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
  36 namespace System
  37 {
  38         [Serializable, ComVisible(true)]
  39         public abstract class StringComparer : IComparer, IEqualityComparer
  40         {
  41                 class StringCultureComparer: StringComparer
  42                 {
  43                         CompareOptions co;
  44                         CompareInfo ci;
  45
  46                         public StringCultureComparer (CultureInfo ci, bool ignore_case)
  47                         {
  48                                 this.ci = ci.CompareInfo;
  49                                 co = ignore_case ? CompareOptions.IgnoreCase : CompareOptions.None;
  50                         }
  51
  52                         public override int Compare (string x, string y)
  53                         {
  54                                 return ci.Compare (x, y, co);
  55                         }
  56
  57                         public override bool Equals (string x, string y)
  58                         {
  59                                 return Compare (x, y) == 0;
  60                         }
  61
  62                         public override int GetHashCode (string s)
  63                         {
  64                                 if (s == null)
  65                                         throw new ArgumentNullException("s");
  66
  67                                 return ci.GetSortKey (s, co).GetHashCode ();
  68                         }
  69                 }
  70
  71                 static StringComparer invariantCultureIgnoreCase = new StringCultureComparer (CultureInfo.InvariantCulture, true);
  72                 static StringComparer invariantCulture = new StringCultureComparer (CultureInfo.InvariantCulture, false);
  73
  74                 // Constructors
  75                 protected StringComparer ()
  76                 {
  77                 }
  78
  79                 // Properties
  80                 public static StringComparer CurrentCulture {
  81                         get {
  82                                 return new StringCultureComparer (CultureInfo.CurrentCulture, false);
  83                         }
  84                 }
  85
  86                 public static StringComparer CurrentCultureIgnoreCase {
  87                         get {
  88                                 return new StringCultureComparer (CultureInfo.CurrentCulture, true);
  89                         }
  90                 }
  91
  92                 public static StringComparer InvariantCulture {
  93                         get {
  94                                 return invariantCulture;
  95                         }
  96                 }
  97
  98                 public static StringComparer InvariantCultureIgnoreCase {
  99                         get {
 100                                 return invariantCultureIgnoreCase;
 101                         }
 102                 }
 103
 104                 // Methods
 105                 public int Compare (object x, object y)
 106                 {
 107                         if (x == y)
 108                                 return 0;
 109                         if (x == null)
 110                                 return -1;
 111                         if (y == null)
 112                                 return 1;
 113
 114                         string s_x = x as string;
 115                         if (s_x != null) {
 116                                 string s_y = y as string;
 117                                 if (s_y != null)
 118                                         return Compare (s_x, s_y);
 119                         }
 120
 121                         IComparable ic = x as IComparable;
 122                         if (ic == null)
 123                                 throw new ArgumentException ();
 124
 125                         return ic.CompareTo (y);
 126                 }
 127
 128                 public new bool Equals (object x, object y)
 129                 {
 130                         if (x == y)
 131                                 return true;
 132                         if (x == null || y == null)
 133                                 return false;
 134
 135                         string s_x = x as string;
 136                         if (s_x != null) {
 137                                 string s_y = y as string;
 138                                 if (s_y != null)
 139                                         return Equals (s_x, s_y);
 140                         }
 141                         return x.Equals (y);
 142                 }
 143
 144                 public int GetHashCode (object o)
 145                 {
 146                         if (o == null)
 147                                 throw new ArgumentNullException("o");
 148
 149                         string s = o as string;
 150                         return s == null ? o.GetHashCode (): GetHashCode(s);
 151                 }
 152
 153                 public abstract int Compare (string x, string y);
 154                 public abstract bool Equals (string x, string y);
 155                 public abstract int GetHashCode (string s);
 156         }
 157 }
 158
 159 #endif