|
// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
/*============================================================
**
** Class: CaseInsensitiveComparer
**
** <OWNER>Microsoft</OWNER>
**
**
**
============================================================*/
namespace System.Collections {
//This class does not contain members and does not need to be serializable
using System;
using System.Collections;
using System.Globalization;
using System.Diagnostics.Contracts;
[Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class CaseInsensitiveComparer : IComparer {
private CompareInfo m_compareInfo;
private static volatile CaseInsensitiveComparer m_InvariantCaseInsensitiveComparer;
public CaseInsensitiveComparer() {
m_compareInfo = CultureInfo.CurrentCulture.CompareInfo;
}
public CaseInsensitiveComparer(CultureInfo culture) {
if (culture==null) {
throw new ArgumentNullException("culture");
}
Contract.EndContractBlock();
m_compareInfo = culture.CompareInfo;
}
public static CaseInsensitiveComparer Default
{
get
{
Contract.Ensures(Contract.Result<CaseInsensitiveComparer>() != null);
return new CaseInsensitiveComparer(CultureInfo.CurrentCulture);
}
}
public static CaseInsensitiveComparer DefaultInvariant
{
get
{
Contract.Ensures(Contract.Result<CaseInsensitiveComparer>() != null);
if (m_InvariantCaseInsensitiveComparer == null) {
m_InvariantCaseInsensitiveComparer = new CaseInsensitiveComparer(CultureInfo.InvariantCulture);
}
return m_InvariantCaseInsensitiveComparer;
}
}
// Behaves exactly like Comparer.Default.Compare except that the comparison is case insensitive
// Compares two Objects by calling CompareTo. If a ==
// b,0 is returned. If a implements
// IComparable, a.CompareTo(b) is returned. If a
// doesn't implement IComparable and b does,
// -(b.CompareTo(a)) is returned, otherwise an
// exception is thrown.
//
public int Compare(Object a, Object b) {
String sa = a as String;
String sb = b as String;
if (sa != null && sb != null)
return m_compareInfo.Compare(sa, sb, CompareOptions.IgnoreCase);
else
return Comparer.Default.Compare(a,b);
}
}
}
|