/* emacs edit mode for this file is -*- C++ -*- */

/**
 * @file cf_generator.h
 *
 * generate integers, elements of finite fields
**/

#ifndef INCL_CF_GENERATOR_H
#define INCL_CF_GENERATOR_H

// #include "config.h"

#include "canonicalform.h"

/*BEGINPUBLIC*/

/**
 * virtual class for generators
**/
class CFGenerator
{
public:
    CFGenerator() {}
    virtual ~CFGenerator() {}
    virtual bool hasItems() const { return false; }
    virtual void reset() {};
    virtual CanonicalForm item() const { return 0; }
    virtual void next() {};
    virtual CFGenerator * clone() const { return new CFGenerator();}
};

/**
 * generate integers starting from 0
**/
class IntGenerator : public CFGenerator
{
private:
    int current;
public:
    IntGenerator() : current(0) {}
    ~IntGenerator() {}
    bool hasItems() const;
    void reset() { current = 0; }
    CanonicalForm item() const;
    void next();
    void operator++ () { next(); }
    void operator++ ( int ) { next(); }
    CFGenerator * clone() const;
};

/**
 * generate all elements in F_p starting from 0
**/
class FFGenerator : public CFGenerator
{
private:
    int current;
public:
    FFGenerator() : current(0) {}
    ~FFGenerator() {}
    bool hasItems() const;
    void reset() { current = 0; }
    CanonicalForm item() const;
    void next();
    void operator++ () { next(); }
    void operator++ ( int ) { next(); }
    CFGenerator * clone() const;
};

/**
 * generate all elements in GF starting from 0
**/
class GFGenerator : public CFGenerator
{
private:
    int current;
public:
    GFGenerator();
    ~GFGenerator() {}
    bool hasItems() const;
    void reset();
    CanonicalForm item() const;
    void next();
    void operator++ () { next(); }
    void operator++ ( int ) { next(); }
    CFGenerator * clone() const;
};

/**
 * generate all elements in F_p(alpha) starting from 0
**/
class AlgExtGenerator: public CFGenerator
{
private:
    Variable algext;
    FFGenerator **gensf;
    GFGenerator **gensg;
    int n;
    bool nomoreitems;
    AlgExtGenerator();
    AlgExtGenerator( const AlgExtGenerator & );
    AlgExtGenerator& operator= ( const AlgExtGenerator & );
public:
    AlgExtGenerator( const Variable & a );
    ~AlgExtGenerator();

    bool hasItems() const { return ! nomoreitems; }
    void reset();
    CanonicalForm item() const;
    void next();
    void operator++ () { next(); }
    void operator++ ( int ) { next(); }
    CFGenerator * clone() const;
};

class CFGenFactory
{
public:
    static CFGenerator* generate();
};

/*ENDPUBLIC*/

#endif /* ! INCL_CF_GENERATOR_H */