1using System;
 2using System.Globalization;
 3
 4namespace jive
 5{
 6  [Serializable]
 7  public class Date :  IComparable<Date>, IComparable, IEquatable<Date>
 8  {
 9    readonly long ticks;
10
11    public Date(int year, int month, int day)
12    {
13      ticks = new DateTime(year, month, day).Ticks;
14    }
15
16    public bool is_in(Year the_year)
17    {
18      return the_year.represents(to_date_time());
19    }
20
21    public DateTime to_date_time()
22    {
23      return new DateTime(ticks);
24    }
25
26    static public implicit operator Date(DateTime date)
27    {
28      return new Date(date.Year, date.Month, date.Day);
29    }
30
31    static public implicit operator DateTime(Date date)
32    {
33      return date.to_date_time();
34    }
35
36    public int CompareTo(Date other)
37    {
38      var the_other_date = other.downcast_to<Date>();
39      if (ticks.Equals(the_other_date.ticks))
40      {
41        return 0;
42      }
43      return ticks > the_other_date.ticks ? 1 : -1;
44    }
45
46    public bool Equals(Date other)
47    {
48      if (ReferenceEquals(null, other)) return false;
49      if (ReferenceEquals(this, other)) return true;
50      return other.ticks == ticks;
51    }
52
53    public override bool Equals(object obj)
54    {
55      if (ReferenceEquals(null, obj)) return false;
56      if (ReferenceEquals(this, obj)) return true;
57      if (obj.GetType() != typeof (Date)) return false;
58      return Equals((Date) obj);
59    }
60
61    public override int GetHashCode()
62    {
63      return ticks.GetHashCode();
64    }
65
66    public static bool operator ==(Date left, Date right)
67    {
68      return Equals(left, right);
69    }
70
71    public static bool operator !=(Date left, Date right)
72    {
73      return !Equals(left, right);
74    }
75
76    public override string ToString()
77    {
78      return new DateTime(ticks, DateTimeKind.Local).ToString("MMM dd yyyy", CultureInfo.InvariantCulture);
79    }
80
81    int IComparable.CompareTo(object obj)
82    {
83      if (obj.is_an_implementation_of<Date>())
84        return CompareTo(obj.downcast_to<Date>());
85      throw new InvalidOperationException();
86    }
87  }
88}