mcs/class/corlib/System/StringComparer.cs

   1 //
   2 // System.StringComparer
   3 //
   4 // Authors:
   5 //      Marek Safar (marek.safar@seznam.cz)
   6 //
   7 // (C) 2005 Novell, Inc (http://www.novell.com)
   8 //
   9
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 #if NET_2_0
  31
  32 using System.Collections;
  33 using System.Globalization;
  34 using System.Runtime.InteropServices;
  35 using System.Collections.Generic;
  36
  37 namespace System
  38 {
  39         [Serializable, ComVisible(true)]
  40         public abstract class StringComparer : IComparer, IEqualityComparer, IComparer<string>, IEqualityComparer<string>
  41         {
  42                 class StringCultureComparer: StringComparer
  43                 {
  44                         CompareOptions co;
  45                         CompareInfo ci;
  46
  47                         public StringCultureComparer (CultureInfo ci, bool ignore_case)
  48                         {
  49                                 this.ci = ci.CompareInfo;
  50                                 co = ignore_case ? CompareOptions.IgnoreCase : CompareOptions.None;
  51                         }
  52
  53                         public override int Compare (string x, string y)
  54                         {
  55                                 return ci.Compare (x, y, co);
  56                         }
  57
  58                         public override bool Equals (string x, string y)
  59                         {
  60                                 return Compare (x, y) == 0;
  61                         }
  62
  63                         public override int GetHashCode (string s)
  64                         {
  65                                 if (s == null)
  66                                         throw new ArgumentNullException("s");
  67
  68                                 return ci.GetSortKey (s, co).GetHashCode ();
  69                         }
  70                 }
  71
  72                 static StringComparer invariantCultureIgnoreCase = new StringCultureComparer (CultureInfo.InvariantCulture, true);
  73                 static StringComparer invariantCulture = new StringCultureComparer (CultureInfo.InvariantCulture, false);
  74
  75                 // Constructors
  76                 protected StringComparer ()
  77                 {
  78                 }
  79
  80                 // Properties
  81                 public static StringComparer CurrentCulture {
  82                         get {
  83                                 return new StringCultureComparer (CultureInfo.CurrentCulture, false);
  84                         }
  85                 }
  86
  87                 public static StringComparer CurrentCultureIgnoreCase {
  88                         get {
  89                                 return new StringCultureComparer (CultureInfo.CurrentCulture, true);
  90                         }
  91                 }
  92
  93                 public static StringComparer InvariantCulture {
  94                         get {
  95                                 return invariantCulture;
  96                         }
  97                 }
  98
  99                 public static StringComparer InvariantCultureIgnoreCase {
 100                         get {
 101                                 return invariantCultureIgnoreCase;
 102                         }
 103                 }
 104
 105                 // Methods
 106                 public int Compare (object x, object y)
 107                 {
 108                         if (x == y)
 109                                 return 0;
 110                         if (x == null)
 111                                 return -1;
 112                         if (y == null)
 113                                 return 1;
 114
 115                         string s_x = x as string;
 116                         if (s_x != null) {
 117                                 string s_y = y as string;
 118                                 if (s_y != null)
 119                                         return Compare (s_x, s_y);
 120                         }
 121
 122                         IComparable ic = x as IComparable;
 123                         if (ic == null)
 124                                 throw new ArgumentException ();
 125
 126                         return ic.CompareTo (y);
 127                 }
 128
 129                 public new bool Equals (object x, object y)
 130                 {
 131                         if (x == y)
 132                                 return true;
 133                         if (x == null || y == null)
 134                                 return false;
 135
 136                         string s_x = x as string;
 137                         if (s_x != null) {
 138                                 string s_y = y as string;
 139                                 if (s_y != null)
 140                                         return Equals (s_x, s_y);
 141                         }
 142                         return x.Equals (y);
 143                 }
 144
 145                 public int GetHashCode (object o)
 146                 {
 147                         if (o == null)
 148                                 throw new ArgumentNullException("o");
 149
 150                         string s = o as string;
 151                         return s == null ? o.GetHashCode (): GetHashCode(s);
 152                 }
 153
 154                 public abstract int Compare (string x, string y);
 155                 public abstract bool Equals (string x, string y);
 156                 public abstract int GetHashCode (string s);
 157         }
 158 }
 159
 160 #endif