mirror of
https://github.com/autc04/Retro68.git
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1134 lines
31 KiB
C++
1134 lines
31 KiB
C++
// Bitmap Allocator. -*- C++ -*-
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// Copyright (C) 2004-2019 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file ext/bitmap_allocator.h
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* This file is a GNU extension to the Standard C++ Library.
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*/
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#ifndef _BITMAP_ALLOCATOR_H
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#define _BITMAP_ALLOCATOR_H 1
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#include <utility> // For std::pair.
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#include <bits/functexcept.h> // For __throw_bad_alloc().
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#include <functional> // For greater_equal, and less_equal.
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#include <new> // For operator new.
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#include <debug/debug.h> // _GLIBCXX_DEBUG_ASSERT
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#include <ext/concurrence.h>
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#include <bits/move.h>
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/** @brief The constant in the expression below is the alignment
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* required in bytes.
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*/
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#define _BALLOC_ALIGN_BYTES 8
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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using std::size_t;
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using std::ptrdiff_t;
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namespace __detail
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{
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/** @class __mini_vector bitmap_allocator.h bitmap_allocator.h
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*
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* @brief __mini_vector<> is a stripped down version of the
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* full-fledged std::vector<>.
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*
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* It is to be used only for built-in types or PODs. Notable
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* differences are:
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*
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* 1. Not all accessor functions are present.
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* 2. Used ONLY for PODs.
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* 3. No Allocator template argument. Uses ::operator new() to get
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* memory, and ::operator delete() to free it.
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* Caveat: The dtor does NOT free the memory allocated, so this a
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* memory-leaking vector!
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*/
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template<typename _Tp>
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class __mini_vector
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{
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__mini_vector(const __mini_vector&);
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__mini_vector& operator=(const __mini_vector&);
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public:
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typedef _Tp value_type;
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typedef _Tp* pointer;
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typedef _Tp& reference;
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typedef const _Tp& const_reference;
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typedef size_t size_type;
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typedef ptrdiff_t difference_type;
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typedef pointer iterator;
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private:
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pointer _M_start;
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pointer _M_finish;
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pointer _M_end_of_storage;
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size_type
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_M_space_left() const throw()
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{ return _M_end_of_storage - _M_finish; }
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_GLIBCXX_NODISCARD pointer
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allocate(size_type __n)
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{ return static_cast<pointer>(::operator new(__n * sizeof(_Tp))); }
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void
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deallocate(pointer __p, size_type)
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{ ::operator delete(__p); }
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public:
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// Members used: size(), push_back(), pop_back(),
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// insert(iterator, const_reference), erase(iterator),
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// begin(), end(), back(), operator[].
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__mini_vector()
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: _M_start(0), _M_finish(0), _M_end_of_storage(0) { }
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size_type
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size() const throw()
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{ return _M_finish - _M_start; }
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iterator
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begin() const throw()
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{ return this->_M_start; }
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iterator
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end() const throw()
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{ return this->_M_finish; }
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reference
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back() const throw()
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{ return *(this->end() - 1); }
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reference
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operator[](const size_type __pos) const throw()
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{ return this->_M_start[__pos]; }
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void
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insert(iterator __pos, const_reference __x);
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void
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push_back(const_reference __x)
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{
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if (this->_M_space_left())
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{
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*this->end() = __x;
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++this->_M_finish;
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}
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else
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this->insert(this->end(), __x);
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}
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void
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pop_back() throw()
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{ --this->_M_finish; }
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void
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erase(iterator __pos) throw();
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void
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clear() throw()
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{ this->_M_finish = this->_M_start; }
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};
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// Out of line function definitions.
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template<typename _Tp>
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void __mini_vector<_Tp>::
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insert(iterator __pos, const_reference __x)
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{
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if (this->_M_space_left())
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{
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size_type __to_move = this->_M_finish - __pos;
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iterator __dest = this->end();
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iterator __src = this->end() - 1;
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++this->_M_finish;
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while (__to_move)
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{
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*__dest = *__src;
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--__dest; --__src; --__to_move;
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}
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*__pos = __x;
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}
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else
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{
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size_type __new_size = this->size() ? this->size() * 2 : 1;
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iterator __new_start = this->allocate(__new_size);
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iterator __first = this->begin();
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iterator __start = __new_start;
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while (__first != __pos)
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{
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*__start = *__first;
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++__start; ++__first;
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}
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*__start = __x;
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++__start;
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while (__first != this->end())
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{
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*__start = *__first;
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++__start; ++__first;
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}
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if (this->_M_start)
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this->deallocate(this->_M_start, this->size());
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this->_M_start = __new_start;
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this->_M_finish = __start;
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this->_M_end_of_storage = this->_M_start + __new_size;
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}
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}
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template<typename _Tp>
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void __mini_vector<_Tp>::
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erase(iterator __pos) throw()
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{
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while (__pos + 1 != this->end())
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{
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*__pos = __pos[1];
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++__pos;
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}
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--this->_M_finish;
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}
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template<typename _Tp>
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struct __mv_iter_traits
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{
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typedef typename _Tp::value_type value_type;
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typedef typename _Tp::difference_type difference_type;
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};
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template<typename _Tp>
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struct __mv_iter_traits<_Tp*>
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{
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typedef _Tp value_type;
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typedef ptrdiff_t difference_type;
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};
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enum
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{
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bits_per_byte = 8,
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bits_per_block = sizeof(size_t) * size_t(bits_per_byte)
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};
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template<typename _ForwardIterator, typename _Tp, typename _Compare>
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_ForwardIterator
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__lower_bound(_ForwardIterator __first, _ForwardIterator __last,
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const _Tp& __val, _Compare __comp)
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{
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typedef typename __mv_iter_traits<_ForwardIterator>::difference_type
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_DistanceType;
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_DistanceType __len = __last - __first;
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_DistanceType __half;
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_ForwardIterator __middle;
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while (__len > 0)
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{
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__half = __len >> 1;
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__middle = __first;
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__middle += __half;
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if (__comp(*__middle, __val))
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{
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__first = __middle;
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++__first;
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__len = __len - __half - 1;
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}
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else
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__len = __half;
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}
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return __first;
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}
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/** @brief The number of Blocks pointed to by the address pair
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* passed to the function.
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*/
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template<typename _AddrPair>
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inline size_t
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__num_blocks(_AddrPair __ap)
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{ return (__ap.second - __ap.first) + 1; }
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/** @brief The number of Bit-maps pointed to by the address pair
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* passed to the function.
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*/
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template<typename _AddrPair>
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inline size_t
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__num_bitmaps(_AddrPair __ap)
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{ return __num_blocks(__ap) / size_t(bits_per_block); }
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// _Tp should be a pointer type.
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template<typename _Tp>
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class _Inclusive_between
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: public std::unary_function<typename std::pair<_Tp, _Tp>, bool>
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{
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typedef _Tp pointer;
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pointer _M_ptr_value;
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typedef typename std::pair<_Tp, _Tp> _Block_pair;
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public:
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_Inclusive_between(pointer __ptr) : _M_ptr_value(__ptr)
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{ }
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bool
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operator()(_Block_pair __bp) const throw()
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{
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if (std::less_equal<pointer>()(_M_ptr_value, __bp.second)
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&& std::greater_equal<pointer>()(_M_ptr_value, __bp.first))
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return true;
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else
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return false;
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}
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};
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// Used to pass a Functor to functions by reference.
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template<typename _Functor>
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class _Functor_Ref
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: public std::unary_function<typename _Functor::argument_type,
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typename _Functor::result_type>
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{
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_Functor& _M_fref;
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public:
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typedef typename _Functor::argument_type argument_type;
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typedef typename _Functor::result_type result_type;
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_Functor_Ref(_Functor& __fref) : _M_fref(__fref)
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{ }
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result_type
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operator()(argument_type __arg)
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{ return _M_fref(__arg); }
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};
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/** @class _Ffit_finder bitmap_allocator.h bitmap_allocator.h
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*
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* @brief The class which acts as a predicate for applying the
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* first-fit memory allocation policy for the bitmap allocator.
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*/
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// _Tp should be a pointer type, and _Alloc is the Allocator for
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// the vector.
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template<typename _Tp>
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class _Ffit_finder
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: public std::unary_function<typename std::pair<_Tp, _Tp>, bool>
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{
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typedef typename std::pair<_Tp, _Tp> _Block_pair;
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typedef typename __detail::__mini_vector<_Block_pair> _BPVector;
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typedef typename _BPVector::difference_type _Counter_type;
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size_t* _M_pbitmap;
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_Counter_type _M_data_offset;
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public:
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_Ffit_finder() : _M_pbitmap(0), _M_data_offset(0)
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{ }
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bool
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operator()(_Block_pair __bp) throw()
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{
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// Set the _rover to the last physical location bitmap,
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// which is the bitmap which belongs to the first free
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// block. Thus, the bitmaps are in exact reverse order of
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// the actual memory layout. So, we count down the bitmaps,
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// which is the same as moving up the memory.
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// If the used count stored at the start of the Bit Map headers
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// is equal to the number of Objects that the current Block can
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// store, then there is definitely no space for another single
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// object, so just return false.
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_Counter_type __diff = __detail::__num_bitmaps(__bp);
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if (*(reinterpret_cast<size_t*>
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(__bp.first) - (__diff + 1)) == __detail::__num_blocks(__bp))
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return false;
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size_t* __rover = reinterpret_cast<size_t*>(__bp.first) - 1;
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for (_Counter_type __i = 0; __i < __diff; ++__i)
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{
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_M_data_offset = __i;
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if (*__rover)
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{
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_M_pbitmap = __rover;
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return true;
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}
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--__rover;
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}
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return false;
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}
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size_t*
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_M_get() const throw()
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{ return _M_pbitmap; }
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_Counter_type
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_M_offset() const throw()
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{ return _M_data_offset * size_t(bits_per_block); }
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};
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/** @class _Bitmap_counter bitmap_allocator.h bitmap_allocator.h
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*
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* @brief The bitmap counter which acts as the bitmap
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* manipulator, and manages the bit-manipulation functions and
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* the searching and identification functions on the bit-map.
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*/
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// _Tp should be a pointer type.
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template<typename _Tp>
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class _Bitmap_counter
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{
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typedef typename
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__detail::__mini_vector<typename std::pair<_Tp, _Tp> > _BPVector;
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typedef typename _BPVector::size_type _Index_type;
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typedef _Tp pointer;
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_BPVector& _M_vbp;
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size_t* _M_curr_bmap;
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size_t* _M_last_bmap_in_block;
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_Index_type _M_curr_index;
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public:
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// Use the 2nd parameter with care. Make sure that such an
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// entry exists in the vector before passing that particular
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// index to this ctor.
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_Bitmap_counter(_BPVector& Rvbp, long __index = -1) : _M_vbp(Rvbp)
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{ this->_M_reset(__index); }
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void
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_M_reset(long __index = -1) throw()
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{
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if (__index == -1)
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{
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_M_curr_bmap = 0;
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_M_curr_index = static_cast<_Index_type>(-1);
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return;
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}
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_M_curr_index = __index;
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_M_curr_bmap = reinterpret_cast<size_t*>
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(_M_vbp[_M_curr_index].first) - 1;
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_GLIBCXX_DEBUG_ASSERT(__index <= (long)_M_vbp.size() - 1);
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_M_last_bmap_in_block = _M_curr_bmap
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- ((_M_vbp[_M_curr_index].second
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- _M_vbp[_M_curr_index].first + 1)
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/ size_t(bits_per_block) - 1);
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}
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// Dangerous Function! Use with extreme care. Pass to this
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// function ONLY those values that are known to be correct,
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// otherwise this will mess up big time.
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void
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_M_set_internal_bitmap(size_t* __new_internal_marker) throw()
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{ _M_curr_bmap = __new_internal_marker; }
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bool
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_M_finished() const throw()
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{ return(_M_curr_bmap == 0); }
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_Bitmap_counter&
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operator++() throw()
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{
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if (_M_curr_bmap == _M_last_bmap_in_block)
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{
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if (++_M_curr_index == _M_vbp.size())
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_M_curr_bmap = 0;
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else
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this->_M_reset(_M_curr_index);
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}
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else
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--_M_curr_bmap;
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return *this;
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}
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size_t*
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_M_get() const throw()
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{ return _M_curr_bmap; }
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pointer
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_M_base() const throw()
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{ return _M_vbp[_M_curr_index].first; }
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_Index_type
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_M_offset() const throw()
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{
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return size_t(bits_per_block)
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* ((reinterpret_cast<size_t*>(this->_M_base())
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- _M_curr_bmap) - 1);
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}
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_Index_type
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_M_where() const throw()
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{ return _M_curr_index; }
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};
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/** @brief Mark a memory address as allocated by re-setting the
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* corresponding bit in the bit-map.
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*/
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inline void
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__bit_allocate(size_t* __pbmap, size_t __pos) throw()
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{
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size_t __mask = 1 << __pos;
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__mask = ~__mask;
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*__pbmap &= __mask;
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}
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/** @brief Mark a memory address as free by setting the
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* corresponding bit in the bit-map.
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*/
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inline void
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__bit_free(size_t* __pbmap, size_t __pos) throw()
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{
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size_t __mask = 1 << __pos;
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*__pbmap |= __mask;
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}
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} // namespace __detail
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/** @brief Generic Version of the bsf instruction.
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*/
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inline size_t
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_Bit_scan_forward(size_t __num)
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{ return static_cast<size_t>(__builtin_ctzl(__num)); }
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/** @class free_list bitmap_allocator.h bitmap_allocator.h
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*
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* @brief The free list class for managing chunks of memory to be
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* given to and returned by the bitmap_allocator.
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*/
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class free_list
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{
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public:
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typedef size_t* value_type;
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typedef __detail::__mini_vector<value_type> vector_type;
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typedef vector_type::iterator iterator;
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typedef __mutex __mutex_type;
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private:
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struct _LT_pointer_compare
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{
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bool
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operator()(const size_t* __pui,
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const size_t __cui) const throw()
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{ return *__pui < __cui; }
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};
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#if defined __GTHREADS
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__mutex_type&
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_M_get_mutex()
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{
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static __mutex_type _S_mutex;
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return _S_mutex;
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}
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#endif
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vector_type&
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_M_get_free_list()
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{
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static vector_type _S_free_list;
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return _S_free_list;
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}
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|
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/** @brief Performs validation of memory based on their size.
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*
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|
* @param __addr The pointer to the memory block to be
|
|
* validated.
|
|
*
|
|
* Validates the memory block passed to this function and
|
|
* appropriately performs the action of managing the free list of
|
|
* blocks by adding this block to the free list or deleting this
|
|
* or larger blocks from the free list.
|
|
*/
|
|
void
|
|
_M_validate(size_t* __addr) throw()
|
|
{
|
|
vector_type& __free_list = _M_get_free_list();
|
|
const vector_type::size_type __max_size = 64;
|
|
if (__free_list.size() >= __max_size)
|
|
{
|
|
// Ok, the threshold value has been reached. We determine
|
|
// which block to remove from the list of free blocks.
|
|
if (*__addr >= *__free_list.back())
|
|
{
|
|
// Ok, the new block is greater than or equal to the
|
|
// last block in the list of free blocks. We just free
|
|
// the new block.
|
|
::operator delete(static_cast<void*>(__addr));
|
|
return;
|
|
}
|
|
else
|
|
{
|
|
// Deallocate the last block in the list of free lists,
|
|
// and insert the new one in its correct position.
|
|
::operator delete(static_cast<void*>(__free_list.back()));
|
|
__free_list.pop_back();
|
|
}
|
|
}
|
|
|
|
// Just add the block to the list of free lists unconditionally.
|
|
iterator __temp = __detail::__lower_bound
|
|
(__free_list.begin(), __free_list.end(),
|
|
*__addr, _LT_pointer_compare());
|
|
|
|
// We may insert the new free list before _temp;
|
|
__free_list.insert(__temp, __addr);
|
|
}
|
|
|
|
/** @brief Decides whether the wastage of memory is acceptable for
|
|
* the current memory request and returns accordingly.
|
|
*
|
|
* @param __block_size The size of the block available in the free
|
|
* list.
|
|
*
|
|
* @param __required_size The required size of the memory block.
|
|
*
|
|
* @return true if the wastage incurred is acceptable, else returns
|
|
* false.
|
|
*/
|
|
bool
|
|
_M_should_i_give(size_t __block_size,
|
|
size_t __required_size) throw()
|
|
{
|
|
const size_t __max_wastage_percentage = 36;
|
|
if (__block_size >= __required_size &&
|
|
(((__block_size - __required_size) * 100 / __block_size)
|
|
< __max_wastage_percentage))
|
|
return true;
|
|
else
|
|
return false;
|
|
}
|
|
|
|
public:
|
|
/** @brief This function returns the block of memory to the
|
|
* internal free list.
|
|
*
|
|
* @param __addr The pointer to the memory block that was given
|
|
* by a call to the _M_get function.
|
|
*/
|
|
inline void
|
|
_M_insert(size_t* __addr) throw()
|
|
{
|
|
#if defined __GTHREADS
|
|
__scoped_lock __bfl_lock(_M_get_mutex());
|
|
#endif
|
|
// Call _M_validate to decide what should be done with
|
|
// this particular free list.
|
|
this->_M_validate(reinterpret_cast<size_t*>(__addr) - 1);
|
|
// See discussion as to why this is 1!
|
|
}
|
|
|
|
/** @brief This function gets a block of memory of the specified
|
|
* size from the free list.
|
|
*
|
|
* @param __sz The size in bytes of the memory required.
|
|
*
|
|
* @return A pointer to the new memory block of size at least
|
|
* equal to that requested.
|
|
*/
|
|
size_t*
|
|
_M_get(size_t __sz) _GLIBCXX_THROW(std::bad_alloc);
|
|
|
|
/** @brief This function just clears the internal Free List, and
|
|
* gives back all the memory to the OS.
|
|
*/
|
|
void
|
|
_M_clear();
|
|
};
|
|
|
|
|
|
// Forward declare the class.
|
|
template<typename _Tp>
|
|
class bitmap_allocator;
|
|
|
|
// Specialize for void:
|
|
template<>
|
|
class bitmap_allocator<void>
|
|
{
|
|
public:
|
|
typedef void* pointer;
|
|
typedef const void* const_pointer;
|
|
|
|
// Reference-to-void members are impossible.
|
|
typedef void value_type;
|
|
template<typename _Tp1>
|
|
struct rebind
|
|
{
|
|
typedef bitmap_allocator<_Tp1> other;
|
|
};
|
|
};
|
|
|
|
/**
|
|
* @brief Bitmap Allocator, primary template.
|
|
* @ingroup allocators
|
|
*/
|
|
template<typename _Tp>
|
|
class bitmap_allocator : private free_list
|
|
{
|
|
public:
|
|
typedef size_t size_type;
|
|
typedef ptrdiff_t difference_type;
|
|
typedef _Tp* pointer;
|
|
typedef const _Tp* const_pointer;
|
|
typedef _Tp& reference;
|
|
typedef const _Tp& const_reference;
|
|
typedef _Tp value_type;
|
|
typedef free_list::__mutex_type __mutex_type;
|
|
|
|
template<typename _Tp1>
|
|
struct rebind
|
|
{
|
|
typedef bitmap_allocator<_Tp1> other;
|
|
};
|
|
|
|
#if __cplusplus >= 201103L
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2103. propagate_on_container_move_assignment
|
|
typedef std::true_type propagate_on_container_move_assignment;
|
|
#endif
|
|
|
|
private:
|
|
template<size_t _BSize, size_t _AlignSize>
|
|
struct aligned_size
|
|
{
|
|
enum
|
|
{
|
|
modulus = _BSize % _AlignSize,
|
|
value = _BSize + (modulus ? _AlignSize - (modulus) : 0)
|
|
};
|
|
};
|
|
|
|
struct _Alloc_block
|
|
{
|
|
char __M_unused[aligned_size<sizeof(value_type),
|
|
_BALLOC_ALIGN_BYTES>::value];
|
|
};
|
|
|
|
|
|
typedef typename std::pair<_Alloc_block*, _Alloc_block*> _Block_pair;
|
|
|
|
typedef typename __detail::__mini_vector<_Block_pair> _BPVector;
|
|
typedef typename _BPVector::iterator _BPiter;
|
|
|
|
template<typename _Predicate>
|
|
static _BPiter
|
|
_S_find(_Predicate __p)
|
|
{
|
|
_BPiter __first = _S_mem_blocks.begin();
|
|
while (__first != _S_mem_blocks.end() && !__p(*__first))
|
|
++__first;
|
|
return __first;
|
|
}
|
|
|
|
#if defined _GLIBCXX_DEBUG
|
|
// Complexity: O(lg(N)). Where, N is the number of block of size
|
|
// sizeof(value_type).
|
|
void
|
|
_S_check_for_free_blocks() throw()
|
|
{
|
|
typedef typename __detail::_Ffit_finder<_Alloc_block*> _FFF;
|
|
_BPiter __bpi = _S_find(_FFF());
|
|
|
|
_GLIBCXX_DEBUG_ASSERT(__bpi == _S_mem_blocks.end());
|
|
}
|
|
#endif
|
|
|
|
/** @brief Responsible for exponentially growing the internal
|
|
* memory pool.
|
|
*
|
|
* @throw std::bad_alloc. If memory cannot be allocated.
|
|
*
|
|
* Complexity: O(1), but internally depends upon the
|
|
* complexity of the function free_list::_M_get. The part where
|
|
* the bitmap headers are written has complexity: O(X),where X
|
|
* is the number of blocks of size sizeof(value_type) within
|
|
* the newly acquired block. Having a tight bound.
|
|
*/
|
|
void
|
|
_S_refill_pool() _GLIBCXX_THROW(std::bad_alloc)
|
|
{
|
|
#if defined _GLIBCXX_DEBUG
|
|
_S_check_for_free_blocks();
|
|
#endif
|
|
|
|
const size_t __num_bitmaps = (_S_block_size
|
|
/ size_t(__detail::bits_per_block));
|
|
const size_t __size_to_allocate = sizeof(size_t)
|
|
+ _S_block_size * sizeof(_Alloc_block)
|
|
+ __num_bitmaps * sizeof(size_t);
|
|
|
|
size_t* __temp =
|
|
reinterpret_cast<size_t*>(this->_M_get(__size_to_allocate));
|
|
*__temp = 0;
|
|
++__temp;
|
|
|
|
// The Header information goes at the Beginning of the Block.
|
|
_Block_pair __bp =
|
|
std::make_pair(reinterpret_cast<_Alloc_block*>
|
|
(__temp + __num_bitmaps),
|
|
reinterpret_cast<_Alloc_block*>
|
|
(__temp + __num_bitmaps)
|
|
+ _S_block_size - 1);
|
|
|
|
// Fill the Vector with this information.
|
|
_S_mem_blocks.push_back(__bp);
|
|
|
|
for (size_t __i = 0; __i < __num_bitmaps; ++__i)
|
|
__temp[__i] = ~static_cast<size_t>(0); // 1 Indicates all Free.
|
|
|
|
_S_block_size *= 2;
|
|
}
|
|
|
|
static _BPVector _S_mem_blocks;
|
|
static size_t _S_block_size;
|
|
static __detail::_Bitmap_counter<_Alloc_block*> _S_last_request;
|
|
static typename _BPVector::size_type _S_last_dealloc_index;
|
|
#if defined __GTHREADS
|
|
static __mutex_type _S_mut;
|
|
#endif
|
|
|
|
public:
|
|
|
|
/** @brief Allocates memory for a single object of size
|
|
* sizeof(_Tp).
|
|
*
|
|
* @throw std::bad_alloc. If memory cannot be allocated.
|
|
*
|
|
* Complexity: Worst case complexity is O(N), but that
|
|
* is hardly ever hit. If and when this particular case is
|
|
* encountered, the next few cases are guaranteed to have a
|
|
* worst case complexity of O(1)! That's why this function
|
|
* performs very well on average. You can consider this
|
|
* function to have a complexity referred to commonly as:
|
|
* Amortized Constant time.
|
|
*/
|
|
pointer
|
|
_M_allocate_single_object() _GLIBCXX_THROW(std::bad_alloc)
|
|
{
|
|
#if defined __GTHREADS
|
|
__scoped_lock __bit_lock(_S_mut);
|
|
#endif
|
|
|
|
// The algorithm is something like this: The last_request
|
|
// variable points to the last accessed Bit Map. When such a
|
|
// condition occurs, we try to find a free block in the
|
|
// current bitmap, or succeeding bitmaps until the last bitmap
|
|
// is reached. If no free block turns up, we resort to First
|
|
// Fit method.
|
|
|
|
// WARNING: Do not re-order the condition in the while
|
|
// statement below, because it relies on C++'s short-circuit
|
|
// evaluation. The return from _S_last_request->_M_get() will
|
|
// NOT be dereference able if _S_last_request->_M_finished()
|
|
// returns true. This would inevitably lead to a NULL pointer
|
|
// dereference if tinkered with.
|
|
while (_S_last_request._M_finished() == false
|
|
&& (*(_S_last_request._M_get()) == 0))
|
|
_S_last_request.operator++();
|
|
|
|
if (__builtin_expect(_S_last_request._M_finished() == true, false))
|
|
{
|
|
// Fall Back to First Fit algorithm.
|
|
typedef typename __detail::_Ffit_finder<_Alloc_block*> _FFF;
|
|
_FFF __fff;
|
|
_BPiter __bpi = _S_find(__detail::_Functor_Ref<_FFF>(__fff));
|
|
|
|
if (__bpi != _S_mem_blocks.end())
|
|
{
|
|
// Search was successful. Ok, now mark the first bit from
|
|
// the right as 0, meaning Allocated. This bit is obtained
|
|
// by calling _M_get() on __fff.
|
|
size_t __nz_bit = _Bit_scan_forward(*__fff._M_get());
|
|
__detail::__bit_allocate(__fff._M_get(), __nz_bit);
|
|
|
|
_S_last_request._M_reset(__bpi - _S_mem_blocks.begin());
|
|
|
|
// Now, get the address of the bit we marked as allocated.
|
|
pointer __ret = reinterpret_cast<pointer>
|
|
(__bpi->first + __fff._M_offset() + __nz_bit);
|
|
size_t* __puse_count =
|
|
reinterpret_cast<size_t*>
|
|
(__bpi->first) - (__detail::__num_bitmaps(*__bpi) + 1);
|
|
|
|
++(*__puse_count);
|
|
return __ret;
|
|
}
|
|
else
|
|
{
|
|
// Search was unsuccessful. We Add more memory to the
|
|
// pool by calling _S_refill_pool().
|
|
_S_refill_pool();
|
|
|
|
// _M_Reset the _S_last_request structure to the first
|
|
// free block's bit map.
|
|
_S_last_request._M_reset(_S_mem_blocks.size() - 1);
|
|
|
|
// Now, mark that bit as allocated.
|
|
}
|
|
}
|
|
|
|
// _S_last_request holds a pointer to a valid bit map, that
|
|
// points to a free block in memory.
|
|
size_t __nz_bit = _Bit_scan_forward(*_S_last_request._M_get());
|
|
__detail::__bit_allocate(_S_last_request._M_get(), __nz_bit);
|
|
|
|
pointer __ret = reinterpret_cast<pointer>
|
|
(_S_last_request._M_base() + _S_last_request._M_offset() + __nz_bit);
|
|
|
|
size_t* __puse_count = reinterpret_cast<size_t*>
|
|
(_S_mem_blocks[_S_last_request._M_where()].first)
|
|
- (__detail::
|
|
__num_bitmaps(_S_mem_blocks[_S_last_request._M_where()]) + 1);
|
|
|
|
++(*__puse_count);
|
|
return __ret;
|
|
}
|
|
|
|
/** @brief Deallocates memory that belongs to a single object of
|
|
* size sizeof(_Tp).
|
|
*
|
|
* Complexity: O(lg(N)), but the worst case is not hit
|
|
* often! This is because containers usually deallocate memory
|
|
* close to each other and this case is handled in O(1) time by
|
|
* the deallocate function.
|
|
*/
|
|
void
|
|
_M_deallocate_single_object(pointer __p) throw()
|
|
{
|
|
#if defined __GTHREADS
|
|
__scoped_lock __bit_lock(_S_mut);
|
|
#endif
|
|
_Alloc_block* __real_p = reinterpret_cast<_Alloc_block*>(__p);
|
|
|
|
typedef typename _BPVector::iterator _Iterator;
|
|
typedef typename _BPVector::difference_type _Difference_type;
|
|
|
|
_Difference_type __diff;
|
|
long __displacement;
|
|
|
|
_GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index >= 0);
|
|
|
|
__detail::_Inclusive_between<_Alloc_block*> __ibt(__real_p);
|
|
if (__ibt(_S_mem_blocks[_S_last_dealloc_index]))
|
|
{
|
|
_GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index
|
|
<= _S_mem_blocks.size() - 1);
|
|
|
|
// Initial Assumption was correct!
|
|
__diff = _S_last_dealloc_index;
|
|
__displacement = __real_p - _S_mem_blocks[__diff].first;
|
|
}
|
|
else
|
|
{
|
|
_Iterator _iter = _S_find(__ibt);
|
|
|
|
_GLIBCXX_DEBUG_ASSERT(_iter != _S_mem_blocks.end());
|
|
|
|
__diff = _iter - _S_mem_blocks.begin();
|
|
__displacement = __real_p - _S_mem_blocks[__diff].first;
|
|
_S_last_dealloc_index = __diff;
|
|
}
|
|
|
|
// Get the position of the iterator that has been found.
|
|
const size_t __rotate = (__displacement
|
|
% size_t(__detail::bits_per_block));
|
|
size_t* __bitmapC =
|
|
reinterpret_cast<size_t*>
|
|
(_S_mem_blocks[__diff].first) - 1;
|
|
__bitmapC -= (__displacement / size_t(__detail::bits_per_block));
|
|
|
|
__detail::__bit_free(__bitmapC, __rotate);
|
|
size_t* __puse_count = reinterpret_cast<size_t*>
|
|
(_S_mem_blocks[__diff].first)
|
|
- (__detail::__num_bitmaps(_S_mem_blocks[__diff]) + 1);
|
|
|
|
_GLIBCXX_DEBUG_ASSERT(*__puse_count != 0);
|
|
|
|
--(*__puse_count);
|
|
|
|
if (__builtin_expect(*__puse_count == 0, false))
|
|
{
|
|
_S_block_size /= 2;
|
|
|
|
// We can safely remove this block.
|
|
// _Block_pair __bp = _S_mem_blocks[__diff];
|
|
this->_M_insert(__puse_count);
|
|
_S_mem_blocks.erase(_S_mem_blocks.begin() + __diff);
|
|
|
|
// Reset the _S_last_request variable to reflect the
|
|
// erased block. We do this to protect future requests
|
|
// after the last block has been removed from a particular
|
|
// memory Chunk, which in turn has been returned to the
|
|
// free list, and hence had been erased from the vector,
|
|
// so the size of the vector gets reduced by 1.
|
|
if ((_Difference_type)_S_last_request._M_where() >= __diff--)
|
|
_S_last_request._M_reset(__diff);
|
|
|
|
// If the Index into the vector of the region of memory
|
|
// that might hold the next address that will be passed to
|
|
// deallocated may have been invalidated due to the above
|
|
// erase procedure being called on the vector, hence we
|
|
// try to restore this invariant too.
|
|
if (_S_last_dealloc_index >= _S_mem_blocks.size())
|
|
{
|
|
_S_last_dealloc_index =(__diff != -1 ? __diff : 0);
|
|
_GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index >= 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
public:
|
|
bitmap_allocator() _GLIBCXX_USE_NOEXCEPT
|
|
{ }
|
|
|
|
bitmap_allocator(const bitmap_allocator&) _GLIBCXX_USE_NOEXCEPT
|
|
{ }
|
|
|
|
template<typename _Tp1>
|
|
bitmap_allocator(const bitmap_allocator<_Tp1>&) _GLIBCXX_USE_NOEXCEPT
|
|
{ }
|
|
|
|
~bitmap_allocator() _GLIBCXX_USE_NOEXCEPT
|
|
{ }
|
|
|
|
_GLIBCXX_NODISCARD pointer
|
|
allocate(size_type __n)
|
|
{
|
|
if (__n > this->max_size())
|
|
std::__throw_bad_alloc();
|
|
|
|
#if __cpp_aligned_new
|
|
if (alignof(value_type) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
|
|
{
|
|
const size_type __b = __n * sizeof(value_type);
|
|
std::align_val_t __al = std::align_val_t(alignof(value_type));
|
|
return static_cast<pointer>(::operator new(__b, __al));
|
|
}
|
|
#endif
|
|
|
|
if (__builtin_expect(__n == 1, true))
|
|
return this->_M_allocate_single_object();
|
|
else
|
|
{
|
|
const size_type __b = __n * sizeof(value_type);
|
|
return reinterpret_cast<pointer>(::operator new(__b));
|
|
}
|
|
}
|
|
|
|
_GLIBCXX_NODISCARD pointer
|
|
allocate(size_type __n, typename bitmap_allocator<void>::const_pointer)
|
|
{ return allocate(__n); }
|
|
|
|
void
|
|
deallocate(pointer __p, size_type __n) throw()
|
|
{
|
|
if (__builtin_expect(__p != 0, true))
|
|
{
|
|
#if __cpp_aligned_new
|
|
// Types with extended alignment are handled by operator delete.
|
|
if (alignof(value_type) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
|
|
{
|
|
::operator delete(__p, std::align_val_t(alignof(value_type)));
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
if (__builtin_expect(__n == 1, true))
|
|
this->_M_deallocate_single_object(__p);
|
|
else
|
|
::operator delete(__p);
|
|
}
|
|
}
|
|
|
|
pointer
|
|
address(reference __r) const _GLIBCXX_NOEXCEPT
|
|
{ return std::__addressof(__r); }
|
|
|
|
const_pointer
|
|
address(const_reference __r) const _GLIBCXX_NOEXCEPT
|
|
{ return std::__addressof(__r); }
|
|
|
|
size_type
|
|
max_size() const _GLIBCXX_USE_NOEXCEPT
|
|
{ return size_type(-1) / sizeof(value_type); }
|
|
|
|
#if __cplusplus >= 201103L
|
|
template<typename _Up, typename... _Args>
|
|
void
|
|
construct(_Up* __p, _Args&&... __args)
|
|
{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
|
|
|
|
template<typename _Up>
|
|
void
|
|
destroy(_Up* __p)
|
|
{ __p->~_Up(); }
|
|
#else
|
|
void
|
|
construct(pointer __p, const_reference __data)
|
|
{ ::new((void *)__p) value_type(__data); }
|
|
|
|
void
|
|
destroy(pointer __p)
|
|
{ __p->~value_type(); }
|
|
#endif
|
|
};
|
|
|
|
template<typename _Tp1, typename _Tp2>
|
|
bool
|
|
operator==(const bitmap_allocator<_Tp1>&,
|
|
const bitmap_allocator<_Tp2>&) throw()
|
|
{ return true; }
|
|
|
|
template<typename _Tp1, typename _Tp2>
|
|
bool
|
|
operator!=(const bitmap_allocator<_Tp1>&,
|
|
const bitmap_allocator<_Tp2>&) throw()
|
|
{ return false; }
|
|
|
|
// Static member definitions.
|
|
template<typename _Tp>
|
|
typename bitmap_allocator<_Tp>::_BPVector
|
|
bitmap_allocator<_Tp>::_S_mem_blocks;
|
|
|
|
template<typename _Tp>
|
|
size_t bitmap_allocator<_Tp>::_S_block_size =
|
|
2 * size_t(__detail::bits_per_block);
|
|
|
|
template<typename _Tp>
|
|
typename bitmap_allocator<_Tp>::_BPVector::size_type
|
|
bitmap_allocator<_Tp>::_S_last_dealloc_index = 0;
|
|
|
|
template<typename _Tp>
|
|
__detail::_Bitmap_counter
|
|
<typename bitmap_allocator<_Tp>::_Alloc_block*>
|
|
bitmap_allocator<_Tp>::_S_last_request(_S_mem_blocks);
|
|
|
|
#if defined __GTHREADS
|
|
template<typename _Tp>
|
|
typename bitmap_allocator<_Tp>::__mutex_type
|
|
bitmap_allocator<_Tp>::_S_mut;
|
|
#endif
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace __gnu_cxx
|
|
|
|
#endif
|