/*
  rational.hh -- declare rational helpers

  source file of the Flower Library

  (c) 1997--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
*/

#ifndef RATIONAL_HH
#define RATIONAL_HH

#include "std-string.hh"

/**
   Rational numbers.  Included is support for + and - infinity.
*/
class Rational
{
  /**
     Sign of rational.
     -2, .. 2

     -2,2 is - and + infinity.
     -1,1 is negative and positive.
     0 if *this is zero.
  */
  int sign_;
  unsigned int num_, den_;
  void normalize ();
  void copy (Rational const &);

public:
  void set_infinite (int sign);
  bool is_infinity () const;
  void invert ();
  int numerator () const { return sign_ * num_; }
  int denominator () const { return den_; }
  int num () const { return numerator (); }
  int den () const { return denominator (); }

  Rational trunc_rat () const;
  Rational div_rat (Rational) const;
  Rational mod_rat (Rational) const;
  Rational abs () const;
  void negate ();
  int to_int () const;

  operator double () const { return to_double (); }
  double to_double () const;

  Rational operator - () const;
  /**
     Initialize to 0.
  */
  Rational ();
  Rational (int);
  explicit Rational (int, int);
  explicit Rational (double);
  Rational (Rational const &r) { copy (r);}
  Rational &operator = (Rational const &r)
  {
    copy (r); return *this;
  }

  Rational &operator *= (Rational);
  Rational &operator /= (Rational);
  Rational &operator += (Rational);
  Rational &operator -= (Rational);
  Rational &operator %= (Rational);
  static int compare (Rational const &, Rational const &);
  int sign () const;
  string to_string () const;
};

#include "arithmetic-operator.hh"

IMPLEMENT_ARITHMETIC_OPERATOR (Rational, /);
IMPLEMENT_ARITHMETIC_OPERATOR (Rational, +);
IMPLEMENT_ARITHMETIC_OPERATOR (Rational, *);
IMPLEMENT_ARITHMETIC_OPERATOR (Rational, -);
IMPLEMENT_ARITHMETIC_OPERATOR (Rational, %);

INSTANTIATE_COMPARE (Rational const &, Rational::compare);

int compare (Rational const &, Rational const &);
int sign (Rational r);

inline void
Rational::copy (Rational const &r)
{
  sign_ = r.sign_;
  num_ = r.num_;
  den_ = r.den_;
}

#if 0
ostream &
operator << (ostream &, Rational);
#endif

const Rational infinity_rat (INT_MAX);

#endif // RATIONAL_HH
