT* __tmp = _M_data();
 442           _M_data(__s._M_data());
 443           __s._M_data(__tmp);
 444         }
 445       // The code below can usually be optimized away.
 446       else
 447         {
 448           const basic_string __tmp1(_M_ibegin(), _M_iend(),
 449                                     __s.get_allocator());
 450           const basic_string __tmp2(__s._M_ibegin(), __s._M_iend(),
 451                                     this->get_allocator());
 452           *this = __tmp2;
 453           __s = __tmp1;
 454         }
 455     }
 456
 457   template<typename _CharT, typename _Traits, typename _Alloc>
 458     typename basic_string<_CharT, _Traits, _Alloc>::_Rep*
 459     basic_string<_CharT, _Traits, _Alloc>::_Rep::
 460     _S_create(size_type __capacity, size_type __old_capacity,
 461               const _Alloc& __alloc)
 462     {
 463       typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
 464       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 465       // 83.  String::npos vs. string::max_size()
 466       if (__capacity > _S_max_size)
 467         __throw_length_error(__N("basic_string::_S_create"));
 468
 469       // The standard places no restriction on allocating more memory
 470       // than is strictly needed within this layer at the moment or as
 471       // requested by an explicit application call to reserve().
 472
 473       // Many malloc implementations perform quite poorly when an
 474       // application attempts to allocate memory in a stepwise fashion
 475       // growing each allocation size by only 1 char.  Additionally,
 476       // it makes little sense to allocate less linear memory than the
 477       // natural blocking size of the malloc implementation.
 478       // Unfortunately, we would need a somewhat low-level calculation
 479       // with tuned parameters to get this perfect for any particular
 480       // malloc implementation.  Fortunately, generalizations about
 481       // common features seen among implementations seems to suffice.
 482
 483       // __pagesize need not match the actual VM page size for good
 484       // results in practice, thus we pick a common value on the low
 485       // side.  __malloc_header_size is an estimate of the amount of
 486       // overhead per memory allocation (in practice seen N * sizeof
 487       // (void*) where N is 0, 2 or 4).  According to folklore,
 488       // picking this value on the high side is better than
 489       // low-balling it (especially when this algorithm is used with
 490       // malloc implementations that allocate memory blocks rounded up
 491       // to a size which is a power of 2).
 492       const size_type __pagesize = 4096; // must be 2^i * __subpagesize
 493       const size_type __subpagesize = 128; // should be >> __malloc_header_size
 494       const size_type __malloc_header_size = 4 * sizeof (void*);
 495
 496       // The below implements an exponential growth policy, necessary to
 497       // meet amortized linear time requirements of the library: see
 498       // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
 499       // It's active for allocations requiring an amount of memory above
 500       // system pagesize. This is consistent with the requirements of the
 501       // standard: http://gcc.gnu.org/ml/libstdc++/2001-07/msg00130.html
 502
 503       // The biggest string which fits in a memory page
 504       const size_type __page_capacity = ((__pagesize - __malloc_header_size
 505                                           - sizeof(_Rep) - sizeof(_CharT))
 506                                          / sizeof(_CharT));
 507
 508       if (__capacity > __old_capacity && __capacity < 2 * __old_capacity
 509           && __capacity > __page_capacity)
 510         __capacity = 2 * __old_capacity;
 511
 512       // NB: Need an array of char_type[__capacity], plus a terminating
 513       // null char_type() element, plus enough for the _Rep data structure.
 514       // Whew. Seemingly so needy, yet so elemental.
 515       size_type __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
 516
 517       const size_type __adj_size = __size + __malloc_header_size;
 518       if (__adj_size > __pagesize)
 519         {
 520           const size_type __extra = __pagesize - __adj_size % __pagesize;
 521           __capacity += __extra / sizeof(_CharT);
 522           // Never allocate a string bigger than _S_max_size.
 523           if (__capacity > _S_max_size)
 524             __capacity = _S_max_size;
 525           __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
 526         }
 527       else if (__size > __subpagesize)
 528         {
 529           const size_type __extra = __subpagesize - __adj_size % __subpagesize;
 530           __capacity += __extra / sizeof(_CharT);
 531           __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
 532         }
 533
 534       // NB: Might throw, but no worries about a leak, mate: _Rep()
 535       // does not throw.
 536       void* __place = _Raw_bytes_alloc(__alloc).allocate(__size);
 537       _Rep *__p = new (__place) _Rep;
 538       __p->_M_capacity = __capacity;
 539       __p->_M_set_sharable();  // One reference.
 540       __p->_M_length = 0;
 541       return __p;
 542     }
 543
 544   template<typename _CharT, typename _Traits, typename _Alloc>
 545     _CharT*
 546     basic_string<_CharT, _Traits, _Alloc>::_Rep::
 547     _M_clone(const _Alloc& __alloc, size_type __res)
 548     {
 549       // Requested capacity of the clone.
 550       const size_type __requested_cap = this->_M_length + __res;
 551       _Rep* __r = _Rep::_S_create(__requested_cap, this->_M_capacity,
 552                                   __alloc);
 553       if (this->_M_length)
 554         traits_type::copy(__r->_M_refdata(), _M_refdata(),
 555                           this->_M_length);
 556
 557       __r->_M_length = this->_M_length;
 558       __r->_M_refdata()[this->_M_length] = _Rep::_S_terminal;
 559       return __r->_M_refdata();
 560     }
 561
 562   template<typename _CharT, typename _Traits, typename _Alloc>
 563     void
 564     basic_string<_CharT, _Traits, _Alloc>::resize(size_type __n, _CharT __c)
 565     {
 566       if (__n > max_size())
 567         __throw_length_error(__N("basic_string::resize"));
 568       const size_type __size = this->size();
 569       if (__size < __n)
 570         this->append(__n - __size, __c);
 571       else if (__n < __size)
 572         this->erase(__n);
 573       // else nothing (in particular, avoid calling _M_mutate() unnecessarily.)
 574     }
 575
 576   template<typename _CharT, typename _Traits, typename _Alloc>
 577     template<typename _InputIterator>
 578       basic_string<_CharT, _Traits, _Alloc>&
 579       basic_string<_CharT, _Traits, _Alloc>::
 580       _M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
 581                           _InputIterator __k2, __false_type)
 582       {
 583         const basic_string __s(__k1, __k2);
 584         const size_type __n1 = __i2 - __i1;
 585         if (this->max_size() - (this->size() - __n1) < __s.size())
 586           __throw_length_error(__N("basic_string::_M_replace_dispatch"));
 587         return _M_replace_safe(__i1 - _M_ibegin(), __n1, __s._M_data(),
 588                                __s.size());
 589       }
 590
 591   template<typename _CharT, typename _Traits, typename _Alloc>
 592     basic_string<_CharT, _Traits, _Alloc>&
 593     basic_string<_CharT, _Traits, _Alloc>::
 594     append(const basic_string& __str)
 595     {
 596       // Iff appending itself, string needs to pre-reserve the
 597       // correct size so that _M_mutate does not clobber the
 598       // pointer __str._M_data() formed here.
 599       const size_type __size = __str.size();
 600       const size_type __len = __size + this->size();
 601       if (__len > this->capacity())
 602         this->reserve(__len);
 603       return _M_replace_safe(this->size(), size_type(0), __str._M_data(),
 604                              __str.size());
 605     }
 606
 607   template<typename _CharT, typename _Traits, typename _Alloc>
 608     basic_string<_CharT, _Traits, _Alloc>&
 609     basic_string<_CharT, _Traits, _Alloc>::
 610     append(const basic_string& __str, size_type __pos, size_type __n)
 611     {
 612       // Iff appending itself, string needs to pre-reserve the
 613       // correct size so that _M_mutate does not clobber the
 614       // pointer __str._M_data() formed here.
 615       __str._M_check(__pos, "basic_string::append");
 616       __n = __str._M_limit(__pos, __n);
 617       const size_type __len = __n + this->size();
 618       if (__len > this->capacity())
 619         this->reserve(__len);
 620       return _M_replace_safe(this->size(), size_type(0), __str._M_data()
 621                              + __pos, __n);
 622     }
 623
 624   template<typename _CharT, typename _Traits, typename _Alloc>
 625     basic_string<_CharT, _Traits, _Alloc>&
 626     basic_string<_CharT, _Traits, _Alloc>::
 627     append(const _CharT* __s, size_type __n)
 628     {
 629       __glibcxx_requires_string_len(__s, __n);
 630       const size_type __len = __n + this->size();
 631       if (__len > this->capacity())
 632         this->reserve(__len);
 633       return _M_replace_safe(this->size(), size_type(0), __s, __n);
 634     }
 635
 636   template<typename _CharT, typename _Traits, typename _Alloc>
 637     basic_string<_CharT, _Traits, _Alloc>
 638     operator+(const _CharT* __lhs,
 639               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
 640     {
 641       __glibcxx_requires_string(__lhs);
 642       typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
 643       typedef typename __string_type::size_type   __size_type;
 644       const __size_type __len = _Traits::length(__lhs);
 645       __string_type __str;
 646       __str.reserve(__len + __rhs.size());
 647       __str.append(__lhs, __len);
 648       __str.append(__rhs);
 649       return __str;
 650     }
 651
 652   template<typename _CharT, typename _Traits, typename _Alloc>
 653     basic_string<_CharT, _Traits, _Alloc>
 654     operator+(_CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs)
 655     {
 656       typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
 657       typedef typename __string_type::size_type   __size_type;
 658       __string_type __str;
 659       const __size_type __len = __rhs.size();
 660       __str.reserve(__len + 1);
 661       __str.append(__size_type(1), __lhs);
 662       __str.append(__rhs);
 663       return __str;
 664     }
 665
 666   template<typename _CharT, typename _Traits, typename _Alloc>
 667     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 668     basic_string<_CharT, _Traits, _Alloc>::
 669     copy(_CharT* __s, size_type __n, size_type __pos) const
 670     {
 671       _M_check(__pos, "basic_string::copy");
 672       __n = _M_limit(__pos, __n);
 673       __glibcxx_requires_string_len(__s, __n);
 674       if (__n)
 675         traits_type::copy(__s, _M_data() + __pos, __n);
 676       // 21.3.5.7 par 3: do not append null.  (good.)
 677       return __n;
 678     }
 679
 680   template<typename _CharT, typename _Traits, typename _Alloc>
 681     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 682     basic_string<_CharT, _Traits, _Alloc>::
 683     find(const _CharT* __s, size_type __pos, size_type __n) const
 684     {
 685       __glibcxx_requires_string_len(__s, __n);
 686       const size_type __size = this->size();
 687       const _CharT* __data = _M_data();
 688       for (; __pos + __n <= __size; ++__pos)
 689         if (traits_type::compare(__data + __pos, __s, __n) == 0)
 690           return __pos;
 691       return npos;
 692     }
 693
 694   template<typename _CharT, typename _Traits, typename _Alloc>
 695     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 696     basic_string<_CharT, _Traits, _Alloc>::
 697     find(_CharT __c, size_type __pos) const
 698     {
 699       const size_type __size = this->size();
 700       size_type __ret = npos;
 701       if (__pos < __size)
 702         {
 703           const _CharT* __data = _M_data();
 704           const size_type __n = __size - __pos;
 705           const _CharT* __p = traits_type::find(__data + __pos, __n, __c);
 706           if (__p)
 707             __ret = __p - __data;
 708         }
 709       return __ret;
 710     }
 711
 712   template<typename _CharT, typename _Traits, typename _Alloc>
 713     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 714     basic_string<_CharT, _Traits, _Alloc>::
 715     rfind(const _CharT* __s, size_type __pos, size_type __n) const
 716     {
 717       __glibcxx_requires_string_len(__s, __n);
 718       const size_type __size = this->size();
 719       if (__n <= __size)
 720         {
 721           __pos = std::min(size_type(__size - __n), __pos);
 722           const _CharT* __data = _M_data();
 723           do
 724             {
 725               if (traits_type::compare(__data + __pos, __s, __n) == 0)
 726                 return __pos;
 727             }
 728           while (__pos-- > 0);
 729         }
 730       return npos;
 731     }
 732
 733   template<typename _CharT, typename _Traits, typename _Alloc>
 734     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 735     basic_string<_CharT, _Traits, _Alloc>::
 736     rfind(_CharT __c, size_type __pos) const
 737     {
 738       size_type __size = this->size();
 739       if (__size)
 740         {
 741           if (--__size > __pos)
 742             __size = __pos;
 743           for (++__size; __size-- > 0; )
 744             if (traits_type::eq(_M_data()[__size], __c))
 745               return __size;
 746         }
 747       return npos;
 748     }
 749
 750   template<typename _CharT, typename _Traits, typename _Alloc>
 751     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 752     basic_string<_CharT, _Traits, _Alloc>::
 753     find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
 754     {
 755       __glibcxx_requires_string_len(__s, __n);
 756       for (; __n && __pos < this->size(); ++__pos)
 757         {
 758           const _CharT* __p = traits_type::find(__s, __n, _M_data()[__pos]);
 759           if (__p)
 760             return __pos;
 761         }
 762       return npos;
 763     }
 764
 765   template<typename _CharT, typename _Traits, typename _Alloc>
 766     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 767     basic_string<_CharT, _Traits, _Alloc>::
 768     find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
 769     {
 770       __glibcxx_requires_string_len(__s, __n);
 771       size_type __size = this->size();
 772       if (__size && __n)
 773         {
 774           if (--__size > __pos)
 775             __size = __pos;
 776           do
 777             {
 778               if (traits_type::find(__s, __n, _M_data()[__size]))
 779                 return __size;
 780             }
 781           while (__size-- != 0);
 782         }
 783       return npos;
 784     }
 785
 786   template<typename _CharT, typename _Traits, typename _Alloc>
 787     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 788     basic_string<_CharT, _Traits, _Alloc>::
 789     find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const
 790     {
 791       __glibcxx_requires_string_len(__s, __n);
 792       for (; __pos < this->size(); ++__pos)
 793         if (!traits_type::find(__s, __n, _M_data()[__pos]))
 794           return __pos;
 795       return npos;
 796     }
 797
 798   template<typename _CharT, typename _Traits, typename _Alloc>
 799     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 800     basic_string<_CharT, _Traits, _Alloc>::
 801     find_first_not_of(_CharT __c, size_type __pos) const
 802     {
 803       for (; __pos < this->size(); ++__pos)
 804         if (!traits_type::eq(_M_data()[__pos], __c))
 805           return __pos;
 806       return npos;
 807     }
 808
 809   template<typename _CharT, typename _Traits, typename _Alloc>
 810     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 811     basic_string<_CharT, _Traits, _Alloc>::
 812     find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const
 813     {
 814       __glibcxx_requires_string_len(__s, __n);
 815       size_type __size = this->size();
 816       if (__size)
 817         {
 818           if (--__size > __pos)
 819             __size = __pos;
 820           do
 821             {
 822               if (!traits_type::find(__s, __n, _M_data()[__size]))
 823                 return __size;
 824             }
 825           while (__size--);
 826         }
 827       return npos;
 828     }
 829
 830   template<typename _CharT, typename _Traits, typename _Alloc>
 831     typename basic_string<_CharT, _Traits, _Alloc>::size_type
 832     basic_string<_CharT, _Traits, _Alloc>::
 833     find_last_not_of(_CharT __c, size_type __pos) const
 834     {
 835       size_type __size = this->size();
 836       if (__size)
 837         {
 838           if (--__size > __pos)
 839             __size = __pos;
 840           do
 841             {
 842               if (!traits_type::eq(_M_data()[__size], __c))
 843                 return __size;
 844             }
 845           while (__size--);
 846         }
 847       return npos;
 848     }
 849
 850   template<typename _CharT, typename _Traits, typename _Alloc>
 851     int
 852     basic_string<_CharT, _Traits, _Alloc>::
 853     compare(size_type __pos, size_type __n, const basic_string& __str) const
 854     {
 855       _M_check(__pos, "basic_string::compare");
 856       __n = _M_limit(__pos, __n);
 857       const size_type __osize = __str.size();
 858       const size_type __len = std::min(__n, __osize);
 859       int __r = traits_type::compare(_M_data() + __pos, __str.data(), __len);
 860       if (!__r)
 861         __r = __n - __osize;
 862       return __r;
 863     }
 864
 865   template<typename _CharT, typename _Traits, typename _Alloc>
 866     int
 867     basic_string<_CharT, _Traits, _Alloc>::
 868     compare(size_type __pos1, size_type __n1, const basic_string& __str,
 869             size_type __pos2, size_type __n2) const
 870     {
 871       _M_check(__pos1, "basic_string::compare");
 872       __str._M_check(__pos2, "basic_string::compare");
 873       __n1 = _M_limit(__pos1, __n1);
 874       __n2 = __str._M_limit(__pos2, __n2);
 875       const size_type __len = std::min(__n1, __n2);
 876       int __r = traits_type::compare(_M_data() + __pos1,
 877                                      __str.data() + __pos2, __len);
 878       if (!__r)
 879         __r = __n1 - __n2;
 880       return __r;
 881     }
 882
 883   template<typename _CharT, typename _Traits, typename _Alloc>
 884     int
 885     basic_string<_CharT, _Traits, _Alloc>::
 886     compare(const _CharT* __s) const
 887     {
 888       __glibcxx_requires_string(__s);
 889       const size_type __size = this->size();
 890       const size_type __osize = traits_type::length(__s);
 891       const size_type __len = std::min(__size, __osize);
 892       int __r = traits_type::compare(_M_data(), __s, __len);
 893       if (!__r)
 894         __r = __size - __osize;
 895       return __r;
 896     }
 897
 898   template<typename _CharT, typename _Traits, typename _Alloc>
 899     int
 900     basic_string <_CharT, _Traits, _Alloc>::
 901     compare(size_type __pos, size_type __n1, const _CharT* __s) const
 902     {
 903       __glibcxx_requires_string(__s);
 904       _M_check(__pos, "basic_string::compare");
 905       __n1 = _M_limit(__pos, __n1);
 906       const size_type __osize = traits_type::length(__s);
 907       const size_type __len = std::min(__n1, __osize);
 908       int __r = traits_type::compare(_M_data() + __pos, __s, __len);
 909       if (!__r)
 910         __r = __n1 - __osize;
 911       return __r;
 912     }
 913
 914   template<typename _CharT, typename _Traits, typename _Alloc>
 915     int
 916     basic_string <_CharT, _Traits, _Alloc>::
 917     compare(size_type __pos, size_type __n1, const _CharT* __s,
 918             size_type __n2) const
 919     {
 920       __glibcxx_requires_string_len(__s, __n2);
 921       _M_check(__pos, "basic_string::compare");
 922       __n1 = _M_limit(__pos, __n1);
 923       const size_type __len = std::min(__n1, __n2);
 924       int __r = traits_type::compare(_M_data() + __pos, __s, __len);
 925       if (!__r)
 926         __r = __n1 - __n2;
 927       return __r;
 928     }
 929
 930   // Inhibit implicit instantiations for required instantiations,
 931   // which are defined via explicit instantiations elsewhere.
 932   // NB: This syntax is a GNU extension.
 933 #if _GLIBCXX_EXTERN_TEMPLATE
 934   extern template class basic_string<char>;
 935   extern template
 936     basic_istream<char>&
 937     operator>>(basic_istream<char>&, string&);
 938   extern template
 939     basic_ostream<char>&
 940     operator<<(basic_ostream<char>&, const string&);
 941   extern template
 942     basic_istream<char>&
 943     getline(basic_istream<char>&, string&, char);
 944   extern template
 945     basic_istream<char>&
 946     getline(basic_istream<char>&, string&);
 947
 948 #ifdef _GLIBCXX_USE_WCHAR_T
 949   extern template class basic_string<wchar_t>;
 950   extern template
 951     basic_istream<wchar_t>&
 952     operator>>(basic_istream<wchar_t>&, wstring&);
 953   extern template
 954     basic_ostream<wchar_t>&
 955     operator<<(basic_ostream<wchar_t>&, const wstring&);
 956   extern template
 957     basic_istream<wchar_t>&
 958     getline(basic_istream<wchar_t>&, wstring&, wchar_t);
 959   extern template
 960     basic_istream<wchar_t>&
 961     getline(basic_istream<wchar_t>&, wstring&);
 962 #endif
 963 #endif
 964 } // namespace std
 965
 966 #endif