JSharedCounter.hh

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#ifndef __JLANG__JSHAREDCOUNTER__
#define __JLANG__JSHAREDCOUNTER__
 
#include <cstdlib>
 
/**
 * \author mdejong
 */
 
namespace JLANG {}
namespace JPP { using namespace JLANG; }
 
namespace JLANG {
 
 
  /**
   * Shared counter.
   */
  class JSharedCounter 
  {
  public:
    /**
     * Default constructor.
     */
    JSharedCounter() :
      counter(NULL)
    {}
 
 
    /**
     * Initialise counter.
     */
    void initialise()
    {
      detach();
 
      counter = new int(1);
    }
 
 
    /**
     * Attach this counter to given shared counter object.
     *
     * \param  object   shared counter
     */
    void attach(const JSharedCounter& object)
    {
      detach();
 
      counter = object.counter;
 
      if (counter != NULL) {
        ++(*counter);
      }
    }
 
 
    /**
     * Detach.
     *
     * \return          true if counter at zero; else false
     */
    bool detach() 
    {
      if (counter != NULL) {
 
        if (--(*counter) == 0) {
 
          delete counter;
 
          counter = NULL;
 
          return true;
        }
 
        counter = NULL;
      }
 
      return false;
    }
 
  protected:
    int* counter;
  };
}
 
#endif