windows-xp/Source/XPSP1/NT/termsrv/remdsk/rds/t120/h/randchnl.h

/*
 *	randchnl.h
 *
 *	Copyright (c) 1995 by DataBeam Corporation, Lexington, KY
 *
 *	Abstract:
 *		This is the interface file for the RandomChannelGenerator class.  This
 *		class inherits from the RandomNumberGenerator class.  On instantiation,
 *		instances of this class will internally generate a random number which
 *		falls within the allowable range of dynamic channel values.  Channel
 *		assignments are then generated by incrementing this value each time a
 *		new assignment is requested.  Once the maximum allowable value has been
 *		assigned, the next value to be generated "wraps around" to the minimum
 *		allowable value.
 *
 *		Obviously, this class does not generate completely random channel
 *		values for each request.  With a completely random generator, it is
 *		possible to delete a channel in MCS, and then have the random number
 *		generator assign the same value as the deleted channel before all
 *		components of the system even know that the channel was deleted to
 *		start with, thus causing erratic behavior in the system.  In this
 *		class, no channel can be reassigned until all other possible channels
 *		have been assigned.
 *
 *		This class can be modifed in the future to incorporate additional
 *		"randomness" into the algorithm and still not reassign any channel
 *		numbers before all other possible values are used.  This, however,
 *		would be at the expense of performance and/or memory resources.
 *                  
 *	Caveats:
 *		None.
 *
 *	Author:
 *		Alan D. May
 */
#ifndef _RANDOM_CHANNEL_GENERATOR_
#define _RANDOM_CHANNEL_GENERATOR_

#include "databeam.h"
#include "random.h"

/*
 *	The definition of the RandomChannelGenerator class.
 */
class RandomChannelGenerator
{
	public:
						RandomChannelGenerator ();
		virtual			~RandomChannelGenerator ();
		RandomValue		GetRandomChannel ();

	private:
		ULong			Current_Channel;
};		
typedef RandomChannelGenerator *		PRandomChannelGenerator;

/*
 *	RandomChannelGenerator ()
 *
 *	Functional Description:
 *		The constructor creates a random channel generator object by calling the
 *		constructor for the parent class, RandomNumberGenerator.  This then
 *		automatically seeds the random number generator with the current time.
 *		The default algorithm will be used.
 *
 *	Formal Parameters:
 *		None.
 *
 *	Return Value:
 *		None.
 *
 *	Side Effects:
 *		None.
 *
 *	Caveats:
 *		None.
 */

/*
 *	~RandomChannelGenerator ()
 *
 *	Public
 *
 *	Functional Description:
 *		This is the destructor for the RandomChannelGenerator class.
 *
 *	Formal Parameters:
 *		None.
 *
 *	Return Value:
 *		None.
 *
 *	Side Effects:
 *		None.
 *
 *	Caveats:
 *		None.
 */

/*
 *	RandomValue		GetRandomChannel ()
 *
 *	Public
 *
 *	Functional Description:
 *		This method returns a valid dynamic channel number.
 *
 *	Formal Parameters:
 *		None.
 *
 *	Return Value:
 *		A RandomValue in the range of valid dynamic channel values.
 *
 *	Side Effects:
 *		None.
 *
 *	Caveats:
 *		None.
 */

#endif