# sso_string_base.h

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    00001 // Short-string-optimized 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/sso_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 _SSO_STRING_BASE_H
    00032 #define _SSO_STRING_BASE_H 1
    00033
    00034 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00035
    00036   template<typename _CharT, typename _Traits, typename _Alloc>
    00037     class __sso_string_base
    00038     : protected __vstring_utility<_CharT, _Traits, _Alloc>
    00039     {
    00040     public:
    00041       typedef _Traits                       traits_type;
    00042       typedef typename _Traits::char_type           value_type;
    00043
    00044       typedef __vstring_utility<_CharT, _Traits, _Alloc>    _Util_Base;
    00045       typedef typename _Util_Base::_CharT_alloc_type        _CharT_alloc_type;
    00046       typedef typename _CharT_alloc_type::size_type     size_type;
    00047
    00048     private:
    00049       // Data Members:
    00050       typename _Util_Base::template _Alloc_hider<_CharT_alloc_type>
    00051                                                             _M_dataplus;
    00052       size_type                                             _M_string_length;
    00053
    00054       enum { _S_local_capacity = 15 };
    00055
    00056       union
    00057       {
    00058     _CharT           _M_local_data[_S_local_capacity + 1];
    00059     size_type        _M_allocated_capacity;
    00060       };
    00061
    00062       void
    00063       _M_data(_CharT* __p)
    00064       { _M_dataplus._M_p = __p; }
    00065
    00066       void
    00067       _M_length(size_type __length)
    00068       { _M_string_length = __length; }
    00069
    00070       void
    00071       _M_capacity(size_type __capacity)
    00072       { _M_allocated_capacity = __capacity; }
    00073
    00074       bool
    00075       _M_is_local() const
    00076       { return _M_data() == _M_local_data; }
    00077
    00078       // Create & Destroy
    00079       _CharT*
    00080       _M_create(size_type&, size_type);
    00081
    00082       void
    00083       _M_dispose()
    00084       {
    00085     if (!_M_is_local())
    00086       _M_destroy(_M_allocated_capacity);
    00087       }
    00088
    00089       void
    00090       _M_destroy(size_type __size) throw()
    00091       { _M_get_allocator().deallocate(_M_data(), __size + 1); }
    00092
    00093       // _M_construct_aux is used to implement the 21.3.1 para 15 which
    00094       // requires special behaviour if _InIterator is an integral type
    00095       template<typename _InIterator>
    00096         void
    00097         _M_construct_aux(_InIterator __beg, _InIterator __end,
    00098              std::__false_type)
    00099     {
    00100           typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
    00101           _M_construct(__beg, __end, _Tag());
    00102     }
    00103
    00104       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00105       // 438. Ambiguity in the "do the right thing" clause
    00106       template<typename _Integer>
    00107         void
    00108         _M_construct_aux(_Integer __beg, _Integer __end, std::__true_type)
    00109     { _M_construct_aux_2(static_cast<size_type>(__beg), __end); }
    00110
    00111       void
    00112       _M_construct_aux_2(size_type __req, _CharT __c)
    00113       { _M_construct(__req, __c); }
    00114
    00115       template<typename _InIterator>
    00116         void
    00117         _M_construct(_InIterator __beg, _InIterator __end)
    00118     {
    00119       typedef typename std::__is_integer<_InIterator>::__type _Integral;
    00120       _M_construct_aux(__beg, __end, _Integral());
    00121         }
    00122
    00123       // For Input Iterators, used in istreambuf_iterators, etc.
    00124       template<typename _InIterator>
    00125         void
    00126         _M_construct(_InIterator __beg, _InIterator __end,
    00127              std::input_iterator_tag);
    00128
    00129       // For forward_iterators up to random_access_iterators, used for
    00130       // string::iterator, _CharT*, etc.
    00131       template<typename _FwdIterator>
    00132         void
    00133         _M_construct(_FwdIterator __beg, _FwdIterator __end,
    00134              std::forward_iterator_tag);
    00135
    00136       void
    00137       _M_construct(size_type __req, _CharT __c);
    00138
    00139     public:
    00140       size_type
    00141       _M_max_size() const
    00142       { return (_M_get_allocator().max_size() - 1) / 2; }
    00143
    00144       _CharT*
    00145       _M_data() const
    00146       { return _M_dataplus._M_p; }
    00147
    00148       size_type
    00149       _M_length() const
    00150       { return _M_string_length; }
    00151
    00152       size_type
    00153       _M_capacity() const
    00154       {
    00155     return _M_is_local() ? size_type(_S_local_capacity)
    00156                          : _M_allocated_capacity;
    00157       }
    00158
    00159       bool
    00160       _M_is_shared() const
    00161       { return false; }
    00162
    00163       void
    00164       _M_set_leaked() { }
    00165
    00166       void
    00167       _M_leak() { }
    00168
    00169       void
    00170       _M_set_length(size_type __n)
    00171       {
    00172     _M_length(__n);
    00173     traits_type::assign(_M_data()[__n], _CharT());
    00174       }
    00175
    00176       __sso_string_base()
    00177       : _M_dataplus(_M_local_data)
    00178       { _M_set_length(0); }
    00179
    00180       __sso_string_base(const _Alloc& __a);
    00181
    00182       __sso_string_base(const __sso_string_base& __rcs);
    00183
    00184 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00185       __sso_string_base(__sso_string_base&& __rcs);
    00186 #endif
    00187
    00188       __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a);
    00189
    00190       template<typename _InputIterator>
    00191         __sso_string_base(_InputIterator __beg, _InputIterator __end,
    00192               const _Alloc& __a);
    00193
    00194       ~__sso_string_base()
    00195       { _M_dispose(); }
    00196
    00197       _CharT_alloc_type&
    00198       _M_get_allocator()
    00199       { return _M_dataplus; }
    00200
    00201       const _CharT_alloc_type&
    00202       _M_get_allocator() const
    00203       { return _M_dataplus; }
    00204
    00205       void
    00206       _M_swap(__sso_string_base& __rcs);
    00207
    00208       void
    00209       _M_assign(const __sso_string_base& __rcs);
    00210
    00211       void
    00212       _M_reserve(size_type __res);
    00213
    00214       void
    00215       _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
    00216         size_type __len2);
    00217
    00218       void
    00219       _M_erase(size_type __pos, size_type __n);
    00220
    00221       void
    00222       _M_clear()
    00223       { _M_set_length(0); }
    00224
    00225       bool
    00226       _M_compare(const __sso_string_base&) const
    00227       { return false; }
    00228     };
    00229
    00230   template<typename _CharT, typename _Traits, typename _Alloc>
    00231     void
    00232     __sso_string_base<_CharT, _Traits, _Alloc>::
    00233     _M_swap(__sso_string_base& __rcs)
    00234     {
    00235       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00236       // 431. Swapping containers with unequal allocators.
    00237       std::__alloc_swap<_CharT_alloc_type>::_S_do_it(_M_get_allocator(),
    00238                              __rcs._M_get_allocator());
    00239
    00240       if (_M_is_local())
    00241     if (__rcs._M_is_local())
    00242       {
    00243         if (_M_length() && __rcs._M_length())
    00244           {
    00245         _CharT __tmp_data[_S_local_capacity + 1];
    00246         traits_type::copy(__tmp_data, __rcs._M_local_data,
    00247                   _S_local_capacity + 1);
    00248         traits_type::copy(__rcs._M_local_data, _M_local_data,
    00249                   _S_local_capacity + 1);
    00250         traits_type::copy(_M_local_data, __tmp_data,
    00251                   _S_local_capacity + 1);
    00252           }
    00253         else if (__rcs._M_length())
    00254           {
    00255         traits_type::copy(_M_local_data, __rcs._M_local_data,
    00256                   _S_local_capacity + 1);
    00257         _M_length(__rcs._M_length());
    00258         __rcs._M_set_length(0);
    00259         return;
    00260           }
    00261         else if (_M_length())
    00262           {
    00263         traits_type::copy(__rcs._M_local_data, _M_local_data,
    00264                   _S_local_capacity + 1);
    00265         __rcs._M_length(_M_length());
    00266         _M_set_length(0);
    00267         return;
    00268           }
    00269       }
    00270     else
    00271       {
    00272         const size_type __tmp_capacity = __rcs._M_allocated_capacity;
    00273         traits_type::copy(__rcs._M_local_data, _M_local_data,
    00274                   _S_local_capacity + 1);
    00275         _M_data(__rcs._M_data());
    00276         __rcs._M_data(__rcs._M_local_data);
    00277         _M_capacity(__tmp_capacity);
    00278       }
    00279       else
    00280     {
    00281       const size_type __tmp_capacity = _M_allocated_capacity;
    00282       if (__rcs._M_is_local())
    00283         {
    00284           traits_type::copy(_M_local_data, __rcs._M_local_data,
    00285                 _S_local_capacity + 1);
    00286           __rcs._M_data(_M_data());
    00287           _M_data(_M_local_data);
    00288         }
    00289       else
    00290         {
    00291           _CharT* __tmp_ptr = _M_data();
    00292           _M_data(__rcs._M_data());
    00293           __rcs._M_data(__tmp_ptr);
    00294           _M_capacity(__rcs._M_allocated_capacity);
    00295         }
    00296       __rcs._M_capacity(__tmp_capacity);
    00297     }
    00298
    00299       const size_type __tmp_length = _M_length();
    00300       _M_length(__rcs._M_length());
    00301       __rcs._M_length(__tmp_length);
    00302     }
    00303
    00304   template<typename _CharT, typename _Traits, typename _Alloc>
    00305     _CharT*
    00306     __sso_string_base<_CharT, _Traits, _Alloc>::
    00307     _M_create(size_type& __capacity, size_type __old_capacity)
    00308     {
    00309       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00310       // 83.  String::npos vs. string::max_size()
    00311       if (__capacity > _M_max_size())
    00312     std::__throw_length_error(__N("__sso_string_base::_M_create"));
    00313
    00314       // The below implements an exponential growth policy, necessary to
    00315       // meet amortized linear time requirements of the library: see
    00316       // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
    00317       if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
    00318     {
    00319       __capacity = 2 * __old_capacity;
    00320       // Never allocate a string bigger than max_size.
    00321       if (__capacity > _M_max_size())
    00322         __capacity = _M_max_size();
    00323     }
    00324
    00325       // NB: Need an array of char_type[__capacity], plus a terminating
    00326       // null char_type() element.
    00327       return _M_get_allocator().allocate(__capacity + 1);
    00328     }
    00329
    00330   template<typename _CharT, typename _Traits, typename _Alloc>
    00331     __sso_string_base<_CharT, _Traits, _Alloc>::
    00332     __sso_string_base(const _Alloc& __a)
    00333     : _M_dataplus(__a, _M_local_data)
    00334     { _M_set_length(0); }
    00335
    00336   template<typename _CharT, typename _Traits, typename _Alloc>
    00337     __sso_string_base<_CharT, _Traits, _Alloc>::
    00338     __sso_string_base(const __sso_string_base& __rcs)
    00339     : _M_dataplus(__rcs._M_get_allocator(), _M_local_data)
    00340     { _M_construct(__rcs._M_data(), __rcs._M_data() + __rcs._M_length()); }
    00341
    00342 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00343   template<typename _CharT, typename _Traits, typename _Alloc>
    00344     __sso_string_base<_CharT, _Traits, _Alloc>::
    00345     __sso_string_base(__sso_string_base&& __rcs)
    00346     : _M_dataplus(__rcs._M_get_allocator(), _M_local_data)
    00347     {
    00348       if (__rcs._M_is_local())
    00349     {
    00350       if (__rcs._M_length())
    00351         traits_type::copy(_M_local_data, __rcs._M_local_data,
    00352                   _S_local_capacity + 1);
    00353     }
    00354       else
    00355     {
    00356       _M_data(__rcs._M_data());
    00357       _M_capacity(__rcs._M_allocated_capacity);
    00358     }
    00359
    00360       _M_length(__rcs._M_length());
    00361       __rcs._M_length(0);
    00362       __rcs._M_data(__rcs._M_local_data);
    00363     }
    00364 #endif
    00365
    00366   template<typename _CharT, typename _Traits, typename _Alloc>
    00367     __sso_string_base<_CharT, _Traits, _Alloc>::
    00368     __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a)
    00369     : _M_dataplus(__a, _M_local_data)
    00370     { _M_construct(__n, __c); }
    00371
    00372   template<typename _CharT, typename _Traits, typename _Alloc>
    00373     template<typename _InputIterator>
    00374     __sso_string_base<_CharT, _Traits, _Alloc>::
    00375     __sso_string_base(_InputIterator __beg, _InputIterator __end,
    00376               const _Alloc& __a)
    00377     : _M_dataplus(__a, _M_local_data)
    00378     { _M_construct(__beg, __end); }
    00379
    00380   // NB: This is the special case for Input Iterators, used in
    00381   // istreambuf_iterators, etc.
    00382   // Input Iterators have a cost structure very different from
    00383   // pointers, calling for a different coding style.
    00384   template<typename _CharT, typename _Traits, typename _Alloc>
    00385     template<typename _InIterator>
    00386       void
    00387       __sso_string_base<_CharT, _Traits, _Alloc>::
    00388       _M_construct(_InIterator __beg, _InIterator __end,
    00389            std::input_iterator_tag)
    00390       {
    00391     size_type __len = 0;
    00392     size_type __capacity = size_type(_S_local_capacity);
    00393
    00394     while (__beg != __end && __len < __capacity)
    00395       {
    00396         _M_data()[__len++] = *__beg;
    00397         ++__beg;
    00398       }
    00399
    00400     __try
    00401       {
    00402         while (__beg != __end)
    00403           {
    00404         if (__len == __capacity)
    00405           {
    00406             // Allocate more space.
    00407             __capacity = __len + 1;
    00408             _CharT* __another = _M_create(__capacity, __len);
    00409             _S_copy(__another, _M_data(), __len);
    00410             _M_dispose();
    00411             _M_data(__another);
    00412             _M_capacity(__capacity);
    00413           }
    00414         _M_data()[__len++] = *__beg;
    00415         ++__beg;
    00416           }
    00417       }
    00418     __catch(...)
    00419       {
    00420         _M_dispose();
    00421         __throw_exception_again;
    00422       }
    00423
    00424     _M_set_length(__len);
    00425       }
    00426
    00427   template<typename _CharT, typename _Traits, typename _Alloc>
    00428     template<typename _InIterator>
    00429       void
    00430       __sso_string_base<_CharT, _Traits, _Alloc>::
    00431       _M_construct(_InIterator __beg, _InIterator __end,
    00432            std::forward_iterator_tag)
    00433       {
    00434     // NB: Not required, but considered best practice.
    00435     if (__is_null_pointer(__beg) && __beg != __end)
    00436       std::__throw_logic_error(__N("__sso_string_base::"
    00437                        "_M_construct NULL not valid"));
    00438
    00439     size_type __dnew = static_cast<size_type>(std::distance(__beg, __end));
    00440
    00441     if (__dnew > size_type(_S_local_capacity))
    00442       {
    00443         _M_data(_M_create(__dnew, size_type(0)));
    00444         _M_capacity(__dnew);
    00445       }
    00446
    00447     // Check for out_of_range and length_error exceptions.
    00448     __try
    00449       { _S_copy_chars(_M_data(), __beg, __end); }
    00450     __catch(...)
    00451       {
    00452         _M_dispose();
    00453         __throw_exception_again;
    00454       }
    00455
    00456     _M_set_length(__dnew);
    00457       }
    00458
    00459   template<typename _CharT, typename _Traits, typename _Alloc>
    00460     void
    00461     __sso_string_base<_CharT, _Traits, _Alloc>::
    00462     _M_construct(size_type __n, _CharT __c)
    00463     {
    00464       if (__n > size_type(_S_local_capacity))
    00465     {
    00466       _M_data(_M_create(__n, size_type(0)));
    00467       _M_capacity(__n);
    00468     }
    00469
    00470       if (__n)
    00471     _S_assign(_M_data(), __n, __c);
    00472
    00473       _M_set_length(__n);
    00474     }
    00475
    00476   template<typename _CharT, typename _Traits, typename _Alloc>
    00477     void
    00478     __sso_string_base<_CharT, _Traits, _Alloc>::
    00479     _M_assign(const __sso_string_base& __rcs)
    00480     {
    00481       if (this != &__rcs)
    00482     {
    00483       const size_type __rsize = __rcs._M_length();
    00484       const size_type __capacity = _M_capacity();
    00485
    00486       if (__rsize > __capacity)
    00487         {
    00488           size_type __new_capacity = __rsize;
    00489           _CharT* __tmp = _M_create(__new_capacity, __capacity);
    00490           _M_dispose();
    00491           _M_data(__tmp);
    00492           _M_capacity(__new_capacity);
    00493         }
    00494
    00495       if (__rsize)
    00496         _S_copy(_M_data(), __rcs._M_data(), __rsize);
    00497
    00498       _M_set_length(__rsize);
    00499     }
    00500     }
    00501
    00502   template<typename _CharT, typename _Traits, typename _Alloc>
    00503     void
    00504     __sso_string_base<_CharT, _Traits, _Alloc>::
    00505     _M_reserve(size_type __res)
    00506     {
    00507       // Make sure we don't shrink below the current size.
    00508       if (__res < _M_length())
    00509     __res = _M_length();
    00510
    00511       const size_type __capacity = _M_capacity();
    00512       if (__res != __capacity)
    00513     {
    00514       if (__res > __capacity
    00515           || __res > size_type(_S_local_capacity))
    00516         {
    00517           _CharT* __tmp = _M_create(__res, __capacity);
    00518           _S_copy(__tmp, _M_data(), _M_length() + 1);
    00519           _M_dispose();
    00520           _M_data(__tmp);
    00521           _M_capacity(__res);
    00522         }
    00523       else if (!_M_is_local())
    00524         {
    00525           _S_copy(_M_local_data, _M_data(), _M_length() + 1);
    00526           _M_destroy(__capacity);
    00527           _M_data(_M_local_data);
    00528         }
    00529     }
    00530     }
    00531
    00532   template<typename _CharT, typename _Traits, typename _Alloc>
    00533     void
    00534     __sso_string_base<_CharT, _Traits, _Alloc>::
    00535     _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
    00536           size_type __len2)
    00537     {
    00538       const size_type __how_much = _M_length() - __pos - __len1;
    00539
    00540       size_type __new_capacity = _M_length() + __len2 - __len1;
    00541       _CharT* __r = _M_create(__new_capacity, _M_capacity());
    00542
    00543       if (__pos)
    00544     _S_copy(__r, _M_data(), __pos);
    00545       if (__s && __len2)
    00546     _S_copy(__r + __pos, __s, __len2);
    00547       if (__how_much)
    00548     _S_copy(__r + __pos + __len2,
    00549         _M_data() + __pos + __len1, __how_much);
    00550
    00551       _M_dispose();
    00552       _M_data(__r);
    00553       _M_capacity(__new_capacity);
    00554     }
    00555
    00556   template<typename _CharT, typename _Traits, typename _Alloc>
    00557     void
    00558     __sso_string_base<_CharT, _Traits, _Alloc>::
    00559     _M_erase(size_type __pos, size_type __n)
    00560     {
    00561       const size_type __how_much = _M_length() - __pos - __n;
    00562
    00563       if (__how_much && __n)
    00564     _S_move(_M_data() + __pos, _M_data() + __pos + __n,
    00565         __how_much);
    00566
    00567       _M_set_length(_M_length() - __n);
    00568     }
    00569
    00570 _GLIBCXX_END_NAMESPACE
    00571
    00572 #endif /* _SSO_STRING_BASE_H */