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

   1 // Bitmap Allocator. Out of line function definitions. -*- C++ -*-
   2
   3 // Copyright (C) 2004-2021 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   using std::size_t;
  32
  33   namespace __detail
  34   {
  35     template class __mini_vector<
  36       std::pair<bitmap_allocator<char>::_Alloc_block*,
  37                 bitmap_allocator<char>::_Alloc_block*> >;
  38
  39     template class __mini_vector<
  40       std::pair<bitmap_allocator<wchar_t>::_Alloc_block*,
  41                 bitmap_allocator<wchar_t>::_Alloc_block*> >;
  42
  43     template class __mini_vector<size_t*>;
  44
  45     template size_t** __lower_bound(size_t**, size_t**, size_t const&,
  46                                     free_list::_LT_pointer_compare);
  47   }
  48
  49   size_t*
  50   free_list::
  51   _M_get(size_t __sz) throw(std::bad_alloc)
  52   {
  53 #if defined __GTHREADS
  54     __mutex_type& __bfl_mutex = _M_get_mutex();
  55     __bfl_mutex.lock();
  56 #endif
  57     const vector_type& __free_list = _M_get_free_list();
  58     using __gnu_cxx::__detail::__lower_bound;
  59     iterator __tmp = __lower_bound(__free_list.begin(), __free_list.end(),
  60                                    __sz, _LT_pointer_compare());
  61
  62     if (__tmp == __free_list.end() || !_M_should_i_give(**__tmp, __sz))
  63       {
  64         // We release the lock here, because operator new is
  65         // guaranteed to be thread-safe by the underlying
  66         // implementation.
  67 #if defined __GTHREADS
  68         __bfl_mutex.unlock();
  69 #endif
  70         // Try twice to get the memory: once directly, and the 2nd
  71         // time after clearing the free list. If both fail, then throw
  72         // std::bad_alloc().
  73         int __ctr = 2;
  74         while (__ctr)
  75           {
  76             size_t* __ret = 0;
  77             --__ctr;
  78             __try
  79               {
  80                 __ret = reinterpret_cast<size_t*>
  81                   (::operator new(__sz + sizeof(size_t)));
  82               }
  83             __catch(const std::bad_alloc&)
  84               {
  85                 this->_M_clear();
  86               }
  87             if (!__ret)
  88               continue;
  89             *__ret = __sz;
  90             return __ret + 1;
  91           }
  92         std::__throw_bad_alloc();
  93       }
  94     else
  95       {
  96         size_t* __ret = *__tmp;
  97         _M_get_free_list().erase(__tmp);
  98 #if defined __GTHREADS
  99         __bfl_mutex.unlock();
 100 #endif
 101         return __ret + 1;
 102       }
 103   }
 104
 105   void
 106   free_list::
 107   _M_clear()
 108   {
 109 #if defined __GTHREADS
 110     __gnu_cxx::__scoped_lock __bfl_lock(_M_get_mutex());
 111 #endif
 112     vector_type& __free_list = _M_get_free_list();
 113     iterator __iter = __free_list.begin();
 114     while (__iter != __free_list.end())
 115       {
 116         ::operator delete((void*)*__iter);
 117         ++__iter;
 118       }
 119     __free_list.clear();
 120   }
 121
 122   // Instantiations.
 123   template class bitmap_allocator<char>;
 124   template class bitmap_allocator<wchar_t>;
 125
 126 _GLIBCXX_END_NAMESPACE_VERSION
 127 } // namespace