-
Notifications
You must be signed in to change notification settings - Fork 2
/
Copy pathspsc_ring_buffer.hpp
286 lines (223 loc) · 10.4 KB
/
spsc_ring_buffer.hpp
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
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
#pragma once
#include <atomic>
#include <cstddef>
#include <type_traits>
#include <array>
#include <limits>
#include "aligned_alloc.hpp"
#include "compile_time_utilities.hpp"
#include "scope_guard.hpp"
template<
int _buffer_size_log2,
int _content_align_log2 = ctu::log2_v<sizeof(void*)>,
typename _difference_type = ptrdiff_t,
int _align_log2 = 7
>
struct alignas(((size_t) 1) << _align_log2) spsc_ring_buffer {
using difference_type = _difference_type;
static const auto size = size_t(1) << _buffer_size_log2;
static const auto mask = ctu::bit_mask_v<size_t, _buffer_size_log2>;
static const auto align = size_t(1) << _align_log2;
static const auto content_align_log2 = _content_align_log2;
static_assert(std::is_signed_v<difference_type>);
static_assert(content_align_log2 >= ctu::log2(sizeof(difference_type)));
template<typename cbtype>
bool produce(size_t length, cbtype callback) noexcept(noexcept(callback(static_cast<void*>(nullptr)))) {
if (length <= 0 || length >= size)
return false;
auto rounded_length = ctu::round_up_bits(length + sizeof(difference_type), content_align_log2);
if constexpr (size >= size_t(std::numeric_limits<difference_type>::max())) {
if (rounded_length > size_t(std::numeric_limits<difference_type>::max()))
return false;
}
auto consume_pos = _consume_pos.load(std::memory_order_acquire);
auto produce_pos = _produce_pos.load(std::memory_order_relaxed);
auto fill_level = (produce_pos - consume_pos);
if (fill_level > size)
fill_level += size;
if (fill_level >= (size - rounded_length))
return false;
auto wrap_distance = size - produce_pos;
if (wrap_distance < rounded_length) {
if (fill_level + wrap_distance >= (size - rounded_length))
return false;
new (_buffer + produce_pos) difference_type(-difference_type(wrap_distance));
produce_pos = 0;
}
new (_buffer + produce_pos) difference_type(difference_type(length));
if (callback(static_cast<void*>(_buffer + produce_pos + sizeof(difference_type)))) {
if (produce_pos + rounded_length == size) {
_produce_pos.store(0, std::memory_order_release);
} else {
_produce_pos.store(produce_pos + rounded_length, std::memory_order_release);
}
return true;
}
return false;
}
template<typename cbtype>
bool consume(cbtype callback) noexcept(noexcept(callback(static_cast<void*>(nullptr), difference_type(0)))) {
auto consume_pos = _consume_pos.load(std::memory_order_relaxed);
auto produce_pos = _produce_pos.load(std::memory_order_acquire);
if (produce_pos == consume_pos)
return false;
difference_type length;
memcpy(&length, _buffer + consume_pos, sizeof(length));
if (length < 0) {
consume_pos = 0;
memcpy(&length, _buffer, sizeof(length));
}
if (callback(static_cast<void*>(_buffer + consume_pos + sizeof(difference_type)), length)) {
auto rounded_length = ctu::round_up_bits(length + sizeof(difference_type), content_align_log2);
if (consume_pos + rounded_length == size) {
_consume_pos.store(0, std::memory_order_release);
} else {
_consume_pos.store(consume_pos + rounded_length, std::memory_order_release);
}
return true;
}
return false;
}
// returns true if buffer is empty after this call
template<typename cbtype>
bool consume_all(cbtype callback) noexcept(noexcept(callback(static_cast<void*>(nullptr), difference_type(0)))) {
auto consume_pos = _consume_pos.load(std::memory_order_relaxed);
auto produce_pos = _produce_pos.load(std::memory_order_acquire);
if (produce_pos == consume_pos)
return true;
scope_guard g([this, &consume_pos]() {
_consume_pos.store(consume_pos, std::memory_order_release);
});
while (consume_pos != produce_pos) {
while (consume_pos != produce_pos) {
difference_type length;
memcpy(&length, _buffer + consume_pos, sizeof(length));
if (length < 0) {
consume_pos = 0;
memcpy(&length, _buffer, sizeof(length));
}
if (callback(static_cast<void*>(_buffer + consume_pos + sizeof(difference_type)), length) == false) {
return false;
}
auto rounded_length = ctu::round_up_bits(length + sizeof(difference_type), content_align_log2);
consume_pos += rounded_length;
if (consume_pos = size) {
consume_pos = 0;
}
}
produce_pos = _produce_pos.load(std::memory_order_acquire);
}
return true;
}
bool is_empty() const noexcept {
auto produce_pos = _produce_pos.load(std::memory_order_acquire);
auto consume_pos = _consume_pos.load(std::memory_order_acquire);
return produce_pos == consume_pos;
}
private:
alignas(align) std::byte _buffer[size]{};
alignas(align) std::atomic<size_t> _produce_pos = 0;
mutable size_t _consume_pos_cache = 0;
alignas(align) std::atomic<size_t> _consume_pos = 0;
mutable size_t _produce_pos_cache = 0;
};
template<
int _buffer_size_log2,
int _content_align_log2 = ctu::log2_v<sizeof(void*)>,
typename _difference_type = ptrdiff_t,
int _align_log2 = 6
>
struct alignas(((size_t) 1) << _align_log2) spsc_ring_buffer_masked {
using difference_type = _difference_type;
static const auto size = size_t(1) << _buffer_size_log2;
static const auto mask = ctu::bit_mask_v<size_t, _buffer_size_log2>;
static const auto align = size_t(1) << _align_log2;
static const auto content_align_log2 = _content_align_log2;
static_assert(std::is_signed_v<difference_type>);
static_assert(content_align_log2 >= ctu::log2(sizeof(difference_type)));
template<typename cbtype>
bool produce(size_t length, cbtype callback) noexcept(noexcept(callback(static_cast<void*>(nullptr)))) {
if (length <= 0 || length >= size)
return false;
auto rounded_length = ctu::round_up_bits(length + sizeof(difference_type), content_align_log2);
if constexpr (size >= size_t(std::numeric_limits<difference_type>::max())) {
if (rounded_length > size_t(std::numeric_limits<difference_type>::max()))
return false;
}
auto consume_pos = _consume_pos.load(std::memory_order_acquire);
auto produce_pos = _produce_pos.load(std::memory_order_relaxed);
if ((produce_pos - consume_pos) > (size - rounded_length))
return false;
auto wrap_distance = size - (produce_pos & mask);
if (wrap_distance < rounded_length) {
if ((produce_pos + wrap_distance - consume_pos) > (size - rounded_length))
return false;
new (_buffer + (produce_pos & mask)) difference_type(-difference_type(wrap_distance));
produce_pos += wrap_distance;
}
new (_buffer + (produce_pos & mask)) difference_type(difference_type(length));
if (callback(static_cast<void*>(_buffer + (produce_pos & mask) + sizeof(difference_type)))) {
_produce_pos.store(produce_pos + rounded_length, std::memory_order_release);
return true;
}
return false;
}
template<typename cbtype>
bool consume(cbtype callback) noexcept(noexcept(callback(static_cast<void*>(nullptr), difference_type(0)))) {
auto consume_pos = _consume_pos.load(std::memory_order_relaxed);
auto produce_pos = _produce_pos.load(std::memory_order_acquire);
if (produce_pos == consume_pos)
return false;
difference_type length;
memcpy(&length, _buffer + (consume_pos & mask), sizeof(length));
if (length < 0) {
consume_pos += -length;
memcpy(&length, _buffer + (consume_pos & mask), sizeof(length));
}
if (callback(static_cast<void*>(_buffer + (consume_pos & mask) + sizeof(difference_type)), length)) {
auto rounded_length = ctu::round_up_bits(length + sizeof(difference_type), content_align_log2);
_consume_pos.store(consume_pos + rounded_length, std::memory_order_release);
return true;
}
return false;
}
// returns true if buffer is empty after this call
template<typename cbtype>
bool consume_all(cbtype callback) noexcept(noexcept(callback(static_cast<void*>(nullptr), difference_type(0)))) {
auto consume_pos = _consume_pos.load(std::memory_order_relaxed);
auto produce_pos = _produce_pos.load(std::memory_order_acquire);
if (produce_pos == consume_pos)
return true;
scope_guard g([this, &consume_pos]() {
_consume_pos.store(consume_pos, std::memory_order_release);
});
while (consume_pos != produce_pos) {
while (consume_pos != produce_pos) {
difference_type length;
memcpy(&length, _buffer + (consume_pos & mask), sizeof(length));
if (length < 0) {
consume_pos += -length;
memcpy(&length, _buffer + (consume_pos & mask), sizeof(length));
}
if (callback(static_cast<void*>(_buffer + (consume_pos & mask) + sizeof(difference_type)), length) == false) {
return false;
}
auto rounded_length = ctu::round_up_bits(length + sizeof(difference_type), content_align_log2);
consume_pos += rounded_length;
}
produce_pos = _produce_pos.load(std::memory_order_acquire);
}
return (consume_pos == produce_pos);
}
bool is_empty() const noexcept {
auto produce_pos = _produce_pos.load(std::memory_order_acquire);
auto consume_pos = _consume_pos.load(std::memory_order_acquire);
return produce_pos == consume_pos;
}
private:
alignas(align) std::byte _buffer[size]{};
alignas(align) std::atomic<size_t> _produce_pos = 0;
mutable size_t _consume_pos_cache = 0;
alignas(align) std::atomic<size_t> _consume_pos = 0;
mutable size_t _produce_pos_cache = 0;
};