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
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
|
/*
* Pooling Allocator
* (C) 1999-2008 Jack Lloyd
* 2005 Matthew Gregan
* 2005-2006 Matt Johnston
*
* Distributed under the terms of the Botan license
*/
#include <botan/internal/mem_pool.h>
#include <botan/internal/rounding.h>
#include <botan/mem_ops.h>
#include <algorithm>
#include <exception>
namespace Botan {
/*
* Memory_Block Constructor
*/
Pooling_Allocator::Memory_Block::Memory_Block(void* buf)
{
buffer = static_cast<byte*>(buf);
bitmap = 0;
buffer_end = buffer + (BLOCK_SIZE * BITMAP_SIZE);
}
/*
* See if ptr is contained by this block
*/
bool Pooling_Allocator::Memory_Block::contains(void* ptr,
size_t length) const
{
return ((buffer <= ptr) &&
(buffer_end >= static_cast<byte*>(ptr) + length * BLOCK_SIZE));
}
/*
* Allocate some memory, if possible
*/
byte* Pooling_Allocator::Memory_Block::alloc(size_t n)
{
if(n == 0 || n > BITMAP_SIZE)
return 0;
if(n == BITMAP_SIZE)
{
if(bitmap)
return 0;
else
{
bitmap = ~bitmap;
return buffer;
}
}
bitmap_type mask = (static_cast<bitmap_type>(1) << n) - 1;
size_t offset = 0;
while(bitmap & mask)
{
mask <<= 1;
++offset;
if((bitmap & mask) == 0)
break;
if(mask >> 63)
break;
}
if(bitmap & mask)
return 0;
bitmap |= mask;
return buffer + offset * BLOCK_SIZE;
}
/*
* Mark this memory as free, if we own it
*/
void Pooling_Allocator::Memory_Block::free(void* ptr, size_t blocks)
{
clear_mem(static_cast<byte*>(ptr), blocks * BLOCK_SIZE);
const size_t offset = (static_cast<byte*>(ptr) - buffer) / BLOCK_SIZE;
if(offset == 0 && blocks == BITMAP_SIZE)
bitmap = ~bitmap;
else
{
for(size_t j = 0; j != blocks; ++j)
bitmap &= ~(static_cast<bitmap_type>(1) << (j+offset));
}
}
/*
* Pooling_Allocator Constructor
*/
Pooling_Allocator::Pooling_Allocator(Mutex* m) : mutex(m)
{
last_used = blocks.begin();
}
/*
* Pooling_Allocator Destructor
*/
Pooling_Allocator::~Pooling_Allocator()
{
delete mutex;
if(blocks.size())
throw Invalid_State("Pooling_Allocator: Never released memory");
}
/*
* Free all remaining memory
*/
void Pooling_Allocator::destroy()
{
Mutex_Holder lock(mutex);
blocks.clear();
for(size_t j = 0; j != allocated.size(); ++j)
dealloc_block(allocated[j].first, allocated[j].second);
allocated.clear();
}
/*
* Allocation
*/
void* Pooling_Allocator::allocate(size_t n)
{
const size_t BITMAP_SIZE = Memory_Block::bitmap_size();
const size_t BLOCK_SIZE = Memory_Block::block_size();
Mutex_Holder lock(mutex);
if(n <= BITMAP_SIZE * BLOCK_SIZE)
{
const size_t block_no = round_up(n, BLOCK_SIZE) / BLOCK_SIZE;
byte* mem = allocate_blocks(block_no);
if(mem)
return mem;
get_more_core(BOTAN_MEM_POOL_CHUNK_SIZE);
mem = allocate_blocks(block_no);
if(mem)
return mem;
throw Memory_Exhaustion();
}
void* new_buf = alloc_block(n);
if(new_buf)
return new_buf;
throw Memory_Exhaustion();
}
/*
* Deallocation
*/
void Pooling_Allocator::deallocate(void* ptr, size_t n)
{
const size_t BITMAP_SIZE = Memory_Block::bitmap_size();
const size_t BLOCK_SIZE = Memory_Block::block_size();
if(ptr == 0 || n == 0)
return;
Mutex_Holder lock(mutex);
if(n > BITMAP_SIZE * BLOCK_SIZE)
dealloc_block(ptr, n);
else
{
const size_t block_no = round_up(n, BLOCK_SIZE) / BLOCK_SIZE;
std::vector<Memory_Block>::iterator i =
std::lower_bound(blocks.begin(), blocks.end(), Memory_Block(ptr));
if(i == blocks.end() || !i->contains(ptr, block_no))
throw Invalid_State("Pointer released to the wrong allocator");
i->free(ptr, block_no);
}
}
/*
* Try to get some memory from an existing block
*/
byte* Pooling_Allocator::allocate_blocks(size_t n)
{
if(blocks.empty())
return 0;
std::vector<Memory_Block>::iterator i = last_used;
do
{
byte* mem = i->alloc(n);
if(mem)
{
last_used = i;
return mem;
}
++i;
if(i == blocks.end())
i = blocks.begin();
}
while(i != last_used);
return 0;
}
/*
* Allocate more memory for the pool
*/
void Pooling_Allocator::get_more_core(size_t in_bytes)
{
const size_t BITMAP_SIZE = Memory_Block::bitmap_size();
const size_t BLOCK_SIZE = Memory_Block::block_size();
const size_t TOTAL_BLOCK_SIZE = BLOCK_SIZE * BITMAP_SIZE;
// upper bound on allocation is 1 MiB
in_bytes = std::min<size_t>(in_bytes, 1024 * 1024);
const size_t in_blocks = round_up(in_bytes, BLOCK_SIZE) / TOTAL_BLOCK_SIZE;
const size_t to_allocate = in_blocks * TOTAL_BLOCK_SIZE;
void* ptr = alloc_block(to_allocate);
if(ptr == 0)
throw Memory_Exhaustion();
allocated.push_back(std::make_pair(ptr, to_allocate));
for(size_t j = 0; j != in_blocks; ++j)
{
byte* byte_ptr = static_cast<byte*>(ptr);
blocks.push_back(Memory_Block(byte_ptr + j * TOTAL_BLOCK_SIZE));
}
std::sort(blocks.begin(), blocks.end());
last_used = std::lower_bound(blocks.begin(), blocks.end(),
Memory_Block(ptr));
}
}
|
