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/* This file is part of the KDE libraries
Copyright (c) 1999 Sean Harmer <sh@astro.keele.ac.uk>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License version 2 as published by the Free Software Foundation.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#ifndef K_RANDOM_SEQUENCE_H
#define K_RANDOM_SEQUENCE_H
#include "kdelibs_export.h"
class KRandomSequencePrivate;
class QGList;
/**
* A class to create a pseudo-random sequence
*
* Given a seed number, this class will produce a sequence of
* pseudo-random numbers. This would typically be used in
* applications like games.
*
* In general, you should instantiate a KRandomSequence object and
* pass along your seed number in the constructor. From then on,
* simply call getDouble() or getLong() to obtain the next
* number in the sequence.
*
* @author Sean Harmer <sh@astro.keele.ac.uk>
*/
class KDECORE_EXPORT KRandomSequence
{
public:
/**
* Creates a pseudo-random sequence based on the seed lngSeed.
*
* A Pseudo-random sequence is different for each seed but can be
* reproduced by starting the sequence with the same seed.
*
* If you need a single value which needs to be unpredictable,
* you need to use kapp->random() instead.
*
* @param lngSeed Seed to initialize the sequence with.
* If lngSeed is 0, the sequence is initialized with a value from
* KApplication::random().
*/
KRandomSequence( long lngSeed = 0 );
/**
* Standard destructor
*/
virtual ~KRandomSequence();
/**
* Copy constructor
*/
KRandomSequence(const KRandomSequence &a);
/**
* Assignment
*/
KRandomSequence &operator=(const KRandomSequence &a);
/**
* Restart the sequence based on lngSeed.
* @param lngSeed Seed to initialize the sequence with.
* If lngSeed is 0, the sequence is initialized with a value from
* KApplication::random().
*/
void setSeed( long lngSeed = 0 );
/**
* Get the next number from the pseudo-random sequence.
*
* @return a pseudo-random double value between [0,1[
*/
double getDouble();
/**
* Get the next number from the pseudo-random sequence.
*
* @return a pseudo-random integer value between [0, max[
* with 0 <= max < 1.000.000
*/
unsigned long getLong(unsigned long max);
/**
* Get a boolean from the pseudo-random sequence.
*
* @return a boolean which is either true or false
*/
bool getBool();
/**
* Put a list in random order.
*
* @param list the list whose order will be modified
*/
void randomize(QGList *list);
/**
* Modulate the random sequence.
*
* If S(i) is the sequence of numbers that will follow
* given the current state after calling modulate(i),
* then S(i) != S(j) for i != j and
* S(i) == S(j) for i == j.
*
* This can be useful in game situation where "undo" restores
* the state of the random sequence. If the game modulates the
* random sequence with the move chosen by the player, the
* random sequence will be identical whenever the player "redo"-s
* his or hers original move, but different when the player
* chooses another move.
*
* With this scenario "undo" can no longer be used to repeat a
* certain move over and over again until the computer reacts
* with a favorable response or to predict the response for a
* certain move based on the response to another move.
* @param i the sequence identified
*/
void modulate(int i);
private:
void Draw(); // Generate the random number
long m_lngSeed1;
long m_lngSeed2;
long m_lngShufflePos;
static const int m_nShuffleTableSize;
long *m_ShuffleArray;
KRandomSequencePrivate *d;
};
#endif
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