class/corlib/System.Globalization/StringInfo.cs

   1 //
   2 // System.Globalization.StringInfo.cs
   3 //
   4 // Author:
   5 //      Dick Porter (dick@ximian.com)
   6 //
   7 // (C) 2002 Ximian, Inc.
   8 // (C) 2004 Novell, Inc.
   9 //
  10
  11 //
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Collections;
  35 using System.Runtime.InteropServices;
  36
  37 namespace System.Globalization {
  38
  39         [Serializable]
  40         [ComVisible(true)]
  41         public class StringInfo {
  42
  43                 public StringInfo () : this (string.Empty)
  44                 {
  45                 }
  46
  47                 string s;
  48                 int length;
  49
  50                 public StringInfo (string value)
  51                 {
  52                         // Argument check in property
  53                         String = value;
  54                 }
  55
  56                 [ComVisible (false)]
  57                 public override bool Equals (object value)
  58                 {
  59                         StringInfo other = value as StringInfo;
  60                         return other != null && s == other.s;
  61                 }
  62
  63                 [ComVisible (false)]
  64                 public override int GetHashCode ()
  65                 {
  66                         return s.GetHashCode ();
  67                 }
  68
  69                 public int LengthInTextElements {
  70                         get {
  71                                 if (length < 0) {
  72                                         length = 0;
  73                                         for (int idx = 0; idx < s.Length; length++)
  74                                                 idx += GetNextTextElementLength (s, idx);
  75                                 }
  76                                 return length;
  77                         }
  78                 }
  79
  80                 public string String {
  81                         get { return s; }
  82                         set {
  83                                 if (value == null)
  84                                         throw new ArgumentNullException ("value");
  85                                 length = -1;
  86                                 s = value;
  87                         }
  88                 }
  89
  90                 public string SubstringByTextElements (int startingTextElement)
  91                 {
  92                         if (startingTextElement < 0 || s.Length == 0)
  93                                 throw new ArgumentOutOfRangeException ("startingTextElement");
  94                         int idx = 0;
  95                         for (int i = 0; i < startingTextElement; i++) {
  96                                 if (idx >= s.Length)
  97                                         throw new ArgumentOutOfRangeException ("startingTextElement");
  98                                 idx += GetNextTextElementLength (s, idx);
  99                         }
 100                         return s.Substring (idx);
 101                 }
 102
 103                 public string SubstringByTextElements (int startingTextElement, int lengthInTextElements)
 104                 {
 105                         if (startingTextElement < 0 || s.Length == 0)
 106                                 throw new ArgumentOutOfRangeException ("startingTextElement");
 107                         if (lengthInTextElements < 0)
 108                                 throw new ArgumentOutOfRangeException ("lengthInTextElements");
 109                         int idx = 0;
 110                         for (int i = 0; i < startingTextElement; i++) {
 111                                 if (idx >= s.Length)
 112                                         throw new ArgumentOutOfRangeException ("startingTextElement");
 113                                 idx += GetNextTextElementLength (s, idx);
 114                         }
 115                         int start = idx;
 116                         for (int i = 0; i < lengthInTextElements; i++) {
 117                                 if (idx >= s.Length)
 118                                         throw new ArgumentOutOfRangeException ("lengthInTextElements");
 119                                 idx += GetNextTextElementLength (s, idx);
 120                         }
 121                         return s.Substring (start, idx - start);
 122                 }
 123
 124                 public static string GetNextTextElement(string str)
 125                 {
 126                         if(str == null || str.Length == 0) {
 127                                 throw new ArgumentNullException("string is null");
 128                         }
 129                         return(GetNextTextElement (str, 0));
 130                 }
 131
 132                 public static string GetNextTextElement(string str, int index)
 133                 {
 134                         int len = GetNextTextElementLength (str, index);
 135                         return len != 1 ? str.Substring (index, len) : new string (str [index], 1);
 136                 }
 137
 138                 static int GetNextTextElementLength(string str, int index)
 139                 {
 140                         if(str == null) {
 141                                 throw new ArgumentNullException("string is null");
 142                         }
 143
 144                         if(index >= str.Length)
 145                                 return 0;
 146                         if(index < 0)
 147                                 throw new ArgumentOutOfRangeException ("Index is not valid");
 148
 149                         /* Find the next base character, surrogate
 150                          * pair or combining character sequence
 151                          */
 152
 153                         char ch = str[index];
 154                         UnicodeCategory cat = char.GetUnicodeCategory (ch);
 155
 156                         if (cat == UnicodeCategory.Surrogate) {
 157                                 /* Check that it's a high surrogate
 158                                  * followed by a low surrogate
 159                                  */
 160                                 if (ch >= 0xD800 && ch <= 0xDBFF) {
 161                                         if ((index + 1) < str.Length &&
 162                                             str[index + 1] >= 0xDC00 &&
 163                                             str[index + 1] <= 0xDFFF) {
 164                                                 /* A valid surrogate pair */
 165                                                 return 2;
 166                                         } else {
 167                                                 /* High surrogate on its own */
 168                                                 return 1;
 169                                         }
 170                                 } else {
 171                                         /* Low surrogate on its own */
 172                                         return 1;
 173                                 }
 174                         } else {
 175                                 /* Look for a base character, which
 176                                  * may or may not be followed by a
 177                                  * series of combining characters
 178                                  */
 179
 180                                 if (cat == UnicodeCategory.NonSpacingMark ||
 181                                     cat == UnicodeCategory.SpacingCombiningMark ||
 182                                     cat == UnicodeCategory.EnclosingMark) {
 183                                         /* Not a base character */
 184                                         return 1;
 185                                 }
 186
 187                                 int count = 1;
 188
 189                                 while (index + count < str.Length) {
 190                                         cat = char.GetUnicodeCategory (str[index + count]);
 191                                         if (cat != UnicodeCategory.NonSpacingMark &&
 192                                             cat != UnicodeCategory.SpacingCombiningMark &&
 193                                             cat != UnicodeCategory.EnclosingMark) {
 194                                                 /* Finished the sequence */
 195                                                 break;
 196                                         }
 197                                         count++;
 198                                 }
 199
 200                                 return count;
 201                         }
 202                 }
 203
 204                 public static TextElementEnumerator GetTextElementEnumerator(string str)
 205                 {
 206                         if(str == null || str.Length == 0) {
 207                                 throw new ArgumentNullException("string is null");
 208                         }
 209                         return(new TextElementEnumerator (str, 0));
 210                 }
 211
 212                 public static TextElementEnumerator GetTextElementEnumerator(string str, int index)
 213                 {
 214                         if(str == null) {
 215                                 throw new ArgumentNullException("string is null");
 216                         }
 217
 218                         if(index < 0 || index >= str.Length) {
 219                                 throw new ArgumentOutOfRangeException ("Index is not valid");
 220                         }
 221
 222                         return(new TextElementEnumerator (str, index));
 223                 }
 224
 225                 public static int[] ParseCombiningCharacters(string str)
 226                 {
 227                         if(str == null) {
 228                                 throw new ArgumentNullException("string is null");
 229                         }
 230
 231                         ArrayList indices = new ArrayList (str.Length);
 232                         TextElementEnumerator tee = GetTextElementEnumerator (str);
 233
 234                         tee.Reset ();
 235                         while(tee.MoveNext ()) {
 236                                 indices.Add (tee.ElementIndex);
 237                         }
 238
 239                         return((int[])indices.ToArray (typeof (int)));
 240                 }
 241         }
 242 }