79 lines
2.2 KiB
C++
79 lines
2.2 KiB
C++
/*
|
|
* Copyright (C) 2023 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 TNT_UTILS_FIXEDCIRCULARBUFFER_H
|
|
#define TNT_UTILS_FIXEDCIRCULARBUFFER_H
|
|
|
|
#include <utils/debug.h>
|
|
|
|
#include <memory>
|
|
#include <optional>
|
|
#include <type_traits>
|
|
|
|
#include <stddef.h>
|
|
|
|
namespace utils {
|
|
|
|
template<typename T>
|
|
class FixedCircularBuffer {
|
|
public:
|
|
explicit FixedCircularBuffer(size_t capacity)
|
|
: mData(std::make_unique<T[]>(capacity)), mCapacity(capacity) {}
|
|
|
|
size_t size() const noexcept { return mSize; }
|
|
size_t capacity() const noexcept { return mCapacity; }
|
|
bool full() const noexcept { return mCapacity > 0 && mSize == mCapacity; }
|
|
bool empty() const noexcept { return mSize == 0; }
|
|
|
|
/**
|
|
* Push v into the buffer. If the buffer is already full, removes the oldest item and returns
|
|
* it. If this buffer has no capacity, simply returns v.
|
|
* @param v the new value to push into the buffer
|
|
* @return if the buffer was full, the oldest value which was displaced
|
|
*/
|
|
std::optional<T> push(T v) noexcept {
|
|
if (mCapacity == 0) {
|
|
return v;
|
|
}
|
|
std::optional<T> displaced = full() ? pop() : std::optional<T>{};
|
|
mData[mEnd] = v;
|
|
mEnd = (mEnd + 1) % mCapacity;
|
|
mSize++;
|
|
return displaced;
|
|
}
|
|
|
|
T pop() noexcept {
|
|
assert_invariant(mSize > 0);
|
|
T result = mData[mBegin];
|
|
mBegin = (mBegin + 1) % mCapacity;
|
|
mSize--;
|
|
return result;
|
|
}
|
|
|
|
private:
|
|
std::unique_ptr<T[]> mData;
|
|
|
|
size_t mBegin = 0;
|
|
size_t mEnd = 0;
|
|
size_t mSize = 0;
|
|
size_t mCapacity;
|
|
};
|
|
|
|
} // namespace utils
|
|
|
|
#endif // TNT_UTILS_FIXEDCIRCULARBUFFER_H
|