mirror of
https://github.com/kingToolbox/WindTerm.git
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90 lines
2.2 KiB
C++
90 lines
2.2 KiB
C++
/*
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* Copyright 2020, WindTerm.
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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 CIRCULARBUFFER_H
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#define CIRCULARBUFFER_H
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#pragma once
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#include <QtAlgorithms>
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#include <QtGlobal>
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#define ROUND_UP_POW2(value) { (1 << (32 - qCountLeadingZeroBits(value))) }
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template <typename T>
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class CircularBuffer {
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public:
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CircularBuffer(quint32 capacity)
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: m_currentIndex(0) {
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Q_ASSERT(capacity < (1 << 31));
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m_capacity = ROUND_UP_POW2(capacity);
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m_mask = m_capacity - 1;
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m_buffer = static_cast<qint64 *>(calloc(m_capacity, sizeof(qint64)));
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clear();
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}
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~CircularBuffer() {
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free(m_buffer);
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m_buffer = nullptr;
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}
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void append(const T &value) {
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m_buffer[++m_currentIndex & m_mask] = value;
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}
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const T &at(qint64 index) const {
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Q_ASSERT(index >= std::max<qint64>(0, m_currentIndex + 1 - m_capacity) && index <= m_currentIndex);
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return m_buffer[index & m_mask];
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}
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int capacity() const { return m_capacity; }
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void clear() {
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m_currentIndex = -1;
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memset(m_buffer, 0xFF, m_capacity * sizeof(qint64));
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#ifdef _DEBUG
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for (int i = 0; i < m_capacity; i++) {
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Q_ASSERT(m_buffer[i] == -1);
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}
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#endif // _DEBUG
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}
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qint64 currentIndex() const { return m_currentIndex; }
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qint64 minIndex() const { return std::max<qint64>(0, m_currentIndex + 1 - m_capacity); }
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const T &operator [](qint64 index) const {
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Q_ASSERT(index >= std::max<qint64>(0, m_currentIndex + 1 - m_capacity) && index <= m_currentIndex);
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return m_buffer[index & m_mask];
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}
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private:
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T *m_buffer;
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qint64 m_currentIndex;
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int m_capacity;
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int m_mask;
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};
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class Int64CircularBuffer : public CircularBuffer<qint64> {
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public:
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Int64CircularBuffer(quint32 capacity)
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: CircularBuffer<qint64>(capacity)
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{}
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};
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#endif // CIRCULARBUFFER_H
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