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//------------------------------------------------------------------------------
// <copyright file="SymbolEqualComparer.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.Util {
using System.Collections;
using System.Globalization;
/// <devdoc>
/// <para>
/// For internal use only. This implements a comparison that only
/// checks for equalilty, so this should only be used in un-sorted data
/// structures like Hastable and ListDictionary. This is a little faster
/// than using CaseInsensitiveComparer because it does a strict character by
/// character equality chech rather than a sorted comparison.
/// </para>
/// </devdoc>
internal class SymbolEqualComparer: IComparer {
/// <devdoc>
/// <para>[To be supplied.]</para>
/// </devdoc>
internal static readonly IComparer Default = new SymbolEqualComparer();
internal SymbolEqualComparer() {
}
int IComparer.Compare(object keyLeft, object keyRight) {
string sLeft = keyLeft as string;
string sRight = keyRight as string;
if (sLeft == null) {
throw new ArgumentNullException("keyLeft");
}
if (sRight == null) {
throw new ArgumentNullException("keyRight");
}
int lLeft = sLeft.Length;
int lRight = sRight.Length;
if (lLeft != lRight) {
return 1;
}
for (int i = 0; i < lLeft; i++) {
char charLeft = sLeft[i];
char charRight = sRight[i];
if (charLeft == charRight) {
continue;
}
UnicodeCategory catLeft = Char.GetUnicodeCategory(charLeft);
UnicodeCategory catRight = Char.GetUnicodeCategory(charRight);
if (catLeft == UnicodeCategory.UppercaseLetter
&& catRight == UnicodeCategory.LowercaseLetter) {
if (Char.ToLower(charLeft, CultureInfo.InvariantCulture) == charRight) {
continue;
}
} else if (catRight == UnicodeCategory.UppercaseLetter
&& catLeft == UnicodeCategory.LowercaseLetter){
if (Char.ToLower(charRight, CultureInfo.InvariantCulture) == charLeft) {
continue;
}
}
return 1;
}
return 0;
}
}
}
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