/*
- rational.cc -- implement Rational related functions
-
+ rational.cc -- implement Rational
+
source file of the Flower Library
- (c) 1997 Han-Wen Nienhuys <hanwen@stack.nl>
+ (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
*/
#include "rational.hh"
-#include "string.hh"
+
+#include <cmath>
+#include <cstdlib>
+
+#include "string-convert.hh"
+#include "libc-extension.hh"
+
+Rational::operator double () const
+{
+ return (double)sign_ * num_ / den_;
+}
+
+#ifdef STREAM_SUPPORT
+ostream &
+operator << (ostream &o, Rational r)
+{
+ o << r.string ();
+ return o;
+}
+#endif
+
+
+Rational
+Rational::trunc_rat () const
+{
+ return Rational (num_ - (num_ % den_), den_);
+}
+
+Rational::Rational ()
+{
+ sign_ = 0;
+ num_ = den_ = 1;
+}
+
+Rational::Rational (int n, int d)
+{
+ sign_ = ::sign (n) * ::sign (d);
+ num_ = abs (n);
+ den_ = abs (d);
+ normalise ();
+}
+
+Rational::Rational (int n)
+{
+ sign_ = ::sign (n);
+ num_ = abs (n);
+ den_= 1;
+}
+
+static inline
+int gcd (int a, int b)
+{
+ int t;
+ while ((t = a % b))
+ {
+ a = b;
+ b = t;
+ }
+ return b;
+}
+
void
-print_rat(Rational const &m)
+Rational::set_infinite (int s)
+{
+ sign_ = ::sign (s) * 2;
+}
+
+Rational
+Rational::operator - () const
+{
+ Rational r (*this);
+ r.negate ();
+ return r;
+}
+
+Rational
+Rational::div_rat (Rational div) const
+{
+ Rational r (*this);
+ r /= div;
+ return r.trunc_rat ();
+}
+
+Rational
+Rational::mod_rat (Rational div) const
+{
+ Rational r (*this);
+ r = (r / div - r.div_rat (div)) * div;
+ return r;
+}
+
+void
+Rational::normalise ()
+{
+ if (!sign_)
+ {
+ den_ = 1;
+ num_ = 0;
+ }
+ else if (!den_)
+ {
+ sign_ = 2;
+ num_ = 1;
+ }
+ else if (!num_)
+ {
+ sign_ = 0;
+ den_ = 1;
+ }
+ else
+ {
+ int g = gcd (num_ , den_);
+
+ num_ /= g;
+ den_ /= g;
+ }
+}
+int
+Rational::sign () const
+{
+ return ::sign (sign_);
+}
+
+int
+Rational::compare (Rational const &r, Rational const &s)
+{
+ if (r.sign_ < s.sign_)
+ return -1;
+ else if (r.sign_ > s.sign_)
+ return 1;
+ else if (r.is_infinity ())
+ return 0;
+ else if (r.sign_ == 0)
+ return 0;
+ else
+ {
+ return r.sign_ * ::sign (int (r.num_ * s.den_) - int (s.num_ * r.den_));
+ }
+}
+
+int
+compare (Rational const &r, Rational const &s)
+{
+ return Rational::compare (r, s );
+}
+
+Rational &
+Rational::operator %= (Rational r)
+{
+ *this = r.mod_rat (r);
+ return *this;
+}
+
+Rational &
+Rational::operator += (Rational r)
{
- cout << String(m) << flush;
+ if (is_infinity ())
+ ;
+ else if (r.is_infinity ())
+ {
+ *this = r;
+ }
+ else
+ {
+ int n = sign_ * num_ *r.den_ + r.sign_ * den_ * r.num_;
+ int d = den_ * r.den_;
+ sign_ = ::sign (n) * ::sign (d);
+ num_ = abs (n);
+ den_ = abs (d);
+ normalise ();
+ }
+ return *this;
}
+/*
+ copied from libg++ 2.8.0
+ */
+Rational::Rational (double x)
+{
+ if (x != 0.0)
+ {
+ sign_ = ::sign (x);
+ x *= sign_;
+
+ int expt;
+ double mantissa = frexp (x, &expt);
+
+ const int FACT = 1 << 20;
+
+ /*
+ Thanks to Afie for this too simple idea.
+
+ do not blindly substitute by libg++ code, since that uses
+ arbitrary-size integers. The rationals would overflow too
+ easily.
+ */
+
+ num_ = (unsigned int) (mantissa * FACT);
+ den_ = (unsigned int) FACT;
+ normalise ();
+ if (expt < 0)
+ den_ <<= -expt;
+ else
+ num_ <<= expt;
+ normalise ();
+ }
+ else
+ {
+ num_ = 0;
+ den_ = 1;
+ sign_ =0;
+ normalise ();
+ }
+}
+
+
+void
+Rational::invert ()
+{
+ int r (num_);
+ num_ = den_;
+ den_ = r;
+}
+
+Rational &
+Rational::operator *= (Rational r)
+{
+ sign_ *= ::sign (r.sign_);
+ if (r.is_infinity ())
+ {
+ sign_ = sign () * 2;
+ goto exit_func;
+ }
+
+ num_ *= r.num_;
+ den_ *= r.den_;
+
+ normalise ();
+ exit_func:
+ return *this;
+}
+
+Rational &
+Rational::operator /= (Rational r)
+{
+ r.invert ();
+ return (*this *= r);
+}
+
+void
+Rational::negate ()
+{
+ sign_ *= -1;
+}
+
+Rational&
+Rational::operator -= (Rational r)
+{
+ r.negate ();
+ return (*this += r);
+}
+
+String
+Rational::to_string () const
+{
+ if (is_infinity ())
+ {
+ String s (sign_ > 0 ? "" : "-" );
+ return String (s + "infinity");
+ }
+
+ String s = ::to_string (num ());
+ if (den () != 1 && num ())
+ s += "/" + ::to_string (den ());
+ return s;
+}
+
+int
+Rational::to_int () const
+{
+ return num () / den ();
+}
+
+int
+sign (Rational r)
+{
+ return r.sign ();
+}
+
+bool
+Rational::is_infinity () const
+{
+ return sign_ == 2 || sign_ == -2;
+}