2 This file is part of LilyPond, the GNU music typesetter.
4 Copyright (C) 1997--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
6 LilyPond is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 LilyPond is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
20 #include "rational.hh"
27 #include "string-convert.hh"
28 #include "libc-extension.hh"
31 Rational::to_double () const
33 if (sign_
== -1 || sign_
== 1 || sign_
== 0)
34 return ((double)sign_
) * num_
/ den_
;
48 operator << (ostream
&o
, Rational r
)
56 Rational::abs () const
58 return Rational (num_
, den_
);
62 Rational::trunc_rat () const
66 return Rational ((num_
- (num_
% den_
)) * sign_
, den_
);
75 Rational::Rational (I64 n
, I64 d
)
77 sign_
= ::sign (n
) * ::sign (d
);
83 Rational::Rational (I64 n
)
90 Rational::Rational (U64 n
)
97 Rational::Rational (int n
)
106 Rational::set_infinite (int s
)
108 sign_
= ::sign (s
) * 2;
113 Rational::operator - () const
121 Rational::div_rat (Rational div
) const
125 return r
.trunc_rat ();
129 Rational::mod_rat (Rational div
) const
132 r
= (r
/ div
- r
.div_rat (div
)) * div
;
138 copy & paste from scm_gcd (GUILE).
152 /* Determine a common factor 2^k */
153 while (!(1 & (u
| v
)))
159 /* Now, any factor 2^n can be eliminated */
185 Rational::normalize ()
204 I64 g
= gcd (num_
, den_
);
211 Rational::sign () const
213 return ::sign (sign_
);
217 Rational::compare (Rational
const &r
, Rational
const &s
)
219 if (r
.sign_
< s
.sign_
)
221 else if (r
.sign_
> s
.sign_
)
223 else if (r
.is_infinity ())
225 else if (r
.sign_
== 0)
227 return r
.sign_
* ::sign ((I64
) (r
.num_
* s
.den_
) - (I64
) (s
.num_
* r
.den_
));
231 compare (Rational
const &r
, Rational
const &s
)
233 return Rational::compare (r
, s
);
237 Rational::operator %= (Rational r
)
244 Rational::operator += (Rational r
)
248 else if (r
.is_infinity ())
252 I64 lcm
= (den_
/ gcd (r
.den_
, den_
)) * r
.den_
;
253 I64 n
= sign_
* num_
* (lcm
/ den_
) + r
.sign_
* r
.num_
* (lcm
/ r
.den_
);
255 sign_
= ::sign (n
) * ::sign (d
);
264 copied from libg++ 2.8.0
266 Rational::Rational (double x
)
274 double mantissa
= frexp (x
, &expt
);
276 const int FACT
= 1 << 20;
279 Thanks to Afie for this too simple idea.
281 do not blindly substitute by libg++ code, since that uses
282 arbitrary-size integers. The rationals would overflow too
286 num_
= (U64
) (mantissa
* FACT
);
313 Rational::operator *= (Rational r
)
315 sign_
*= ::sign (r
.sign_
);
316 if (r
.is_infinity ())
331 Rational::operator /= (Rational r
)
344 Rational::operator -= (Rational r
)
351 Rational::to_string () const
355 string
s (sign_
> 0 ? "" : "-");
356 return string (s
+ "infinity");
359 string s
= ::to_string (num ());
360 if (den () != 1 && num ())
361 s
+= "/" + ::to_string (den ());
366 Rational::to_int () const
368 return (int) num () / den ();
378 Rational::is_infinity () const
380 return sign_
== 2 || sign_
== -2;