1 // Bitmap Allocator. -*- C++ -*-
3 // Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 2, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
30 /** @file ext/bitmap_allocator.h
31 * This file is a GNU extension to the Standard C++ Library.
34 #ifndef _BITMAP_ALLOCATOR_H
35 #define _BITMAP_ALLOCATOR_H 1
37 #include <cstddef> // For std::size_t, and ptrdiff_t.
38 #include <bits/functexcept.h> // For __throw_bad_alloc().
39 #include <utility> // For std::pair.
40 #include <functional> // For greater_equal, and less_equal.
41 #include <new> // For operator new.
42 #include <debug/debug.h> // _GLIBCXX_DEBUG_ASSERT
43 #include <ext/concurrence.h>
44 #include <bits/stl_move.h>
46 /** @brief The constant in the expression below is the alignment
49 #define _BALLOC_ALIGN_BYTES 8
51 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx
)
58 /** @class __mini_vector bitmap_allocator.h bitmap_allocator.h
60 * @brief __mini_vector<> is a stripped down version of the
61 * full-fledged std::vector<>.
63 * It is to be used only for built-in types or PODs. Notable
67 * 1. Not all accessor functions are present.
68 * 2. Used ONLY for PODs.
69 * 3. No Allocator template argument. Uses ::operator new() to get
70 * memory, and ::operator delete() to free it.
71 * Caveat: The dtor does NOT free the memory allocated, so this a
72 * memory-leaking vector!
74 template<typename _Tp
>
77 __mini_vector(const __mini_vector
&);
78 __mini_vector
& operator=(const __mini_vector
&);
81 typedef _Tp value_type
;
83 typedef _Tp
& reference
;
84 typedef const _Tp
& const_reference
;
85 typedef size_t size_type
;
86 typedef ptrdiff_t difference_type
;
87 typedef pointer iterator
;
92 pointer _M_end_of_storage
;
95 _M_space_left() const throw()
96 { return _M_end_of_storage
- _M_finish
; }
99 allocate(size_type __n
)
100 { return static_cast<pointer
>(::operator new(__n
* sizeof(_Tp
))); }
103 deallocate(pointer __p
, size_type
)
104 { ::operator delete(__p
); }
107 // Members used: size(), push_back(), pop_back(),
108 // insert(iterator, const_reference), erase(iterator),
109 // begin(), end(), back(), operator[].
111 __mini_vector() : _M_start(0), _M_finish(0),
120 this->deallocate(this->_M_start
, this->_M_end_of_storage
128 { return _M_finish
- _M_start
; }
131 begin() const throw()
132 { return this->_M_start
; }
136 { return this->_M_finish
; }
140 { return *(this->end() - 1); }
143 operator[](const size_type __pos
) const throw()
144 { return this->_M_start
[__pos
]; }
147 insert(iterator __pos
, const_reference __x
);
150 push_back(const_reference __x
)
152 if (this->_M_space_left())
158 this->insert(this->end(), __x
);
163 { --this->_M_finish
; }
166 erase(iterator __pos
) throw();
170 { this->_M_finish
= this->_M_start
; }
173 // Out of line function definitions.
174 template<typename _Tp
>
175 void __mini_vector
<_Tp
>::
176 insert(iterator __pos
, const_reference __x
)
178 if (this->_M_space_left())
180 size_type __to_move
= this->_M_finish
- __pos
;
181 iterator __dest
= this->end();
182 iterator __src
= this->end() - 1;
188 --__dest
; --__src
; --__to_move
;
194 size_type __new_size
= this->size() ? this->size() * 2 : 1;
195 iterator __new_start
= this->allocate(__new_size
);
196 iterator __first
= this->begin();
197 iterator __start
= __new_start
;
198 while (__first
!= __pos
)
201 ++__start
; ++__first
;
205 while (__first
!= this->end())
208 ++__start
; ++__first
;
211 this->deallocate(this->_M_start
, this->size());
213 this->_M_start
= __new_start
;
214 this->_M_finish
= __start
;
215 this->_M_end_of_storage
= this->_M_start
+ __new_size
;
219 template<typename _Tp
>
220 void __mini_vector
<_Tp
>::
221 erase(iterator __pos
) throw()
223 while (__pos
+ 1 != this->end())
232 template<typename _Tp
>
233 struct __mv_iter_traits
235 typedef typename
_Tp::value_type value_type
;
236 typedef typename
_Tp::difference_type difference_type
;
239 template<typename _Tp
>
240 struct __mv_iter_traits
<_Tp
*>
242 typedef _Tp value_type
;
243 typedef ptrdiff_t difference_type
;
249 bits_per_block
= sizeof(size_t) * size_t(bits_per_byte
)
252 template<typename _ForwardIterator
, typename _Tp
, typename _Compare
>
254 __lower_bound(_ForwardIterator __first
, _ForwardIterator __last
,
255 const _Tp
& __val
, _Compare __comp
)
257 typedef typename __mv_iter_traits
<_ForwardIterator
>::value_type
259 typedef typename __mv_iter_traits
<_ForwardIterator
>::difference_type
262 _DistanceType __len
= __last
- __first
;
263 _DistanceType __half
;
264 _ForwardIterator __middle
;
271 if (__comp(*__middle
, __val
))
275 __len
= __len
- __half
- 1;
283 template<typename _InputIterator
, typename _Predicate
>
284 inline _InputIterator
285 __find_if(_InputIterator __first
, _InputIterator __last
, _Predicate __p
)
287 while (__first
!= __last
&& !__p(*__first
))
292 /** @brief The number of Blocks pointed to by the address pair
293 * passed to the function.
295 template<typename _AddrPair
>
297 __num_blocks(_AddrPair __ap
)
298 { return (__ap
.second
- __ap
.first
) + 1; }
300 /** @brief The number of Bit-maps pointed to by the address pair
301 * passed to the function.
303 template<typename _AddrPair
>
305 __num_bitmaps(_AddrPair __ap
)
306 { return __num_blocks(__ap
) / size_t(bits_per_block
); }
308 // _Tp should be a pointer type.
309 template<typename _Tp
>
310 class _Inclusive_between
311 : public std::unary_function
<typename
std::pair
<_Tp
, _Tp
>, bool>
314 pointer _M_ptr_value
;
315 typedef typename
std::pair
<_Tp
, _Tp
> _Block_pair
;
318 _Inclusive_between(pointer __ptr
) : _M_ptr_value(__ptr
)
322 operator()(_Block_pair __bp
) const throw()
324 if (std::less_equal
<pointer
>()(_M_ptr_value
, __bp
.second
)
325 && std::greater_equal
<pointer
>()(_M_ptr_value
, __bp
.first
))
332 // Used to pass a Functor to functions by reference.
333 template<typename _Functor
>
335 : public std::unary_function
<typename
_Functor::argument_type
,
336 typename
_Functor::result_type
>
341 typedef typename
_Functor::argument_type argument_type
;
342 typedef typename
_Functor::result_type result_type
;
344 _Functor_Ref(_Functor
& __fref
) : _M_fref(__fref
)
348 operator()(argument_type __arg
)
349 { return _M_fref(__arg
); }
352 /** @class _Ffit_finder bitmap_allocator.h bitmap_allocator.h
354 * @brief The class which acts as a predicate for applying the
355 * first-fit memory allocation policy for the bitmap allocator.
357 // _Tp should be a pointer type, and _Alloc is the Allocator for
359 template<typename _Tp
>
361 : public std::unary_function
<typename
std::pair
<_Tp
, _Tp
>, bool>
363 typedef typename
std::pair
<_Tp
, _Tp
> _Block_pair
;
364 typedef typename
__detail::__mini_vector
<_Block_pair
> _BPVector
;
365 typedef typename
_BPVector::difference_type _Counter_type
;
368 _Counter_type _M_data_offset
;
371 _Ffit_finder() : _M_pbitmap(0), _M_data_offset(0)
375 operator()(_Block_pair __bp
) throw()
377 // Set the _rover to the last physical location bitmap,
378 // which is the bitmap which belongs to the first free
379 // block. Thus, the bitmaps are in exact reverse order of
380 // the actual memory layout. So, we count down the bitmaps,
381 // which is the same as moving up the memory.
383 // If the used count stored at the start of the Bit Map headers
384 // is equal to the number of Objects that the current Block can
385 // store, then there is definitely no space for another single
386 // object, so just return false.
387 _Counter_type __diff
=
388 __gnu_cxx::__detail::__num_bitmaps(__bp
);
390 if (*(reinterpret_cast<size_t*>
391 (__bp
.first
) - (__diff
+ 1))
392 == __gnu_cxx::__detail::__num_blocks(__bp
))
395 size_t* __rover
= reinterpret_cast<size_t*>(__bp
.first
) - 1;
397 for (_Counter_type __i
= 0; __i
< __diff
; ++__i
)
399 _M_data_offset
= __i
;
402 _M_pbitmap
= __rover
;
412 _M_get() const throw()
413 { return _M_pbitmap
; }
416 _M_offset() const throw()
417 { return _M_data_offset
* size_t(bits_per_block
); }
421 /** @class _Bitmap_counter bitmap_allocator.h bitmap_allocator.h
423 * @brief The bitmap counter which acts as the bitmap
424 * manipulator, and manages the bit-manipulation functions and
425 * the searching and identification functions on the bit-map.
427 // _Tp should be a pointer type.
428 template<typename _Tp
>
429 class _Bitmap_counter
431 typedef typename
__detail::__mini_vector
<typename
std::pair
<_Tp
, _Tp
> >
433 typedef typename
_BPVector::size_type _Index_type
;
437 size_t* _M_curr_bmap
;
438 size_t* _M_last_bmap_in_block
;
439 _Index_type _M_curr_index
;
442 // Use the 2nd parameter with care. Make sure that such an
443 // entry exists in the vector before passing that particular
444 // index to this ctor.
445 _Bitmap_counter(_BPVector
& Rvbp
, long __index
= -1) : _M_vbp(Rvbp
)
446 { this->_M_reset(__index
); }
449 _M_reset(long __index
= -1) throw()
454 _M_curr_index
= static_cast<_Index_type
>(-1);
458 _M_curr_index
= __index
;
459 _M_curr_bmap
= reinterpret_cast<size_t*>
460 (_M_vbp
[_M_curr_index
].first
) - 1;
462 _GLIBCXX_DEBUG_ASSERT(__index
<= (long)_M_vbp
.size() - 1);
464 _M_last_bmap_in_block
= _M_curr_bmap
465 - ((_M_vbp
[_M_curr_index
].second
466 - _M_vbp
[_M_curr_index
].first
+ 1)
467 / size_t(bits_per_block
) - 1);
470 // Dangerous Function! Use with extreme care. Pass to this
471 // function ONLY those values that are known to be correct,
472 // otherwise this will mess up big time.
474 _M_set_internal_bitmap(size_t* __new_internal_marker
) throw()
475 { _M_curr_bmap
= __new_internal_marker
; }
478 _M_finished() const throw()
479 { return(_M_curr_bmap
== 0); }
484 if (_M_curr_bmap
== _M_last_bmap_in_block
)
486 if (++_M_curr_index
== _M_vbp
.size())
489 this->_M_reset(_M_curr_index
);
497 _M_get() const throw()
498 { return _M_curr_bmap
; }
501 _M_base() const throw()
502 { return _M_vbp
[_M_curr_index
].first
; }
505 _M_offset() const throw()
507 return size_t(bits_per_block
)
508 * ((reinterpret_cast<size_t*>(this->_M_base())
509 - _M_curr_bmap
) - 1);
513 _M_where() const throw()
514 { return _M_curr_index
; }
517 /** @brief Mark a memory address as allocated by re-setting the
518 * corresponding bit in the bit-map.
521 __bit_allocate(size_t* __pbmap
, size_t __pos
) throw()
523 size_t __mask
= 1 << __pos
;
528 /** @brief Mark a memory address as free by setting the
529 * corresponding bit in the bit-map.
532 __bit_free(size_t* __pbmap
, size_t __pos
) throw()
534 size_t __mask
= 1 << __pos
;
537 } // namespace __detail
539 /** @brief Generic Version of the bsf instruction.
542 _Bit_scan_forward(size_t __num
)
543 { return static_cast<size_t>(__builtin_ctzl(__num
)); }
545 /** @class free_list bitmap_allocator.h bitmap_allocator.h
547 * @brief The free list class for managing chunks of memory to be
548 * given to and returned by the bitmap_allocator.
552 typedef size_t* value_type
;
553 typedef __detail::__mini_vector
<value_type
> vector_type
;
554 typedef vector_type::iterator iterator
;
555 typedef __mutex __mutex_type
;
557 struct _LT_pointer_compare
560 operator()(const size_t* __pui
,
561 const size_t __cui
) const throw()
562 { return *__pui
< __cui
; }
565 #if defined __GTHREADS
569 static __mutex_type _S_mutex
;
577 static vector_type _S_free_list
;
581 /** @brief Performs validation of memory based on their size.
583 * @param __addr The pointer to the memory block to be
586 * @detail Validates the memory block passed to this function and
587 * appropriately performs the action of managing the free list of
588 * blocks by adding this block to the free list or deleting this
589 * or larger blocks from the free list.
592 _M_validate(size_t* __addr
) throw()
594 vector_type
& __free_list
= _M_get_free_list();
595 const vector_type::size_type __max_size
= 64;
596 if (__free_list
.size() >= __max_size
)
598 // Ok, the threshold value has been reached. We determine
599 // which block to remove from the list of free blocks.
600 if (*__addr
>= *__free_list
.back())
602 // Ok, the new block is greater than or equal to the
603 // last block in the list of free blocks. We just free
605 ::operator delete(static_cast<void*>(__addr
));
610 // Deallocate the last block in the list of free lists,
611 // and insert the new one in its correct position.
612 ::operator delete(static_cast<void*>(__free_list
.back()));
613 __free_list
.pop_back();
617 // Just add the block to the list of free lists unconditionally.
618 iterator __temp
= __gnu_cxx::__detail::__lower_bound
619 (__free_list
.begin(), __free_list
.end(),
620 *__addr
, _LT_pointer_compare());
622 // We may insert the new free list before _temp;
623 __free_list
.insert(__temp
, __addr
);
626 /** @brief Decides whether the wastage of memory is acceptable for
627 * the current memory request and returns accordingly.
629 * @param __block_size The size of the block available in the free
632 * @param __required_size The required size of the memory block.
634 * @return true if the wastage incurred is acceptable, else returns
638 _M_should_i_give(size_t __block_size
,
639 size_t __required_size
) throw()
641 const size_t __max_wastage_percentage
= 36;
642 if (__block_size
>= __required_size
&&
643 (((__block_size
- __required_size
) * 100 / __block_size
)
644 < __max_wastage_percentage
))
651 /** @brief This function returns the block of memory to the
652 * internal free list.
654 * @param __addr The pointer to the memory block that was given
655 * by a call to the _M_get function.
658 _M_insert(size_t* __addr
) throw()
660 #if defined __GTHREADS
661 __gnu_cxx::__scoped_lock
__bfl_lock(_M_get_mutex());
663 // Call _M_validate to decide what should be done with
664 // this particular free list.
665 this->_M_validate(reinterpret_cast<size_t*>(__addr
) - 1);
666 // See discussion as to why this is 1!
669 /** @brief This function gets a block of memory of the specified
670 * size from the free list.
672 * @param __sz The size in bytes of the memory required.
674 * @return A pointer to the new memory block of size at least
675 * equal to that requested.
678 _M_get(size_t __sz
) throw(std::bad_alloc
);
680 /** @brief This function just clears the internal Free List, and
681 * gives back all the memory to the OS.
688 // Forward declare the class.
689 template<typename _Tp
>
690 class bitmap_allocator
;
692 // Specialize for void:
694 class bitmap_allocator
<void>
697 typedef void* pointer
;
698 typedef const void* const_pointer
;
700 // Reference-to-void members are impossible.
701 typedef void value_type
;
702 template<typename _Tp1
>
705 typedef bitmap_allocator
<_Tp1
> other
;
709 template<typename _Tp
>
710 class bitmap_allocator
: private free_list
713 typedef size_t size_type
;
714 typedef ptrdiff_t difference_type
;
715 typedef _Tp
* pointer
;
716 typedef const _Tp
* const_pointer
;
717 typedef _Tp
& reference
;
718 typedef const _Tp
& const_reference
;
719 typedef _Tp value_type
;
720 typedef free_list::__mutex_type __mutex_type
;
722 template<typename _Tp1
>
725 typedef bitmap_allocator
<_Tp1
> other
;
729 template<size_t _BSize
, size_t _AlignSize
>
734 modulus
= _BSize
% _AlignSize
,
735 value
= _BSize
+ (modulus
? _AlignSize
- (modulus
) : 0)
741 char __M_unused
[aligned_size
<sizeof(value_type
),
742 _BALLOC_ALIGN_BYTES
>::value
];
746 typedef typename
std::pair
<_Alloc_block
*, _Alloc_block
*> _Block_pair
;
749 __detail::__mini_vector
<_Block_pair
> _BPVector
;
751 #if defined _GLIBCXX_DEBUG
752 // Complexity: O(lg(N)). Where, N is the number of block of size
753 // sizeof(value_type).
755 _S_check_for_free_blocks() throw()
758 __gnu_cxx::__detail::_Ffit_finder
<_Alloc_block
*> _FFF
;
760 typedef typename
_BPVector::iterator _BPiter
;
762 __gnu_cxx::__detail::__find_if
763 (_S_mem_blocks
.begin(), _S_mem_blocks
.end(),
764 __gnu_cxx::__detail::_Functor_Ref
<_FFF
>(__fff
));
766 _GLIBCXX_DEBUG_ASSERT(__bpi
== _S_mem_blocks
.end());
770 /** @brief Responsible for exponentially growing the internal
773 * @throw std::bad_alloc. If memory can not be allocated.
775 * @detail Complexity: O(1), but internally depends upon the
776 * complexity of the function free_list::_M_get. The part where
777 * the bitmap headers are written has complexity: O(X),where X
778 * is the number of blocks of size sizeof(value_type) within
779 * the newly acquired block. Having a tight bound.
782 _S_refill_pool() throw(std::bad_alloc
)
784 #if defined _GLIBCXX_DEBUG
785 _S_check_for_free_blocks();
788 const size_t __num_bitmaps
= (_S_block_size
789 / size_t(__detail::bits_per_block
));
790 const size_t __size_to_allocate
= sizeof(size_t)
791 + _S_block_size
* sizeof(_Alloc_block
)
792 + __num_bitmaps
* sizeof(size_t);
795 reinterpret_cast<size_t*>
796 (this->_M_get(__size_to_allocate
));
800 // The Header information goes at the Beginning of the Block.
802 std::make_pair(reinterpret_cast<_Alloc_block
*>
803 (__temp
+ __num_bitmaps
),
804 reinterpret_cast<_Alloc_block
*>
805 (__temp
+ __num_bitmaps
)
806 + _S_block_size
- 1);
808 // Fill the Vector with this information.
809 _S_mem_blocks
.push_back(__bp
);
811 size_t __bit_mask
= 0; // 0 Indicates all Allocated.
812 __bit_mask
= ~__bit_mask
; // 1 Indicates all Free.
814 for (size_t __i
= 0; __i
< __num_bitmaps
; ++__i
)
815 __temp
[__i
] = __bit_mask
;
821 static _BPVector _S_mem_blocks
;
822 static size_t _S_block_size
;
823 static __gnu_cxx::__detail::
824 _Bitmap_counter
<_Alloc_block
*> _S_last_request
;
825 static typename
_BPVector::size_type _S_last_dealloc_index
;
826 #if defined __GTHREADS
827 static __mutex_type _S_mut
;
832 /** @brief Allocates memory for a single object of size
835 * @throw std::bad_alloc. If memory can not be allocated.
837 * @detail Complexity: Worst case complexity is O(N), but that
838 * is hardly ever hit. If and when this particular case is
839 * encountered, the next few cases are guaranteed to have a
840 * worst case complexity of O(1)! That's why this function
841 * performs very well on average. You can consider this
842 * function to have a complexity referred to commonly as:
843 * Amortized Constant time.
846 _M_allocate_single_object() throw(std::bad_alloc
)
848 #if defined __GTHREADS
849 __gnu_cxx::__scoped_lock
__bit_lock(_S_mut
);
852 // The algorithm is something like this: The last_request
853 // variable points to the last accessed Bit Map. When such a
854 // condition occurs, we try to find a free block in the
855 // current bitmap, or succeeding bitmaps until the last bitmap
856 // is reached. If no free block turns up, we resort to First
859 // WARNING: Do not re-order the condition in the while
860 // statement below, because it relies on C++'s short-circuit
861 // evaluation. The return from _S_last_request->_M_get() will
862 // NOT be dereference able if _S_last_request->_M_finished()
863 // returns true. This would inevitably lead to a NULL pointer
864 // dereference if tinkered with.
865 while (_S_last_request
._M_finished() == false
866 && (*(_S_last_request
._M_get()) == 0))
868 _S_last_request
.operator++();
871 if (__builtin_expect(_S_last_request
._M_finished() == true, false))
873 // Fall Back to First Fit algorithm.
875 __gnu_cxx::__detail::_Ffit_finder
<_Alloc_block
*> _FFF
;
877 typedef typename
_BPVector::iterator _BPiter
;
879 __gnu_cxx::__detail::__find_if
880 (_S_mem_blocks
.begin(), _S_mem_blocks
.end(),
881 __gnu_cxx::__detail::_Functor_Ref
<_FFF
>(__fff
));
883 if (__bpi
!= _S_mem_blocks
.end())
885 // Search was successful. Ok, now mark the first bit from
886 // the right as 0, meaning Allocated. This bit is obtained
887 // by calling _M_get() on __fff.
888 size_t __nz_bit
= _Bit_scan_forward(*__fff
._M_get());
889 __detail::__bit_allocate(__fff
._M_get(), __nz_bit
);
891 _S_last_request
._M_reset(__bpi
- _S_mem_blocks
.begin());
893 // Now, get the address of the bit we marked as allocated.
894 pointer __ret
= reinterpret_cast<pointer
>
895 (__bpi
->first
+ __fff
._M_offset() + __nz_bit
);
896 size_t* __puse_count
=
897 reinterpret_cast<size_t*>
899 - (__gnu_cxx::__detail::__num_bitmaps(*__bpi
) + 1);
906 // Search was unsuccessful. We Add more memory to the
907 // pool by calling _S_refill_pool().
910 // _M_Reset the _S_last_request structure to the first
911 // free block's bit map.
912 _S_last_request
._M_reset(_S_mem_blocks
.size() - 1);
914 // Now, mark that bit as allocated.
918 // _S_last_request holds a pointer to a valid bit map, that
919 // points to a free block in memory.
920 size_t __nz_bit
= _Bit_scan_forward(*_S_last_request
._M_get());
921 __detail::__bit_allocate(_S_last_request
._M_get(), __nz_bit
);
923 pointer __ret
= reinterpret_cast<pointer
>
924 (_S_last_request
._M_base() + _S_last_request
._M_offset() + __nz_bit
);
926 size_t* __puse_count
= reinterpret_cast<size_t*>
927 (_S_mem_blocks
[_S_last_request
._M_where()].first
)
928 - (__gnu_cxx::__detail::
929 __num_bitmaps(_S_mem_blocks
[_S_last_request
._M_where()]) + 1);
935 /** @brief Deallocates memory that belongs to a single object of
938 * @detail Complexity: O(lg(N)), but the worst case is not hit
939 * often! This is because containers usually deallocate memory
940 * close to each other and this case is handled in O(1) time by
941 * the deallocate function.
944 _M_deallocate_single_object(pointer __p
) throw()
946 #if defined __GTHREADS
947 __gnu_cxx::__scoped_lock
__bit_lock(_S_mut
);
949 _Alloc_block
* __real_p
= reinterpret_cast<_Alloc_block
*>(__p
);
951 typedef typename
_BPVector::iterator _Iterator
;
952 typedef typename
_BPVector::difference_type _Difference_type
;
954 _Difference_type __diff
;
957 _GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index
>= 0);
960 if (__gnu_cxx::__detail::_Inclusive_between
<_Alloc_block
*>
961 (__real_p
) (_S_mem_blocks
[_S_last_dealloc_index
]))
963 _GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index
964 <= _S_mem_blocks
.size() - 1);
966 // Initial Assumption was correct!
967 __diff
= _S_last_dealloc_index
;
968 __displacement
= __real_p
- _S_mem_blocks
[__diff
].first
;
972 _Iterator _iter
= __gnu_cxx::__detail::
973 __find_if(_S_mem_blocks
.begin(),
975 __gnu_cxx::__detail::
976 _Inclusive_between
<_Alloc_block
*>(__real_p
));
978 _GLIBCXX_DEBUG_ASSERT(_iter
!= _S_mem_blocks
.end());
980 __diff
= _iter
- _S_mem_blocks
.begin();
981 __displacement
= __real_p
- _S_mem_blocks
[__diff
].first
;
982 _S_last_dealloc_index
= __diff
;
985 // Get the position of the iterator that has been found.
986 const size_t __rotate
= (__displacement
987 % size_t(__detail::bits_per_block
));
989 reinterpret_cast<size_t*>
990 (_S_mem_blocks
[__diff
].first
) - 1;
991 __bitmapC
-= (__displacement
/ size_t(__detail::bits_per_block
));
993 __detail::__bit_free(__bitmapC
, __rotate
);
994 size_t* __puse_count
= reinterpret_cast<size_t*>
995 (_S_mem_blocks
[__diff
].first
)
996 - (__gnu_cxx::__detail::__num_bitmaps(_S_mem_blocks
[__diff
]) + 1);
998 _GLIBCXX_DEBUG_ASSERT(*__puse_count
!= 0);
1002 if (__builtin_expect(*__puse_count
== 0, false))
1006 // We can safely remove this block.
1007 // _Block_pair __bp = _S_mem_blocks[__diff];
1008 this->_M_insert(__puse_count
);
1009 _S_mem_blocks
.erase(_S_mem_blocks
.begin() + __diff
);
1011 // Reset the _S_last_request variable to reflect the
1012 // erased block. We do this to protect future requests
1013 // after the last block has been removed from a particular
1014 // memory Chunk, which in turn has been returned to the
1015 // free list, and hence had been erased from the vector,
1016 // so the size of the vector gets reduced by 1.
1017 if ((_Difference_type
)_S_last_request
._M_where() >= __diff
--)
1018 _S_last_request
._M_reset(__diff
);
1020 // If the Index into the vector of the region of memory
1021 // that might hold the next address that will be passed to
1022 // deallocated may have been invalidated due to the above
1023 // erase procedure being called on the vector, hence we
1024 // try to restore this invariant too.
1025 if (_S_last_dealloc_index
>= _S_mem_blocks
.size())
1027 _S_last_dealloc_index
=(__diff
!= -1 ? __diff
: 0);
1028 _GLIBCXX_DEBUG_ASSERT(_S_last_dealloc_index
>= 0);
1034 bitmap_allocator() throw()
1037 bitmap_allocator(const bitmap_allocator
&)
1040 template<typename _Tp1
>
1041 bitmap_allocator(const bitmap_allocator
<_Tp1
>&) throw()
1044 ~bitmap_allocator() throw()
1048 allocate(size_type __n
)
1050 if (__builtin_expect(__n
> this->max_size(), false))
1051 std::__throw_bad_alloc();
1053 if (__builtin_expect(__n
== 1, true))
1054 return this->_M_allocate_single_object();
1057 const size_type __b
= __n
* sizeof(value_type
);
1058 return reinterpret_cast<pointer
>(::operator new(__b
));
1063 allocate(size_type __n
, typename bitmap_allocator
<void>::const_pointer
)
1064 { return allocate(__n
); }
1067 deallocate(pointer __p
, size_type __n
) throw()
1069 if (__builtin_expect(__p
!= 0, true))
1071 if (__builtin_expect(__n
== 1, true))
1072 this->_M_deallocate_single_object(__p
);
1074 ::operator delete(__p
);
1079 address(reference __r
) const
1083 address(const_reference __r
) const
1087 max_size() const throw()
1088 { return size_type(-1) / sizeof(value_type
); }
1091 construct(pointer __p
, const_reference __data
)
1092 { ::new((void *)__p
) value_type(__data
); }
1094 #ifdef __GXX_EXPERIMENTAL_CXX0X__
1095 template<typename
... _Args
>
1097 construct(pointer __p
, _Args
&&... __args
)
1098 { ::new((void *)__p
) _Tp(std::forward
<_Args
>(__args
)...); }
1102 destroy(pointer __p
)
1103 { __p
->~value_type(); }
1106 template<typename _Tp1
, typename _Tp2
>
1108 operator==(const bitmap_allocator
<_Tp1
>&,
1109 const bitmap_allocator
<_Tp2
>&) throw()
1112 template<typename _Tp1
, typename _Tp2
>
1114 operator!=(const bitmap_allocator
<_Tp1
>&,
1115 const bitmap_allocator
<_Tp2
>&) throw()
1118 // Static member definitions.
1119 template<typename _Tp
>
1120 typename bitmap_allocator
<_Tp
>::_BPVector
1121 bitmap_allocator
<_Tp
>::_S_mem_blocks
;
1123 template<typename _Tp
>
1124 size_t bitmap_allocator
<_Tp
>::_S_block_size
=
1125 2 * size_t(__detail::bits_per_block
);
1127 template<typename _Tp
>
1128 typename
__gnu_cxx::bitmap_allocator
<_Tp
>::_BPVector::size_type
1129 bitmap_allocator
<_Tp
>::_S_last_dealloc_index
= 0;
1131 template<typename _Tp
>
1132 __gnu_cxx::__detail::_Bitmap_counter
1133 <typename bitmap_allocator
<_Tp
>::_Alloc_block
*>
1134 bitmap_allocator
<_Tp
>::_S_last_request(_S_mem_blocks
);
1136 #if defined __GTHREADS
1137 template<typename _Tp
>
1138 typename bitmap_allocator
<_Tp
>::__mutex_type
1139 bitmap_allocator
<_Tp
>::_S_mut
;
1142 _GLIBCXX_END_NAMESPACE