Ring.icc

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/*
  Copyright (C) 2002-2018 CERN for the benefit of the ATLAS collaboration
*/
/*
 */
/**
 * @file CxxUtils/Ring.icc
 * @author scott snyder <snyder@bnl.gov>
 * @date May, 2018
 * @brief A simple ring buffer.
 */
 
 
namespace CxxUtils {
 
 
/** 
 * @brief Clear the buffer and set its size.
 * @param size New size of the buffer.
 */
template <class T>
inline
void Ring<T>::reset (size_t size)
{
  m_data.clear();
  m_data.resize (size);
  m_pos = 0;
}
 
 
/**
 * @brief Add a new item to the buffer.
 * @param x Item to add.
 */
template <class T>
inline
void Ring<T>::push (const T& x)
{
  m_data[m_pos++] = x;
  if (m_pos >= m_data.size()) {
    m_pos = 0;
  }
}
 
 
/**
 * @brief Return a copy of keys in the buffer.
 *
 * Immediately adjacent duplicates and unfilled entries will be removed,
 * so the result may be smaller than the size of the buffer.
 */
template <class T>
std::vector<T>
Ring<T>::getKeysDedup() const
{
  size_t sz = m_data.size();
  std::vector<T> keys;
  keys.reserve (sz);
  T last_key = T();
 
  for (size_t pos = m_pos; pos < sz; ++pos) {
    if (m_data[pos] != last_key) {
      last_key = m_data[pos];
      keys.push_back (last_key);
    }
  }
 
  for (size_t pos = 0; pos < m_pos; ++pos) {
    if (m_data[pos] != last_key) {
      last_key = m_data[pos];
      keys.push_back (last_key);
    }
  }
 
  return keys;
}
 
 
} // namespace CxxUtils