libstdc++-v3/src/bitmap_allocator.cc

   1 // Bitmap Allocator. Out of line function definitions. -*- C++ -*-
   2
   3 // Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009
   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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 #include <ext/bitmap_allocator.h>
  27
  28 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  29
  30   namespace __detail
  31   {
  32     template class __mini_vector<
  33       std::pair<bitmap_allocator<char>::_Alloc_block*,
  34                 bitmap_allocator<char>::_Alloc_block*> >;
  35
  36     template class __mini_vector<
  37       std::pair<bitmap_allocator<wchar_t>::_Alloc_block*,
  38                 bitmap_allocator<wchar_t>::_Alloc_block*> >;
  39
  40     template class __mini_vector<size_t*>;
  41
  42     template size_t** __lower_bound(size_t**, size_t**, size_t const&,
  43                                     free_list::_LT_pointer_compare);
  44   }
  45
  46   size_t*
  47   free_list::
  48   _M_get(size_t __sz) throw(std::bad_alloc)
  49   {
  50 #if defined __GTHREADS
  51     __mutex_type& __bfl_mutex = _M_get_mutex();
  52 #endif
  53     const vector_type& __free_list = _M_get_free_list();
  54     using __gnu_cxx::__detail::__lower_bound;
  55     iterator __tmp = __lower_bound(__free_list.begin(), __free_list.end(),
  56                                    __sz, _LT_pointer_compare());
  57
  58     if (__tmp == __free_list.end() || !_M_should_i_give(**__tmp, __sz))
  59       {
  60         // We release the lock here, because operator new is
  61         // guaranteed to be thread-safe by the underlying
  62         // implementation.
  63 #if defined __GTHREADS
  64         __bfl_mutex.unlock();
  65 #endif
  66         // Try twice to get the memory: once directly, and the 2nd
  67         // time after clearing the free list. If both fail, then throw
  68         // std::bad_alloc().
  69         int __ctr = 2;
  70         while (__ctr)
  71           {
  72             size_t* __ret = 0;
  73             --__ctr;
  74             __try
  75               {
  76                 __ret = reinterpret_cast<size_t*>
  77                   (::operator new(__sz + sizeof(size_t)));
  78               }
  79             __catch(const std::bad_alloc&)
  80               {
  81                 this->_M_clear();
  82               }
  83             if (!__ret)
  84               continue;
  85             *__ret = __sz;
  86             return __ret + 1;
  87           }
  88         std::__throw_bad_alloc();
  89       }
  90     else
  91       {
  92         size_t* __ret = *__tmp;
  93         _M_get_free_list().erase(__tmp);
  94 #if defined __GTHREADS
  95         __bfl_mutex.unlock();
  96 #endif
  97         return __ret + 1;
  98       }
  99   }
 100
 101   void
 102   free_list::
 103   _M_clear()
 104   {
 105 #if defined __GTHREADS
 106     __gnu_cxx::__scoped_lock __bfl_lock(_M_get_mutex());
 107 #endif
 108     vector_type& __free_list = _M_get_free_list();
 109     iterator __iter = __free_list.begin();
 110     while (__iter != __free_list.end())
 111       {
 112         ::operator delete((void*)*__iter);
 113         ++__iter;
 114       }
 115     __free_list.clear();
 116   }
 117
 118   // Instantiations.
 119   template class bitmap_allocator<char>;
 120   template class bitmap_allocator<wchar_t>;
 121
 122 _GLIBCXX_END_NAMESPACE