/*
- 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--2008 Han-Wen Nienhuys <hanwen@xs4all.nl>
*/
#include "rational.hh"
-#include "string.hh"
+
+#include <cmath>
+#include <cassert>
+#include <cstdlib>
+using namespace std;
+
+#include "string-convert.hh"
+#include "libc-extension.hh"
+
+double
+Rational::to_double () const
+{
+ if (sign_ == -1 || sign_ == 1 || sign_ == 0)
+ return ((double)sign_) * num_ / den_;
+ if (sign_ == -2)
+ return -HUGE_VAL;
+ else if (sign_ == 2)
+ return HUGE_VAL;
+ else
+ assert (false);
+
+ return 0.0;
+}
+
+
+#ifdef STREAM_SUPPORT
+ostream &
+operator << (ostream &o, Rational r)
+{
+ o << r.string ();
+ return o;
+}
+#endif
+
+Rational
+Rational::abs () const
+{
+ return Rational (num_, den_);
+}
+
+Rational
+Rational::trunc_rat () const
+{
+ if (is_infinity())
+ return *this;
+ return Rational ((num_ - (num_ % den_)) * sign_, den_);
+}
+
+Rational::Rational ()
+{
+ sign_ = 0;
+ num_ = den_ = 1;
+}
+
+Rational::Rational (I64 n, I64 d)
+{
+ sign_ = ::sign (n) * ::sign (d);
+ num_ = ::abs (n);
+ den_ = ::abs (d);
+ normalize ();
+}
+
+Rational::Rational (I64 n)
+{
+ sign_ = ::sign (n);
+ num_ = ::abs (n);
+ den_ = 1;
+}
+
+Rational::Rational (U64 n)
+{
+ sign_ = 1;
+ num_ = n;
+ den_ = 1;
+}
+
+Rational::Rational (int n)
+{
+ sign_ = ::sign (n);
+ num_ = ::abs (n);
+ den_ = 1;
+}
+
+
+void
+Rational::set_infinite (int s)
+{
+ sign_ = ::sign (s) * 2;
+ num_ = 1;
+}
+
+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;
+}
+
+
+/*
+ copy & paste from scm_gcd (GUILE).
+ */
+static I64
+gcd (I64 u, I64 v)
+{
+ I64 result = 0;
+ if (u == 0)
+ result = v;
+ else if (v == 0)
+ result = u;
+ else
+ {
+ I64 k = 1;
+ I64 t;
+ /* Determine a common factor 2^k */
+ while (!(1 & (u | v)))
+ {
+ k <<= 1;
+ u >>= 1;
+ v >>= 1;
+ }
+ /* Now, any factor 2^n can be eliminated */
+ if (u & 1)
+ t = -v;
+ else
+ {
+ t = u;
+ b3:
+ t = t >> 1;
+ }
+ if (!(1 & t))
+ goto b3;
+ if (t > 0)
+ u = t;
+ else
+ v = -t;
+ t = u - v;
+ if (t != 0)
+ goto b3;
+ result = u * k;
+ }
+
+ return result;
+}
+
+
+void
+Rational::normalize ()
+{
+ if (!sign_)
+ {
+ den_ = 1;
+ num_ = 0;
+ }
+ else if (!den_)
+ {
+ sign_ = 2;
+ num_ = 1;
+ }
+ else if (!num_)
+ {
+ sign_ = 0;
+ den_ = 1;
+ }
+ else
+ {
+ I64 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;
+ return r.sign_ * ::sign ((I64) (r.num_ * s.den_) - (I64) (s.num_ * r.den_));
+}
+
+int
+compare (Rational const &r, Rational const &s)
+{
+ return Rational::compare (r, s);
+}
+
+Rational &
+Rational::operator %= (Rational r)
+{
+ *this = mod_rat (r);
+ return *this;
+}
+
+Rational &
+Rational::operator += (Rational r)
+{
+ if (is_infinity ())
+ ;
+ else if (r.is_infinity ())
+ *this = r;
+ else
+ {
+ I64 lcm = (den_ / gcd (r.den_, den_)) * r.den_;
+ I64 n = sign_ * num_ * (lcm / den_) + r.sign_ * r.num_ * (lcm / r.den_);
+ I64 d = lcm;
+ sign_ = ::sign (n) * ::sign (d);
+ num_ = ::abs (n);
+ den_ = ::abs (d);
+ normalize ();
+ }
+ 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_ = (U64) (mantissa * FACT);
+ den_ = (U64) FACT;
+ normalize ();
+ if (expt < 0)
+ den_ <<= -expt;
+ else
+ num_ <<= expt;
+ normalize ();
+ }
+ else
+ {
+ num_ = 0;
+ den_ = 1;
+ sign_ = 0;
+ normalize ();
+ }
+}
void
-print_rat (Rational const &m)
+Rational::invert ()
{
- cout << String (m) << flush;
+ I64 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_;
+
+ normalize ();
+ 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 (int) num () / den ();
+}
+
+int
+sign (Rational r)
+{
+ return r.sign ();
+}
+
+bool
+Rational::is_infinity () const
+{
+ return sign_ == 2 || sign_ == -2;
+}
projects / lilypond.git / blobdiff