uibhmQueue.h

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/************************************************************************
**
** Copyright (C) 2014 by Carlos Augusto Teixera Mendes
** All rights reserved.
**
** This file is part of the "GeMA" software. It's use should respect
** the terms in the license agreement that can be found together
** with this source code.
** It is provided AS IS, with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE.
**
************************************************************************/
 
#ifndef _UIBHM_QUEUE_H_
#define _UIBHM_QUEUE_H_
 
#include <QVector>
#include <assert.h>
 
 
template <class T> class UibhmQueue 
{
public:
  UibhmQueue() : _data(16), _head(0), _tail(0), _size(0) {}
 
  bool empty() const { return !_size; }
  int  size()  const { return _size; }
 
  void enqueue(const T& value) 
  {
    grow();
    _data[_tail] = value;
    _tail = (_tail + 1) % _data.size();
    _size++;
  }
 
  T dequeue()
  {
    assert(!empty());
    T value = _data[_head];
    _head = (_head + 1) % _data.size();
    _size--;
    return value;
  }
 
private:
  void grow() {
    if(_size < _data.size())
      return;
    QVector<T> newData(_size * 2);
 
    for(int i = 0; i < _size; i++)
      newData[i] = _data[(_head + i) % _size];
 
    _data.swap(newData);
    _head = 0;
    _tail = _size;
  }
 
  QVector<T> _data;  
  int        _head;  
  int        _tail;  
  int        _size;  
};
 
 
#endif