flower/include/rational.hh

   1 /*
   2   rational.hh -- declare rational helpers
   3
   4   source file of the Flower Library
   5
   6   (c) 1997--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #ifndef RATIONAL_HH
  10 #define RATIONAL_HH
  11
  12 #include "flower-proto.hh"
  13 #include "std-string.hh"
  14 #include <limits.h>
  15
  16 /**
  17    Rational numbers.  Included is support for + and - infinity.
  18 */
  19 class Rational
  20 {
  21   /**
  22      Sign of rational.
  23      -2, .. 2
  24
  25      -2,2 is - and + infinity.
  26      -1,1 is negative and positive.
  27      0 if *this is zero.
  28   */
  29   int sign_;
  30   U64 num_, den_;
  31   void normalize ();
  32   void copy (Rational const &);
  33
  34 public:
  35   void set_infinite (int sign);
  36   bool is_infinity () const;
  37   void invert ();
  38   I64 numerator () const { return sign_ * num_; }
  39   I64 denominator () const { return den_; }
  40   I64 num () const { return numerator (); }
  41   I64 den () const { return denominator (); }
  42
  43   Rational trunc_rat () const;
  44   Rational div_rat (Rational) const;
  45   Rational mod_rat (Rational) const;
  46   Rational abs () const;
  47   void negate ();
  48   int to_int () const;
  49
  50   operator double () const { return to_double (); }
  51   double to_double () const;
  52
  53   Rational operator - () const;
  54   /**
  55      Initialize to 0.
  56   */
  57   Rational ();
  58   Rational (int);
  59   Rational (I64);
  60   Rational (U64);
  61   explicit Rational (I64, I64);
  62   explicit Rational (double);
  63   Rational (Rational const &r) { copy (r);}
  64   Rational &operator = (Rational const &r)
  65   {
  66     copy (r); return *this;
  67   }
  68
  69   Rational &operator *= (Rational);
  70   Rational &operator /= (Rational);
  71   Rational &operator += (Rational);
  72   Rational &operator -= (Rational);
  73   Rational &operator %= (Rational);
  74   static int compare (Rational const &, Rational const &);
  75   int sign () const;
  76   string to_string () const;
  77 };
  78
  79 #include "arithmetic-operator.hh"
  80
  81 IMPLEMENT_ARITHMETIC_OPERATOR (Rational, /);
  82 IMPLEMENT_ARITHMETIC_OPERATOR (Rational, +);
  83 IMPLEMENT_ARITHMETIC_OPERATOR (Rational, *);
  84 IMPLEMENT_ARITHMETIC_OPERATOR (Rational, -);
  85 IMPLEMENT_ARITHMETIC_OPERATOR (Rational, %);
  86
  87 INSTANTIATE_COMPARE (Rational const &, Rational::compare);
  88
  89 int compare (Rational const &, Rational const &);
  90 int sign (Rational r);
  91
  92 inline void
  93 Rational::copy (Rational const &r)
  94 {
  95   sign_ = r.sign_;
  96   num_ = r.num_;
  97   den_ = r.den_;
  98 }
  99
 100 #if 0
 101 ostream &
 102 operator << (ostream &, Rational);
 103 #endif
 104
 105 const Rational infinity_rat (U64_MAX);
 106
 107 #endif // RATIONAL_HH