libstdc++-v3/src/c++98/bitmap_allocator.cc

   1 // Bitmap Allocator. Out of line function definitions. -*- C++ -*-
   2
   3 // Copyright (C) 2004-2017 Free Software Foundation, Inc.
   4 //
   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 3, or (at your option)
   9 // any later version.
  10
  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.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <ext/bitmap_allocator.h>
  26
  27 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  28 {
  29 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  30
  31   namespace __detail
  32   {
  33     template class __mini_vector<
  34       std::pair<bitmap_allocator<char>::_Alloc_block*,
  35                 bitmap_allocator<char>::_Alloc_block*> >;
  36
  37     template class __mini_vector<
  38       std::pair<bitmap_allocator<wchar_t>::_Alloc_block*,
  39                 bitmap_allocator<wchar_t>::_Alloc_block*> >;
  40
  41     template class __mini_vector<size_t*>;
  42
  43     template size_t** __lower_bound(size_t**, size_t**, size_t const&,
  44                                     free_list::_LT_pointer_compare);
  45   }
  46
  47   size_t*
  48   free_list::
  49   _M_get(size_t __sz) throw(std::bad_alloc)
  50   {
  51 #if defined __GTHREADS
  52     __mutex_type& __bfl_mutex = _M_get_mutex();
  53     __bfl_mutex.lock();
  54 #endif
  55     const vector_type& __free_list = _M_get_free_list();
  56     using __gnu_cxx::__detail::__lower_bound;
  57     iterator __tmp = __lower_bound(__free_list.begin(), __free_list.end(),
  58                                    __sz, _LT_pointer_compare());
  59
  60     if (__tmp == __free_list.end() || !_M_should_i_give(**__tmp, __sz))
  61       {
  62         // We release the lock here, because operator new is
  63         // guaranteed to be thread-safe by the underlying
  64         // implementation.
  65 #if defined __GTHREADS
  66         __bfl_mutex.unlock();
  67 #endif
  68         // Try twice to get the memory: once directly, and the 2nd
  69         // time after clearing the free list. If both fail, then throw
  70         // std::bad_alloc().
  71         int __ctr = 2;
  72         while (__ctr)
  73           {
  74             size_t* __ret = 0;
  75             --__ctr;
  76             __try
  77               {
  78                 __ret = reinterpret_cast<size_t*>
  79                   (::operator new(__sz + sizeof(size_t)));
  80               }
  81             __catch(const std::bad_alloc&)
  82               {
  83                 this->_M_clear();
  84               }
  85             if (!__ret)
  86               continue;
  87             *__ret = __sz;
  88             return __ret + 1;
  89           }
  90         std::__throw_bad_alloc();
  91       }
  92     else
  93       {
  94         size_t* __ret = *__tmp;
  95         _M_get_free_list().erase(__tmp);
  96 #if defined __GTHREADS
  97         __bfl_mutex.unlock();
  98 #endif
  99         return __ret + 1;
 100       }
 101   }
 102
 103   void
 104   free_list::
 105   _M_clear()
 106   {
 107 #if defined __GTHREADS
 108     __gnu_cxx::__scoped_lock __bfl_lock(_M_get_mutex());
 109 #endif
 110     vector_type& __free_list = _M_get_free_list();
 111     iterator __iter = __free_list.begin();
 112     while (__iter != __free_list.end())
 113       {
 114         ::operator delete((void*)*__iter);
 115         ++__iter;
 116       }
 117     __free_list.clear();
 118   }
 119
 120   // Instantiations.
 121   template class bitmap_allocator<char>;
 122   template class bitmap_allocator<wchar_t>;
 123
 124 _GLIBCXX_END_NAMESPACE_VERSION
 125 } // namespace