3 // Copyright (C) 2004 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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.
34 #include <bits/c++config.h>
36 #include <ext/pool_allocator.h>
38 namespace __gnu_internal
40 __glibcxx_mutex_define_initialized(palloc_init_mutex
);
45 // Definitions for __pool_alloc_base.
46 __pool_alloc_base::_Obj
* volatile*
47 __pool_alloc_base::_M_get_free_list(size_t __bytes
)
49 size_t __i
= ((__bytes
+ (size_t)_S_align
- 1) / (size_t)_S_align
- 1);
50 return _S_free_list
+ __i
;
54 __pool_alloc_base::_M_get_mutex()
55 { return __gnu_internal::palloc_init_mutex
; }
57 // Allocate memory in large chunks in order to avoid fragmenting the
58 // heap too much. Assume that __n is properly aligned. We hold the
61 __pool_alloc_base::_M_allocate_chunk(size_t __n
, int& __nobjs
)
64 size_t __total_bytes
= __n
* __nobjs
;
65 size_t __bytes_left
= _S_end_free
- _S_start_free
;
67 if (__bytes_left
>= __total_bytes
)
69 __result
= _S_start_free
;
70 _S_start_free
+= __total_bytes
;
73 else if (__bytes_left
>= __n
)
75 __nobjs
= (int)(__bytes_left
/ __n
);
76 __total_bytes
= __n
* __nobjs
;
77 __result
= _S_start_free
;
78 _S_start_free
+= __total_bytes
;
83 // Try to make use of the left-over piece.
86 _Obj
* volatile* __free_list
= _M_get_free_list(__bytes_left
);
87 ((_Obj
*)(void*)_S_start_free
)->_M_free_list_link
= *__free_list
;
88 *__free_list
= (_Obj
*)(void*)_S_start_free
;
91 size_t __bytes_to_get
= (2 * __total_bytes
92 + _M_round_up(_S_heap_size
>> 4));
93 _S_start_free
= static_cast<char*>(::operator new(__bytes_to_get
));
94 if (_S_start_free
== 0)
96 // Try to make do with what we have. That can't hurt. We
97 // do not try smaller requests, since that tends to result
98 // in disaster on multi-process machines.
100 for (; __i
<= (size_t) _S_max_bytes
; __i
+= (size_t) _S_align
)
102 _Obj
* volatile* __free_list
= _M_get_free_list(__i
);
103 _Obj
* __p
= *__free_list
;
106 *__free_list
= __p
->_M_free_list_link
;
107 _S_start_free
= (char*)__p
;
108 _S_end_free
= _S_start_free
+ __i
;
109 return _M_allocate_chunk(__n
, __nobjs
);
110 // Any leftover piece will eventually make it to the
114 _S_end_free
= 0; // In case of exception.
116 // This should either throw an exception or remedy the situation.
117 // Thus we assume it succeeded.
118 _S_start_free
= static_cast<char*>(::operator new(__bytes_to_get
));
120 _S_heap_size
+= __bytes_to_get
;
121 _S_end_free
= _S_start_free
+ __bytes_to_get
;
122 return _M_allocate_chunk(__n
, __nobjs
);
126 // Returns an object of size __n, and optionally adds to "size
127 // __n"'s free list. We assume that __n is properly aligned. We
128 // hold the allocation lock.
130 __pool_alloc_base::_M_refill(size_t __n
)
133 char* __chunk
= _M_allocate_chunk(__n
, __nobjs
);
134 _Obj
* volatile* __free_list
;
141 __free_list
= _M_get_free_list(__n
);
143 // Build free list in chunk.
144 __result
= (_Obj
*)(void*)__chunk
;
145 *__free_list
= __next_obj
= (_Obj
*)(void*)(__chunk
+ __n
);
146 for (int __i
= 1; ; __i
++)
148 __current_obj
= __next_obj
;
149 __next_obj
= (_Obj
*)(void*)((char*)__next_obj
+ __n
);
150 if (__nobjs
- 1 == __i
)
152 __current_obj
->_M_free_list_link
= 0;
156 __current_obj
->_M_free_list_link
= __next_obj
;
161 __pool_alloc_base::_Obj
* volatile __pool_alloc_base::_S_free_list
[_S_free_list_size
];
163 char* __pool_alloc_base::_S_start_free
= 0;
165 char* __pool_alloc_base::_S_end_free
= 0;
167 size_t __pool_alloc_base::_S_heap_size
= 0;
170 template class __pool_alloc
<char>;
171 template class __pool_alloc
<wchar_t>;
172 } // namespace __gnu_cxx