X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=flower%2Frational.cc;h=54ac55bdaf8cdc04b75a9a099e6e895afc7a237e;hb=7e72a1e50e94a7f9738d62599de79fe7745f600c;hp=cf99657acbfd6081f1bd0963c734594ece3fbf57;hpb=59ed0cee2aae58a3f0483f21261c68aee406fa10;p=lilypond.git

diff --git a/flower/rational.cc b/flower/rational.cc
index cf99657acb..54ac55bdaf 100644
--- a/flower/rational.cc
+++ b/flower/rational.cc
@@ -3,40 +3,34 @@
   
   source file of the Flower Library
 
-  (c)  1997--1998 Han-Wen Nienhuys <hanwen@cs.uu.nl>
+  (c) 1997--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
 */
+#include <math.h>
 #include <stdlib.h>
 #include "rational.hh"
 #include "string.hh"
 #include "string-convert.hh"  
 #include "libc-extension.hh"
 
-Rational::operator bool () const
-{
-  return sign_;
-}
-
-Rational::operator int () const
-{
-  return sign_ * num_ / den_;
-}
-
 Rational::operator double () const
 {
   return (double)sign_ * num_ / den_;
 }
 
+#ifdef STREAM_SUPPORT
 ostream &
 operator << (ostream &o, Rational r)
 {
-  o <<  r.str ();
+  o <<  r.string ();
   return o;
 }
+#endif
+
 
 Rational
-Rational::truncated () const
+Rational::trunc_rat () const
 {
-  return Rational(num_ - (num_ % den_), den_);
+  return Rational (num_ - (num_ % den_), den_);
 }
 
 Rational::Rational ()
@@ -53,9 +47,11 @@ Rational::Rational (int n, int d)
   normalise ();
 }
 
-Rational::Rational (Rational const &r)
+Rational::Rational (int n)
 {
-  copy (r);
+  sign_ = ::sign (n);
+  num_ = abs (n);
+  den_= 1;
 }
 
 static
@@ -70,11 +66,13 @@ int gcd (int a, int b)
   return b;
 }
 
+#if 0
 static
 int lcm (int a, int b)
 {
   return abs (a*b / gcd (a,b));
 }
+#endif
 
 void
 Rational::set_infinite (int s)
@@ -85,11 +83,27 @@ Rational::set_infinite (int s)
 Rational
 Rational::operator - () const
 {
-  Rational r(*this);
+  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 ()
 {
@@ -97,31 +111,31 @@ Rational::normalise ()
     {
       den_ = 1;
       num_ = 0;
-      return ;
     }
-  if (!den_)
-    sign_ = 2;
-  if (!num_)
-    sign_ = 0;
-
-  int g = gcd (num_ , den_);
+  else if (!den_)
+    {
+      sign_ = 2;
+      num_ = 1;
+    }
+  else if (!num_)
+    {
+      sign_ = 0;
+      den_ = 1;
+    }
+  else
+    {
+      int g = gcd (num_ , den_);
 
-  num_ /= g;
-  den_ /= g;
+      num_ /= g;
+      den_ /= g;
+    }
 }
-
 int
 Rational::sign () const
 {
   return ::sign (sign_);
 }
 
-bool
-Rational::infty_b () const
-{
-  return abs (sign_) > 1;
-}
-
 int
 Rational::compare (Rational const &r, Rational const &s)
 {
@@ -129,10 +143,14 @@ Rational::compare (Rational const &r, Rational const &s)
     return -1;
   else if (r.sign_ > s.sign_)
     return 1;
-  else if (r.infty_b ())
+  else if (r.is_infinity ())
     return 0;
-
-  return  (r - s).sign ();
+  else if (r.sign_ == 0)
+    return 0;
+  else
+    {
+      return r.sign_ * ::sign  (int (r.num_ * s.den_) - int (s.num_ * r.den_));
+    }
 }
 
 int
@@ -141,12 +159,19 @@ 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)
 {
-  if (infty_b ())
+  if (is_infinity ())
     ;
-  else if (r.infty_b ())
+  else if (r.is_infinity ())
     {
       *this = r;
     }
@@ -154,7 +179,7 @@ Rational::operator += (Rational r)
     {
       int n = sign_ * num_ *r.den_ + r.sign_ * den_ * r.num_;
       int d = den_ * r.den_;
-      sign_ =  ::sign (n) * ::sign(d);
+      sign_ =  ::sign (n) * ::sign (d);
       num_ = abs (n);
       den_ = abs (d);
       normalise ();
@@ -166,7 +191,7 @@ Rational::operator += (Rational r)
 /*
   copied from libg++ 2.8.0
  */ 
-Rational::Rational(double x)
+Rational::Rational (double x)
 {
   if (x != 0.0)
     {
@@ -174,21 +199,26 @@ Rational::Rational(double x)
       x *= sign_;
 
       int expt;
-      double mantissa = frexp(x, &expt);
+      double mantissa = frexp (x, &expt);
 
       const int FACT = 1 << 20;
 
       /*
-	FIXME
+	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.
+      */
 
-	SHOULD TEST THIS
-	
-	suck me gently with a vacuum cleaner.  Thanks to Afie for this wierd idea.
-       */
       num_ = (unsigned int) (mantissa * FACT);
       den_ = (unsigned int) FACT;
+      normalise ();      
+      if (expt < 0)
+	den_ <<= -expt;
+      else
+	num_ <<= expt;
       normalise ();
-      num_ <<= expt;
     }
   else
     {
@@ -212,7 +242,7 @@ Rational &
 Rational::operator *= (Rational r)
 {
   sign_ *= ::sign (r.sign_);
-  if (r.infty_b ())
+  if (r.is_infinity ())
     {	
       sign_ = sign () * 2;
       goto exit_func;
@@ -246,32 +276,35 @@ Rational::operator -= (Rational r)
   return (*this += r);
 }
 
-/*
-  be paranoid about overiding libg++ stuff
- */
-Rational &
-Rational::operator = (Rational const &r)
-{
-  copy (r);
-  return *this;
-}
-
 String
-Rational::str () const
+Rational::to_string () const
 {
-  if (infty_b ())
+  if (is_infinity ())
     {
       String s (sign_ > 0 ? "" : "-" );
       return String (s + "infinity");
     }
-  String s = to_str (num ());
+
+  String s = ::to_string (num ());
   if (den () != 1 && num ())
-    s += "/" + to_str (den ());
+    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;
+}