text: /*=========================================================================
   *
   *  Copyright NumFOCUS
   *
   *  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
   *
   *         https://www.apache.org/licenses/LICENSE-2.0.txt
   *
   *  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.
   *
   *=========================================================================*/
  #include "itkBarrier.h"
  
  namespace itk
  {
  Barrier::Barrier() = default;
  
  Barrier::~Barrier() = default;
  
  void
  Barrier::Initialize(unsigned int n)
  {
    m_NumberExpected = n;
  }
  
  void
  Barrier::Wait()
  {
    std::unique_lock<std::mutex> lockHolder{ m_Mutex };
    unsigned int                 lGeneration = m_Generation;
    ++m_NumberArrived;
    if (m_NumberArrived == m_NumberExpected)
    {
      // Clear all blocked threads
      ++m_Generation;
      m_NumberArrived = 0;
      m_ConditionVariable.notify_all();
    }
    else
    {
      // Block this thread
      m_ConditionVariable.wait(lockHolder, [this, lGeneration] { return lGeneration != m_Generation; });
    }
  }
  
  } // end namespace itk
  