-// Bitmapped Allocator. -*- C++ -*-
+// Bitmap Allocator. -*- C++ -*-
-// Copyright (C) 2004 Free Software Foundation, Inc.
+// Copyright (C) 2004-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 2, or (at your option)
+// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING. If not, write to the Free
-// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-// USA.
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
-// As a special exception, you may use this file as part of a free software
-// library without restriction. Specifically, if other files instantiate
-// templates or use macros or inline functions from this file, or you compile
-// this file and link it with other files to produce an executable, this
-// file does not by itself cause the resulting executable to be covered by
-// the GNU General Public License. This exception does not however
-// invalidate any other reasons why the executable file might be covered by
-// the GNU General Public License.
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+/** @file ext/bitmap_allocator.h
+ * This file is a GNU extension to the Standard C++ Library.
+ */
-
-#if !defined _BITMAP_ALLOCATOR_H
+#ifndef _BITMAP_ALLOCATOR_H
#define _BITMAP_ALLOCATOR_H 1
-#include <cstddef>
-//For std::size_t, and ptrdiff_t.
-#include <utility>
-//For std::pair.
-#include <algorithm>
-//std::find_if, and std::lower_bound.
-#include <vector>
-//For the free list of exponentially growing memory blocks. At max,
-//size of the vector should be not more than the number of bits in an
-//integer or an unsigned integer.
-#include <functional>
-//For greater_equal, and less_equal.
-#include <new>
-//For operator new.
-#include <bits/gthr.h>
-//For __gthread_mutex_t, __gthread_mutex_lock and __gthread_mutex_unlock.
-#include <ext/new_allocator.h>
-//For __gnu_cxx::new_allocator for std::vector.
-
-#include <cassert>
-#define NDEBUG
-
-//#define CHECK_FOR_ERRORS
-//#define __CPU_HAS_BACKWARD_BRANCH_PREDICTION
-
-namespace __gnu_cxx
-{
- namespace {
-#if defined __GTHREADS
- bool const __threads_enabled = __gthread_active_p();
-#endif
+#include <bits/requires_hosted.h> // GNU extensions are currently omitted
- }
+#include <utility> // For std::pair.
+#include <bits/functexcept.h> // For __throw_bad_alloc().
+#include <bits/stl_function.h> // For greater_equal, and less_equal.
+#include <new> // For operator new.
+#include <debug/debug.h> // _GLIBCXX_DEBUG_ASSERT
+#include <ext/concurrence.h>
+#include <bits/move.h>
-#if defined __GTHREADS
- class _Mutex {
- __gthread_mutex_t _M_mut;
- //Prevent Copying and assignment.
- _Mutex (_Mutex const&);
- _Mutex& operator= (_Mutex const&);
- public:
- _Mutex ()
- {
- if (__threads_enabled)
- {
-#if !defined __GTHREAD_MUTEX_INIT
- __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mut);
-#else
- __gthread_mutex_t __mtemp = __GTHREAD_MUTEX_INIT;
- _M_mut = __mtemp;
-#endif
- }
- }
- ~_Mutex ()
- {
- //Gthreads does not define a Mutex Destruction Function.
- }
- __gthread_mutex_t *_M_get() { return &_M_mut; }
- };
+/** @brief The constant in the expression below is the alignment
+ * required in bytes.
+ */
+#define _BALLOC_ALIGN_BYTES 8
- class _Lock {
- _Mutex* _M_pmt;
- bool _M_locked;
- //Prevent Copying and assignment.
- _Lock (_Lock const&);
- _Lock& operator= (_Lock const&);
- public:
- _Lock(_Mutex* __mptr)
- : _M_pmt(__mptr), _M_locked(false)
- { this->_M_lock(); }
- void _M_lock()
- {
- if (__threads_enabled)
- {
- _M_locked = true;
- __gthread_mutex_lock(_M_pmt->_M_get());
- }
- }
- void _M_unlock()
- {
- if (__threads_enabled)
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ namespace __detail
+ {
+ /** @class __mini_vector bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief __mini_vector<> is a stripped down version of the
+ * full-fledged std::vector<>.
+ *
+ * It is to be used only for built-in types or PODs. Notable
+ * differences are:
+ *
+ * 1. Not all accessor functions are present.
+ * 2. Used ONLY for PODs.
+ * 3. No Allocator template argument. Uses ::operator new() to get
+ * memory, and ::operator delete() to free it.
+ * Caveat: The dtor does NOT free the memory allocated, so this a
+ * memory-leaking vector!
+ */
+ template<typename _Tp>
+ class __mini_vector
+ {
+ __mini_vector(const __mini_vector&);
+ __mini_vector& operator=(const __mini_vector&);
+
+ public:
+ typedef _Tp value_type;
+ typedef _Tp* pointer;
+ typedef _Tp& reference;
+ typedef const _Tp& const_reference;
+ typedef std::size_t size_type;
+ typedef std::ptrdiff_t difference_type;
+ typedef pointer iterator;
+
+ private:
+ pointer _M_start;
+ pointer _M_finish;
+ pointer _M_end_of_storage;
+
+ size_type
+ _M_space_left() const throw()
+ { return _M_end_of_storage - _M_finish; }
+
+ _GLIBCXX_NODISCARD pointer
+ allocate(size_type __n)
+ { return static_cast<pointer>(::operator new(__n * sizeof(_Tp))); }
+
+ void
+ deallocate(pointer __p, size_type)
+ { ::operator delete(__p); }
+
+ public:
+ // Members used: size(), push_back(), pop_back(),
+ // insert(iterator, const_reference), erase(iterator),
+ // begin(), end(), back(), operator[].
+
+ __mini_vector()
+ : _M_start(0), _M_finish(0), _M_end_of_storage(0) { }
+
+ size_type
+ size() const throw()
+ { return _M_finish - _M_start; }
+
+ iterator
+ begin() const throw()
+ { return this->_M_start; }
+
+ iterator
+ end() const throw()
+ { return this->_M_finish; }
+
+ reference
+ back() const throw()
+ { return *(this->end() - 1); }
+
+ reference
+ operator[](const size_type __pos) const throw()
+ { return this->_M_start[__pos]; }
+
+ void
+ insert(iterator __pos, const_reference __x);
+
+ void
+ push_back(const_reference __x)
{
- if (__builtin_expect(_M_locked, true))
+ if (this->_M_space_left())
{
- __gthread_mutex_unlock(_M_pmt->_M_get());
- _M_locked = false;
+ *this->end() = __x;
+ ++this->_M_finish;
}
+ else
+ this->insert(this->end(), __x);
}
- }
- ~_Lock() { this->_M_unlock(); }
- };
-#endif
+ void
+ pop_back() throw()
+ { --this->_M_finish; }
+ void
+ erase(iterator __pos) throw();
- namespace __aux_balloc {
- static const unsigned int _Bits_Per_Byte = 8;
- static const unsigned int _Bits_Per_Block = sizeof(unsigned int) * _Bits_Per_Byte;
+ void
+ clear() throw()
+ { this->_M_finish = this->_M_start; }
+ };
- template <typename _Addr_Pair_t>
- inline size_t __balloc_num_blocks (_Addr_Pair_t __ap)
- {
- return (__ap.second - __ap.first) + 1;
- }
+ // Out of line function definitions.
+ template<typename _Tp>
+ void __mini_vector<_Tp>::
+ insert(iterator __pos, const_reference __x)
+ {
+ if (this->_M_space_left())
+ {
+ size_type __to_move = this->_M_finish - __pos;
+ iterator __dest = this->end();
+ iterator __src = this->end() - 1;
- template <typename _Addr_Pair_t>
- inline size_t __balloc_num_bit_maps (_Addr_Pair_t __ap)
- {
- return __balloc_num_blocks(__ap) / _Bits_Per_Block;
- }
+ ++this->_M_finish;
+ while (__to_move)
+ {
+ *__dest = *__src;
+ --__dest; --__src; --__to_move;
+ }
+ *__pos = __x;
+ }
+ else
+ {
+ size_type __new_size = this->size() ? this->size() * 2 : 1;
+ iterator __new_start = this->allocate(__new_size);
+ iterator __first = this->begin();
+ iterator __start = __new_start;
+ while (__first != __pos)
+ {
+ *__start = *__first;
+ ++__start; ++__first;
+ }
+ *__start = __x;
+ ++__start;
+ while (__first != this->end())
+ {
+ *__start = *__first;
+ ++__start; ++__first;
+ }
+ if (this->_M_start)
+ this->deallocate(this->_M_start, this->size());
- //T should be a pointer type.
- template <typename _Tp>
- class _Inclusive_between : public std::unary_function<typename std::pair<_Tp, _Tp>, bool> {
- typedef _Tp pointer;
- pointer _M_ptr_value;
- typedef typename std::pair<_Tp, _Tp> _Block_pair;
+ this->_M_start = __new_start;
+ this->_M_finish = __start;
+ this->_M_end_of_storage = this->_M_start + __new_size;
+ }
+ }
- public:
- _Inclusive_between (pointer __ptr) : _M_ptr_value(__ptr) { }
- bool operator () (_Block_pair __bp) const throw ()
+ template<typename _Tp>
+ void __mini_vector<_Tp>::
+ erase(iterator __pos) throw()
{
- if (std::less_equal<pointer> ()(_M_ptr_value, __bp.second) &&
- std::greater_equal<pointer> ()(_M_ptr_value, __bp.first))
- return true;
- else
- return false;
+ while (__pos + 1 != this->end())
+ {
+ *__pos = __pos[1];
+ ++__pos;
+ }
+ --this->_M_finish;
}
- };
-
- //Used to pass a Functor to functions by reference.
- template <typename _Functor>
- class _Functor_Ref :
- public std::unary_function<typename _Functor::argument_type, typename _Functor::result_type> {
- _Functor& _M_fref;
-
- public:
- typedef typename _Functor::argument_type argument_type;
- typedef typename _Functor::result_type result_type;
- _Functor_Ref (_Functor& __fref) : _M_fref(__fref) { }
- result_type operator() (argument_type __arg) { return _M_fref (__arg); }
- };
-
-
- //T should be a pointer type, and A is the Allocator for the vector.
- template <typename _Tp, typename _Alloc>
- class _Ffit_finder
- : public std::unary_function<typename std::pair<_Tp, _Tp>, bool> {
- typedef typename std::vector<std::pair<_Tp, _Tp>, _Alloc> _BPVector;
- typedef typename _BPVector::difference_type _Counter_type;
- typedef typename std::pair<_Tp, _Tp> _Block_pair;
- unsigned int *_M_pbitmap;
- unsigned int _M_data_offset;
-
- public:
- _Ffit_finder ()
- : _M_pbitmap (0), _M_data_offset (0)
- { }
+ template<typename _Tp>
+ struct __mv_iter_traits
+ {
+ typedef typename _Tp::value_type value_type;
+ typedef typename _Tp::difference_type difference_type;
+ };
- bool operator() (_Block_pair __bp) throw()
+ template<typename _Tp>
+ struct __mv_iter_traits<_Tp*>
{
- //Set the _rover to the last unsigned integer, which is the
- //bitmap to the first free block. Thus, the bitmaps are in exact
- //reverse order of the actual memory layout. So, we count down
- //the bimaps, which is the same as moving up the memory.
-
- //If the used count stored at the start of the Bit Map headers
- //is equal to the number of Objects that the current Block can
- //store, then there is definitely no space for another single
- //object, so just return false.
- _Counter_type __diff = __gnu_cxx::__aux_balloc::__balloc_num_bit_maps (__bp);
-
- assert (*(reinterpret_cast<unsigned int*>(__bp.first) - (__diff + 1)) <=
- __gnu_cxx::__aux_balloc::__balloc_num_blocks (__bp));
-
- if (*(reinterpret_cast<unsigned int*>(__bp.first) - (__diff + 1)) ==
- __gnu_cxx::__aux_balloc::__balloc_num_blocks (__bp))
- return false;
+ typedef _Tp value_type;
+ typedef std::ptrdiff_t difference_type;
+ };
+
+ enum
+ {
+ bits_per_byte = 8,
+ bits_per_block = sizeof(std::size_t) * std::size_t(bits_per_byte)
+ };
+
+ template<typename _ForwardIterator, typename _Tp, typename _Compare>
+ _ForwardIterator
+ __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
+ const _Tp& __val, _Compare __comp)
+ {
+ typedef typename __mv_iter_traits<_ForwardIterator>::difference_type
+ _DistanceType;
+
+ _DistanceType __len = __last - __first;
+ _DistanceType __half;
+ _ForwardIterator __middle;
- unsigned int *__rover = reinterpret_cast<unsigned int*>(__bp.first) - 1;
- for (_Counter_type __i = 0; __i < __diff; ++__i)
+ while (__len > 0)
{
- _M_data_offset = __i;
- if (*__rover)
+ __half = __len >> 1;
+ __middle = __first;
+ __middle += __half;
+ if (__comp(*__middle, __val))
{
- _M_pbitmap = __rover;
- return true;
+ __first = __middle;
+ ++__first;
+ __len = __len - __half - 1;
}
- --__rover;
+ else
+ __len = __half;
}
- return false;
+ return __first;
}
-
- unsigned int *_M_get () { return _M_pbitmap; }
- unsigned int _M_offset () { return _M_data_offset * _Bits_Per_Block; }
- };
+
+ /** @brief The number of Blocks pointed to by the address pair
+ * passed to the function.
+ */
+ template<typename _AddrPair>
+ inline std::size_t
+ __num_blocks(_AddrPair __ap)
+ { return (__ap.second - __ap.first) + 1; }
+
+ /** @brief The number of Bit-maps pointed to by the address pair
+ * passed to the function.
+ */
+ template<typename _AddrPair>
+ inline std::size_t
+ __num_bitmaps(_AddrPair __ap)
+ { return __num_blocks(__ap) / std::size_t(bits_per_block); }
+
+ // _Tp should be a pointer type.
+ template<typename _Tp>
+ class _Inclusive_between
+ {
+ typedef _Tp pointer;
+ pointer _M_ptr_value;
+ typedef typename std::pair<_Tp, _Tp> _Block_pair;
+
+ public:
+ _Inclusive_between(pointer __ptr) : _M_ptr_value(__ptr)
+ { }
+
+ bool
+ operator()(_Block_pair __bp) const throw()
+ {
+ if (std::less_equal<pointer>()(_M_ptr_value, __bp.second)
+ && std::greater_equal<pointer>()(_M_ptr_value, __bp.first))
+ return true;
+ else
+ return false;
+ }
+ };
- //T should be a pointer type.
- template <typename _Tp, typename _Alloc>
- class _Bit_map_counter {
-
- typedef typename std::vector<std::pair<_Tp, _Tp>, _Alloc> _BPVector;
- typedef typename _BPVector::size_type _Index_type;
- typedef _Tp pointer;
-
- _BPVector& _M_vbp;
- unsigned int *_M_curr_bmap;
- unsigned int *_M_last_bmap_in_block;
- _Index_type _M_curr_index;
-
- public:
- //Use the 2nd parameter with care. Make sure that such an entry
- //exists in the vector before passing that particular index to
- //this ctor.
- _Bit_map_counter (_BPVector& Rvbp, int __index = -1)
- : _M_vbp(Rvbp)
+ // Used to pass a Functor to functions by reference.
+ template<typename _Functor>
+ class _Functor_Ref
{
- this->_M_reset(__index);
- }
-
- void _M_reset (int __index = -1) throw()
+ _Functor& _M_fref;
+
+ public:
+ typedef typename _Functor::argument_type argument_type;
+ typedef typename _Functor::result_type result_type;
+
+ _Functor_Ref(_Functor& __fref) : _M_fref(__fref)
+ { }
+
+ result_type
+ operator()(argument_type __arg)
+ { return _M_fref(__arg); }
+ };
+
+ /** @class _Ffit_finder bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief The class which acts as a predicate for applying the
+ * first-fit memory allocation policy for the bitmap allocator.
+ */
+ // _Tp should be a pointer type, and _Alloc is the Allocator for
+ // the vector.
+ template<typename _Tp>
+ class _Ffit_finder
{
- if (__index == -1)
- {
- _M_curr_bmap = 0;
- _M_curr_index = (_Index_type)-1;
- return;
- }
+ typedef std::pair<_Tp, _Tp> _Block_pair;
+ typedef __detail::__mini_vector<_Block_pair> _BPVector;
+ typedef typename _BPVector::difference_type _Counter_type;
- _M_curr_index = __index;
- _M_curr_bmap = reinterpret_cast<unsigned int*>(_M_vbp[_M_curr_index].first) - 1;
+ std::size_t* _M_pbitmap;
+ _Counter_type _M_data_offset;
- assert (__index <= (int)_M_vbp.size() - 1);
-
- _M_last_bmap_in_block = _M_curr_bmap -
- ((_M_vbp[_M_curr_index].second - _M_vbp[_M_curr_index].first + 1) / _Bits_Per_Block - 1);
- }
+ public:
+ typedef bool result_type;
+ typedef _Block_pair argument_type;
+
+ _Ffit_finder() : _M_pbitmap(0), _M_data_offset(0)
+ { }
+
+ bool
+ operator()(_Block_pair __bp) throw()
+ {
+ using std::size_t;
+ // Set the _rover to the last physical location bitmap,
+ // which is the bitmap which belongs to the first free
+ // block. Thus, the bitmaps are in exact reverse order of
+ // the actual memory layout. So, we count down the bitmaps,
+ // which is the same as moving up the memory.
+
+ // If the used count stored at the start of the Bit Map headers
+ // is equal to the number of Objects that the current Block can
+ // store, then there is definitely no space for another single
+ // object, so just return false.
+ _Counter_type __diff = __detail::__num_bitmaps(__bp);
+
+ if (*(reinterpret_cast<size_t*>
+ (__bp.first) - (__diff + 1)) == __detail::__num_blocks(__bp))
+ return false;
+
+ size_t* __rover = reinterpret_cast<size_t*>(__bp.first) - 1;
+
+ for (_Counter_type __i = 0; __i < __diff; ++__i)
+ {
+ _M_data_offset = __i;
+ if (*__rover)
+ {
+ _M_pbitmap = __rover;
+ return true;
+ }
+ --__rover;
+ }
+ return false;
+ }
- //Dangerous Function! Use with extreme care. Pass to this
- //function ONLY those values that are known to be correct,
- //otherwise this will mess up big time.
- void _M_set_internal_bit_map (unsigned int *__new_internal_marker) throw()
+ std::size_t*
+ _M_get() const throw()
+ { return _M_pbitmap; }
+
+ _Counter_type
+ _M_offset() const throw()
+ { return _M_data_offset * std::size_t(bits_per_block); }
+ };
+
+ /** @class _Bitmap_counter bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief The bitmap counter which acts as the bitmap
+ * manipulator, and manages the bit-manipulation functions and
+ * the searching and identification functions on the bit-map.
+ */
+ // _Tp should be a pointer type.
+ template<typename _Tp>
+ class _Bitmap_counter
{
- _M_curr_bmap = __new_internal_marker;
- }
+ typedef typename
+ __detail::__mini_vector<typename std::pair<_Tp, _Tp> > _BPVector;
+ typedef typename _BPVector::size_type _Index_type;
+ typedef _Tp pointer;
+
+ _BPVector& _M_vbp;
+ std::size_t* _M_curr_bmap;
+ std::size_t* _M_last_bmap_in_block;
+ _Index_type _M_curr_index;
- bool _M_finished () const throw()
- {
- return (_M_curr_bmap == 0);
- }
+ public:
+ // Use the 2nd parameter with care. Make sure that such an
+ // entry exists in the vector before passing that particular
+ // index to this ctor.
+ _Bitmap_counter(_BPVector& Rvbp, long __index = -1) : _M_vbp(Rvbp)
+ { this->_M_reset(__index); }
- _Bit_map_counter& operator++ () throw()
- {
- if (_M_curr_bmap == _M_last_bmap_in_block)
- {
- if (++_M_curr_index == _M_vbp.size())
- {
+ void
+ _M_reset(long __index = -1) throw()
+ {
+ if (__index == -1)
+ {
+ _M_curr_bmap = 0;
+ _M_curr_index = static_cast<_Index_type>(-1);
+ return;
+ }
+
+ _M_curr_index = __index;
+ _M_curr_bmap = reinterpret_cast<std::size_t*>
+ (_M_vbp[_M_curr_index].first) - 1;
+
+ _GLIBCXX_DEBUG_ASSERT(__index <= (long)_M_vbp.size() - 1);
+
+ _M_last_bmap_in_block = _M_curr_bmap
+ - ((_M_vbp[_M_curr_index].second
+ - _M_vbp[_M_curr_index].first + 1)
+ / std::size_t(bits_per_block) - 1);
+ }
+
+ // Dangerous Function! Use with extreme care. Pass to this
+ // function ONLY those values that are known to be correct,
+ // otherwise this will mess up big time.
+ void
+ _M_set_internal_bitmap(std::size_t* __new_internal_marker) throw()
+ { _M_curr_bmap = __new_internal_marker; }
+
+ bool
+ _M_finished() const throw()
+ { return(_M_curr_bmap == 0); }
+
+ _Bitmap_counter&
+ operator++() throw()
+ {
+ if (_M_curr_bmap == _M_last_bmap_in_block)
+ {
+ if (++_M_curr_index == _M_vbp.size())
_M_curr_bmap = 0;
- }
- else
- {
- this->_M_reset (_M_curr_index);
- }
- }
- else
- {
+ else
+ this->_M_reset(_M_curr_index);
+ }
+ else
--_M_curr_bmap;
- }
- return *this;
- }
-
- unsigned int *_M_get ()
- {
- return _M_curr_bmap;
- }
+ return *this;
+ }
- pointer _M_base () { return _M_vbp[_M_curr_index].first; }
- unsigned int _M_offset ()
- {
- return _Bits_Per_Block * ((reinterpret_cast<unsigned int*>(this->_M_base()) - _M_curr_bmap) - 1);
- }
+ std::size_t*
+ _M_get() const throw()
+ { return _M_curr_bmap; }
- unsigned int _M_where () { return _M_curr_index; }
- };
- }
+ pointer
+ _M_base() const throw()
+ { return _M_vbp[_M_curr_index].first; }
- //Generic Version of the bsf instruction.
- typedef unsigned int _Bit_map_type;
- static inline unsigned int _Bit_scan_forward (register _Bit_map_type __num)
- {
- return static_cast<unsigned int>(__builtin_ctz(__num));
- }
-
- struct _OOM_handler {
- static std::new_handler _S_old_handler;
- static bool _S_handled_oom;
- typedef void (*_FL_clear_proc)(void);
- static _FL_clear_proc _S_oom_fcp;
+ _Index_type
+ _M_offset() const throw()
+ {
+ return std::size_t(bits_per_block)
+ * ((reinterpret_cast<std::size_t*>(this->_M_base())
+ - _M_curr_bmap) - 1);
+ }
- _OOM_handler (_FL_clear_proc __fcp)
+ _Index_type
+ _M_where() const throw()
+ { return _M_curr_index; }
+ };
+
+ /** @brief Mark a memory address as allocated by re-setting the
+ * corresponding bit in the bit-map.
+ */
+ inline void
+ __bit_allocate(std::size_t* __pbmap, std::size_t __pos) throw()
{
- _S_oom_fcp = __fcp;
- _S_old_handler = std::set_new_handler (_S_handle_oom_proc);
- _S_handled_oom = false;
+ std::size_t __mask = 1 << __pos;
+ __mask = ~__mask;
+ *__pbmap &= __mask;
}
-
- static void _S_handle_oom_proc()
+
+ /** @brief Mark a memory address as free by setting the
+ * corresponding bit in the bit-map.
+ */
+ inline void
+ __bit_free(std::size_t* __pbmap, std::size_t __pos) throw()
{
- _S_oom_fcp();
- std::set_new_handler (_S_old_handler);
- _S_handled_oom = true;
+ std::size_t __mask = 1 << __pos;
+ *__pbmap |= __mask;
}
+ } // namespace __detail
+
+ /** @brief Generic Version of the bsf instruction.
+ */
+ inline std::size_t
+ _Bit_scan_forward(std::size_t __num)
+ { return static_cast<std::size_t>(__builtin_ctzl(__num)); }
+
+ /** @class free_list bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief The free list class for managing chunks of memory to be
+ * given to and returned by the bitmap_allocator.
+ */
+ class free_list
+ {
+ public:
+ typedef std::size_t* value_type;
+ typedef __detail::__mini_vector<value_type> vector_type;
+ typedef vector_type::iterator iterator;
+ typedef __mutex __mutex_type;
- ~_OOM_handler ()
+ private:
+ struct _LT_pointer_compare
{
- if (!_S_handled_oom)
- std::set_new_handler (_S_old_handler);
- }
- };
-
- std::new_handler _OOM_handler::_S_old_handler;
- bool _OOM_handler::_S_handled_oom = false;
- _OOM_handler::_FL_clear_proc _OOM_handler::_S_oom_fcp = 0;
-
-
- class _BA_free_list_store {
- struct _LT_pointer_compare {
- template <typename _Tp>
- bool operator() (_Tp* __pt, _Tp const& __crt) const throw()
- {
- return *__pt < __crt;
- }
+ bool
+ operator()(const std::size_t* __pui,
+ const std::size_t __cui) const throw()
+ { return *__pui < __cui; }
};
#if defined __GTHREADS
- static _Mutex _S_bfl_mutex;
+ __mutex_type&
+ _M_get_mutex()
+ {
+ static __mutex_type _S_mutex;
+ return _S_mutex;
+ }
#endif
- static std::vector<unsigned int*> _S_free_list;
- typedef std::vector<unsigned int*>::iterator _FLIter;
- static void _S_validate_free_list(unsigned int *__addr) throw()
+ vector_type&
+ _M_get_free_list()
{
- const unsigned int __max_size = 64;
- if (_S_free_list.size() >= __max_size)
+ static vector_type _S_free_list;
+ return _S_free_list;
+ }
+
+ /** @brief Performs validation of memory based on their size.
+ *
+ * @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(std::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 >= *_S_free_list.back())
+ // 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((void*)__addr);
+ // 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 it's correct position.
- operator delete((void*)_S_free_list.back());
- _S_free_list.pop_back();
+ // 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.
- _FLIter __temp = std::lower_bound(_S_free_list.begin(), _S_free_list.end(),
- *__addr, _LT_pointer_compare ());
- //We may insert the new free list before _temp;
- _S_free_list.insert(__temp, __addr);
+ // 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);
}
- static bool _S_should_i_give(unsigned int __block_size, unsigned int __required_size) throw()
+ /** @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(std::size_t __block_size,
+ std::size_t __required_size) throw()
{
- const unsigned int __max_wastage_percentage = 36;
+ const std::size_t __max_wastage_percentage = 36;
if (__block_size >= __required_size &&
- (((__block_size - __required_size) * 100 / __block_size) < __max_wastage_percentage))
+ (((__block_size - __required_size) * 100 / __block_size)
+ < __max_wastage_percentage))
return true;
else
return false;
}
public:
- typedef _BA_free_list_store _BFL_type;
-
- static inline void _S_insert_free_list(unsigned int *__addr) throw()
+ /** @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(std::size_t* __addr) throw()
{
#if defined __GTHREADS
- _Lock __bfl_lock(&_S_bfl_mutex);
+ __scoped_lock __bfl_lock(_M_get_mutex());
#endif
- //Call _S_validate_free_list to decide what should be done with this
- //particular free list.
- _S_validate_free_list(--__addr);
+ // Call _M_validate to decide what should be done with
+ // this particular free list.
+ this->_M_validate(reinterpret_cast<std::size_t*>(__addr) - 1);
+ // See discussion as to why this is 1!
}
- static unsigned int *_S_get_free_list(unsigned int __sz) throw (std::bad_alloc)
+ /** @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.
+ */
+ std::size_t*
+ _M_get(std::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>
{
-#if defined __GTHREADS
- _Lock __bfl_lock(&_S_bfl_mutex);
-#endif
- _FLIter __temp = std::lower_bound(_S_free_list.begin(), _S_free_list.end(),
- __sz, _LT_pointer_compare());
- if (__temp == _S_free_list.end() || !_S_should_i_give (**__temp, __sz))
- {
- //We hold the lock because the OOM_Handler is a stateless
- //entity.
- _OOM_handler __set_handler(_BFL_type::_S_clear);
- unsigned int *__ret_val = reinterpret_cast<unsigned int*>
- (operator new (__sz + sizeof(unsigned int)));
- *__ret_val = __sz;
- return ++__ret_val;
- }
- else
+ public:
+ typedef void* pointer;
+ typedef const void* const_pointer;
+
+ // Reference-to-void members are impossible.
+ typedef void value_type;
+ template<typename _Tp1>
+ struct rebind
{
- unsigned int* __ret_val = *__temp;
- _S_free_list.erase (__temp);
- return ++__ret_val;
- }
- }
+ typedef bitmap_allocator<_Tp1> other;
+ };
+ };
- //This function just clears the internal Free List, and gives back
- //all the memory to the OS.
- static void _S_clear()
+ /**
+ * @brief Bitmap Allocator, primary template.
+ * @ingroup allocators
+ */
+ template<typename _Tp>
+ class bitmap_allocator : private free_list
{
-#if defined __GTHREADS
- _Lock __bfl_lock(&_S_bfl_mutex);
+ public:
+ typedef std::size_t size_type;
+ typedef std::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
- _FLIter __iter = _S_free_list.begin();
- while (__iter != _S_free_list.end())
+
+ private:
+ template<std::size_t _BSize, std::size_t _AlignSize>
+ struct aligned_size
{
- operator delete((void*)*__iter);
- ++__iter;
- }
- _S_free_list.clear();
- }
+ 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];
+ };
- };
-#if defined __GTHREADS
- _Mutex _BA_free_list_store::_S_bfl_mutex;
-#endif
- std::vector<unsigned int*> _BA_free_list_store::_S_free_list;
+ typedef typename std::pair<_Alloc_block*, _Alloc_block*> _Block_pair;
- 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; };
- };
+ typedef typename __detail::__mini_vector<_Block_pair> _BPVector;
+ typedef typename _BPVector::iterator _BPiter;
- template <typename _Tp> class bitmap_allocator : private _BA_free_list_store {
- 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;
- template <typename _Tp1> struct rebind { typedef bitmap_allocator<_Tp1> other; };
+ 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;
+ }
- private:
- static const unsigned int _Bits_Per_Byte = 8;
- static const unsigned int _Bits_Per_Block = sizeof(unsigned int) * _Bits_Per_Byte;
+#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());
- static inline void _S_bit_allocate(unsigned int *__pbmap, unsigned int __pos) throw()
- {
- unsigned int __mask = 1 << __pos;
- __mask = ~__mask;
- *__pbmap &= __mask;
- }
-
- static inline void _S_bit_free(unsigned int *__pbmap, unsigned int __pos) throw()
- {
- unsigned int __mask = 1 << __pos;
- *__pbmap |= __mask;
- }
+ _GLIBCXX_DEBUG_ASSERT(__bpi == _S_mem_blocks.end());
+ }
+#endif
- static inline void *_S_memory_get(size_t __sz) throw (std::bad_alloc)
- {
- return operator new(__sz);
- }
+ /** @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)
+ {
+ using std::size_t;
+#if defined _GLIBCXX_DEBUG
+ _S_check_for_free_blocks();
+#endif
- static inline void _S_memory_put(void *__vptr) throw ()
- {
- operator delete(__vptr);
- }
+ 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);
- typedef typename std::pair<pointer, pointer> _Block_pair;
- typedef typename __gnu_cxx::new_allocator<_Block_pair> _BPVec_allocator_type;
- typedef typename std::vector<_Block_pair, _BPVec_allocator_type> _BPVector;
+ for (size_t __i = 0; __i < __num_bitmaps; ++__i)
+ __temp[__i] = ~static_cast<size_t>(0); // 1 Indicates all Free.
+ _S_block_size *= 2;
+ }
-#if defined CHECK_FOR_ERRORS
- //Complexity: O(lg(N)). Where, N is the number of block of size
- //sizeof(value_type).
- static void _S_check_for_free_blocks() throw()
- {
- typedef typename __gnu_cxx::__aux_balloc::_Ffit_finder<pointer, _BPVec_allocator_type> _FFF;
- _FFF __fff;
- typedef typename _BPVector::iterator _BPiter;
- _BPiter __bpi = std::find_if(_S_mem_blocks.begin(), _S_mem_blocks.end(),
- __gnu_cxx::__aux_balloc::_Functor_Ref<_FFF>(__fff));
- assert(__bpi == _S_mem_blocks.end());
- }
+ static _BPVector _S_mem_blocks;
+ static std::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:
- //Complexity: O(1), but internally depends upon the complexity of
- //the function _BA_free_list_store::_S_get_free_list. The part
- //where the bitmap headers are written is of worst case complexity:
- //O(X),where X is the number of blocks of size sizeof(value_type)
- //within the newly acquired block. Having a tight bound.
- static void _S_refill_pool() throw (std::bad_alloc)
- {
-#if defined CHECK_FOR_ERRORS
- _S_check_for_free_blocks();
+ /** @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)
+ {
+ using std::size_t;
+#if defined __GTHREADS
+ __scoped_lock __bit_lock(_S_mut);
#endif
- const unsigned int __num_bit_maps = _S_block_size / _Bits_Per_Block;
- const unsigned int __size_to_allocate = sizeof(unsigned int) +
- _S_block_size * sizeof(value_type) + __num_bit_maps*sizeof(unsigned int);
+ // 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++();
- unsigned int *__temp =
- reinterpret_cast<unsigned int*>(_BA_free_list_store::_S_get_free_list(__size_to_allocate));
- *__temp = 0;
- ++__temp;
+ 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));
- //The Header information goes at the Beginning of the Block.
- _Block_pair __bp = std::make_pair(reinterpret_cast<pointer>(__temp + __num_bit_maps),
- reinterpret_cast<pointer>(__temp + __num_bit_maps)
- + _S_block_size - 1);
+ 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();
- //Fill the Vector with this information.
- _S_mem_blocks.push_back(__bp);
+ // _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);
- unsigned int __bit_mask = 0; //0 Indicates all Allocated.
- __bit_mask = ~__bit_mask; //1 Indicates all Free.
+ // Now, mark that bit as allocated.
+ }
+ }
- for (unsigned int __i = 0; __i < __num_bit_maps; ++__i)
- __temp[__i] = __bit_mask;
+ // _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);
- //On some implementations, operator new might throw bad_alloc, or
- //malloc might fail if the size passed is too large, therefore, we
- //limit the size passed to malloc or operator new.
- _S_block_size *= 2;
- }
+ pointer __ret = reinterpret_cast<pointer>
+ (_S_last_request._M_base() + _S_last_request._M_offset() + __nz_bit);
- static _BPVector _S_mem_blocks;
- static unsigned int _S_block_size;
- static __gnu_cxx::__aux_balloc::_Bit_map_counter<pointer, _BPVec_allocator_type> _S_last_request;
- static typename _BPVector::size_type _S_last_dealloc_index;
-#if defined __GTHREADS
- static _Mutex _S_mut;
-#endif
+ 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);
- //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 the average. you
- //can consider this function to be having a complexity refrred to
- //commonly as: Amortized Constant time.
- static pointer _S_allocate_single_object()
- {
+ ++(*__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()
+ {
+ using std::size_t;
#if defined __GTHREADS
- _Lock __bit_lock(&_S_mut);
+ __scoped_lock __bit_lock(_S_mut);
#endif
+ _Alloc_block* __real_p = reinterpret_cast<_Alloc_block*>(__p);
- //The algorithm is something like this: The last_requst 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 dereferenceable if _S_last_request->_M_finished() returns
- //true. This would inevitibly 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 __gnu_cxx::__aux_balloc::_Ffit_finder<pointer, _BPVec_allocator_type> _FFF;
- _FFF __fff;
- typedef typename _BPVector::iterator _BPiter;
- _BPiter __bpi = std::find_if(_S_mem_blocks.begin(), _S_mem_blocks.end(),
- __gnu_cxx::__aux_balloc::_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.
- unsigned int __nz_bit = _Bit_scan_forward(*__fff._M_get());
- _S_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_val = __bpi->first + __fff._M_offset() + __nz_bit;
- unsigned int *__puse_count = reinterpret_cast<unsigned int*>(__bpi->first) -
- (__gnu_cxx::__aux_balloc::__balloc_num_bit_maps(*__bpi) + 1);
- ++(*__puse_count);
- return __ret_val;
- }
- else
- {
- //Search was unsuccessful. We Add more memory to the pool
- //by calling _S_refill_pool().
- _S_refill_pool();
+ typedef typename _BPVector::iterator _Iterator;
+ typedef typename _BPVector::difference_type _Difference_type;
- //_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);
+ _Difference_type __diff;
+ long __displacement;
- //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.
- unsigned int __nz_bit = _Bit_scan_forward(*_S_last_request._M_get());
- _S_bit_allocate(_S_last_request._M_get(), __nz_bit);
-
- pointer __ret_val = _S_last_request._M_base() + _S_last_request._M_offset() + __nz_bit;
-
- unsigned int *__puse_count = reinterpret_cast<unsigned int*>
- (_S_mem_blocks[_S_last_request._M_where()].first) -
- (__gnu_cxx::__aux_balloc::__balloc_num_bit_maps(_S_mem_blocks[_S_last_request._M_where()]) + 1);
- ++(*__puse_count);
- return __ret_val;
- }
+ _GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index >= 0);
- //Complexity: O(lg(N)), but the worst case is hit quite often! I
- //need to do something about this. I'll be able to work on it, only
- //when I have some solid figures from a few real apps.
- static void _S_deallocate_single_object(pointer __p) throw()
- {
-#if defined __GTHREADS
- _Lock __bit_lock(&_S_mut);
-#endif
+ __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);
- typedef typename _BPVector::iterator _Iterator;
- typedef typename _BPVector::difference_type _Difference_type;
+ // Initial Assumption was correct!
+ __diff = _S_last_dealloc_index;
+ __displacement = __real_p - _S_mem_blocks[__diff].first;
+ }
+ else
+ {
+ _Iterator _iter = _S_find(__ibt);
- _Difference_type __diff;
- int __displacement;
+ _GLIBCXX_DEBUG_ASSERT(_iter != _S_mem_blocks.end());
- assert(_S_last_dealloc_index >= 0);
+ __diff = _iter - _S_mem_blocks.begin();
+ __displacement = __real_p - _S_mem_blocks[__diff].first;
+ _S_last_dealloc_index = __diff;
+ }
- if (__gnu_cxx::__aux_balloc::_Inclusive_between<pointer>(__p)(_S_mem_blocks[_S_last_dealloc_index]))
- {
- assert(_S_last_dealloc_index <= _S_mem_blocks.size() - 1);
+ // 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);
- //Initial Assumption was correct!
- __diff = _S_last_dealloc_index;
- __displacement = __p - _S_mem_blocks[__diff].first;
- }
- else
- {
- _Iterator _iter = (std::find_if(_S_mem_blocks.begin(), _S_mem_blocks.end(),
- __gnu_cxx::__aux_balloc::_Inclusive_between<pointer>(__p)));
- assert(_iter != _S_mem_blocks.end());
+ --(*__puse_count);
- __diff = _iter - _S_mem_blocks.begin();
- __displacement = __p - _S_mem_blocks[__diff].first;
- _S_last_dealloc_index = __diff;
- }
+ 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);
+ }
+ }
+ }
- //Get the position of the iterator that has been found.
- const unsigned int __rotate = __displacement % _Bits_Per_Block;
- unsigned int *__bit_mapC = reinterpret_cast<unsigned int*>(_S_mem_blocks[__diff].first) - 1;
- __bit_mapC -= (__displacement / _Bits_Per_Block);
-
- _S_bit_free(__bit_mapC, __rotate);
- unsigned int *__puse_count = reinterpret_cast<unsigned int*>
- (_S_mem_blocks[__diff].first) -
- (__gnu_cxx::__aux_balloc::__balloc_num_bit_maps(_S_mem_blocks[__diff]) + 1);
+ public:
+ bitmap_allocator() _GLIBCXX_USE_NOEXCEPT
+ { }
- assert(*__puse_count != 0);
+ bitmap_allocator(const bitmap_allocator&) _GLIBCXX_USE_NOEXCEPT
+ { }
- --(*__puse_count);
+ template<typename _Tp1>
+ bitmap_allocator(const bitmap_allocator<_Tp1>&) _GLIBCXX_USE_NOEXCEPT
+ { }
- if (__builtin_expect(*__puse_count == 0, false))
- {
- _S_block_size /= 2;
-
- //We may safely remove this block.
- _Block_pair __bp = _S_mem_blocks[__diff];
- _S_insert_free_list(__puse_count);
- _S_mem_blocks.erase(_S_mem_blocks.begin() + __diff);
-
- //We 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);
- // assert(__diff >= 0);
- }
+ ~bitmap_allocator() _GLIBCXX_USE_NOEXCEPT
+ { }
- //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);
- assert(_S_last_dealloc_index >= 0);
- }
- }
- }
+ _GLIBCXX_NODISCARD pointer
+ allocate(size_type __n)
+ {
+ if (__n > this->max_size())
+ std::__throw_bad_alloc();
- public:
- bitmap_allocator() throw()
- { }
+#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
- bitmap_allocator(const bitmap_allocator&) { }
+ 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));
+ }
+ }
- template <typename _Tp1> bitmap_allocator(const bitmap_allocator<_Tp1>&) throw()
- { }
+ _GLIBCXX_NODISCARD pointer
+ allocate(size_type __n, typename bitmap_allocator<void>::const_pointer)
+ { return allocate(__n); }
- ~bitmap_allocator() throw()
- { }
+ 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
- //Complexity: O(1), but internally the complexity depends upon the
- //complexity of the function(s) _S_allocate_single_object and
- //_S_memory_get.
- pointer allocate(size_type __n)
- {
- if (__builtin_expect(__n == 1, true))
- return _S_allocate_single_object();
- else
- return reinterpret_cast<pointer>(_S_memory_get(__n * sizeof(value_type)));
- }
+ if (__builtin_expect(__n == 1, true))
+ this->_M_deallocate_single_object(__p);
+ else
+ ::operator delete(__p);
+ }
+ }
- //Complexity: Worst case complexity is O(N) where N is the number of
- //blocks of size sizeof(value_type) within the free lists that the
- //allocator holds. However, this worst case is hit only when the
- //user supplies a bogus argument to hint. If the hint argument is
- //sensible, then the complexity drops to O(lg(N)), and in extreme
- //cases, even drops to as low as O(1). So, if the user supplied
- //argument is good, then this function performs very well.
- pointer allocate(size_type __n, typename bitmap_allocator<void>::const_pointer)
- {
- return allocate(__n);
- }
+ pointer
+ address(reference __r) const _GLIBCXX_NOEXCEPT
+ { return std::__addressof(__r); }
- void deallocate(pointer __p, size_type __n) throw()
- {
- if (__builtin_expect(__n == 1, true))
- _S_deallocate_single_object(__p);
- else
- _S_memory_put(__p);
- }
+ const_pointer
+ address(const_reference __r) const _GLIBCXX_NOEXCEPT
+ { return std::__addressof(__r); }
- pointer address(reference r) const { return &r; }
- const_pointer address(const_reference r) const { return &r; }
+ size_type
+ max_size() const _GLIBCXX_USE_NOEXCEPT
+ { return size_type(-1) / sizeof(value_type); }
- size_type max_size(void) const throw() { 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)...); }
- void construct (pointer p, const_reference __data)
- {
- ::new(p) value_type(__data);
- }
+ 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();
- }
+ 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; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+ template<typename _Tp1, typename _Tp2>
+ bool
+ operator!=(const bitmap_allocator<_Tp1>&,
+ const bitmap_allocator<_Tp2>&) throw()
+ { return false; }
+#endif
- template <typename _Tp>
- typename bitmap_allocator<_Tp>::_BPVector bitmap_allocator<_Tp>::_S_mem_blocks;
+ // Static member definitions.
+ template<typename _Tp>
+ typename bitmap_allocator<_Tp>::_BPVector
+ bitmap_allocator<_Tp>::_S_mem_blocks;
- template <typename _Tp>
- unsigned int bitmap_allocator<_Tp>::_S_block_size = bitmap_allocator<_Tp>::_Bits_Per_Block;
+ template<typename _Tp>
+ std::size_t bitmap_allocator<_Tp>::_S_block_size
+ = 2 * std::size_t(__detail::bits_per_block);
- template <typename _Tp>
- typename __gnu_cxx::bitmap_allocator<_Tp>::_BPVector::size_type
- bitmap_allocator<_Tp>::_S_last_dealloc_index = 0;
+ template<typename _Tp>
+ typename bitmap_allocator<_Tp>::_BPVector::size_type
+ bitmap_allocator<_Tp>::_S_last_dealloc_index = 0;
- template <typename _Tp>
- __gnu_cxx::__aux_balloc::_Bit_map_counter
- <typename bitmap_allocator<_Tp>::pointer, typename bitmap_allocator<_Tp>::_BPVec_allocator_type>
- bitmap_allocator<_Tp>::_S_last_request(_S_mem_blocks);
+ 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>
- __gnu_cxx::_Mutex
- bitmap_allocator<_Tp>::_S_mut;
+ template<typename _Tp>
+ typename bitmap_allocator<_Tp>::__mutex_type
+ bitmap_allocator<_Tp>::_S_mut;
#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;
- }
-}
-
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace __gnu_cxx
-#endif //_BITMAP_ALLOCATOR_H
+#endif
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