mcs/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                 public StringInfo()
  43                 {
  44                 }
  45
  46                 string s;
  47                 int length;
  48
  49                 public StringInfo (string value)
  50                 {
  51                         // Argument check in property
  52                         String = value;
  53                 }
  54
  55                 [ComVisible (false)]
  56                 public override bool Equals (object value)
  57                 {
  58                         StringInfo other = value as StringInfo;
  59                         return other != null && s == other.s;
  60                 }
  61
  62                 [ComVisible (false)]
  63                 public override int GetHashCode ()
  64                 {
  65                         return s.GetHashCode ();
  66                 }
  67
  68                 public int LengthInTextElements {
  69                         get {
  70                                 if (length < 0) {
  71                                         length = 0;
  72                                         for (int idx = 0; idx < s.Length; length++)
  73                                                 idx += GetNextTextElementLength (s, idx);
  74                                 }
  75                                 return length;
  76                         }
  77                 }
  78
  79                 public string String {
  80                         get { return s; }
  81                         set {
  82                                 if (value == null)
  83                                         throw new ArgumentNullException ("value");
  84                                 length = -1;
  85                                 s = value;
  86                         }
  87                 }
  88
  89                 public string SubstringByTextElements (int startingTextElement)
  90                 {
  91                         if (startingTextElement < 0 || s.Length == 0)
  92                                 throw new ArgumentOutOfRangeException ("startingTextElement");
  93                         int idx = 0;
  94                         for (int i = 0; i < startingTextElement; i++) {
  95                                 if (idx >= s.Length)
  96                                         throw new ArgumentOutOfRangeException ("startingTextElement");
  97                                 idx += GetNextTextElementLength (s, idx);
  98                         }
  99                         return s.Substring (idx);
 100                 }
 101
 102                 public string SubstringByTextElements (int startingTextElement, int lengthInTextElements)
 103                 {
 104                         if (startingTextElement < 0 || s.Length == 0)
 105                                 throw new ArgumentOutOfRangeException ("startingTextElement");
 106                         if (lengthInTextElements < 0)
 107                                 throw new ArgumentOutOfRangeException ("lengthInTextElements");
 108                         int idx = 0;
 109                         for (int i = 0; i < startingTextElement; i++) {
 110                                 if (idx >= s.Length)
 111                                         throw new ArgumentOutOfRangeException ("startingTextElement");
 112                                 idx += GetNextTextElementLength (s, idx);
 113                         }
 114                         int start = idx;
 115                         for (int i = 0; i < lengthInTextElements; i++) {
 116                                 if (idx >= s.Length)
 117                                         throw new ArgumentOutOfRangeException ("lengthInTextElements");
 118                                 idx += GetNextTextElementLength (s, idx);
 119                         }
 120                         return s.Substring (start, idx - start);
 121                 }
 122
 123                 public static string GetNextTextElement(string str)
 124                 {
 125                         if(str == null || str.Length == 0) {
 126                                 throw new ArgumentNullException("string is null");
 127                         }
 128                         return(GetNextTextElement (str, 0));
 129                 }
 130
 131                 public static string GetNextTextElement(string str, int index)
 132                 {
 133                         int len = GetNextTextElementLength (str, index);
 134                         return len != 1 ? str.Substring (index, len) : new string (str [index], 1);
 135                 }
 136
 137                 static int GetNextTextElementLength(string str, int index)
 138                 {
 139                         if(str == null) {
 140                                 throw new ArgumentNullException("string is null");
 141                         }
 142
 143                         if(index >= str.Length)
 144                                 return 0;
 145                         if(index < 0)
 146                                 throw new ArgumentOutOfRangeException ("Index is not valid");
 147
 148                         /* Find the next base character, surrogate
 149                          * pair or combining character sequence
 150                          */
 151
 152                         char ch = str[index];
 153                         UnicodeCategory cat = char.GetUnicodeCategory (ch);
 154
 155                         if (cat == UnicodeCategory.Surrogate) {
 156                                 /* Check that it's a high surrogate
 157                                  * followed by a low surrogate
 158                                  */
 159                                 if (ch >= 0xD800 && ch <= 0xDBFF) {
 160                                         if ((index + 1) < str.Length &&
 161                                             str[index + 1] >= 0xDC00 &&
 162                                             str[index + 1] <= 0xDFFF) {
 163                                                 /* A valid surrogate pair */
 164                                                 return 2;
 165                                         } else {
 166                                                 /* High surrogate on its own */
 167                                                 return 1;
 168                                         }
 169                                 } else {
 170                                         /* Low surrogate on its own */
 171                                         return 1;
 172                                 }
 173                         } else {
 174                                 /* Look for a base character, which
 175                                  * may or may not be followed by a
 176                                  * series of combining characters
 177                                  */
 178
 179                                 if (cat == UnicodeCategory.NonSpacingMark ||
 180                                     cat == UnicodeCategory.SpacingCombiningMark ||
 181                                     cat == UnicodeCategory.EnclosingMark) {
 182                                         /* Not a base character */
 183                                         return 1;
 184                                 }
 185
 186                                 int count = 1;
 187
 188                                 while (index + count < str.Length) {
 189                                         cat = char.GetUnicodeCategory (str[index + count]);
 190                                         if (cat != UnicodeCategory.NonSpacingMark &&
 191                                             cat != UnicodeCategory.SpacingCombiningMark &&
 192                                             cat != UnicodeCategory.EnclosingMark) {
 193                                                 /* Finished the sequence */
 194                                                 break;
 195                                         }
 196                                         count++;
 197                                 }
 198
 199                                 return count;
 200                         }
 201                 }
 202
 203                 public static TextElementEnumerator GetTextElementEnumerator(string str)
 204                 {
 205                         if(str == null || str.Length == 0) {
 206                                 throw new ArgumentNullException("string is null");
 207                         }
 208                         return(new TextElementEnumerator (str, 0));
 209                 }
 210
 211                 public static TextElementEnumerator GetTextElementEnumerator(string str, int index)
 212                 {
 213                         if(str == null) {
 214                                 throw new ArgumentNullException("string is null");
 215                         }
 216
 217                         if(index < 0 || index >= str.Length) {
 218                                 throw new ArgumentOutOfRangeException ("Index is not valid");
 219                         }
 220
 221                         return(new TextElementEnumerator (str, index));
 222                 }
 223
 224                 public static int[] ParseCombiningCharacters(string str)
 225                 {
 226                         if(str == null) {
 227                                 throw new ArgumentNullException("string is null");
 228                         }
 229
 230                         ArrayList indices = new ArrayList (str.Length);
 231                         TextElementEnumerator tee = GetTextElementEnumerator (str);
 232
 233                         tee.Reset ();
 234                         while(tee.MoveNext ()) {
 235                                 indices.Add (tee.ElementIndex);
 236                         }
 237
 238                         return((int[])indices.ToArray (typeof (int)));
 239                 }
 240         }
 241 }