mcs/class/corlib/System.IO/SearchPattern.cs

   1 //\r
   2 // System.IO.SearchPattern.cs: Filename glob support.\r
   3 //\r
   4 // Author:\r
   5 //   Dan Lewis (dihlewis@yahoo.co.uk)\r
   6 //\r
   7 // (C) 2002\r
   8 //\r
   9 \r
  10 //\r
  11 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)\r
  12 //\r
  13 // Permission is hereby granted, free of charge, to any person obtaining\r
  14 // a copy of this software and associated documentation files (the\r
  15 // "Software"), to deal in the Software without restriction, including\r
  16 // without limitation the rights to use, copy, modify, merge, publish,\r
  17 // distribute, sublicense, and/or sell copies of the Software, and to\r
  18 // permit persons to whom the Software is furnished to do so, subject to\r
  19 // the following conditions:\r
  20 // \r
  21 // The above copyright notice and this permission notice shall be\r
  22 // included in all copies or substantial portions of the Software.\r
  23 // \r
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,\r
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF\r
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND\r
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE\r
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION\r
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION\r
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
  31 //\r
  32 \r
  33 using System;\r
  34 \r
  35 namespace System.IO {\r
  36 \r
  37         // FIXME: there's a complication with this algorithm under windows.\r
  38         // the pattern '*.*' matches all files (i think . matches the extension),\r
  39         // whereas under UNIX it should only match files containing the '.' character.\r
  40 \r
  41         class SearchPattern {\r
  42                 public SearchPattern (string pattern) : this (pattern, false) { }\r
  43 \r
  44                 public SearchPattern (string pattern, bool ignore)\r
  45                 {\r
  46                         this.ignore = ignore;\r
  47                         Compile (pattern);\r
  48                 }\r
  49 \r
  50                 public bool IsMatch (string text)\r
  51                 {\r
  52                         return Match (ops, text, 0);\r
  53                 }\r
  54 \r
  55                 // private\r
  56 \r
  57                 private Op ops;         // the compiled pattern\r
  58                 private bool ignore;    // ignore case\r
  59 \r
  60                 private void Compile (string pattern)\r
  61                 {\r
  62                         if (pattern == null || pattern.IndexOfAny (InvalidChars) >= 0)\r
  63                                 throw new ArgumentException ("Invalid search pattern.");\r
  64 \r
  65                         if (pattern == "*") {   // common case\r
  66                                 ops = new Op (OpCode.True);\r
  67                                 return;\r
  68                         }\r
  69 \r
  70                         ops = null;\r
  71 \r
  72                         int ptr = 0;\r
  73                         Op last_op = null;\r
  74                         while (ptr < pattern.Length) {\r
  75                                 Op op;\r
  76                         \r
  77                                 switch (pattern [ptr]) {\r
  78                                 case '?':\r
  79                                         op = new Op (OpCode.AnyChar);\r
  80                                         ++ ptr;\r
  81                                         break;\r
  82 \r
  83                                 case '*':\r
  84                                         op = new Op (OpCode.AnyString);\r
  85                                         ++ ptr;\r
  86                                         break;\r
  87                                         \r
  88                                 default:\r
  89                                         op = new Op (OpCode.ExactString);\r
  90                                         int end = pattern.IndexOfAny (WildcardChars, ptr);\r
  91                                         if (end < 0)\r
  92                                                 end = pattern.Length;\r
  93 \r
  94                                         op.Argument = pattern.Substring (ptr, end - ptr);\r
  95                                         if (ignore)\r
  96                                                 op.Argument = op.Argument.ToLowerInvariant ();\r
  97 \r
  98                                         ptr = end;\r
  99                                         break;\r
 100                                 }\r
 101 \r
 102                                 if (last_op == null)\r
 103                                         ops = op;\r
 104                                 else\r
 105                                         last_op.Next = op;\r
 106 \r
 107                                 last_op = op;\r
 108                         }\r
 109 \r
 110                         if (last_op == null)\r
 111                                 ops = new Op (OpCode.End);\r
 112                         else\r
 113                                 last_op.Next = new Op (OpCode.End);\r
 114                 }\r
 115 \r
 116                 private bool Match (Op op, string text, int ptr)\r
 117                 {\r
 118                         while (op != null) {\r
 119                                 switch (op.Code) {\r
 120                                 case OpCode.True:\r
 121                                         return true;\r
 122 \r
 123                                 case OpCode.End:\r
 124                                         if (ptr == text.Length)\r
 125                                                 return true;\r
 126 \r
 127                                         return false;\r
 128                                 \r
 129                                 case OpCode.ExactString:\r
 130                                         int length = op.Argument.Length;\r
 131                                         if (ptr + length > text.Length)\r
 132                                                 return false;\r
 133 \r
 134                                         string str = text.Substring (ptr, length);\r
 135                                         if (ignore)\r
 136                                                 str = str.ToLowerInvariant ();\r
 137 \r
 138                                         if (str != op.Argument)\r
 139                                                 return false;\r
 140 \r
 141                                         ptr += length;\r
 142                                         break;\r
 143 \r
 144                                 case OpCode.AnyChar:\r
 145                                         if (++ ptr > text.Length)\r
 146                                                 return false;\r
 147                                         break;\r
 148 \r
 149                                 case OpCode.AnyString:\r
 150                                         while (ptr <= text.Length) {\r
 151                                                 if (Match (op.Next, text, ptr))\r
 152                                                         return true;\r
 153 \r
 154                                                 ++ ptr;\r
 155                                         }\r
 156 \r
 157                                         return false;\r
 158                                 }\r
 159 \r
 160                                 op = op.Next;\r
 161                         }\r
 162 \r
 163                         return true;\r
 164                 }\r
 165 \r
 166                 // private static\r
 167 \r
 168                 internal static readonly char [] WildcardChars = { '*', '?' };\r
 169                 internal static readonly char [] InvalidChars = { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar };\r
 170 \r
 171                 private class Op {\r
 172                         public Op (OpCode code)\r
 173                         {\r
 174                                 this.Code = code;\r
 175                                 this.Argument = null;\r
 176                                 this.Next = null;\r
 177                         }\r
 178                 \r
 179                         public OpCode Code;\r
 180                         public string Argument;\r
 181                         public Op Next;\r
 182                 }\r
 183 \r
 184                 private enum OpCode {\r
 185                         ExactString,            // literal\r
 186                         AnyChar,                // ?\r
 187                         AnyString,              // *\r
 188                         End,                    // end of pattern\r
 189                         True                    // always succeeds\r
 190                 };\r
 191         }\r
 192 }\r