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