//
// System.Collections.CaseInsensitiveHashCodeProvider.cs
//
// Authors:
// Sergey Chaban (serge@wildwestsoftware.com)
// Andreas Nahr (ClassDevelopment@A-SoftTech.com)
// Sebastien Pouliot <sebastien@ximian.com>
//
// Copyright (C) 2004-2005 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.Globalization;
using System.Runtime.InteropServices;
namespace System.Collections{
[Serializable]
[ComVisible(true)]
[Obsolete ("Please use StringComparer instead.")]
#if INSIDE_CORLIB
public
#else
internal
#endif
class CaseInsensitiveHashCodeProvider : IHashCodeProvider
{
static readonly CaseInsensitiveHashCodeProvider singletonInvariant = new CaseInsensitiveHashCodeProvider (
CultureInfo.InvariantCulture);
static CaseInsensitiveHashCodeProvider singleton;
static readonly object sync = new object ();
TextInfo m_text; // must match MS name for serialization
// Public instance constructor
public CaseInsensitiveHashCodeProvider ()
{
CultureInfo culture = CultureInfo.CurrentCulture;
if (!AreEqual (culture, CultureInfo.InvariantCulture))
m_text = CultureInfo.CurrentCulture.TextInfo;
}
public CaseInsensitiveHashCodeProvider (CultureInfo culture)
{
if (culture == null)
throw new ArgumentNullException ("culture");
if (!AreEqual (culture, CultureInfo.InvariantCulture))
m_text = culture.TextInfo;
}
//
// Public static properties
//
public static CaseInsensitiveHashCodeProvider Default {
get {
// MS actually constructs a new instance on each call, for
// performance reasons we're only constructing a new instance
// if the CurrentCulture changes
lock (sync) {
if (singleton == null) {
singleton = new CaseInsensitiveHashCodeProvider ();
} else if (singleton.m_text == null) {
if (!AreEqual (CultureInfo.CurrentCulture, CultureInfo.InvariantCulture))
singleton = new CaseInsensitiveHashCodeProvider ();
} else if (!AreEqual (singleton.m_text, CultureInfo.CurrentCulture)) {
singleton = new CaseInsensitiveHashCodeProvider ();
}
return singleton;
}
}
}
static bool AreEqual (CultureInfo a, CultureInfo b)
{
#if !NET_2_1
return a.LCID == b.LCID;
#else
return a.Name == b.Name;
#endif
}
static bool AreEqual (TextInfo info, CultureInfo culture)
{
#if !NET_2_1
return info.LCID == culture.LCID;
#else
return info.CultureName == culture.Name;
#endif
}
#if NET_1_1
public
#else
internal
#endif
static CaseInsensitiveHashCodeProvider DefaultInvariant {
get {
return singletonInvariant;
}
}
//
// IHashCodeProvider
//
public int GetHashCode (object obj)
{
if (obj == null)
throw new ArgumentNullException ("obj");
string str = obj as string;
if (str == null)
return obj.GetHashCode ();
int h = 0;
char c;
if ((m_text != null) && !AreEqual (m_text, CultureInfo.InvariantCulture)) {
str = m_text.ToLower (str);
for (int i = 0; i < str.Length; i++) {
c = str [i];
h = h * 31 + c;
}
} else {
for (int i = 0; i < str.Length; i++) {
c = Char.ToLower (str [i], CultureInfo.InvariantCulture);
h = h * 31 + c;
}
}
return h;
}
}
}
|