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

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