libstdc++
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00001 // Reference-counted versatile string base -*- C++ -*- 00002 00003 // Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file ext/rc_string_base.h 00026 * This file is a GNU extension to the Standard C++ Library. 00027 * This is an internal header file, included by other library headers. 00028 * You should not attempt to use it directly. 00029 */ 00030 00031 #ifndef _RC_STRING_BASE_H 00032 #define _RC_STRING_BASE_H 1 00033 00034 #include <ext/atomicity.h> 00035 #include <bits/stl_iterator_base_funcs.h> 00036 00037 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 00038 00039 /** 00040 * Documentation? What's that? 00041 * Nathan Myers <ncm@cantrip.org>. 00042 * 00043 * A string looks like this: 00044 * 00045 * @code 00046 * [_Rep] 00047 * _M_length 00048 * [__rc_string_base<char_type>] _M_capacity 00049 * _M_dataplus _M_refcount 00050 * _M_p ----------------> unnamed array of char_type 00051 * @endcode 00052 * 00053 * Where the _M_p points to the first character in the string, and 00054 * you cast it to a pointer-to-_Rep and subtract 1 to get a 00055 * pointer to the header. 00056 * 00057 * This approach has the enormous advantage that a string object 00058 * requires only one allocation. All the ugliness is confined 00059 * within a single pair of inline functions, which each compile to 00060 * a single "add" instruction: _Rep::_M_refdata(), and 00061 * __rc_string_base::_M_rep(); and the allocation function which gets a 00062 * block of raw bytes and with room enough and constructs a _Rep 00063 * object at the front. 00064 * 00065 * The reason you want _M_data pointing to the character array and 00066 * not the _Rep is so that the debugger can see the string 00067 * contents. (Probably we should add a non-inline member to get 00068 * the _Rep for the debugger to use, so users can check the actual 00069 * string length.) 00070 * 00071 * Note that the _Rep object is a POD so that you can have a 00072 * static "empty string" _Rep object already "constructed" before 00073 * static constructors have run. The reference-count encoding is 00074 * chosen so that a 0 indicates one reference, so you never try to 00075 * destroy the empty-string _Rep object. 00076 * 00077 * All but the last paragraph is considered pretty conventional 00078 * for a C++ string implementation. 00079 */ 00080 template<typename _CharT, typename _Traits, typename _Alloc> 00081 class __rc_string_base 00082 : protected __vstring_utility<_CharT, _Traits, _Alloc> 00083 { 00084 public: 00085 typedef _Traits traits_type; 00086 typedef typename _Traits::char_type value_type; 00087 typedef _Alloc allocator_type; 00088 00089 typedef __vstring_utility<_CharT, _Traits, _Alloc> _Util_Base; 00090 typedef typename _Util_Base::_CharT_alloc_type _CharT_alloc_type; 00091 typedef typename _CharT_alloc_type::size_type size_type; 00092 00093 private: 00094 // _Rep: string representation 00095 // Invariants: 00096 // 1. String really contains _M_length + 1 characters: due to 21.3.4 00097 // must be kept null-terminated. 00098 // 2. _M_capacity >= _M_length 00099 // Allocated memory is always (_M_capacity + 1) * sizeof(_CharT). 00100 // 3. _M_refcount has three states: 00101 // -1: leaked, one reference, no ref-copies allowed, non-const. 00102 // 0: one reference, non-const. 00103 // n>0: n + 1 references, operations require a lock, const. 00104 // 4. All fields == 0 is an empty string, given the extra storage 00105 // beyond-the-end for a null terminator; thus, the shared 00106 // empty string representation needs no constructor. 00107 struct _Rep 00108 { 00109 union 00110 { 00111 struct 00112 { 00113 size_type _M_length; 00114 size_type _M_capacity; 00115 _Atomic_word _M_refcount; 00116 } _M_info; 00117 00118 // Only for alignment purposes. 00119 _CharT _M_align; 00120 }; 00121 00122 typedef typename _Alloc::template rebind<_Rep>::other _Rep_alloc_type; 00123 00124 _CharT* 00125 _M_refdata() throw() 00126 { return reinterpret_cast<_CharT*>(this + 1); } 00127 00128 _CharT* 00129 _M_refcopy() throw() 00130 { 00131 __atomic_add_dispatch(&_M_info._M_refcount, 1); 00132 return _M_refdata(); 00133 } // XXX MT 00134 00135 void 00136 _M_set_length(size_type __n) 00137 { 00138 _M_info._M_refcount = 0; // One reference. 00139 _M_info._M_length = __n; 00140 // grrr. (per 21.3.4) 00141 // You cannot leave those LWG people alone for a second. 00142 traits_type::assign(_M_refdata()[__n], _CharT()); 00143 } 00144 00145 // Create & Destroy 00146 static _Rep* 00147 _S_create(size_type, size_type, const _Alloc&); 00148 00149 void 00150 _M_destroy(const _Alloc&) throw(); 00151 00152 _CharT* 00153 _M_clone(const _Alloc&, size_type __res = 0); 00154 }; 00155 00156 struct _Rep_empty 00157 : public _Rep 00158 { 00159 _CharT _M_terminal; 00160 }; 00161 00162 static _Rep_empty _S_empty_rep; 00163 00164 // The maximum number of individual char_type elements of an 00165 // individual string is determined by _S_max_size. This is the 00166 // value that will be returned by max_size(). (Whereas npos 00167 // is the maximum number of bytes the allocator can allocate.) 00168 // If one was to divvy up the theoretical largest size string, 00169 // with a terminating character and m _CharT elements, it'd 00170 // look like this: 00171 // npos = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT) 00172 // + sizeof(_Rep) - 1 00173 // (NB: last two terms for rounding reasons, see _M_create below) 00174 // Solving for m: 00175 // m = ((npos - 2 * sizeof(_Rep) + 1) / sizeof(_CharT)) - 1 00176 // In addition, this implementation halves this amount. 00177 enum { _S_max_size = (((static_cast<size_type>(-1) - 2 * sizeof(_Rep) 00178 + 1) / sizeof(_CharT)) - 1) / 2 }; 00179 00180 // Data Member (private): 00181 mutable typename _Util_Base::template _Alloc_hider<_Alloc> _M_dataplus; 00182 00183 void 00184 _M_data(_CharT* __p) 00185 { _M_dataplus._M_p = __p; } 00186 00187 _Rep* 00188 _M_rep() const 00189 { return &((reinterpret_cast<_Rep*>(_M_data()))[-1]); } 00190 00191 _CharT* 00192 _M_grab(const _Alloc& __alloc) const 00193 { 00194 return (!_M_is_leaked() && _M_get_allocator() == __alloc) 00195 ? _M_rep()->_M_refcopy() : _M_rep()->_M_clone(__alloc); 00196 } 00197 00198 void 00199 _M_dispose() 00200 { 00201 if (__exchange_and_add_dispatch(&_M_rep()->_M_info._M_refcount, 00202 -1) <= 0) 00203 _M_rep()->_M_destroy(_M_get_allocator()); 00204 } // XXX MT 00205 00206 bool 00207 _M_is_leaked() const 00208 { return _M_rep()->_M_info._M_refcount < 0; } 00209 00210 void 00211 _M_set_sharable() 00212 { _M_rep()->_M_info._M_refcount = 0; } 00213 00214 void 00215 _M_leak_hard(); 00216 00217 // _S_construct_aux is used to implement the 21.3.1 para 15 which 00218 // requires special behaviour if _InIterator is an integral type 00219 template<typename _InIterator> 00220 static _CharT* 00221 _S_construct_aux(_InIterator __beg, _InIterator __end, 00222 const _Alloc& __a, std::__false_type) 00223 { 00224 typedef typename iterator_traits<_InIterator>::iterator_category _Tag; 00225 return _S_construct(__beg, __end, __a, _Tag()); 00226 } 00227 00228 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00229 // 438. Ambiguity in the "do the right thing" clause 00230 template<typename _Integer> 00231 static _CharT* 00232 _S_construct_aux(_Integer __beg, _Integer __end, 00233 const _Alloc& __a, std::__true_type) 00234 { return _S_construct(static_cast<size_type>(__beg), __end, __a); } 00235 00236 template<typename _InIterator> 00237 static _CharT* 00238 _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a) 00239 { 00240 typedef typename std::__is_integer<_InIterator>::__type _Integral; 00241 return _S_construct_aux(__beg, __end, __a, _Integral()); 00242 } 00243 00244 // For Input Iterators, used in istreambuf_iterators, etc. 00245 template<typename _InIterator> 00246 static _CharT* 00247 _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, 00248 std::input_iterator_tag); 00249 00250 // For forward_iterators up to random_access_iterators, used for 00251 // string::iterator, _CharT*, etc. 00252 template<typename _FwdIterator> 00253 static _CharT* 00254 _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a, 00255 std::forward_iterator_tag); 00256 00257 static _CharT* 00258 _S_construct(size_type __req, _CharT __c, const _Alloc& __a); 00259 00260 public: 00261 size_type 00262 _M_max_size() const 00263 { return size_type(_S_max_size); } 00264 00265 _CharT* 00266 _M_data() const 00267 { return _M_dataplus._M_p; } 00268 00269 size_type 00270 _M_length() const 00271 { return _M_rep()->_M_info._M_length; } 00272 00273 size_type 00274 _M_capacity() const 00275 { return _M_rep()->_M_info._M_capacity; } 00276 00277 bool 00278 _M_is_shared() const 00279 { return _M_rep()->_M_info._M_refcount > 0; } 00280 00281 void 00282 _M_set_leaked() 00283 { _M_rep()->_M_info._M_refcount = -1; } 00284 00285 void 00286 _M_leak() // for use in begin() & non-const op[] 00287 { 00288 if (!_M_is_leaked()) 00289 _M_leak_hard(); 00290 } 00291 00292 void 00293 _M_set_length(size_type __n) 00294 { _M_rep()->_M_set_length(__n); } 00295 00296 __rc_string_base() 00297 : _M_dataplus(_S_empty_rep._M_refcopy()) { } 00298 00299 __rc_string_base(const _Alloc& __a); 00300 00301 __rc_string_base(const __rc_string_base& __rcs); 00302 00303 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00304 __rc_string_base(__rc_string_base&& __rcs) 00305 : _M_dataplus(__rcs._M_get_allocator(), __rcs._M_data()) 00306 { __rcs._M_data(_S_empty_rep._M_refcopy()); } 00307 #endif 00308 00309 __rc_string_base(size_type __n, _CharT __c, const _Alloc& __a); 00310 00311 template<typename _InputIterator> 00312 __rc_string_base(_InputIterator __beg, _InputIterator __end, 00313 const _Alloc& __a); 00314 00315 ~__rc_string_base() 00316 { _M_dispose(); } 00317 00318 allocator_type& 00319 _M_get_allocator() 00320 { return _M_dataplus; } 00321 00322 const allocator_type& 00323 _M_get_allocator() const 00324 { return _M_dataplus; } 00325 00326 void 00327 _M_swap(__rc_string_base& __rcs); 00328 00329 void 00330 _M_assign(const __rc_string_base& __rcs); 00331 00332 void 00333 _M_reserve(size_type __res); 00334 00335 void 00336 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, 00337 size_type __len2); 00338 00339 void 00340 _M_erase(size_type __pos, size_type __n); 00341 00342 void 00343 _M_clear() 00344 { _M_erase(size_type(0), _M_length()); } 00345 00346 bool 00347 _M_compare(const __rc_string_base&) const 00348 { return false; } 00349 }; 00350 00351 template<typename _CharT, typename _Traits, typename _Alloc> 00352 typename __rc_string_base<_CharT, _Traits, _Alloc>::_Rep_empty 00353 __rc_string_base<_CharT, _Traits, _Alloc>::_S_empty_rep; 00354 00355 template<typename _CharT, typename _Traits, typename _Alloc> 00356 typename __rc_string_base<_CharT, _Traits, _Alloc>::_Rep* 00357 __rc_string_base<_CharT, _Traits, _Alloc>::_Rep:: 00358 _S_create(size_type __capacity, size_type __old_capacity, 00359 const _Alloc& __alloc) 00360 { 00361 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00362 // 83. String::npos vs. string::max_size() 00363 if (__capacity > size_type(_S_max_size)) 00364 std::__throw_length_error(__N("__rc_string_base::_Rep::_S_create")); 00365 00366 // The standard places no restriction on allocating more memory 00367 // than is strictly needed within this layer at the moment or as 00368 // requested by an explicit application call to reserve(). 00369 00370 // Many malloc implementations perform quite poorly when an 00371 // application attempts to allocate memory in a stepwise fashion 00372 // growing each allocation size by only 1 char. Additionally, 00373 // it makes little sense to allocate less linear memory than the 00374 // natural blocking size of the malloc implementation. 00375 // Unfortunately, we would need a somewhat low-level calculation 00376 // with tuned parameters to get this perfect for any particular 00377 // malloc implementation. Fortunately, generalizations about 00378 // common features seen among implementations seems to suffice. 00379 00380 // __pagesize need not match the actual VM page size for good 00381 // results in practice, thus we pick a common value on the low 00382 // side. __malloc_header_size is an estimate of the amount of 00383 // overhead per memory allocation (in practice seen N * sizeof 00384 // (void*) where N is 0, 2 or 4). According to folklore, 00385 // picking this value on the high side is better than 00386 // low-balling it (especially when this algorithm is used with 00387 // malloc implementations that allocate memory blocks rounded up 00388 // to a size which is a power of 2). 00389 const size_type __pagesize = 4096; 00390 const size_type __malloc_header_size = 4 * sizeof(void*); 00391 00392 // The below implements an exponential growth policy, necessary to 00393 // meet amortized linear time requirements of the library: see 00394 // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html. 00395 if (__capacity > __old_capacity && __capacity < 2 * __old_capacity) 00396 { 00397 __capacity = 2 * __old_capacity; 00398 // Never allocate a string bigger than _S_max_size. 00399 if (__capacity > size_type(_S_max_size)) 00400 __capacity = size_type(_S_max_size); 00401 } 00402 00403 // NB: Need an array of char_type[__capacity], plus a terminating 00404 // null char_type() element, plus enough for the _Rep data structure, 00405 // plus sizeof(_Rep) - 1 to upper round to a size multiple of 00406 // sizeof(_Rep). 00407 // Whew. Seemingly so needy, yet so elemental. 00408 size_type __size = ((__capacity + 1) * sizeof(_CharT) 00409 + 2 * sizeof(_Rep) - 1); 00410 00411 const size_type __adj_size = __size + __malloc_header_size; 00412 if (__adj_size > __pagesize && __capacity > __old_capacity) 00413 { 00414 const size_type __extra = __pagesize - __adj_size % __pagesize; 00415 __capacity += __extra / sizeof(_CharT); 00416 if (__capacity > size_type(_S_max_size)) 00417 __capacity = size_type(_S_max_size); 00418 __size = (__capacity + 1) * sizeof(_CharT) + 2 * sizeof(_Rep) - 1; 00419 } 00420 00421 // NB: Might throw, but no worries about a leak, mate: _Rep() 00422 // does not throw. 00423 _Rep* __place = _Rep_alloc_type(__alloc).allocate(__size / sizeof(_Rep)); 00424 _Rep* __p = new (__place) _Rep; 00425 __p->_M_info._M_capacity = __capacity; 00426 return __p; 00427 } 00428 00429 template<typename _CharT, typename _Traits, typename _Alloc> 00430 void 00431 __rc_string_base<_CharT, _Traits, _Alloc>::_Rep:: 00432 _M_destroy(const _Alloc& __a) throw () 00433 { 00434 const size_type __size = ((_M_info._M_capacity + 1) * sizeof(_CharT) 00435 + 2 * sizeof(_Rep) - 1); 00436 _Rep_alloc_type(__a).deallocate(this, __size / sizeof(_Rep)); 00437 } 00438 00439 template<typename _CharT, typename _Traits, typename _Alloc> 00440 _CharT* 00441 __rc_string_base<_CharT, _Traits, _Alloc>::_Rep:: 00442 _M_clone(const _Alloc& __alloc, size_type __res) 00443 { 00444 // Requested capacity of the clone. 00445 const size_type __requested_cap = _M_info._M_length + __res; 00446 _Rep* __r = _Rep::_S_create(__requested_cap, _M_info._M_capacity, 00447 __alloc); 00448 00449 if (_M_info._M_length) 00450 _S_copy(__r->_M_refdata(), _M_refdata(), _M_info._M_length); 00451 00452 __r->_M_set_length(_M_info._M_length); 00453 return __r->_M_refdata(); 00454 } 00455 00456 template<typename _CharT, typename _Traits, typename _Alloc> 00457 __rc_string_base<_CharT, _Traits, _Alloc>:: 00458 __rc_string_base(const _Alloc& __a) 00459 : _M_dataplus(__a, _S_construct(size_type(), _CharT(), __a)) { } 00460 00461 template<typename _CharT, typename _Traits, typename _Alloc> 00462 __rc_string_base<_CharT, _Traits, _Alloc>:: 00463 __rc_string_base(const __rc_string_base& __rcs) 00464 : _M_dataplus(__rcs._M_get_allocator(), 00465 __rcs._M_grab(__rcs._M_get_allocator())) { } 00466 00467 template<typename _CharT, typename _Traits, typename _Alloc> 00468 __rc_string_base<_CharT, _Traits, _Alloc>:: 00469 __rc_string_base(size_type __n, _CharT __c, const _Alloc& __a) 00470 : _M_dataplus(__a, _S_construct(__n, __c, __a)) { } 00471 00472 template<typename _CharT, typename _Traits, typename _Alloc> 00473 template<typename _InputIterator> 00474 __rc_string_base<_CharT, _Traits, _Alloc>:: 00475 __rc_string_base(_InputIterator __beg, _InputIterator __end, 00476 const _Alloc& __a) 00477 : _M_dataplus(__a, _S_construct(__beg, __end, __a)) { } 00478 00479 template<typename _CharT, typename _Traits, typename _Alloc> 00480 void 00481 __rc_string_base<_CharT, _Traits, _Alloc>:: 00482 _M_leak_hard() 00483 { 00484 if (_M_is_shared()) 00485 _M_erase(0, 0); 00486 _M_set_leaked(); 00487 } 00488 00489 // NB: This is the special case for Input Iterators, used in 00490 // istreambuf_iterators, etc. 00491 // Input Iterators have a cost structure very different from 00492 // pointers, calling for a different coding style. 00493 template<typename _CharT, typename _Traits, typename _Alloc> 00494 template<typename _InIterator> 00495 _CharT* 00496 __rc_string_base<_CharT, _Traits, _Alloc>:: 00497 _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, 00498 std::input_iterator_tag) 00499 { 00500 if (__beg == __end && __a == _Alloc()) 00501 return _S_empty_rep._M_refcopy(); 00502 00503 // Avoid reallocation for common case. 00504 _CharT __buf[128]; 00505 size_type __len = 0; 00506 while (__beg != __end && __len < sizeof(__buf) / sizeof(_CharT)) 00507 { 00508 __buf[__len++] = *__beg; 00509 ++__beg; 00510 } 00511 _Rep* __r = _Rep::_S_create(__len, size_type(0), __a); 00512 _S_copy(__r->_M_refdata(), __buf, __len); 00513 __try 00514 { 00515 while (__beg != __end) 00516 { 00517 if (__len == __r->_M_info._M_capacity) 00518 { 00519 // Allocate more space. 00520 _Rep* __another = _Rep::_S_create(__len + 1, __len, __a); 00521 _S_copy(__another->_M_refdata(), __r->_M_refdata(), __len); 00522 __r->_M_destroy(__a); 00523 __r = __another; 00524 } 00525 __r->_M_refdata()[__len++] = *__beg; 00526 ++__beg; 00527 } 00528 } 00529 __catch(...) 00530 { 00531 __r->_M_destroy(__a); 00532 __throw_exception_again; 00533 } 00534 __r->_M_set_length(__len); 00535 return __r->_M_refdata(); 00536 } 00537 00538 template<typename _CharT, typename _Traits, typename _Alloc> 00539 template<typename _InIterator> 00540 _CharT* 00541 __rc_string_base<_CharT, _Traits, _Alloc>:: 00542 _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, 00543 std::forward_iterator_tag) 00544 { 00545 if (__beg == __end && __a == _Alloc()) 00546 return _S_empty_rep._M_refcopy(); 00547 00548 // NB: Not required, but considered best practice. 00549 if (__builtin_expect(__is_null_pointer(__beg) && __beg != __end, 0)) 00550 std::__throw_logic_error(__N("__rc_string_base::" 00551 "_S_construct NULL not valid")); 00552 00553 const size_type __dnew = static_cast<size_type>(std::distance(__beg, 00554 __end)); 00555 // Check for out_of_range and length_error exceptions. 00556 _Rep* __r = _Rep::_S_create(__dnew, size_type(0), __a); 00557 __try 00558 { _S_copy_chars(__r->_M_refdata(), __beg, __end); } 00559 __catch(...) 00560 { 00561 __r->_M_destroy(__a); 00562 __throw_exception_again; 00563 } 00564 __r->_M_set_length(__dnew); 00565 return __r->_M_refdata(); 00566 } 00567 00568 template<typename _CharT, typename _Traits, typename _Alloc> 00569 _CharT* 00570 __rc_string_base<_CharT, _Traits, _Alloc>:: 00571 _S_construct(size_type __n, _CharT __c, const _Alloc& __a) 00572 { 00573 if (__n == 0 && __a == _Alloc()) 00574 return _S_empty_rep._M_refcopy(); 00575 00576 // Check for out_of_range and length_error exceptions. 00577 _Rep* __r = _Rep::_S_create(__n, size_type(0), __a); 00578 if (__n) 00579 _S_assign(__r->_M_refdata(), __n, __c); 00580 00581 __r->_M_set_length(__n); 00582 return __r->_M_refdata(); 00583 } 00584 00585 template<typename _CharT, typename _Traits, typename _Alloc> 00586 void 00587 __rc_string_base<_CharT, _Traits, _Alloc>:: 00588 _M_swap(__rc_string_base& __rcs) 00589 { 00590 if (_M_is_leaked()) 00591 _M_set_sharable(); 00592 if (__rcs._M_is_leaked()) 00593 __rcs._M_set_sharable(); 00594 00595 _CharT* __tmp = _M_data(); 00596 _M_data(__rcs._M_data()); 00597 __rcs._M_data(__tmp); 00598 00599 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00600 // 431. Swapping containers with unequal allocators. 00601 std::__alloc_swap<allocator_type>::_S_do_it(_M_get_allocator(), 00602 __rcs._M_get_allocator()); 00603 } 00604 00605 template<typename _CharT, typename _Traits, typename _Alloc> 00606 void 00607 __rc_string_base<_CharT, _Traits, _Alloc>:: 00608 _M_assign(const __rc_string_base& __rcs) 00609 { 00610 if (_M_rep() != __rcs._M_rep()) 00611 { 00612 _CharT* __tmp = __rcs._M_grab(_M_get_allocator()); 00613 _M_dispose(); 00614 _M_data(__tmp); 00615 } 00616 } 00617 00618 template<typename _CharT, typename _Traits, typename _Alloc> 00619 void 00620 __rc_string_base<_CharT, _Traits, _Alloc>:: 00621 _M_reserve(size_type __res) 00622 { 00623 // Make sure we don't shrink below the current size. 00624 if (__res < _M_length()) 00625 __res = _M_length(); 00626 00627 if (__res != _M_capacity() || _M_is_shared()) 00628 { 00629 _CharT* __tmp = _M_rep()->_M_clone(_M_get_allocator(), 00630 __res - _M_length()); 00631 _M_dispose(); 00632 _M_data(__tmp); 00633 } 00634 } 00635 00636 template<typename _CharT, typename _Traits, typename _Alloc> 00637 void 00638 __rc_string_base<_CharT, _Traits, _Alloc>:: 00639 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, 00640 size_type __len2) 00641 { 00642 const size_type __how_much = _M_length() - __pos - __len1; 00643 00644 _Rep* __r = _Rep::_S_create(_M_length() + __len2 - __len1, 00645 _M_capacity(), _M_get_allocator()); 00646 00647 if (__pos) 00648 _S_copy(__r->_M_refdata(), _M_data(), __pos); 00649 if (__s && __len2) 00650 _S_copy(__r->_M_refdata() + __pos, __s, __len2); 00651 if (__how_much) 00652 _S_copy(__r->_M_refdata() + __pos + __len2, 00653 _M_data() + __pos + __len1, __how_much); 00654 00655 _M_dispose(); 00656 _M_data(__r->_M_refdata()); 00657 } 00658 00659 template<typename _CharT, typename _Traits, typename _Alloc> 00660 void 00661 __rc_string_base<_CharT, _Traits, _Alloc>:: 00662 _M_erase(size_type __pos, size_type __n) 00663 { 00664 const size_type __new_size = _M_length() - __n; 00665 const size_type __how_much = _M_length() - __pos - __n; 00666 00667 if (_M_is_shared()) 00668 { 00669 // Must reallocate. 00670 _Rep* __r = _Rep::_S_create(__new_size, _M_capacity(), 00671 _M_get_allocator()); 00672 00673 if (__pos) 00674 _S_copy(__r->_M_refdata(), _M_data(), __pos); 00675 if (__how_much) 00676 _S_copy(__r->_M_refdata() + __pos, 00677 _M_data() + __pos + __n, __how_much); 00678 00679 _M_dispose(); 00680 _M_data(__r->_M_refdata()); 00681 } 00682 else if (__how_much && __n) 00683 { 00684 // Work in-place. 00685 _S_move(_M_data() + __pos, 00686 _M_data() + __pos + __n, __how_much); 00687 } 00688 00689 _M_rep()->_M_set_length(__new_size); 00690 } 00691 00692 template<> 00693 inline bool 00694 __rc_string_base<char, std::char_traits<char>, 00695 std::allocator<char> >:: 00696 _M_compare(const __rc_string_base& __rcs) const 00697 { 00698 if (_M_rep() == __rcs._M_rep()) 00699 return true; 00700 return false; 00701 } 00702 00703 #ifdef _GLIBCXX_USE_WCHAR_T 00704 template<> 00705 inline bool 00706 __rc_string_base<wchar_t, std::char_traits<wchar_t>, 00707 std::allocator<wchar_t> >:: 00708 _M_compare(const __rc_string_base& __rcs) const 00709 { 00710 if (_M_rep() == __rcs._M_rep()) 00711 return true; 00712 return false; 00713 } 00714 #endif 00715 00716 _GLIBCXX_END_NAMESPACE 00717 00718 #endif /* _RC_STRING_BASE_H */