mcs/class/System/System.Text.RegularExpressions/MatchCollection.cs

   1 //
   2 // System.Text.RegularExpressions.MatchCollection
   3 //
   4 // Authors:
   5 //      Dan Lewis (dlewis@gmx.co.uk)
   6 //      Dick Porter (dick@ximian.com)
   7 //
   8 // (C) 2002 Dan Lewis
   9 // (C) 2004 Novell, Inc.
  10 //
  11
  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 using System.Collections;
  35
  36 namespace System.Text.RegularExpressions
  37 {
  38         [Serializable]
  39         public class MatchCollection: ICollection, IEnumerable {
  40                 private Match current;
  41
  42                 // Stores all the matches before 'current'.  If !current.Success, it has all the successful matches.
  43                 private ArrayList list;
  44
  45                 /* No public constructor */
  46                 internal MatchCollection (Match start)
  47                 {
  48                         current = start;
  49                         list = new ArrayList ();
  50                 }
  51
  52                 public int Count {
  53                         get { return FullList.Count; }
  54                 }
  55
  56                 public bool IsReadOnly {
  57                         get { return true; }
  58                 }
  59
  60                 public bool IsSynchronized {
  61                         get { return false; }
  62                 }
  63
  64
  65                 public virtual Match this [int i] {
  66                         get {
  67                                 if (i < 0 || !TryToGet (i))
  68                                         throw new ArgumentOutOfRangeException ("i");
  69                                 return i < list.Count ? (Match) list [i] : current;
  70                         }
  71                 }
  72
  73                 public object SyncRoot {
  74                         get { return list; }
  75                 }
  76
  77                 public void CopyTo (Array array, int arrayIndex)
  78                 {
  79                         FullList.CopyTo (array, arrayIndex);
  80                 }
  81
  82                 public IEnumerator GetEnumerator ()
  83                 {
  84                         // If !current.Success, the list is fully populated.  So, just use it.
  85                         return current.Success ? new Enumerator (this) : list.GetEnumerator ();
  86                 }
  87
  88                 // Returns true when: i < list.Count                     => this [i] == list [i]
  89                 //                    i == list.Count && current.Success => this [i] == current
  90                 private bool TryToGet (int i)
  91                 {
  92                         while (i > list.Count && current.Success) {
  93                                 list.Add (current);
  94                                 current = current.NextMatch ();
  95                         }
  96                         // Here we have: !(i > list.Count && current.Success)
  97                         // or in a slightly more useful form: i > list.Count => current.Success == false
  98                         return i < list.Count || current.Success;
  99                 }
 100
 101                 private ICollection FullList {
 102                         get {
 103                                 if (TryToGet (Int32.MaxValue)) {
 104                                         // list.Count == Int32.MaxValue && current.Success
 105                                         // i.e., we have more than Int32.MaxValue matches.
 106                                         // We can't represent that number with Int32.
 107                                         throw new SystemException ("too many matches");
 108                                 }
 109                                 return list;
 110                         }
 111                 }
 112
 113                 class Enumerator : IEnumerator {
 114                         int index;
 115                         MatchCollection coll;
 116
 117                         internal Enumerator (MatchCollection coll)
 118                         {
 119                                 this.coll = coll;
 120                                 index = -1;
 121                         }
 122
 123                         void IEnumerator.Reset ()
 124                         {
 125                                 index = -1;
 126                         }
 127
 128                         object IEnumerator.Current {
 129                                 get {
 130                                         if (index < 0)
 131                                                 throw new InvalidOperationException ("'Current' called before 'MoveNext()'");
 132                                         if (index > coll.list.Count)
 133                                                 throw new SystemException ("MatchCollection in invalid state");
 134                                         if (index == coll.list.Count && !coll.current.Success)
 135                                                 throw new InvalidOperationException ("'Current' called after 'MoveNext()' returned false");
 136                                         return index < coll.list.Count ? coll.list [index] : coll.current;
 137                                 }
 138                         }
 139
 140                         bool IEnumerator.MoveNext ()
 141                         {
 142                                 if (index > coll.list.Count)
 143                                         throw new SystemException ("MatchCollection in invalid state");
 144                                 if (index == coll.list.Count && !coll.current.Success)
 145                                         return false;
 146                                 return coll.TryToGet (++index);
 147                         }
 148                 }
 149         }
 150 }