Util/SemWeb/UriMap.cs

   1 using System;
   2 using System.Collections;
   3 using System.Collections.Specialized;
   4
   5 namespace SemWeb.Util {
   6         internal class UriMap : IDictionary {
   7                 private static char[] splitchars = { '\\', '/', '#' };
   8
   9                 Node Root;
  10                 int count;
  11
  12                 public UriMap() {
  13                         Clear();
  14                 }
  15
  16                 bool ICollection.IsSynchronized { get { return false; } }
  17                 object ICollection.SyncRoot { get { return null; } }
  18
  19                 bool IDictionary.IsFixedSize { get { return false; } }
  20                 bool IDictionary.IsReadOnly { get { return false; } }
  21
  22                 object IDictionary.this[object key] {
  23                         get {
  24                                 return this[(string)key];
  25                         }
  26                         set {
  27                                 this[(string)key] = value;
  28                         }
  29                 }
  30
  31                 void IDictionary.Add(object key, object value) {
  32                         this[(string)key] = value;
  33                 }
  34
  35                 bool IDictionary.Contains(object key) {
  36                         return Contains((string)key);
  37                 }
  38
  39                 ICollection IDictionary.Keys { get { throw new NotImplementedException(); } }
  40                 ICollection IDictionary.Values { get { throw new NotImplementedException(); } }
  41                 IDictionaryEnumerator IDictionary.GetEnumerator() { throw new NotImplementedException(); }
  42
  43                 void IDictionary.Remove(object key) {
  44                         Remove((string)key);
  45                 }
  46
  47                 void ICollection.CopyTo(Array dest, int index) { throw new NotImplementedException(); }
  48
  49                 IEnumerator IEnumerable.GetEnumerator() { throw new NotImplementedException(); }
  50
  51                 public object this[string uri] {
  52                         get {
  53                                 Node node = FindNode(uri, false);
  54                                 if (node == null) return null;
  55                                 return node.Value;
  56                         }
  57                         set {
  58                                 Node node = FindNode(uri, true);
  59                                 node.Value = value;
  60                         }
  61                 }
  62
  63                 public void Clear() {
  64                         Root = new Node();
  65                         count = 0;
  66                 }
  67
  68                 public bool Contains(string uri) {
  69                         Node node = FindNode(uri, false);
  70                         return node != null;
  71                 }
  72
  73                 public int Count { get { return count; } }
  74
  75                 Node FindNode(string uri, bool create) {
  76                         Node node = Root;
  77                         int pos; string piece;
  78                         NextPieceStart(out pos);
  79                         while ((piece = NextPiece(uri, ref pos)) != null) {
  80                                 bool created;
  81                                 node = node.FindChild(piece, create, out created);
  82                                 if (created) count++;
  83                                 if (node == null) return null;
  84                         }
  85
  86                         return node;
  87                 }
  88
  89                 public void Remove(string uri) {
  90                         Node node = Root;
  91
  92                         int pos;
  93                         NextPieceStart(out pos);
  94                         string piece = NextPiece(uri, ref pos);
  95                         string next = NextPiece(uri, ref pos);
  96                         while (piece != null) {
  97                                 if (next != null) {
  98                                         bool created;
  99                                         node = node.FindChild(piece, false, out created);
 100                                         if (node == null) return;
 101                                 } else {
 102                                         if (node.RemoveChild(piece))
 103                                                 count--;
 104                                 }
 105                                 piece = next;
 106                                 next = NextPiece(uri, ref pos);
 107                         }
 108                 }
 109
 110                 void NextPieceStart(out int position) {
 111                         position = 0;
 112                 }
 113
 114                 string NextPiece(string uri, ref int position) {
 115                         if (position == uri.Length) return null;
 116
 117                         // Get the next stopping position
 118                         int look = position;
 119                         if (position == 0 && uri.Length > 15) look = 15;
 120                         int next = uri.IndexOfAny(splitchars, look);
 121                         if (next == -1) {
 122                                 string r = uri.Substring(position);
 123                                 position = uri.Length;
 124                                 return r;
 125                         }
 126
 127                         // Grab sequences of the same character in a row.
 128                         while (next != uri.Length-1 && uri[next] == uri[next+1])
 129                                 next++;
 130
 131                         string ret = uri.Substring(position, next-position+1);
 132                         position = next+1;
 133
 134                         return ret;
 135                 }
 136
 137                 private class Node {
 138                         public IDictionary Children;
 139                         public object Value;
 140
 141                         public Node FindChild(string name, bool create, out bool created) {
 142                                 if (Children == null && !create) {
 143                                         created = false;
 144                                         return null;
 145                                 }
 146
 147                                 if (Children == null)
 148                                         Children = new HybridDictionary();
 149
 150                                 Node ret = (Node)Children[name];
 151                                 if (ret != null || !create) {
 152                                         created = false;
 153                                         return ret;
 154                                 } else {
 155                                         created = true;
 156                                         ret = new Node();
 157                                         Children[name] = ret;
 158                                         return ret;
 159                                 }
 160                         }
 161
 162                         public bool RemoveChild(string name) {
 163                                 if (Children != null && Children.Contains(name)) {
 164                                         Children.Remove(name);
 165                                         return true;
 166                                 }
 167                                 return false;
 168                         }
 169
 170                 }
 171         }
 172 }