flower/include/interval.hh

   1 /*
   2   interval.hh -- part of flowerlib
   3
   4   (c) 1996 Han-Wen Nienhuys
   5 */
   6
   7 #ifndef INTERVAL_HH
   8 #define INTERVAL_HH
   9
  10 #include <assert.h>
  11 #include "fproto.hh"
  12 #include "real.hh"
  13
  14
  15 /** a T interval.  this represents the closed interval [left,right].
  16   No invariants. T must be a totally ordered ring (with division, anyway ..)
  17   At instantiation, the function infinity() has to be defined explicitely.
  18
  19   */
  20 template<class T>
  21 struct Interval_t {
  22   T left, right;
  23
  24   /* ************** */
  25
  26   static T infinity() ;
  27
  28   T center() { return (left + right) / T(2);}
  29   void translate (T t) {
  30     left += t;
  31     right += t;
  32   }
  33   T& idx (int j) {
  34     if (j==-1)
  35       return left;
  36     else if (j==1)
  37       return right;
  38     else
  39       assert (false);
  40     return left;
  41   }
  42   T& operator[](int j) {
  43     return idx (j);
  44   }
  45   T operator[](int j) const {
  46     return ((Interval_t<T> *)this)->idx (j);
  47   }
  48   T &max() { return right;}
  49   T max() const { return right;}
  50   T min() const{ return left; }
  51   T &min(){ return left; }
  52   /**
  53     PRE
  54     *this and h are comparable
  55     */
  56   void unite (Interval_t<T> h);
  57   void intersect (Interval_t<T> h);
  58
  59   T length() const;
  60   void set_empty() ;
  61   bool empty_b() const { return left > right; }
  62   bool contains_b (Interval_t<T> const&) const;
  63   Interval_t() {
  64     set_empty();
  65   }
  66   Interval_t (T m, T M) {
  67     left =m;
  68     right = M;
  69   }
  70   Interval_t<T> &operator += (T r) {
  71     left += r;
  72     right +=r;
  73     return *this;
  74   }
  75   Interval_t<T> &operator *=(T r) {
  76     left *= r;
  77     right *= r;
  78     if (r < T(0)) {
  79       T t = left;
  80       left = right;
  81       right = t;
  82     }
  83     return *this;
  84   }
  85   String str() const;
  86   bool elt_b (T r);
  87 };
  88
  89
  90 /**
  91   inclusion ordering. Crash if not comparable.
  92   */
  93 template<class T>
  94 int Interval__compare (const Interval_t<T>&,Interval_t<T> const&);
  95
  96 /*
  97   INLINE
  98  */
  99
 100 #include "compare.hh"
 101
 102 TEMPLATE_INSTANTIATE_COMPARE(Interval_t<T>&, Interval__compare, template<class T>);
 103
 104
 105 template<class T>
 106 inline Interval_t<T>
 107 intersection (Interval_t<T> a, Interval_t<T> const&b)
 108 {
 109   a.intersect (b);
 110   return a;
 111
 112 }
 113
 114 template<class T>
 115 inline
 116 Interval_t<T> operator +(T a,Interval_t<T> i)
 117 {
 118   i += a;
 119   return i;
 120 }
 121
 122 template<class T>
 123 inline
 124 Interval_t<T> operator +(Interval_t<T> i,T a){
 125   return a+i;
 126 }
 127
 128 template<class T>
 129 inline
 130 Interval_t<T> operator *(T a,Interval_t<T> i)
 131 {
 132   i *= a;
 133   return i;
 134 }
 135
 136 template<class T>
 137 inline
 138 Interval_t<T> operator *(Interval_t<T> i,T a){
 139   return a*i;
 140 }
 141
 142 typedef Interval_t<Real> Interval;
 143
 144
 145
 146
 147 #endif // INTERVAL_HH
 148
 149
 150