/*

    File:       Random.h

    Contains:   TRandom is a stackbased utility class for random number generation.

                TRandom.h contains the header file information for the class.

    Written by:     

    Copyright:  Copyright © 1991-1999 by Apple Computer, Inc., All Rights Reserved.

                You may incorporate this Apple sample source code into your program(s) without

                restriction. This Apple sample source code has been provided "AS IS" and the

                responsibility for its operation is yours. You are not permitted to redistribute

                this Apple sample source code as "Apple sample source code" after having made

                changes. If you're going to re-distribute the source, we require that you make

                it clear in the source that the code was descended from Apple sample source

                code, but that you've made changes.

    Change History (most recent first):

                8/18/1999   Karl Groethe    Updated for Metrowerks Codewarror Pro 2.1

*/

// Declare label for this header file

#ifndef _RANDOM_

#define _RANDOM_

// HEADER FILES

#ifndef _DTSCPLUSLIBRARY_

#include "DTSCPlusLibrary.h"

#endif

//  TOOLBOX INCLUDES

#ifndef __TYPES__

#include <Types.h>

#endif

#ifndef __OSUTILS__

#include <OSUtils.h>

#endif

#ifndef __kQUICKDRAW__

#include <Quickdraw.h>

#endif

#ifndef __EVENTS__

#include <Events.h>

#endif

//  EXTERNAL FUNCTIONS

// _________________________________________________________________________________________________________ //

//  TRandom Interface

class TRandom

// The Random number class will produce random numbers within a certain range

// which could be specified. Compared with the Toolbox Random function 

// TRandom is also able to swith between various alternate random algorithms

// and the random generator could be cloned using copy constructors

{

public:

    //  TYPEDEFS AND ENUMS

    enum ERandType

    {

        kMACOS, kSHUFFLE, kPM

    };                                          // selected random number generator

    //  CONSTRUCTORS & DESTRUCTORS

    TRandom(ERandType = kMACOS,

            long theSeed = 1,

            unsigned short low = 0,

            unsigned short high = 100);         // default constructor

    TRandom(const TRandom&);                    // copy constructor

    TRandom& operator=(const TRandom&);         // assignment operator

    virtual~ TRandom();                         // virtual destructor

protected:

    Boolean IRandom(ERandType);                 // initialize needed class information

public:

    //  MAIN INTERFACES

    unsigned short Next();                      // get next random number

    TRandom& ShuffleSeed();                     // set seed value

    TRandom& SetRandomGenerator(ERandType);     // select random number algorithm

    //  PUBLIC ACCESSORS AND MUTATORS

    long GetSeedValue() const;                  // get current seed value

    TRandom& SetSeedValue(const long theSeed);  // get seed value and return a this pointer to a class

    ERandType GetAlgorithmType() const;         // get currently used algoritm type

protected:

    //  RANDOM GENERATOR ALGORITHMS/MEMBER FUNCTIONS

    unsigned short MacRandom();                 // Toolbox Random function

    unsigned short ShuffleRandom();             // shuffle Toolbox random values

    TRandom& InitShuffleRandom();               // initialize the shuffle algorithm

    unsigned short ParkMiller();                // Park&Miller Random generator

protected:

    //  TYPEDEFS AND ENUMS (INTERNAL IMPLEMENTATION)

    enum eSIZE

    {

        kSHUFFLETABLE = 128, kPM1 = 2836, kPM2 = 16807, k16BIT = 65536, kPM3 = 127773, kMSEED = 1618003398, eBIG = 1000000000, kACM_MAX = 2147483647

    };

    typedef unsigned short(TRandom::* RandGen)();// ptr to actual selected random routine

    //  FIELDS

    RandGen fGenerator;                         // selected random generator function

    ERandType fAlgorithm;                       // selected algorithm

    unsigned short fLow;                        // lower limit of random number

    unsigned short fHigh;                       // higher limit of random number

    unsigned short fRange;                      // max size random number

    long fSeed;                                 // random generator seed

    Boolean fState;                             // current state of object, OK or BAD

    unsigned short fPrevNum;                    // previous random number

    unsigned short fShuffleBuf[kSHUFFLETABLE];  // buffer for the shuffle algorithm

};

#endif 

// _________________________________________________________________________________________________________ //

/*  Change History (most recent last):

  No        Init.   Date        Comment

  1         khs     6/2/92      New file

  2         khs     1/7/93      Cleanup

*/