/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Microsoft Public License.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Collections.Generic;
using System.Text;
namespace Microsoft.Scripting.Debugging{
internal static class CollectionUtils {
internal static T[] RemoveLast<T>(this T[] array) {
T[] result = new T[array.Length - 1];
Array.Copy(array, 0, result, 0, result.Length);
return result;
}
internal static bool ListEquals<T>(this ICollection<T> first, ICollection<T> second) {
if (first.Count != second.Count) {
return false;
}
var cmp = EqualityComparer<T>.Default;
var f = first.GetEnumerator();
var s = second.GetEnumerator();
while (f.MoveNext()) {
s.MoveNext();
if (!cmp.Equals(f.Current, s.Current)) {
return false;
}
}
return true;
}
internal static int ListHashCode<T>(this IEnumerable<T> list) {
var cmp = EqualityComparer<T>.Default;
int h = 6551;
foreach (T t in list) {
h ^= (h << 5) ^ cmp.GetHashCode(t);
}
return h;
}
}
// Compares two ICollection<T>'s using element equality
internal sealed class ListEqualityComparer<T> : EqualityComparer<ICollection<T>> {
internal static readonly ListEqualityComparer<T> Instance = new ListEqualityComparer<T>();
private ListEqualityComparer() { }
// EqualityComparer<T> handles null and object identity for us
public override bool Equals(ICollection<T> x, ICollection<T> y) {
return x.ListEquals(y);
}
public override int GetHashCode(ICollection<T> obj) {
return obj.ListHashCode();
}
}
}
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