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                 [Serializable]
  43                 class StringCultureComparer: StringComparer
  44                 {
  45                         CompareOptions co;
  46                         CompareInfo ci;
  47
  48                         public StringCultureComparer (CultureInfo ci, bool ignore_case)
  49                         {
  50                                 this.ci = ci.CompareInfo;
  51                                 co = ignore_case ? CompareOptions.IgnoreCase : CompareOptions.None;
  52                         }
  53
  54                         public override int Compare (string x, string y)
  55                         {
  56                                 return ci.Compare (x, y, co);
  57                         }
  58
  59                         public override bool Equals (string x, string y)
  60                         {
  61                                 return Compare (x, y) == 0;
  62                         }
  63
  64                         public override int GetHashCode (string s)
  65                         {
  66                                 if (s == null)
  67                                         throw new ArgumentNullException("s");
  68
  69                                 return ci.GetSortKey (s, co).GetHashCode ();
  70                         }
  71                 }
  72
  73                 [Serializable]
  74                 class OrdinalComparer : StringComparer
  75                 {
  76                         public OrdinalComparer ()
  77                         {
  78                         }
  79
  80                         public override int Compare (string x, string y)
  81                         {
  82                                 return String.CompareOrdinal (x, y);
  83                         }
  84
  85                         public override bool Equals (string x, string y)
  86                         {
  87                                 return x == y;
  88                         }
  89
  90                         public override int GetHashCode (string s)
  91                         {
  92                                 return s.GetHashCode ();
  93                         }
  94                 }
  95
  96                 [Serializable]
  97                 class OrdinalIgnoreCaseComparer : StringComparer
  98                 {
  99                         public OrdinalIgnoreCaseComparer ()
 100                         {
 101                         }
 102
 103                         public override int Compare (string x, string y)
 104                         {
 105                                 // copied from String.CompareOrdinal()
 106                                 if (x == null) {
 107                                         if (y == null)
 108                                                 return 0;
 109                                         else
 110                                                 return -1;
 111                                 }
 112                                 else if (y == null) {
 113                                         return 1;
 114                                 }
 115
 116                                 int max = x.Length > y.Length ? y.Length : x.Length;
 117                                 for (int i = 0; i < max; i++) {
 118                                         if (x [i] == y [i])
 119                                                 continue;
 120                                         char xc = Char.ToUpperInvariant (x [i]);
 121                                         char yc = Char.ToUpperInvariant (y [i]);
 122                                         if (xc != yc)
 123                                                 return xc - yc;
 124                                 }
 125                                 return max < x.Length ? -1 :
 126                                         max == y.Length ? 0 : 1;
 127                         }
 128
 129                         public override bool Equals (string x, string y)
 130                         {
 131                                 return Compare (x, y) == 0;
 132                         }
 133
 134                         public override int GetHashCode (string s)
 135                         {
 136                                 return s.GetCaseInsensitiveHashCode ();
 137                         }
 138                 }
 139
 140                 static StringComparer invariantCultureIgnoreCase = new StringCultureComparer (CultureInfo.InvariantCulture, true);
 141                 static StringComparer invariantCulture = new StringCultureComparer (CultureInfo.InvariantCulture, false);
 142                 static StringComparer ordinalIgnoreCase =
 143                         new OrdinalIgnoreCaseComparer ();
 144                 static StringComparer ordinal = new OrdinalComparer ();
 145
 146                 // Constructors
 147                 protected StringComparer ()
 148                 {
 149                 }
 150
 151                 // Properties
 152                 public static StringComparer CurrentCulture {
 153                         get {
 154                                 return new StringCultureComparer (CultureInfo.CurrentCulture, false);
 155                         }
 156                 }
 157
 158                 public static StringComparer CurrentCultureIgnoreCase {
 159                         get {
 160                                 return new StringCultureComparer (CultureInfo.CurrentCulture, true);
 161                         }
 162                 }
 163
 164                 public static StringComparer InvariantCulture {
 165                         get {
 166                                 return invariantCulture;
 167                         }
 168                 }
 169
 170                 public static StringComparer InvariantCultureIgnoreCase {
 171                         get {
 172                                 return invariantCultureIgnoreCase;
 173                         }
 174                 }
 175
 176                 public static StringComparer Ordinal {
 177                         get { return ordinal; }
 178                 }
 179
 180                 public static StringComparer OrdinalIgnoreCase {
 181                         get { return ordinalIgnoreCase; }
 182                 }
 183
 184                 // Methods
 185                 public static StringComparer Create (CultureInfo culture, bool ignoreCase)
 186                 {
 187                         return new StringCultureComparer (culture, ignoreCase);
 188                 }
 189
 190                 public int Compare (object x, object y)
 191                 {
 192                         if (x == y)
 193                                 return 0;
 194                         if (x == null)
 195                                 return -1;
 196                         if (y == null)
 197                                 return 1;
 198
 199                         string s_x = x as string;
 200                         if (s_x != null) {
 201                                 string s_y = y as string;
 202                                 if (s_y != null)
 203                                         return Compare (s_x, s_y);
 204                         }
 205
 206                         IComparable ic = x as IComparable;
 207                         if (ic == null)
 208                                 throw new ArgumentException ();
 209
 210                         return ic.CompareTo (y);
 211                 }
 212
 213                 public new bool Equals (object x, object y)
 214                 {
 215                         if (x == y)
 216                                 return true;
 217                         if (x == null || y == null)
 218                                 return false;
 219
 220                         string s_x = x as string;
 221                         if (s_x != null) {
 222                                 string s_y = y as string;
 223                                 if (s_y != null)
 224                                         return Equals (s_x, s_y);
 225                         }
 226                         return x.Equals (y);
 227                 }
 228
 229                 public int GetHashCode (object o)
 230                 {
 231                         if (o == null)
 232                                 throw new ArgumentNullException("o");
 233
 234                         string s = o as string;
 235                         return s == null ? o.GetHashCode (): GetHashCode(s);
 236                 }
 237
 238                 public abstract int Compare (string x, string y);
 239                 public abstract bool Equals (string x, string y);
 240                 public abstract int GetHashCode (string s);
 241         }
 242 }
 243
 244 #endif