1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
// Allocator details.
// Copyright (C) 2004 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)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// 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.
// 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.
//
// ISO C++ 14882:
//
#include <bits/c++config.h>
#include <cstdlib>
#include <ext/pool_allocator.h>
namespace __gnu_internal
{
__glibcxx_mutex_define_initialized(palloc_init_mutex);
}
namespace __gnu_cxx
{
// Definitions for __pool_alloc_base.
__pool_alloc_base::_Obj* volatile*
__pool_alloc_base::_M_get_free_list(size_t __bytes)
{
size_t __i = ((__bytes + (size_t)_S_align - 1) / (size_t)_S_align - 1);
return _S_free_list + __i;
}
mutex_type&
__pool_alloc_base::_M_get_mutex()
{ return __gnu_internal::palloc_init_mutex; }
// Allocate memory in large chunks in order to avoid fragmenting the
// heap too much. Assume that __n is properly aligned. We hold the
// allocation lock.
char*
__pool_alloc_base::_M_allocate_chunk(size_t __n, int& __nobjs)
{
char* __result;
size_t __total_bytes = __n * __nobjs;
size_t __bytes_left = _S_end_free - _S_start_free;
if (__bytes_left >= __total_bytes)
{
__result = _S_start_free;
_S_start_free += __total_bytes;
return __result ;
}
else if (__bytes_left >= __n)
{
__nobjs = (int)(__bytes_left / __n);
__total_bytes = __n * __nobjs;
__result = _S_start_free;
_S_start_free += __total_bytes;
return __result;
}
else
{
// Try to make use of the left-over piece.
if (__bytes_left > 0)
{
_Obj* volatile* __free_list = _M_get_free_list(__bytes_left);
((_Obj*)(void*)_S_start_free)->_M_free_list_link = *__free_list;
*__free_list = (_Obj*)(void*)_S_start_free;
}
size_t __bytes_to_get = (2 * __total_bytes
+ _M_round_up(_S_heap_size >> 4));
try
{
_S_start_free = static_cast<char*>(::operator new(__bytes_to_get));
}
catch (...)
{
// Try to make do with what we have. That can't hurt. We
// do not try smaller requests, since that tends to result
// in disaster on multi-process machines.
size_t __i = __n;
for (; __i <= (size_t) _S_max_bytes; __i += (size_t) _S_align)
{
_Obj* volatile* __free_list = _M_get_free_list(__i);
_Obj* __p = *__free_list;
if (__p != 0)
{
*__free_list = __p->_M_free_list_link;
_S_start_free = (char*)__p;
_S_end_free = _S_start_free + __i;
return _M_allocate_chunk(__n, __nobjs);
// Any leftover piece will eventually make it to the
// right free list.
}
}
// What we have wasn't enough. Rethrow.
_S_start_free = _S_end_free = 0; // We have no chunk.
__throw_exception_again;
}
_S_heap_size += __bytes_to_get;
_S_end_free = _S_start_free + __bytes_to_get;
return _M_allocate_chunk(__n, __nobjs);
}
}
// Returns an object of size __n, and optionally adds to "size
// __n"'s free list. We assume that __n is properly aligned. We
// hold the allocation lock.
void*
__pool_alloc_base::_M_refill(size_t __n)
{
int __nobjs = 20;
char* __chunk = _M_allocate_chunk(__n, __nobjs);
_Obj* volatile* __free_list;
_Obj* __result;
_Obj* __current_obj;
_Obj* __next_obj;
if (__nobjs == 1)
return __chunk;
__free_list = _M_get_free_list(__n);
// Build free list in chunk.
__result = (_Obj*)(void*)__chunk;
*__free_list = __next_obj = (_Obj*)(void*)(__chunk + __n);
for (int __i = 1; ; __i++)
{
__current_obj = __next_obj;
__next_obj = (_Obj*)(void*)((char*)__next_obj + __n);
if (__nobjs - 1 == __i)
{
__current_obj->_M_free_list_link = 0;
break;
}
else
__current_obj->_M_free_list_link = __next_obj;
}
return __result;
}
__pool_alloc_base::_Obj* volatile __pool_alloc_base::_S_free_list[_S_free_list_size];
char* __pool_alloc_base::_S_start_free = 0;
char* __pool_alloc_base::_S_end_free = 0;
size_t __pool_alloc_base::_S_heap_size = 0;
// Instantiations.
template class __pool_alloc<char>;
template class __pool_alloc<wchar_t>;
} // namespace __gnu_cxx
|
