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 }