/* This file is part of the KDE libraries
   Copyright (c) 2005 Klaus Niederkrueger <kniederk@math.uni-koeln.de>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   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.
*/

#include "knumber_priv.h"

#include <cmath>
#include <config-kcalc.h>
#include <cstdlib>
#ifdef Q_OS_LINUX
#include <csignal>
#include <csetjmp>
#endif

#include <QRegExp>

#if defined(Q_OS_SOLARIS) && defined(__SUNPRO_CC)
// Strictly by the standard, ininf() is a c99-ism which
// is unavailable in C++. The IEEE FP headers provide
// a function with similar functionality, so use that instead.
// However, !finite(a) == isinf(a) || isnan(a), so it's
// not 100% correct.
#include <ieeefp.h>
#define isinf(a) !finite(a)
#endif


detail::knumerror::knumerror(const knumber &num)
{
    switch (num.type()) {
    case SpecialType:
        error_ = dynamic_cast<const knumerror &>(num).error_;
        break;
    case IntegerType:
    case FractionType:
    case FloatType:
        // TODO: What should I do here?
        break;
    }
}

detail::knuminteger::knuminteger(qint64 num)
{
    mpz_init(mpz_);
#if SIZEOF_SIGNED_LONG == 8
    mpz_set_si(mpz_, static_cast<signed long int>(num));
#elif SIZEOF_SIGNED_LONG == 4
    mpz_set_si(mpz_, static_cast<signed long int>(num >> 32));
    mpz_mul_2exp(mpz_, mpz_, 32);
    mpz_add_ui(mpz_, mpz_, static_cast<signed long int>(num));
#else
#error "SIZEOF_SIGNED_LONG is a unhandled case"
#endif
}

detail::knuminteger::knuminteger(quint64 num)
{
    mpz_init(mpz_);
#if SIZEOF_UNSIGNED_LONG == 8
    mpz_set_ui(mpz_, static_cast<unsigned long int>(num));
#elif SIZEOF_UNSIGNED_LONG == 4
    mpz_set_ui(mpz_, static_cast<unsigned long int>(num >> 32));
    mpz_mul_2exp(mpz_, mpz_, 32);
    mpz_add_ui(mpz_, mpz_, static_cast<unsigned long int>(num));
#else
#error "SIZEOF_UNSIGNED_LONG is a unhandled case"
#endif
}

detail::knuminteger::knuminteger(const knumber &num)
{
    mpz_init(mpz_);

    switch (num.type()) {
    case IntegerType:
        mpz_set(mpz_, dynamic_cast<const knuminteger &>(num).mpz_);
        break;
    case FractionType:
    case FloatType:
    case SpecialType:
        // TODO: What should I do here?
        break;
    }
}

detail::knumfraction::knumfraction(const knumber &num)
{
    mpq_init(mpq_);

    switch (num.type()) {
    case IntegerType:
        mpq_set_z(mpq_, dynamic_cast<const knuminteger &>(num).mpz_);
        break;
    case FractionType:
        mpq_set(mpq_, dynamic_cast<const knumfraction &>(num).mpq_);
        break;
    case FloatType:
    case SpecialType:
        // TODO: What should I do here?
        break;
    }
}

detail::knumfloat::knumfloat(const knumber &num)
{
    mpf_init(mpf_);

    switch (num.type()) {
    case IntegerType:
        mpf_set_z(mpf_, dynamic_cast<const knuminteger &>(num).mpz_);
        break;
    case FractionType:
        mpf_set_q(mpf_, dynamic_cast<const knumfraction &>(num).mpq_);
        break;
    case FloatType:
        mpf_set(mpf_, dynamic_cast<const knumfloat &>(num).mpf_);
        break;
    case SpecialType:
        // What should I do here?
        break;
    }
}

detail::knumerror::knumerror(const QString &num)
{
    if (num == QLatin1String( "nan" ))       error_ = UndefinedNumber;
    else if (num == QLatin1String( "inf" ))  error_ = Infinity;
    else if (num == QLatin1String( "-inf" )) error_ = MinusInfinity;
    else                    error_ = UndefinedNumber;
}

detail::knuminteger::knuminteger(const QString &num)
{
    mpz_init(mpz_);
    mpz_set_str(mpz_, num.toAscii(), 10);
}

detail::knumfraction::knumfraction(const QString &num)
{
    mpq_init(mpq_);
    if (QRegExp(QLatin1String( "^[+-]?\\d+(\\.\\d*)?(e[+-]?\\d+)?$" )).exactMatch(num)) {
        // my hand-made conversion is terrible
        // first me convert the mantissa
        unsigned long int digits_after_dot = ((num.section(QLatin1Char( '.' ), 1, 1)).section(QLatin1Char( 'e' ), 0, 0)).length();

        QString tmp_num = num.section(QLatin1Char( 'e' ), 0, 0).remove(QLatin1Char( '.' ));
        mpq_set_str(mpq_, tmp_num.toAscii(), 10);

        mpz_t tmp_int;
        mpz_init(tmp_int);
        mpz_ui_pow_ui(tmp_int, 10, digits_after_dot);
        mpz_mul(mpq_denref(mpq_), mpq_denref(mpq_), tmp_int);

        // now we take care of the exponent
        if (!(tmp_num = num.section(QLatin1Char( 'e' ), 1, 1)).isEmpty()) {
            long int tmp_exp = tmp_num.toLong();
            if (tmp_exp > 0) {
                mpz_ui_pow_ui(tmp_int,
                              10,
                              static_cast<unsigned long int>(tmp_exp));

                mpz_mul(mpq_numref(mpq_), mpq_numref(mpq_), tmp_int);
            } else {
                mpz_ui_pow_ui(tmp_int,
                              10,
                              static_cast<unsigned long int>(-tmp_exp));

                mpz_mul(mpq_denref(mpq_), mpq_denref(mpq_), tmp_int);
            }
        }
        mpz_clear(tmp_int);
    } else {
        mpq_set_str(mpq_, num.toAscii(), 10);
    }

    mpq_canonicalize(mpq_);
}

detail::knumfloat::knumfloat(const QString &num)
{
    mpf_init(mpf_);
    mpf_set_str(mpf_, num.toAscii(), 10);
}

const detail::knuminteger &detail::knuminteger::operator=(const knuminteger &num)
{
    if (this == &num) {
        return *this;
    }

    mpz_set(mpz_, num.mpz_);
    return *this;
}

QString detail::knumerror::ascii(int prec) const
{
    Q_UNUSED(prec);

    // TODO: i18n these strings here and elsewhere, as they're user visible
    switch (error_) {
    case UndefinedNumber:
        return QLatin1String( "nan" );
    case Infinity:
        return QLatin1String( "inf" );
    case MinusInfinity:
        return QLatin1String( "-inf" );
    default:
        return QString();
    }
}

QString detail::knuminteger::ascii(int prec) const
{
    Q_UNUSED(prec);

    // get the size of the string
    const size_t size = gmp_snprintf(NULL, 0, "%Zd", mpz_) + 1;

    char *const tmp_ptr = new char[size];
    gmp_snprintf(tmp_ptr, size, "%Zd", mpz_);

    const QString ret_str = QLatin1String( tmp_ptr );

    delete [] tmp_ptr;
    return ret_str;
}

QString detail::knumfraction::ascii(int prec) const
{
    Q_UNUSED(prec);

    char *tmp_ptr = mpq_get_str(0, 10, mpq_);
    const QString ret_str = QLatin1String( tmp_ptr );
    free(tmp_ptr);

    return ret_str;
}

QString detail::knumfloat::ascii(int prec) const
{
    size_t size;

    if (prec > 0) {
        size = gmp_snprintf(NULL, 0, (QLatin1String( "%." ) + QString::number(prec) + QLatin1String( "Fg" )).toAscii(), mpf_) + 1;
    } else {
        size = gmp_snprintf(NULL, 0, "%Fg", mpf_) + 1;
    }

    char *const tmp_ptr = new char[size];

    if (prec > 0) {
        gmp_snprintf(tmp_ptr, size, (QLatin1String( "%." ) + QString::number(prec) + QLatin1String( "Fg" )).toAscii(), mpf_);
    } else {
        gmp_snprintf(tmp_ptr, size, "%Fg", mpf_);
    }

    const QString ret_str = QLatin1String( tmp_ptr );

    delete [] tmp_ptr;
    return ret_str;
}


bool detail::knumfraction::isInteger() const
{
    return (mpz_cmp_ui(mpq_denref(mpq_), 1) == 0);
}


detail::knumber *detail::knumerror::abs() const
{
    knumerror *const tmp_num = new knumerror(*this);

    if (error_ == MinusInfinity) {
        tmp_num->error_ = Infinity;
    }

    return tmp_num;
}

detail::knumber *detail::knuminteger::abs() const
{
    knuminteger *const tmp_num = new knuminteger();
    mpz_abs(tmp_num->mpz_, mpz_);
    return tmp_num;
}

detail::knumber *detail::knumfraction::abs() const
{
    knumfraction *const tmp_num = new knumfraction();
    mpq_abs(tmp_num->mpq_, mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfloat::abs() const
{
    detail::knumfloat *const tmp_num = new detail::knumfloat();
    mpf_abs(tmp_num->mpf_, mpf_);
    return tmp_num;
}

detail::knumber *detail::knumerror::intPart() const
{
    return new knumerror(*this);
}

detail::knumber *detail::knuminteger::intPart() const
{
    detail::knuminteger *const tmp_num = new detail::knuminteger();
    mpz_set(tmp_num->mpz_, mpz_);
    return tmp_num;
}

detail::knumber *detail::knumfraction::intPart() const
{
    detail::knuminteger *tmp_num = new detail::knuminteger();
    mpz_set_q(tmp_num->mpz_, mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfloat::intPart() const
{
    detail::knuminteger *tmp_num = new detail::knuminteger();
    mpz_set_f(tmp_num->mpz_, mpf_);
    return tmp_num;
}


int detail::knumerror::sign() const
{
    switch (error_) {
    case Infinity:
        return 1;
    case MinusInfinity:
        return -1;
    default:
        return 0;
    }
}

int detail::knuminteger::sign() const
{
    return mpz_sgn(mpz_);
}

int detail::knumfraction::sign() const
{
    return mpq_sgn(mpq_);
}

int detail::knumfloat::sign() const
{
    return mpf_sgn(mpf_);
}

#ifdef __GNUC__
#warning "cube_root for now this is a stupid work around"
#endif

namespace {
void cube_root(mpf_t &num)
{
#ifdef Q_CC_MSVC
    const double tmp_num = pow(mpf_get_d(num), 1. / 3.);
#else
    const double tmp_num = ::cbrt(mpf_get_d(num));
#endif
    mpf_init_set_d(num, tmp_num);
}
}

detail::knumber *detail::knumerror::cbrt() const
{
    // infty ^3 = infty;  -infty^3 = -infty
    return new knumerror(*this);
}

detail::knumber *detail::knuminteger::cbrt() const
{
    knuminteger *const tmp_num = new knuminteger();

    if (mpz_root(tmp_num->mpz_, mpz_, 3)) {
        return tmp_num; // root is perfect
    }

    delete tmp_num; // root was not perfect, result will be float

    knumfloat *const tmp_num2 = new knumfloat();
    mpf_set_z(tmp_num2->mpf_, mpz_);
    cube_root(tmp_num2->mpf_);
    return tmp_num2;
}

detail::knumber *detail::knumfraction::cbrt() const
{
    knumfraction *const tmp_num = new knumfraction();

    if (mpz_root(mpq_numref(tmp_num->mpq_), mpq_numref(mpq_), 3) &&
        mpz_root(mpq_denref(tmp_num->mpq_), mpq_denref(mpq_), 3)) {

        return tmp_num; // root is perfect
    }

    delete tmp_num; // root was not perfect, result will be float

    knumfloat *const tmp_num2 = new knumfloat();
    mpf_set_q(tmp_num2->mpf_, mpq_);
    cube_root(tmp_num2->mpf_);
    return tmp_num2;
}

detail::knumber *detail::knumfloat::cbrt() const
{
    knumfloat *const tmp_num = new knumfloat(*this);
    cube_root(tmp_num->mpf_);
    return tmp_num;
}

detail::knumber *detail::knumerror::sqrt() const
{
    knumerror *const tmp_num = new knumerror(*this);

    if (error_ == MinusInfinity) {
        tmp_num->error_ = UndefinedNumber;
    }

    return tmp_num;
}

detail::knumber *detail::knuminteger::sqrt() const
{
    if (mpz_sgn(mpz_) < 0) {
        return new knumerror(UndefinedNumber);
    }

    if (mpz_perfect_square_p(mpz_)) {
        knuminteger *const tmp_num = new knuminteger();
        mpz_sqrt(tmp_num->mpz_, mpz_);
        return tmp_num;
    } else {
        knumfloat *const tmp_num = new knumfloat();
        mpf_set_z(tmp_num->mpf_, mpz_);
        mpf_sqrt(tmp_num->mpf_, tmp_num->mpf_);
        return tmp_num;
    }
}

detail::knumber *detail::knumfraction::sqrt() const
{
    if (mpq_sgn(mpq_) < 0) {
        knumerror *const tmp_num = new knumerror(UndefinedNumber);
        return tmp_num;
    }

    if (mpz_perfect_square_p(mpq_numref(mpq_)) &&
        mpz_perfect_square_p(mpq_denref(mpq_))) {

        knumfraction *const tmp_num = new knumfraction();
        mpq_set(tmp_num->mpq_, mpq_);
        mpz_sqrt(mpq_numref(tmp_num->mpq_), mpq_numref(tmp_num->mpq_));
        mpz_sqrt(mpq_denref(tmp_num->mpq_), mpq_denref(tmp_num->mpq_));

        return tmp_num;
    } else {
        knumfloat *const tmp_num = new knumfloat();
        mpf_set_q(tmp_num->mpf_, mpq_);
        mpf_sqrt(tmp_num->mpf_, tmp_num->mpf_);

        return tmp_num;
    }

    return new knumfraction();
}

detail::knumber *detail::knumfloat::sqrt() const
{
    if (mpf_sgn(mpf_) < 0) {
        return new knumerror(UndefinedNumber);
    }

    knumfloat *const tmp_num = new knumfloat();
    mpf_sqrt(tmp_num->mpf_, mpf_);
    return tmp_num;
}

detail::knumber *detail::knumerror::factorial() const
{
    return new knumerror(*this);
}

#ifdef Q_OS_LINUX
static jmp_buf abort_factorial;
static void factorial_abort_handler(int)
{
    longjmp(abort_factorial, 1);
}
#endif

detail::knumber *detail::knuminteger::factorial() const
{
    if (mpz_sgn(mpz_) < 0) {
        return new knumerror(UndefinedNumber);
    }

#ifdef Q_OS_LINUX
    struct sigaction new_sa;
    struct sigaction old_sa;

    sigemptyset(&new_sa.sa_mask);
    new_sa.sa_handler = factorial_abort_handler;
    sigaction(SIGABRT, &new_sa, &old_sa);

    if(setjmp(abort_factorial)) {
        sigaction(SIGABRT, &old_sa, 0);
        return new knumerror(UndefinedNumber);
    }
#endif

    knuminteger *const tmp_num = new knuminteger();
    mpz_fac_ui(tmp_num->mpz_, mpz_get_ui(mpz_));

#ifdef Q_OS_LINUX
    sigaction(SIGABRT, &old_sa, 0);
#endif

    return tmp_num;
}

detail::knumber *detail::knumfraction::factorial() const
{
    if (mpq_sgn(mpq_) < 0) {
        return new knumerror(UndefinedNumber);
    }

    knuminteger tmp_num;
    mpz_set_q(tmp_num.mpz_, mpq_);
    const unsigned long int op = mpz_get_ui(tmp_num.mpz_);

    knuminteger *const tmp_num2 = new knuminteger();
    mpz_fac_ui(tmp_num2->mpz_, op);
    return tmp_num2;
}

detail::knumber *detail::knumfloat::factorial() const
{
    if (mpf_sgn(mpf_) < 0) {
        return new knumerror(UndefinedNumber);
    }

    knuminteger tmp_num;
    mpz_set_f(tmp_num.mpz_, mpf_);
    const unsigned long int op = mpz_get_ui(tmp_num.mpz_);

    knuminteger *const tmp_num2 = new knuminteger();
    mpz_fac_ui(tmp_num2->mpz_, op);
    return tmp_num2;
}

detail::knumber *detail::knumerror::change_sign() const
{
    knumerror *const tmp_num = new knumerror();

    if (error_ == Infinity)      tmp_num->error_ = MinusInfinity;
    if (error_ == MinusInfinity) tmp_num->error_ = Infinity;

    return tmp_num;
}

detail::knumber *detail::knuminteger::change_sign() const
{
    knuminteger *const tmp_num = new knuminteger();
    mpz_neg(tmp_num->mpz_, mpz_);
    return tmp_num;
}

detail::knumber *detail::knumfraction::change_sign() const
{
    knumfraction *const tmp_num = new knumfraction();
    mpq_neg(tmp_num->mpq_, mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfloat::change_sign() const
{
    knumfloat *const tmp_num = new knumfloat();
    mpf_neg(tmp_num->mpf_, mpf_);
    return tmp_num;
}


detail::knumber *detail::knumerror::reciprocal() const
{
    switch (error_) {
    case Infinity:
    case MinusInfinity:
        return new knuminteger(0);
    case UndefinedNumber:
    default:
        return new knumerror(UndefinedNumber);
    }
}

detail::knumber *detail::knuminteger::reciprocal() const
{
    if (mpz_cmp_si(mpz_, 0) == 0) {
        return new knumerror(Infinity);
    }

    knumfraction *const tmp_num = new knumfraction(*this);
    mpq_inv(tmp_num->mpq_, tmp_num->mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfraction::reciprocal() const
{
    if (mpq_cmp_si(mpq_, 0, 1) == 0) {
        return new knumerror(Infinity);
    }

    knumfraction *const tmp_num = new knumfraction();
    mpq_inv(tmp_num->mpq_, mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfloat::reciprocal() const
{
    if (mpf_cmp_si(mpf_, 0) == 0) {
        return new knumerror(Infinity);
    }

    knumfloat *const tmp_num = new knumfloat();
    mpf_div(tmp_num->mpf_, knumfloat(QLatin1String( "1.0" )).mpf_, mpf_);
    return tmp_num;
}

detail::knumber *detail::knumerror::add(const knumber &arg2) const
{
    if (arg2.type() != SpecialType) {
        return new knumerror(error_);
    }

    const knumerror &tmp_arg2 = static_cast<const knumerror &>(arg2);

    if (error_ == UndefinedNumber ||
        tmp_arg2.error_ == UndefinedNumber ||
        (error_ == Infinity && tmp_arg2.error_ == MinusInfinity) ||
        (error_ == MinusInfinity && tmp_arg2.error_ == Infinity)) {

        return new knumerror(UndefinedNumber);
    }

    return new knumerror(error_);
}

detail::knumber *detail::knuminteger::add(const knumber &arg2) const
{
    if (arg2.type() != IntegerType) {
        return arg2.add(*this);
    }

    knuminteger *const tmp_num = new knuminteger();

    mpz_add(tmp_num->mpz_, mpz_, dynamic_cast<const knuminteger &>(arg2).mpz_);

    return tmp_num;
}

detail::knumber *detail::knumfraction::add(const knumber &arg2) const
{
    if (arg2.type() == IntegerType) {
        // need to cast arg2 to fraction
        knumfraction tmp_num(arg2);
        return tmp_num.add(*this);
    }


    if (arg2.type() == FloatType || arg2.type() == SpecialType) {
        return arg2.add(*this);
    }

    knumfraction *const tmp_num = new knumfraction();
    mpq_add(tmp_num->mpq_, mpq_, dynamic_cast<const knumfraction &>(arg2).mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfloat::add(const knumber &arg2) const
{
    if (arg2.type() == SpecialType) {
        return arg2.add(*this);
    }

    if (arg2.type() != FloatType) {
        // need to cast arg2 to float
        knumfloat tmp_num(arg2);
        return tmp_num.add(*this);
    }

    knumfloat *const tmp_num = new knumfloat();
    mpf_add(tmp_num->mpf_, mpf_, dynamic_cast<const knumfloat &>(arg2).mpf_);
    return tmp_num;
}


detail::knumber *detail::knumerror::multiply(const knumber &arg2) const
{
    //improve this
    switch (arg2.type()) {
    case SpecialType: {
        const knumerror &tmp_arg2 = static_cast<const knumerror &>(arg2);

        if (error_ == UndefinedNumber || tmp_arg2.error_ == UndefinedNumber) {
            return new knumerror(UndefinedNumber);
        }

        if (this->sign() * arg2.sign() > 0) {
            return new knumerror(Infinity);
        } else {
            return new knumerror(MinusInfinity);
        }
    }
    case IntegerType:
    case FractionType:
    case FloatType: {
        int sign_arg2 = arg2.sign();

        if (error_ == UndefinedNumber || sign_arg2 == 0) {
            return new knumerror(UndefinedNumber);
        }

        if ((error_ == Infinity && sign_arg2 > 0) ||
           (error_ == MinusInfinity && sign_arg2 < 0)) {
            return new knumerror(Infinity);
        }

        return new knumerror(MinusInfinity);
    }
    }

    return new knumerror(error_);
}


detail::knumber *detail::knuminteger::multiply(const knumber &arg2) const
{
    if (arg2.type() != IntegerType) {
        return arg2.multiply(*this);
    }

    knuminteger *const tmp_num = new knuminteger();
    mpz_mul(tmp_num->mpz_, mpz_, dynamic_cast<const knuminteger &>(arg2).mpz_);
    return tmp_num;
}

detail::knumber *detail::knumfraction::multiply(const knumber &arg2) const
{
    if (arg2.type() == IntegerType) {
        // need to cast arg2 to fraction
        knumfraction tmp_num(arg2);
        return tmp_num.multiply(*this);
    }

    if (arg2.type() == FloatType || arg2.type() == SpecialType) {
        return arg2.multiply(*this);
    }

    knumfraction *const tmp_num = new knumfraction();
    mpq_mul(tmp_num->mpq_, mpq_, dynamic_cast<const knumfraction &>(arg2).mpq_);
    return tmp_num;
}

detail::knumber *detail::knumfloat::multiply(const knumber &arg2) const
{
    if (arg2.type() == SpecialType) {
        return arg2.multiply(*this);
    }

    if (arg2.type() == IntegerType &&
        mpz_cmp_si(dynamic_cast<const knuminteger &>(arg2).mpz_, 0) == 0) {

        // if arg2 == 0 return integer 0!!
        return new knuminteger(0);
    }

    if (arg2.type() != FloatType) {
        // need to cast arg2 to float
        knumfloat tmp_num(arg2);
        return tmp_num.multiply(*this);
    }

    knumfloat *const tmp_num = new knumfloat();
    mpf_mul(tmp_num->mpf_, mpf_, dynamic_cast<const knumfloat &>(arg2).mpf_);
    return tmp_num;
}

detail::knumber *detail::knumber::divide(const knumber &arg2) const
{
    knumber *const tmp_num = arg2.reciprocal();
    knumber *const rslt_num = this->multiply(*tmp_num);
    delete tmp_num;
    return rslt_num;
}

detail::knumber *detail::knumfloat::divide(const knumber &arg2) const
{
    if (mpf_cmp_si(mpf_, 0) == 0) {
        return new knumerror(Infinity);
    }

    // automatically casts arg2 to float
    knumfloat *const tmp_num = new knumfloat(arg2);
    mpf_div(tmp_num->mpf_, mpf_, tmp_num->mpf_);
    return tmp_num;
}

detail::knumber *detail::knumerror::power(const knumber &/*exponent*/) const
{
    return new knumerror(UndefinedNumber);
}

detail::knumber *detail::knuminteger::power(const knumber &exponent) const
{
    if (exponent.type() == IntegerType) {

        mpz_t tmp_mpz;
        mpz_init_set(tmp_mpz,
                     dynamic_cast<const knuminteger &>(exponent).mpz_);

        if (!mpz_fits_ulong_p(tmp_mpz)) {
            // conversion wouldn't work, so use floats
            mpz_clear(tmp_mpz);

            // need to cast everything to float
            const knumfloat tmp_num1(*this);
            const knumfloat tmp_num2(exponent);
            return tmp_num1.power(tmp_num2);
        }

        const unsigned long int tmp_int = mpz_get_ui(tmp_mpz);
        mpz_clear(tmp_mpz);

        knuminteger *const tmp_num = new knuminteger();
        mpz_pow_ui(tmp_num->mpz_, mpz_, tmp_int);
        return tmp_num;
    }

    if (exponent.type() == FractionType) {
        if (mpz_sgn(mpz_) < 0) {
            return new knumerror(UndefinedNumber);
        }

        // GMP only supports few root functions, so we need to convert
        // into signed long int
        mpz_t tmp_mpz;
        mpz_init_set(tmp_mpz,
                     mpq_denref(dynamic_cast<const knumfraction &>(exponent).mpq_));

        if (!mpz_fits_ulong_p(tmp_mpz)) {
            // conversion wouldn't work, so use floats
            mpz_clear(tmp_mpz);

            // need to cast everything to float
            const knumfloat tmp_num1(*this);
            const knumfloat tmp_num2(exponent);
            return tmp_num1.power(tmp_num2);
        }

        unsigned long int tmp_int = mpz_get_ui(tmp_mpz);
        mpz_clear(tmp_mpz);

        // first check if result will be an integer
        knuminteger *const tmp_num = new knuminteger();
        const int flag = mpz_root(tmp_num->mpz_, mpz_, tmp_int);

        if (flag == 0) {   // result is not exact
            delete tmp_num;

            // need to cast everything to float
            const knumfloat tmp_num1(*this);
            const knumfloat tmp_num2(exponent);
            return tmp_num1.power(tmp_num2);
        }

        // result is exact

        mpz_init_set(tmp_mpz,
                     mpq_numref(dynamic_cast<const knumfraction &>(exponent).mpq_));

        if (!mpz_fits_ulong_p(tmp_mpz)) {     // conversion wouldn't work, so
            // use floats
            mpz_clear(tmp_mpz);

            // need to cast everything to float
            const knumfloat tmp_num1(*this);
            const knumfloat tmp_num2(exponent);
            return tmp_num1.power(tmp_num2);
        }

        tmp_int = mpz_get_ui(tmp_mpz);
        mpz_clear(tmp_mpz);

        mpz_pow_ui(tmp_num->mpz_, tmp_num->mpz_, tmp_int);

        return tmp_num;
    }

    if (exponent.type() == FloatType) {
        // need to cast everything to float
        const knumfloat tmp_num(*this);
        return tmp_num.power(exponent);
    }

    return new knumerror(Infinity);
}

detail::knumber *detail::knumfraction::power(const knumber &exponent) const
{
    knuminteger tmp_num;

    mpz_set(tmp_num.mpz_, mpq_numref(mpq_));
    knumber *const numer = tmp_num.power(exponent);

    mpz_set(tmp_num.mpz_, mpq_denref(mpq_));
    knumber *const denom = tmp_num.power(exponent);

    knumber *result;

    if (numer->type() == SpecialType) {
        result = new knumerror(*numer);
    } else if (denom->type() == SpecialType) {
        result = new knumerror(*denom);
    } else {
        result = numer->divide(*denom);
    }

    delete numer;
    delete denom;
    return result;
}

detail::knumber *detail::knumfloat::power(const knumber &exponent) const
{
    const double result = pow(static_cast<double>(*this),
                              static_cast<double>(exponent));
    if (isnan(result)) {
        return new knumerror(UndefinedNumber);
    }

    if (isinf(result)) {
        return new knumerror(Infinity);
    }

    return new knumfloat(result);
}

int detail::knumerror::compare(const knumber &arg2) const
{
    if (arg2.type() != SpecialType) {
        switch (error_) {
        case Infinity:
            return 1;
        case MinusInfinity:
            return -1;
        default:
            return 1; // Not really o.k., but what should I return
        }
    }

    switch (error_) {
    case Infinity:
        // Infinity is larger than anything else, but itself
        return (dynamic_cast<const knumerror &>(arg2).error_ == Infinity) ? 0 : 1;
    case MinusInfinity:
        // MinusInfinity is smaller than anything else, but itself
        return (dynamic_cast<const knumerror &>(arg2).error_ == MinusInfinity) ? 0 : -1;
    default:
        // Undefined only equal to itself
        return (dynamic_cast<const knumerror &>(arg2).error_ == UndefinedNumber) ? 0 : -arg2.compare(*this);
    }
}

int detail::knuminteger::compare(const knumber &arg2) const
{
    if (arg2.type() != IntegerType) {
        return - arg2.compare(*this);
    }

    return mpz_cmp(mpz_, dynamic_cast<const knuminteger &>(arg2).mpz_);
}

int detail::knumfraction::compare(const knumber &arg2) const
{
    if (arg2.type() != FractionType) {
        if (arg2.type() == IntegerType) {
            mpq_t tmp_frac;
            mpq_init(tmp_frac);
            mpq_set_z(tmp_frac,
                      dynamic_cast<const knuminteger &>(arg2).mpz_);

            const int cmp_result =  mpq_cmp(mpq_, tmp_frac);
            mpq_clear(tmp_frac);
            return cmp_result;
        } else {
            return -arg2.compare(*this);
        }
    }

    return mpq_cmp(mpq_, dynamic_cast<const knumfraction &>(arg2).mpq_);
}

int detail::knumfloat::compare(const knumber &arg2) const
{
    if (arg2.type() != FloatType) {
        mpf_t tmp_float;

        if (arg2.type() == IntegerType) {
            mpf_init(tmp_float);
            mpf_set_z(tmp_float,
                      dynamic_cast<const knuminteger &>(arg2).mpz_);
        } else if (arg2.type() == FractionType) {
            mpf_init(tmp_float);
            mpf_set_q(tmp_float,
                      dynamic_cast<const knumfraction &>(arg2).mpq_);
        } else {
            return -arg2.compare(*this);
        }

        const int cmp_result =  mpf_cmp(mpf_, tmp_float);
        mpf_clear(tmp_float);
        return cmp_result;
    }

    return mpf_cmp(mpf_, dynamic_cast<const knumfloat &>(arg2).mpf_);
}

detail::knumerror::operator long int() const
{
    // what would be the correct return values here?
    if (error_ == Infinity)           return 0;
    else if (error_ == MinusInfinity) return 0;
    else                              return 0;
}

detail::knumerror::operator unsigned long int() const
{
    // what would be the correct return values here?
    if (error_ == Infinity)           return 0;
    else if (error_ == MinusInfinity) return 0;
    else                              return 0;
}

detail::knumerror::operator long long int() const
{
    // what would be the correct return values here?
    if (error_ == Infinity)           return 0;
    else if (error_ == MinusInfinity) return 0;
    else                              return 0;
}

detail::knumerror::operator unsigned long long int() const
{
    // what would be the correct return values here?
    if (error_ == Infinity)           return 0;
    else if (error_ == MinusInfinity) return 0;
    else                              return 0;
}

detail::knuminteger::operator long int() const
{
    return mpz_get_si(mpz_);
}

detail::knumfraction::operator long int() const
{
    return static_cast<long int>(mpq_get_d(mpq_));
}

detail::knumfloat::operator long int() const
{
    return mpf_get_si(mpf_);
}

detail::knuminteger::operator unsigned long int() const
{
    return mpz_get_ui(mpz_);
}

detail::knuminteger::operator long long int() const
{
    // libgmp doesn't have long long conversion
    // so convert to string and then to long long
    char *const tmpchar = new char[mpz_sizeinbase(mpz_, 10) + 2];
    mpz_get_str(tmpchar, 10, mpz_);
    const QString tmpstring = QLatin1String( tmpchar );
    delete [] tmpchar;

    bool ok;
    long long int value = tmpstring.toLongLong(&ok, 10);

    if (!ok) {
        // TODO: what to do if error?
        value = 0;
    }
    return value;
}

detail::knuminteger::operator unsigned long long int() const
{
    // libgmp doesn't have unsigned long long conversion
    // so convert to string and then to unsigned long long
    char *const tmpchar = new char[mpz_sizeinbase(mpz_, 10) + 2];
    mpz_get_str(tmpchar, 10, mpz_);
    const QString tmpstring =QLatin1String( tmpchar );
    delete [] tmpchar;

    bool ok;
    unsigned long long int value;

    if (sign() < 0) {
        const long long signedvalue = tmpstring.toLongLong(&ok, 10);
        value = static_cast<unsigned long long>(signedvalue);
    } else {
        value = tmpstring.toULongLong(&ok, 10);
    }

    if (!ok) {
        // TODO: what to do if error?
        value = 0;
    }
    return value;
}

detail::knumfraction::operator unsigned long int() const
{
    return static_cast<unsigned long int>(mpq_get_d(mpq_));
}

detail::knumfraction::operator long long int() const
{
    return static_cast<long long int>(mpq_get_d(mpq_));
}

detail::knumfraction::operator unsigned long long int() const
{
    return static_cast<unsigned long long int>(mpq_get_d(mpq_));
}

detail::knumfloat::operator unsigned long int() const
{
    return mpf_get_ui(mpf_);
}

detail::knumfloat::operator long long int() const
{
    return static_cast<long long int>(mpf_get_si(mpf_));
}

detail::knumfloat::operator unsigned long long int() const
{
    return static_cast<unsigned long long int>(mpf_get_ui(mpf_));
}

detail::knumerror::operator double() const
{
    if (error_ == Infinity)           return INFINITY;
    else if (error_ == MinusInfinity) return -INFINITY;
    else                              return NAN;
}

detail::knuminteger::operator double() const
{
    return mpz_get_d(mpz_);
}

detail::knumfraction::operator double() const
{
    return mpq_get_d(mpq_);
}

detail::knumfloat::operator double() const
{
    return mpf_get_d(mpf_);
}

detail::knuminteger *detail::knuminteger::intAnd(const knuminteger &arg2) const
{
    knuminteger *const tmp_num = new knuminteger();
    mpz_and(tmp_num->mpz_, mpz_, arg2.mpz_);
    return tmp_num;
}

detail::knuminteger *detail::knuminteger::intOr(const knuminteger &arg2) const
{
    knuminteger *const tmp_num = new knuminteger();
    mpz_ior(tmp_num->mpz_, mpz_, arg2.mpz_);
    return tmp_num;
}

detail::knumber *detail::knuminteger::mod(const knuminteger &arg2) const
{
    if (mpz_cmp_si(arg2.mpz_, 0) == 0) {
        return new knumerror(UndefinedNumber);
    }

    knuminteger *const tmp_num = new knuminteger();
    mpz_mod(tmp_num->mpz_, mpz_, arg2.mpz_);
    return tmp_num;
}

detail::knumber *detail::knuminteger::shift(const knuminteger &arg2) const
{
    mpz_t tmp_mpz;

    mpz_init_set(tmp_mpz, arg2.mpz_);

    if (!mpz_fits_slong_p(tmp_mpz)) {
        mpz_clear(tmp_mpz);
        return new knumerror(UndefinedNumber);
    }

    const signed long int tmp_arg2 = mpz_get_si(tmp_mpz);
    mpz_clear(tmp_mpz);


    knuminteger *const tmp_num = new knuminteger();

    if (tmp_arg2 > 0)    // left shift
        mpz_mul_2exp(tmp_num->mpz_, mpz_, tmp_arg2);
    else {
        // right shift
        if(mpz_sgn(mpz_) < 0) {
            mpz_fdiv_q_2exp(tmp_num->mpz_, mpz_, -tmp_arg2);
        } else {
            mpz_tdiv_q_2exp(tmp_num->mpz_, mpz_, -tmp_arg2);
        }
    }

    return tmp_num;
}

