utils.h

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/*
 * Copyright 2015-2019 CNRS-UM LIRMM, CNRS-AIST JRL
 */
 
#pragma once
 
#include <mc_rtc/logging.h>
 
#include <atomic>
 
namespace
{
 
template<typename T, size_t Size>
struct CircularBuffer
{
public:
  enum
  {
    Capacity = Size + 1
  };
 
  CircularBuffer() : tail_(0), head_(0)
  {
    if(!tail_.is_lock_free())
    {
      mc_rtc::log::warning("Your platform does not support std::atomic_size_t as lock free operations");
    }
  }
 
  bool push(const T & item)
  {
    size_t tail = tail_;
    auto next_tail = increment(tail);
    if(next_tail != head_)
    {
      data_[tail] = item;
      tail_ = next_tail;
      return true;
    }
    return false;
  }
 
  bool pop(T & item)
  {
    const size_t head = head_;
    if(head == tail_) { return false; }
    item = data_[head];
    head_ = increment(head);
    return true;
  }
 
  bool empty() { return head_ == tail_; }
 
private:
  size_t increment(size_t idx) const { return (idx + 1) % Capacity; }
 
  T data_[Capacity];
  std::atomic_size_t tail_;
  std::atomic_size_t head_;
};
 
} // namespace