3 // Copyright (C) 2004-2017 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
29 #include <bits/c++config.h>
31 #include <ext/pool_allocator.h>
38 static __gnu_cxx::__mutex palloc_mutex
;
41 } // anonymous namespace
43 namespace __gnu_cxx
_GLIBCXX_VISIBILITY(default)
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
47 // Definitions for __pool_alloc_base.
48 __pool_alloc_base::_Obj
* volatile*
49 __pool_alloc_base::_M_get_free_list(size_t __bytes
) throw ()
51 size_t __i
= ((__bytes
+ (size_t)_S_align
- 1) / (size_t)_S_align
- 1);
52 return _S_free_list
+ __i
;
56 __pool_alloc_base::_M_get_mutex() throw ()
57 { return get_palloc_mutex(); }
59 // Allocate memory in large chunks in order to avoid fragmenting the
60 // heap too much. Assume that __n is properly aligned. We hold the
63 __pool_alloc_base::_M_allocate_chunk(size_t __n
, int& __nobjs
)
66 size_t __total_bytes
= __n
* __nobjs
;
67 size_t __bytes_left
= _S_end_free
- _S_start_free
;
69 if (__bytes_left
>= __total_bytes
)
71 __result
= _S_start_free
;
72 _S_start_free
+= __total_bytes
;
75 else if (__bytes_left
>= __n
)
77 __nobjs
= (int)(__bytes_left
/ __n
);
78 __total_bytes
= __n
* __nobjs
;
79 __result
= _S_start_free
;
80 _S_start_free
+= __total_bytes
;
85 // Try to make use of the left-over piece.
88 _Obj
* volatile* __free_list
= _M_get_free_list(__bytes_left
);
89 ((_Obj
*)(void*)_S_start_free
)->_M_free_list_link
= *__free_list
;
90 *__free_list
= (_Obj
*)(void*)_S_start_free
;
93 size_t __bytes_to_get
= (2 * __total_bytes
94 + _M_round_up(_S_heap_size
>> 4));
97 _S_start_free
= static_cast<char*>(::operator new(__bytes_to_get
));
99 __catch(const std::bad_alloc
&)
101 // Try to make do with what we have. That can't hurt. We
102 // do not try smaller requests, since that tends to result
103 // in disaster on multi-process machines.
105 for (; __i
<= (size_t) _S_max_bytes
; __i
+= (size_t) _S_align
)
107 _Obj
* volatile* __free_list
= _M_get_free_list(__i
);
108 _Obj
* __p
= *__free_list
;
111 *__free_list
= __p
->_M_free_list_link
;
112 _S_start_free
= (char*)__p
;
113 _S_end_free
= _S_start_free
+ __i
;
114 return _M_allocate_chunk(__n
, __nobjs
);
115 // Any leftover piece will eventually make it to the
119 // What we have wasn't enough. Rethrow.
120 _S_start_free
= _S_end_free
= 0; // We have no chunk.
121 __throw_exception_again
;
123 _S_heap_size
+= __bytes_to_get
;
124 _S_end_free
= _S_start_free
+ __bytes_to_get
;
125 return _M_allocate_chunk(__n
, __nobjs
);
129 // Returns an object of size __n, and optionally adds to "size
130 // __n"'s free list. We assume that __n is properly aligned. We
131 // hold the allocation lock.
133 __pool_alloc_base::_M_refill(size_t __n
)
136 char* __chunk
= _M_allocate_chunk(__n
, __nobjs
);
137 _Obj
* volatile* __free_list
;
144 __free_list
= _M_get_free_list(__n
);
146 // Build free list in chunk.
147 __result
= (_Obj
*)(void*)__chunk
;
148 *__free_list
= __next_obj
= (_Obj
*)(void*)(__chunk
+ __n
);
149 for (int __i
= 1; ; __i
++)
151 __current_obj
= __next_obj
;
152 __next_obj
= (_Obj
*)(void*)((char*)__next_obj
+ __n
);
153 if (__nobjs
- 1 == __i
)
155 __current_obj
->_M_free_list_link
= 0;
159 __current_obj
->_M_free_list_link
= __next_obj
;
164 __pool_alloc_base::_Obj
* volatile __pool_alloc_base::_S_free_list
[_S_free_list_size
];
166 char* __pool_alloc_base::_S_start_free
= 0;
168 char* __pool_alloc_base::_S_end_free
= 0;
170 size_t __pool_alloc_base::_S_heap_size
= 0;
173 template class __pool_alloc
<char>;
174 template class __pool_alloc
<wchar_t>;
176 _GLIBCXX_END_NAMESPACE_VERSION