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
|
/*
* Copyright (C) 2001-2019 Jacek Sieka, arnetheduck on gmail point com
*
* This program 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 of the License, or
* (at your option) any later version.
*
* This program 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 program. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include "CriticalSection.h"
#include "debug.h"
namespace dcpp {
#ifndef _DEBUG
struct FastAllocBase {
static FastCriticalSection cs;
};
/**
* Fast new/delete replacements for constant sized objects, that also give nice
* reference locality...
*/
template<class T>
struct FastAlloc : public FastAllocBase {
// Custom new & delete that (hopefully) use the node allocator
static void* operator new(size_t s) {
if(s != sizeof(T))
return ::operator new(s);
return allocate();
}
// Avoid hiding placement new that's needed by the stl containers...
static void* operator new(size_t, void* m) {
return m;
}
// ...and the warning about missing placement delete...
static void operator delete(void*, void*) {
// ? We didn't allocate so...
}
static void operator delete(void* m, size_t s) {
if (s != sizeof(T)) {
::operator delete(m);
} else if(m != NULL) {
deallocate((uint8_t*)m);
}
}
protected:
~FastAlloc() { }
private:
static void* allocate() {
FastLock l(cs);
if(freeList == NULL) {
grow();
}
void* tmp = freeList;
freeList = *((void**)freeList);
return tmp;
}
static void deallocate(void* p) {
FastLock l(cs);
*(void**)p = freeList;
freeList = p;
}
static void* freeList;
static void grow() {
dcassert(sizeof(T) >= sizeof(void*));
// We want to grow by approximately 128kb at a time...
size_t items = ((128*1024 + sizeof(T) - 1)/sizeof(T));
freeList = new uint8_t[sizeof(T)*items];
uint8_t* tmp = (uint8_t*)freeList;
for(size_t i = 0; i < items - 1; i++) {
*(void**)tmp = tmp + sizeof(T);
tmp += sizeof(T);
}
*(void**)tmp = NULL;
}
};
template<class T> void* FastAlloc<T>::freeList = NULL;
#else
template<class T> struct FastAlloc { };
#endif
} // namespace dcpp
|
