X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=flower%2Frational.cc;h=559e1646a0cade47b932d7cfab048f0feb641da8;hb=5d84bfad4626892bcffd05adcced53c8a2329047;hp=748a8698413e2b86a3569a0a25731e2bf70c7067;hpb=c67ada694cf6de9e92bd836c8e589e658667ba35;p=lilypond.git diff --git a/flower/rational.cc b/flower/rational.cc index 748a869841..559e1646a0 100644 --- a/flower/rational.cc +++ b/flower/rational.cc @@ -1,9 +1,20 @@ /* - rational.cc -- implement Rational + This file is part of LilyPond, the GNU music typesetter. - source file of the Flower Library + Copyright (C) 1997--2015 Han-Wen Nienhuys - (c) 1997--2006 Han-Wen Nienhuys + LilyPond is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + LilyPond is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with LilyPond. If not, see . */ #include "rational.hh" @@ -16,10 +27,11 @@ using namespace std; #include "string-convert.hh" #include "libc-extension.hh" -Rational::operator double () const +double +Rational::to_double () const { if (sign_ == -1 || sign_ == 1 || sign_ == 0) - return ((double)sign_) * num_ / den_; + return (double)sign_ * (double)num_ / (double)den_; if (sign_ == -2) return -HUGE_VAL; else if (sign_ == 2) @@ -30,7 +42,6 @@ Rational::operator double () const return 0.0; } - #ifdef STREAM_SUPPORT ostream & operator << (ostream &o, Rational r) @@ -49,7 +60,9 @@ Rational::abs () const Rational Rational::trunc_rat () const { - return Rational (num_ - (num_ % den_), den_); + if (is_infinity ()) + return *this; + return Rational ((num_ - (num_ % den_)) * sign_, den_); } Rational::Rational () @@ -58,7 +71,7 @@ Rational::Rational () num_ = den_ = 1; } -Rational::Rational (int n, int d) +Rational::Rational (I64 n, I64 d) { sign_ = ::sign (n) * ::sign (d); num_ = ::abs (n); @@ -66,33 +79,32 @@ Rational::Rational (int n, int d) normalize (); } -Rational::Rational (int n) +Rational::Rational (I64 n) { sign_ = ::sign (n); num_ = ::abs (n); den_ = 1; } +Rational::Rational (U64 n) +{ + sign_ = 1; + num_ = n; + den_ = 1; +} -/* - We can actually do a little better. See Knuth 4.5.2 - */ -static inline -int gcd (int a, int b) +Rational::Rational (int n) { - int t; - while ((t = a % b)) - { - a = b; - b = t; - } - return b; + sign_ = ::sign (n); + num_ = ::abs (n); + den_ = 1; } void Rational::set_infinite (int s) { sign_ = ::sign (s) * 2; + num_ = 1; } Rational @@ -119,6 +131,52 @@ Rational::mod_rat (Rational div) const 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 () { @@ -139,7 +197,7 @@ Rational::normalize () } else { - int g = gcd (num_, den_); + I64 g = gcd (num_, den_); num_ /= g; den_ /= g; @@ -158,11 +216,11 @@ Rational::compare (Rational const &r, Rational const &s) return -1; else if (r.sign_ > s.sign_) return 1; - else if (r.is_infinity ()) + else if (r.is_infinity ()) // here s is also infinite with the same sign return 0; - else if (r.sign_ == 0) + else if (r.sign_ == 0) // here s.sign_ is also zero return 0; - return r.sign_ * ::sign (int (r.num_ * s.den_) - int (s.num_ * r.den_)); + return ::sign (r - s); } int @@ -187,9 +245,9 @@ Rational::operator += (Rational r) *this = r; else { - int lcm = (den_ / gcd (r.den_, den_)) * r.den_; - int n = sign_ * num_ * (lcm / den_) + r.sign_ * r.num_ * (lcm / r.den_); - int d = lcm; + 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); @@ -214,20 +272,20 @@ Rational::Rational (double x) const int FACT = 1 << 20; /* - Thanks to Afie for this too simple idea. + 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. + 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; + num_ = (U64) (mantissa * FACT); + den_ = (U64) FACT; normalize (); if (expt < 0) - den_ <<= -expt; + den_ <<= -expt; else - num_ <<= expt; + num_ <<= expt; normalize (); } else @@ -242,7 +300,7 @@ Rational::Rational (double x) void Rational::invert () { - int r (num_); + I64 r (num_); num_ = den_; den_ = r; } @@ -261,7 +319,7 @@ Rational::operator *= (Rational r) den_ *= r.den_; normalize (); - exit_func: +exit_func: return *this; } @@ -303,7 +361,7 @@ Rational::to_string () const int Rational::to_int () const { - return (int) num () / den (); + return (int) (num () / den ()); } int