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82856cf816
The implementation of wpi::circular_buffer has been effectively replaced with a dynamically sized copy of wpi::static_circular_buffer with a resize() member function.
65 lines
1.9 KiB
C++
65 lines
1.9 KiB
C++
// Copyright (c) FIRST and other WPILib contributors.
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// Open Source Software; you can modify and/or share it under the terms of
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// the WPILib BSD license file in the root directory of this project.
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#pragma once
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#include "wpi/circular_buffer.h"
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namespace wpi {
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/**
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* Resizes internal buffer to given size.
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*/
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template <class T>
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void circular_buffer<T>::resize(size_t size) {
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if (size > m_data.size()) {
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// Find end of buffer
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size_t insertLocation = (m_front + m_length) % m_data.size();
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// If insertion location precedes front of buffer, push front index back
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if (insertLocation <= m_front) {
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m_front += size - m_data.size();
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}
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// Add elements to end of buffer
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m_data.insert(m_data.begin() + insertLocation, size - m_data.size(), 0);
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} else if (size < m_data.size()) {
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/* 1) Shift element block start at "front" left as many blocks as were
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* removed up to but not exceeding buffer[0]
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* 2) Shrink buffer, which will remove even more elements automatically if
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* necessary
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*/
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size_t elemsToRemove = m_data.size() - size;
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auto frontIter = m_data.begin() + m_front;
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if (m_front < elemsToRemove) {
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/* Remove elements from end of buffer before shifting start of element
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* block. Doing so saves a few copies.
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*/
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m_data.erase(frontIter + size, m_data.end());
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// Shift start of element block to left
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m_data.erase(m_data.begin(), frontIter);
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// Update metadata
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m_front = 0;
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} else {
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// Shift start of element block to left
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m_data.erase(frontIter - elemsToRemove, frontIter);
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// Update metadata
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m_front -= elemsToRemove;
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}
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/* Length only changes during a shrink if all unused spaces have been
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* removed. Length decreases as used spaces are removed to meet the
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* required size.
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*/
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if (m_length > size) {
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m_length = size;
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}
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}
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}
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} // namespace wpi
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