libstdc++-v3/src/bitmap_allocator.cc

   1 // Bitmap Allocator. Out of line function definitions. -*- C++ -*-
   2
   3 // Copyright (C) 2004, 2005 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 2, 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 // 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,
  19 // USA.
  20
  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.
  29
  30 #include <ext/bitmap_allocator.h>
  31
  32 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  33
  34   namespace balloc
  35   {
  36     template class __mini_vector<std::pair<bitmap_allocator<char>::_Alloc_block*, bitmap_allocator<char>::_Alloc_block*> >;
  37     template class __mini_vector<std::pair<bitmap_allocator<wchar_t>::_Alloc_block*, bitmap_allocator<wchar_t>::_Alloc_block*> >;
  38     template class __mini_vector<size_t*>;
  39
  40     template size_t** __lower_bound(size_t**, size_t**, size_t const&,
  41                                     free_list::_LT_pointer_compare);
  42   }
  43
  44   size_t*
  45   free_list::
  46   _M_get(size_t __sz) throw(std::bad_alloc)
  47   {
  48 #if defined __GTHREADS
  49     mutex_type& __bfl_mutex = _M_get_mutex();
  50 #endif
  51     const vector_type& __free_list = _M_get_free_list();
  52     using __gnu_cxx::balloc::__lower_bound;
  53     iterator __tmp = __lower_bound(__free_list.begin(), __free_list.end(),
  54                                    __sz, _LT_pointer_compare());
  55
  56     if (__tmp == __free_list.end() || !_M_should_i_give(**__tmp, __sz))
  57       {
  58         // We release the lock here, because operator new is
  59         // guaranteed to be thread-safe by the underlying
  60         // implementation.
  61 #if defined __GTHREADS
  62         __bfl_mutex.unlock();
  63 #endif
  64         // Try twice to get the memory: once directly, and the 2nd
  65         // time after clearing the free list. If both fail, then throw
  66         // std::bad_alloc().
  67         int __ctr = 2;
  68         while (__ctr)
  69           {
  70             size_t* __ret = 0;
  71             --__ctr;
  72             try
  73               {
  74                 __ret = reinterpret_cast<size_t*>(::operator new(__sz + sizeof(size_t)));
  75               }
  76             catch(...)
  77               {
  78                 this->_M_clear();
  79               }
  80             if (!__ret)
  81               continue;
  82             *__ret = __sz;
  83             return __ret + 1;
  84           }
  85         std::__throw_bad_alloc();
  86       }
  87     else
  88       {
  89         size_t* __ret = *__tmp;
  90         _M_get_free_list().erase(__tmp);
  91 #if defined __GTHREADS
  92         __bfl_mutex.unlock();
  93 #endif
  94         return __ret + 1;
  95       }
  96   }
  97
  98   void
  99   free_list::
 100   _M_clear()
 101   {
 102 #if defined __GTHREADS
 103     __gnu_cxx::__scoped_lock __bfl_lock(_M_get_mutex());
 104 #endif
 105     vector_type& __free_list = _M_get_free_list();
 106     iterator __iter = __free_list.begin();
 107     while (__iter != __free_list.end())
 108       {
 109         ::operator delete((void*)*__iter);
 110         ++__iter;
 111       }
 112     __free_list.clear();
 113   }
 114
 115   // Instantiations.
 116   template class bitmap_allocator<char>;
 117   template class bitmap_allocator<wchar_t>;
 118
 119 _GLIBCXX_END_NAMESPACE