mcs/class/corlib/System/CharEnumerator.cs

   1 //
   2 // System.CharEnumerator.cs
   3 //
   4 // Author: Duncan Mak  (duncan@ximian.com)
   5 //
   6 // (C) Ximian, Inc.
   7 //
   8
   9 using System.Collections;
  10
  11 namespace System
  12 {
  13            [Serializable]
  14            public sealed class CharEnumerator : IEnumerator, ICloneable
  15            {
  16                  private string str;
  17                  private int idx;
  18                  private int len;
  19
  20            // Constructor
  21                  internal CharEnumerator (string s)
  22                  {
  23                             str = s;
  24                             idx = -1;
  25                                 len = s.Length;
  26                  }
  27
  28                  // Property
  29                  public char Current
  30                  {
  31                             get {
  32                                   if (idx == -1)
  33                                                 throw new InvalidOperationException ("The position is not valid.");
  34
  35                                   return str[idx];
  36                             }
  37                  }
  38
  39                  object IEnumerator.Current {
  40                             get {
  41                                           if (idx == -1)
  42                                                         throw new InvalidOperationException ("The position is not valid");
  43                                           return str [idx];
  44                             }
  45                  }
  46
  47                  // Methods
  48                  public object Clone ()
  49                  {
  50                             CharEnumerator x = new CharEnumerator (str);
  51                             x.idx = idx;
  52                             return x;
  53                  }
  54
  55                  public bool MoveNext ()
  56                  {
  57                             if (len < 0)
  58                                           return false;
  59
  60                             idx++;
  61
  62                             if (idx > len) {
  63                                           idx = -2;
  64                                           return false;
  65                             }
  66
  67                             return true;
  68                  }
  69
  70                  public void Reset ()
  71                  {
  72                             idx = -1;
  73                  }
  74    }
  75 }