X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=flower%2Frational.cc;h=a0c0d22410e235726eeee037b760fee1f7dcaef9;hb=a26c1338d1a399ba16f27a6f37b2ccd461aaa59d;hp=10b3bc9c2c3a2d46d26c6be05ff70bf9f32daf87;hpb=1cf3d59c1559fb9774c4c1c8cae155cfe54a927c;p=lilypond.git diff --git a/flower/rational.cc b/flower/rational.cc index 10b3bc9c2c..a0c0d22410 100644 --- a/flower/rational.cc +++ b/flower/rational.cc @@ -1,47 +1,48 @@ /* rational.cc -- implement Rational - + source file of the Flower Library - (c) 1997--1998 Han-Wen Nienhuys + (c) 1997--2006 Han-Wen Nienhuys */ -#include + #include "rational.hh" -#include "string.hh" -#include "string-convert.hh" -#include "libc-extension.hh" -Rational::operator bool () const -{ - return sign_; -} +#include +#include +using namespace std; + +#include "string-convert.hh" +#include "libc-extension.hh" -Rational::operator int () const +Rational::operator double () const { - return sign_ * num_ / den_; + return ((double)sign_) * num_ / den_; } -Rational::operator double () const +Rational::operator bool () const { - return (double)sign_ * num_ / den_; + return sign_ && num_; } +#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 () { - sign_ = 1; + sign_ = 0; num_ = den_ = 1; } @@ -53,8 +54,14 @@ Rational::Rational (int n, int d) normalise (); } +Rational::Rational (int n) +{ + sign_ = ::sign (n); + num_ = abs (n); + den_ = 1; +} -static +static inline int gcd (int a, int b) { int t; @@ -66,26 +73,36 @@ int gcd (int a, int b) return b; } -static -int lcm (int a, int b) -{ - return abs (a*b / gcd (a,b)); -} - void Rational::set_infinite (int s) { - sign_ = ::sign (s) * 2; + sign_ = ::sign (s) * 2; } 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 () { @@ -93,31 +110,31 @@ 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) { @@ -125,44 +142,50 @@ 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; + 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 ); + return Rational::compare (r, s); +} + +Rational & +Rational::operator %= (Rational r) +{ + *this = mod_rat (r); + return *this; } Rational & Rational::operator += (Rational r) { - if (infty_b ()) + if (is_infinity ()) ; - else if (r.infty_b ()) - { - *this = r; - } - else + 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); + 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; + sign_ = ::sign (n) * ::sign (d); num_ = abs (n); den_ = abs (d); normalise (); } return *this; } - /* copied from libg++ 2.8.0 - */ -Rational::Rational(double x) +*/ +Rational::Rational (double x) { if (x != 0.0) { @@ -170,37 +193,41 @@ 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 (); - num_ <<= expt; + if (expt < 0) + den_ <<= -expt; + else + num_ <<= expt; + normalise (); } else { num_ = 0; den_ = 1; - sign_ =0; + sign_ = 0; normalise (); } } - void Rational::invert () { int r (num_); - num_ = den_; + num_ = den_; den_ = r; } @@ -208,8 +235,8 @@ Rational & Rational::operator *= (Rational r) { sign_ *= ::sign (r.sign_); - if (r.infty_b ()) - { + if (r.is_infinity ()) + { sign_ = sign () * 2; goto exit_func; } @@ -221,7 +248,7 @@ Rational::operator *= (Rational r) exit_func: return *this; } - + Rational & Rational::operator /= (Rational r) { @@ -235,44 +262,42 @@ Rational::negate () sign_ *= -1; } -Rational& +Rational & Rational::operator -= (Rational r) { r.negate (); return (*this += r); } -/* - be paranoid about overiding libg++ stuff - */ -Rational & -Rational::operator = (Rational const &r) -{ - copy (r); - return *this; -} - -Rational::Rational (Rational const &r) -{ - copy (r); -} - -String -Rational::str () const +string +Rational::to_string () const { - if (infty_b ()) + if (is_infinity ()) { - String s (sign_ > 0 ? "" : "-" ); - return String (s + "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 (int) num () / den (); +} + int sign (Rational r) { return r.sign (); } + +bool +Rational::is_infinity () const +{ + return sign_ == 2 || sign_ == -2; +}