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
|
#pragma once
#include <Common/Arena.h>
#include <Common/Allocator.h>
namespace DB
{
/// Allocator which proxies all allocations to Arena. Used in aggregate functions.
class ArenaAllocator
{
public:
static void * alloc(size_t size, Arena * arena)
{
return arena->alloc(size);
}
static void * realloc(void * buf, size_t old_size, size_t new_size, Arena * arena)
{
char const * data = reinterpret_cast<char *>(buf);
// Invariant should be maintained: new_size > old_size
if (data + old_size == arena->head->pos)
{
// Consecutive optimization
arena->allocContinue(new_size - old_size, data);
return reinterpret_cast<void *>(const_cast<char *>(data));
}
else
{
return arena->realloc(data, old_size, new_size);
}
}
static void free(void * /*buf*/, size_t /*size*/)
{
// Do nothing, trash in arena remains.
}
protected:
static constexpr size_t getStackThreshold()
{
return 0;
}
};
/// Allocates in Arena with proper alignment.
template <size_t alignment>
class AlignedArenaAllocator
{
public:
static void * alloc(size_t size, Arena * arena)
{
return arena->alignedAlloc(size, alignment);
}
static void * realloc(void * buf, size_t old_size, size_t new_size, Arena * arena)
{
char const * data = reinterpret_cast<char *>(buf);
if (data + old_size == arena->head->pos)
{
arena->allocContinue(new_size - old_size, data, alignment);
return reinterpret_cast<void *>(const_cast<char *>(data));
}
else
{
return arena->alignedRealloc(data, old_size, new_size, alignment);
}
}
static void free(void * /*buf*/, size_t /*size*/)
{
}
protected:
static constexpr size_t getStackThreshold()
{
return 0;
}
};
/// Switches to ordinary Allocator after REAL_ALLOCATION_TRESHOLD bytes to avoid fragmentation and trash in Arena.
template <size_t REAL_ALLOCATION_TRESHOLD = 4096, typename TRealAllocator = Allocator<false>, typename TArenaAllocator = ArenaAllocator, size_t alignment = 0>
class MixedArenaAllocator : private TRealAllocator
{
public:
void * alloc(size_t size, Arena * arena)
{
return (size < REAL_ALLOCATION_TRESHOLD) ? TArenaAllocator::alloc(size, arena) : TRealAllocator::alloc(size, alignment);
}
void * realloc(void * buf, size_t old_size, size_t new_size, Arena * arena)
{
// Invariant should be maintained: new_size > old_size
if (new_size < REAL_ALLOCATION_TRESHOLD)
return TArenaAllocator::realloc(buf, old_size, new_size, arena);
if (old_size >= REAL_ALLOCATION_TRESHOLD)
return TRealAllocator::realloc(buf, old_size, new_size, alignment);
void * new_buf = TRealAllocator::alloc(new_size, alignment);
memcpy(new_buf, buf, old_size);
return new_buf;
}
void free(void * buf, size_t size)
{
if (size >= REAL_ALLOCATION_TRESHOLD)
TRealAllocator::free(buf, size);
}
protected:
static constexpr size_t getStackThreshold()
{
return 0;
}
};
template <size_t alignment, size_t REAL_ALLOCATION_TRESHOLD = 4096>
using MixedAlignedArenaAllocator = MixedArenaAllocator<REAL_ALLOCATION_TRESHOLD, Allocator<false>, AlignedArenaAllocator<alignment>, alignment>;
template <size_t N = 64, typename Base = ArenaAllocator>
class ArenaAllocatorWithStackMemory : public Base
{
char stack_memory[N];
public:
void * alloc(size_t size, Arena * arena)
{
return (size > N) ? Base::alloc(size, arena) : stack_memory;
}
void * realloc(void * buf, size_t old_size, size_t new_size, Arena * arena)
{
/// Was in stack_memory, will remain there.
if (new_size <= N)
return buf;
/// Already was big enough to not fit in stack_memory.
if (old_size > N)
return Base::realloc(buf, old_size, new_size, arena);
/// Was in stack memory, but now will not fit there.
void * new_buf = Base::alloc(new_size, arena);
memcpy(new_buf, buf, old_size);
return new_buf;
}
void free(void * /*buf*/, size_t /*size*/) {}
protected:
static constexpr size_t getStackThreshold()
{
return N;
}
};
}
|
