1 | /* |
2 | * Copyright 2018-present Facebook, Inc. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | |
17 | #pragma once |
18 | |
19 | #include <folly/stats/detail/SlidingWindow.h> |
20 | |
21 | #include <algorithm> |
22 | |
23 | namespace folly { |
24 | namespace detail { |
25 | |
26 | template <typename BucketT> |
27 | SlidingWindow<BucketT>::SlidingWindow( |
28 | Function<BucketT(void)> fn, |
29 | size_t numBuckets) |
30 | : fn_(std::move(fn)), curHead_(0) { |
31 | buckets_.reserve(numBuckets); |
32 | for (size_t i = 0; i < numBuckets; ++i) { |
33 | buckets_.push_back(fn_()); |
34 | } |
35 | std::reverse(buckets_.begin(), buckets_.end()); |
36 | } |
37 | |
38 | template <typename BucketT> |
39 | SlidingWindow<BucketT>::SlidingWindow(SlidingWindow<BucketT>&& rhs) |
40 | : fn_(std::move(rhs.fn_)), |
41 | buckets_(std::move(rhs.buckets_)), |
42 | curHead_(rhs.curHead_) {} |
43 | |
44 | template <typename BucketT> |
45 | std::vector<BucketT> SlidingWindow<BucketT>::get() const { |
46 | std::vector<BucketT> buckets; |
47 | buckets.reserve(buckets_.size()); |
48 | buckets.insert(buckets.end(), buckets_.begin() + curHead_, buckets_.end()); |
49 | buckets.insert(buckets.end(), buckets_.begin(), buckets_.begin() + curHead_); |
50 | return buckets; |
51 | } |
52 | |
53 | template <typename BucketT> |
54 | BucketT SlidingWindow<BucketT>::front() const { |
55 | return buckets_[curHead_]; |
56 | } |
57 | |
58 | template <typename BucketT> |
59 | void SlidingWindow<BucketT>::set(size_t idx, BucketT bucket) { |
60 | if (idx < buckets_.size()) { |
61 | idx = (curHead_ + idx) % buckets_.size(); |
62 | buckets_[idx] = std::move(bucket); |
63 | } |
64 | } |
65 | |
66 | template <typename BucketT> |
67 | void SlidingWindow<BucketT>::slide(size_t nBuckets) { |
68 | nBuckets = std::min(nBuckets, buckets_.size()); |
69 | for (size_t i = 0; i < nBuckets; ++i) { |
70 | if (curHead_ == 0) { |
71 | curHead_ = buckets_.size() - 1; |
72 | } else { |
73 | curHead_--; |
74 | } |
75 | buckets_[curHead_] = fn_(); |
76 | } |
77 | } |
78 | |
79 | } // namespace detail |
80 | } // namespace folly |
81 | |