1 // Short-string-optimized versatile string base -*- C++ -*-
3 // Copyright (C) 2005, 2006 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 2, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
30 /** @file ext/sso_string_base.h
31 * This file is a GNU extension to the Standard C++ Library.
32 * This is an internal header file, included by other library headers.
33 * You should not attempt to use it directly.
36 #ifndef _SSO_STRING_BASE_H
37 #define _SSO_STRING_BASE_H 1
41 template<typename _CharT, typename _Traits, typename _Alloc>
42 class __sso_string_base
43 : protected __vstring_utility<_CharT, _Traits, _Alloc>
46 typedef _Traits traits_type;
47 typedef typename _Traits::char_type value_type;
49 typedef __vstring_utility<_CharT, _Traits, _Alloc> _Util_Base;
50 typedef typename _Util_Base::_CharT_alloc_type _CharT_alloc_type;
51 typedef typename _CharT_alloc_type::size_type size_type;
54 // The maximum number of individual char_type elements of an
55 // individual string is determined by _S_max_size. This is the
56 // value that will be returned by max_size(). (Whereas npos
57 // is the maximum number of bytes the allocator can allocate.)
58 // If one was to divvy up the theoretical largest size string,
59 // with a terminating character and m _CharT elements, it'd
61 // npos = m * sizeof(_CharT) + sizeof(_CharT)
63 // m = npos / sizeof(_CharT) - 1
64 // In addition, this implementation quarters this amount.
65 enum { _S_max_size = (((static_cast<size_type>(-1)
66 / sizeof(_CharT)) - 1) / 4) };
68 // Data Members (private):
69 typename _Util_Base::template _Alloc_hider<_CharT_alloc_type>
71 size_type _M_string_length;
73 enum { _S_local_capacity = 15 };
77 _CharT _M_local_data[_S_local_capacity + 1];
78 size_type _M_allocated_capacity;
83 { _M_dataplus._M_p = __p; }
86 _M_length(size_type __length)
87 { _M_string_length = __length; }
90 _M_capacity(size_type __capacity)
91 { _M_allocated_capacity = __capacity; }
95 { return _M_data() == _M_local_data; }
99 _M_create(size_type&, size_type);
105 _M_destroy(_M_allocated_capacity);
109 _M_destroy(size_type) throw();
111 // _M_construct_aux is used to implement the 21.3.1 para 15 which
112 // requires special behaviour if _InIterator is an integral type
113 template<typename _InIterator>
115 _M_construct_aux(_InIterator __beg, _InIterator __end, __false_type)
117 typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
118 _M_construct(__beg, __end, _Tag());
121 template<typename _InIterator>
123 _M_construct_aux(_InIterator __beg, _InIterator __end, __true_type)
124 { _M_construct(static_cast<size_type>(__beg),
125 static_cast<value_type>(__end)); }
127 template<typename _InIterator>
129 _M_construct(_InIterator __beg, _InIterator __end)
131 typedef typename std::__is_integer<_InIterator>::__type _Integral;
132 _M_construct_aux(__beg, __end, _Integral());
135 // For Input Iterators, used in istreambuf_iterators, etc.
136 template<typename _InIterator>
138 _M_construct(_InIterator __beg, _InIterator __end,
139 std::input_iterator_tag);
141 // For forward_iterators up to random_access_iterators, used for
142 // string::iterator, _CharT*, etc.
143 template<typename _FwdIterator>
145 _M_construct(_FwdIterator __beg, _FwdIterator __end,
146 std::forward_iterator_tag);
149 _M_construct(size_type __req, _CharT __c);
154 { return size_type(_S_max_size); }
158 { return _M_dataplus._M_p; }
162 { return _M_string_length; }
167 return _M_is_local() ? size_type(_S_local_capacity)
168 : _M_allocated_capacity;
182 _M_set_length(size_type __n)
185 traits_type::assign(_M_data()[__n], _CharT());
189 : _M_dataplus(_Alloc(), _M_local_data)
190 { _M_set_length(0); }
192 __sso_string_base(const _Alloc& __a);
194 __sso_string_base(const __sso_string_base& __rcs);
196 __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a);
198 template<typename _InputIterator>
199 __sso_string_base(_InputIterator __beg, _InputIterator __end,
207 { return _M_dataplus; }
209 const _CharT_alloc_type&
210 _M_get_allocator() const
211 { return _M_dataplus; }
214 _M_swap(__sso_string_base& __rcs);
217 _M_assign(const __sso_string_base& __rcs);
220 _M_reserve(size_type __res);
223 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
227 _M_erase(size_type __pos, size_type __n);
230 _M_compare(const __sso_string_base&) const
234 template<typename _CharT, typename _Traits, typename _Alloc>
236 __sso_string_base<_CharT, _Traits, _Alloc>::
237 _M_destroy(size_type __size) throw()
238 { _M_dataplus._CharT_alloc_type::deallocate(_M_data(), __size + 1); }
240 template<typename _CharT, typename _Traits, typename _Alloc>
242 __sso_string_base<_CharT, _Traits, _Alloc>::
243 _M_swap(__sso_string_base& __rcs)
245 // NB: Implement Option 3 of DR 431 (see N1599).
246 std::__alloc_swap<_CharT_alloc_type>::_S_do_it(_M_get_allocator(),
247 __rcs._M_get_allocator());
250 if (__rcs._M_is_local())
252 if (_M_length() && __rcs._M_length())
254 _CharT __tmp_data[_S_local_capacity + 1];
255 traits_type::copy(__tmp_data, __rcs._M_local_data,
256 _S_local_capacity + 1);
257 traits_type::copy(__rcs._M_local_data, _M_local_data,
258 _S_local_capacity + 1);
259 traits_type::copy(_M_local_data, __tmp_data,
260 _S_local_capacity + 1);
262 else if (__rcs._M_length())
264 traits_type::copy(_M_local_data, __rcs._M_local_data,
265 _S_local_capacity + 1);
266 _M_length(__rcs._M_length());
267 __rcs._M_set_length(0);
270 else if (_M_length())
272 traits_type::copy(__rcs._M_local_data, _M_local_data,
273 _S_local_capacity + 1);
274 __rcs._M_length(_M_length());
281 const size_type __tmp_capacity = __rcs._M_allocated_capacity;
282 traits_type::copy(__rcs._M_local_data, _M_local_data,
283 _S_local_capacity + 1);
284 _M_data(__rcs._M_data());
285 __rcs._M_data(__rcs._M_local_data);
286 _M_capacity(__tmp_capacity);
290 const size_type __tmp_capacity = _M_allocated_capacity;
291 if (__rcs._M_is_local())
293 traits_type::copy(_M_local_data, __rcs._M_local_data,
294 _S_local_capacity + 1);
295 __rcs._M_data(_M_data());
296 _M_data(_M_local_data);
300 _CharT* __tmp_ptr = _M_data();
301 _M_data(__rcs._M_data());
302 __rcs._M_data(__tmp_ptr);
303 _M_capacity(__rcs._M_allocated_capacity);
305 __rcs._M_capacity(__tmp_capacity);
308 const size_type __tmp_length = _M_length();
309 _M_length(__rcs._M_length());
310 __rcs._M_length(__tmp_length);
313 template<typename _CharT, typename _Traits, typename _Alloc>
315 __sso_string_base<_CharT, _Traits, _Alloc>::
316 _M_create(size_type& __capacity, size_type __old_capacity)
318 // _GLIBCXX_RESOLVE_LIB_DEFECTS
319 // 83. String::npos vs. string::max_size()
320 if (__capacity > size_type(_S_max_size))
321 std::__throw_length_error(__N("__sso_string_base::_M_create"));
323 // The below implements an exponential growth policy, necessary to
324 // meet amortized linear time requirements of the library: see
325 // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
326 if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
327 __capacity = 2 * __old_capacity;
329 // NB: Need an array of char_type[__capacity], plus a terminating
330 // null char_type() element.
331 return _M_dataplus._CharT_alloc_type::allocate(__capacity + 1);
334 template<typename _CharT, typename _Traits, typename _Alloc>
335 __sso_string_base<_CharT, _Traits, _Alloc>::
336 __sso_string_base(const _Alloc& __a)
337 : _M_dataplus(__a, _M_local_data)
338 { _M_set_length(0); }
340 template<typename _CharT, typename _Traits, typename _Alloc>
341 __sso_string_base<_CharT, _Traits, _Alloc>::
342 __sso_string_base(const __sso_string_base& __rcs)
343 : _M_dataplus(__rcs._M_get_allocator(), _M_local_data)
344 { _M_construct(__rcs._M_data(), __rcs._M_data() + __rcs._M_length()); }
346 template<typename _CharT, typename _Traits, typename _Alloc>
347 __sso_string_base<_CharT, _Traits, _Alloc>::
348 __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a)
349 : _M_dataplus(__a, _M_local_data)
350 { _M_construct(__n, __c); }
352 template<typename _CharT, typename _Traits, typename _Alloc>
353 template<typename _InputIterator>
354 __sso_string_base<_CharT, _Traits, _Alloc>::
355 __sso_string_base(_InputIterator __beg, _InputIterator __end,
357 : _M_dataplus(__a, _M_local_data)
358 { _M_construct(__beg, __end); }
360 // NB: This is the special case for Input Iterators, used in
361 // istreambuf_iterators, etc.
362 // Input Iterators have a cost structure very different from
363 // pointers, calling for a different coding style.
364 template<typename _CharT, typename _Traits, typename _Alloc>
365 template<typename _InIterator>
367 __sso_string_base<_CharT, _Traits, _Alloc>::
368 _M_construct(_InIterator __beg, _InIterator __end,
369 std::input_iterator_tag)
372 size_type __capacity = size_type(_S_local_capacity);
374 while (__beg != __end && __len < __capacity)
376 _M_data()[__len++] = *__beg;
382 while (__beg != __end)
384 if (__len == __capacity)
386 // Allocate more space.
387 __capacity = __len + 1;
388 _CharT* __another = _M_create(__capacity, __len);
389 _S_copy(__another, _M_data(), __len);
392 _M_capacity(__capacity);
394 _M_data()[__len++] = *__beg;
401 __throw_exception_again;
404 _M_set_length(__len);
407 template<typename _CharT, typename _Traits, typename _Alloc>
408 template<typename _InIterator>
410 __sso_string_base<_CharT, _Traits, _Alloc>::
411 _M_construct(_InIterator __beg, _InIterator __end,
412 std::forward_iterator_tag)
414 // NB: Not required, but considered best practice.
415 if (__builtin_expect(_S_is_null_pointer(__beg) && __beg != __end, 0))
416 std::__throw_logic_error(__N("__sso_string_base::"
417 "_M_construct NULL not valid"));
419 size_type __dnew = static_cast<size_type>(std::distance(__beg, __end));
421 if (__dnew > size_type(_S_local_capacity))
423 _M_data(_M_create(__dnew, size_type(0)));
427 // Check for out_of_range and length_error exceptions.
429 { _S_copy_chars(_M_data(), __beg, __end); }
433 __throw_exception_again;
436 _M_set_length(__dnew);
439 template<typename _CharT, typename _Traits, typename _Alloc>
441 __sso_string_base<_CharT, _Traits, _Alloc>::
442 _M_construct(size_type __n, _CharT __c)
444 if (__n > size_type(_S_local_capacity))
446 _M_data(_M_create(__n, size_type(0)));
451 _S_assign(_M_data(), __n, __c);
456 template<typename _CharT, typename _Traits, typename _Alloc>
458 __sso_string_base<_CharT, _Traits, _Alloc>::
459 _M_assign(const __sso_string_base& __rcs)
463 const size_type __rsize = __rcs._M_length();
464 const size_type __capacity = _M_capacity();
466 if (__rsize > __capacity)
468 size_type __new_capacity = __rsize;
469 _CharT* __tmp = _M_create(__new_capacity, __capacity);
472 _M_capacity(__new_capacity);
476 _S_copy(_M_data(), __rcs._M_data(), __rsize);
478 _M_set_length(__rsize);
482 template<typename _CharT, typename _Traits, typename _Alloc>
484 __sso_string_base<_CharT, _Traits, _Alloc>::
485 _M_reserve(size_type __res)
487 // Make sure we don't shrink below the current size.
488 if (__res < _M_length())
491 const size_type __capacity = _M_capacity();
492 if (__res != __capacity)
494 if (__res > __capacity
495 || __res > size_type(_S_local_capacity))
497 _CharT* __tmp = _M_create(__res, __capacity);
498 _S_copy(__tmp, _M_data(), _M_length() + 1);
503 else if (!_M_is_local())
505 _S_copy(_M_local_data, _M_data(), _M_length() + 1);
506 _M_destroy(__capacity);
507 _M_data(_M_local_data);
512 template<typename _CharT, typename _Traits, typename _Alloc>
514 __sso_string_base<_CharT, _Traits, _Alloc>::
515 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
516 const size_type __len2)
518 const size_type __how_much = _M_length() - __pos - __len1;
520 size_type __new_capacity = _M_length() + __len2 - __len1;
521 _CharT* __r = _M_create(__new_capacity, _M_capacity());
524 _S_copy(__r, _M_data(), __pos);
526 _S_copy(__r + __pos, __s, __len2);
528 _S_copy(__r + __pos + __len2,
529 _M_data() + __pos + __len1, __how_much);
533 _M_capacity(__new_capacity);
536 template<typename _CharT, typename _Traits, typename _Alloc>
538 __sso_string_base<_CharT, _Traits, _Alloc>::
539 _M_erase(size_type __pos, size_type __n)
541 const size_type __how_much = _M_length() - __pos - __n;
543 if (__how_much && __n)
544 _S_move(_M_data() + __pos, _M_data() + __pos + __n,
547 _M_set_length(_M_length() - __n);
552 __sso_string_base<char, std::char_traits<char>,
553 std::allocator<char> >::
554 _M_compare(const __sso_string_base& __rcs) const
563 __sso_string_base<wchar_t, std::char_traits<wchar_t>,
564 std::allocator<wchar_t> >::
565 _M_compare(const __sso_string_base& __rcs) const
571 } // namespace __gnu_cxx
573 #endif /* _SSO_STRING_BASE_H */