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
|
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_LIBARTBASE_BASE_BOUNDED_FIFO_H_
#define ART_LIBARTBASE_BASE_BOUNDED_FIFO_H_
#include <android-base/logging.h>
#include "bit_utils.h"
namespace art {
// A bounded fifo is a fifo which has a bounded size. The power of two version uses a bit mask to
// avoid needing to deal with wrapping integers around or using a modulo operation.
template <typename T, const size_t kMaxSize>
class BoundedFifoPowerOfTwo {
static_assert(IsPowerOfTwo(kMaxSize), "kMaxSize must be a power of 2.");
public:
BoundedFifoPowerOfTwo() {
clear();
}
void clear() {
back_index_ = 0;
size_ = 0;
}
bool empty() const {
return size() == 0;
}
size_t size() const {
return size_;
}
void push_back(const T& value) {
++size_;
DCHECK_LE(size_, kMaxSize);
// Relies on integer overflow behavior.
data_[back_index_++ & mask_] = value;
}
const T& front() const {
DCHECK_GT(size_, 0U);
return data_[(back_index_ - size_) & mask_];
}
void pop_front() {
DCHECK_GT(size_, 0U);
--size_;
}
private:
static const size_t mask_ = kMaxSize - 1;
size_t back_index_, size_;
T data_[kMaxSize];
};
} // namespace art
#endif // ART_LIBARTBASE_BASE_BOUNDED_FIFO_H_
|
