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//
// System.CharEnumerator.cs
//
// Author:
// Duncan Mak (duncan@ximian.com)
//
// (C) Ximian, Inc.
//
//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Collections;
#if NET_2_0
using System.Collections.Generic;
#endif
using System.Runtime.InteropServices;
namespace System
{
[Serializable]
#if NET_2_0
[ComVisible (true)]
#endif
public sealed class CharEnumerator : IEnumerator, ICloneable
#if NET_2_0
, IEnumerator <char>
#endif
{
private string str;
private int index;
private int length;
// Representation invariant:
// length == str.Length
// -1 <= index <= length
// Constructor
internal CharEnumerator (string s)
{
str = s;
index = -1;
length = s.Length;
}
// Properties
public char Current {
get {
if (index == -1 || index >= length)
throw new InvalidOperationException (Locale.GetText ("The position is not valid."));
return str [index];
}
}
object IEnumerator.Current {
get {
return Current;
}
}
// Methods
public object Clone ()
{
CharEnumerator x = new CharEnumerator (str);
x.index = index;
return x;
}
public bool MoveNext ()
{
// Representation invariant holds: -1 <= index <= length
index ++;
// Now: 0 <= index <= length+1;
// <=>
// 0 <= index < length (OK) ||
// length <= index <= length+1 (Out of bounds)
if (index >= length) {
index = length;
// Invariant restored:
// length == index
// =>
// -1 <= index <= length
return false;
}
else
return true;
}
public void Reset ()
{
index = -1;
}
#if NET_2_0
void IDisposable.Dispose ()
{
// nop
}
#endif
}
}
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