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//---------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//
// Description: The PartialArray struct is used when the developer needs to pass a CLR array range to
// a function that takes generic IList interface. For cases when the whole array needs to be passed,
// CLR array already implements IList.
//
//
// History:
// 06/25/2004 : mleonov - Created
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using SR = MS.Internal.PresentationCore.SR;
using SRID = MS.Internal.PresentationCore.SRID;
namespace MS.Internal
{
/// <summary>
/// The PartialArray struct is used when someone needs to pass a CLR array range to
/// a function that takes generic IList interface. For cases when the whole array needs to be passed,
/// CLR array already implements IList.
/// </summary>
internal struct PartialArray<T> : IList<T>
{
private T[] _array;
private int _initialIndex;
private int _count;
public PartialArray(T[] array, int initialIndex, int count)
{
// make sure early that the caller didn't miscalculate index and count
Debug.Assert(initialIndex >= 0 && initialIndex + count <= array.Length);
_array = array;
_initialIndex = initialIndex;
_count = count;
}
/// <summary>
/// Convenience helper for passing the whole array.
/// </summary>
/// <param name="array"></param>
public PartialArray(T[] array) : this(array, 0, array.Length)
{}
#region IList<T> Members
public bool IsReadOnly
{
get
{
return false;
}
}
public bool Contains(T item)
{
return IndexOf(item) >= 0;
}
public bool IsFixedSize
{
get
{
return true;
}
}
public bool Remove(T item)
{
throw new NotSupportedException(SR.Get(SRID.CollectionIsFixedSize));
}
public void RemoveAt(int index)
{
throw new NotSupportedException(SR.Get(SRID.CollectionIsFixedSize));
}
public void Clear()
{
throw new NotSupportedException();
}
public void Add(T item)
{
throw new NotSupportedException(SR.Get(SRID.CollectionIsFixedSize));
}
public void Insert(int index, T item)
{
throw new NotSupportedException(SR.Get(SRID.CollectionIsFixedSize));
}
public T this[int index]
{
get
{
return _array[index + _initialIndex];
}
set
{
_array[index + _initialIndex] = value;
}
}
public int IndexOf(T item)
{
int index = Array.IndexOf<T>(_array, item, _initialIndex, _count);
if (index >= 0)
{
return index - _initialIndex;
}
else
{
return -1;
}
}
#endregion
#region ICollection<T> Members
public int Count
{
get
{
return _count;
}
}
public void CopyTo(T[] array, int arrayIndex)
{
// parameter validations
if (array == null)
{
throw new ArgumentNullException("array");
}
if (array.Rank != 1)
{
throw new ArgumentException(
SR.Get(SRID.Collection_CopyTo_ArrayCannotBeMultidimensional),
"array");
}
if (arrayIndex < 0)
{
throw new ArgumentOutOfRangeException("arrayIndex");
}
if (arrayIndex >= array.Length)
{
throw new ArgumentException(
SR.Get(
SRID.Collection_CopyTo_IndexGreaterThanOrEqualToArrayLength,
"arrayIndex",
"array"),
"arrayIndex");
}
if ((array.Length - Count - arrayIndex) < 0)
{
throw new ArgumentException(
SR.Get(
SRID.Collection_CopyTo_NumberOfElementsExceedsArrayLength,
"arrayIndex",
"array"));
}
// do the copying here
for (int i = 0; i < Count; i++)
{
array[arrayIndex + i] = this[i];
}
}
#endregion
#region IEnumerable<T> Members
IEnumerator<T> IEnumerable<T>.GetEnumerator()
{
for (int i = 0; i < Count; i++)
{
yield return this[i];
}
}
#endregion
#region IEnumerable Members
IEnumerator IEnumerable.GetEnumerator()
{
return ((IEnumerable<T>)this).GetEnumerator();
}
#endregion
}
}
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