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
|
//
// detail/thread_info_base.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef ASIO_DETAIL_THREAD_INFO_BASE_HPP
#define ASIO_DETAIL_THREAD_INFO_BASE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <climits>
#include <cstddef>
#include "asio/detail/noncopyable.hpp"
#include "asio/detail/push_options.hpp"
namespace asio {
namespace detail {
class thread_info_base
: private noncopyable
{
public:
struct default_tag
{
enum { mem_index = 0 };
};
struct awaitee_tag
{
enum { mem_index = 1 };
};
thread_info_base()
{
for (int i = 0; i < max_mem_index; ++i)
reusable_memory_[i] = 0;
}
~thread_info_base()
{
for (int i = 0; i < max_mem_index; ++i)
if (reusable_memory_[i])
::operator delete(reusable_memory_[i]);
}
static void* allocate(thread_info_base* this_thread, std::size_t size)
{
return allocate(default_tag(), this_thread, size);
}
static void deallocate(thread_info_base* this_thread,
void* pointer, std::size_t size)
{
deallocate(default_tag(), this_thread, pointer, size);
}
template <typename Purpose>
static void* allocate(Purpose, thread_info_base* this_thread,
std::size_t size)
{
std::size_t chunks = (size + chunk_size - 1) / chunk_size;
if (this_thread && this_thread->reusable_memory_[Purpose::mem_index])
{
void* const pointer = this_thread->reusable_memory_[Purpose::mem_index];
this_thread->reusable_memory_[Purpose::mem_index] = 0;
unsigned char* const mem = static_cast<unsigned char*>(pointer);
if (static_cast<std::size_t>(mem[0]) >= chunks)
{
mem[size] = mem[0];
return pointer;
}
::operator delete(pointer);
}
void* const pointer = ::operator new(chunks * chunk_size + 1);
unsigned char* const mem = static_cast<unsigned char*>(pointer);
mem[size] = (chunks <= UCHAR_MAX) ? static_cast<unsigned char>(chunks) : 0;
return pointer;
}
template <typename Purpose>
static void deallocate(Purpose, thread_info_base* this_thread,
void* pointer, std::size_t size)
{
if (size <= chunk_size * UCHAR_MAX)
{
if (this_thread && this_thread->reusable_memory_[Purpose::mem_index] == 0)
{
unsigned char* const mem = static_cast<unsigned char*>(pointer);
mem[0] = mem[size];
this_thread->reusable_memory_[Purpose::mem_index] = pointer;
return;
}
}
::operator delete(pointer);
}
private:
enum { chunk_size = 4 };
enum { max_mem_index = 2 };
void* reusable_memory_[max_mem_index];
};
} // namespace detail
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // ASIO_DETAIL_THREAD_INFO_BASE_HPP
|
