mcs/class/Mono.CodeContracts/Mono.CodeContracts.Static.DataStructures/ImmutableIntMap.cs

   1 //
   2 // ImmutableIntMap.cs
   3 //
   4 // Authors:
   5 //      Alexander Chebaturkin (chebaturkin@gmail.com)
   6 //
   7 // Copyright (C) 2011 Alexander Chebaturkin
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Collections.Generic;
  31 using System.Linq;
  32
  33 namespace Mono.CodeContracts.Static.DataStructures {
  34         class ImmutableIntMap<T> : IImmutableIntMap<T> {
  35                 private readonly Dictionary<int, T> map = new Dictionary<int, T> ();
  36
  37                 private ImmutableIntMap (Dictionary<int, T> map)
  38                 {
  39                         this.map = map;
  40                 }
  41
  42                 #region Implementation of IImm  utableIntMap<T>
  43                 public T this [int key]
  44                 {
  45                         get
  46                         {
  47                                 if (this.map == null || !this.map.ContainsKey (key))
  48                                         return default(T);
  49
  50                                 return this.map [key];
  51                         }
  52                 }
  53
  54                 public T Any
  55                 {
  56                         get
  57                         {
  58                                 if (this.map == null)
  59                                         return default(T);
  60                                 return this.map.Values.First ();
  61                         }
  62                 }
  63
  64                 public IEnumerable<T> Values
  65                 {
  66                         get
  67                         {
  68                                 if (this.map == null)
  69                                         return Enumerable.Empty<T> ();
  70                                 return this.map.Values;
  71                         }
  72                 }
  73
  74                 public IEnumerable<int> Keys
  75                 {
  76                         get
  77                         {
  78                                 if (this.map == null)
  79                                         return Enumerable.Empty<int> ();
  80                                 return this.map.Keys;
  81                         }
  82                 }
  83
  84                 public int Count
  85                 {
  86                         get
  87                         {
  88                                 if (this.map == null)
  89                                         return 0;
  90                                 return this.map.Count;
  91                         }
  92                 }
  93
  94                 public T Lookup (int key)
  95                 {
  96                         if (this.map == null)
  97                                 return default(T);
  98                         return this.map [key];
  99                 }
 100
 101                 public bool Contains (int key)
 102                 {
 103                         if (this.map == null)
 104                                 return false;
 105                         return this.map.ContainsKey (key);
 106                 }
 107
 108                 public IImmutableIntMap<T> Add (int key, T value)
 109                 {
 110                         if (this.map == null)
 111                                 return new ImmutableIntMap<T> (new Dictionary<int, T> {{key, value}});
 112
 113                         var newDict = new Dictionary<int, T> (this.map);
 114                         newDict [key] = value;
 115                         return new ImmutableIntMap<T> (newDict);
 116                 }
 117
 118                 public IImmutableIntMap<T> Remove (int key)
 119                 {
 120                         if (this.map == null || !this.map.ContainsKey (key))
 121                                 return this;
 122
 123                         var newDict = new Dictionary<int, T> (this.map);
 124                         newDict.Remove (key);
 125                         return new ImmutableIntMap<T> (newDict);
 126                 }
 127
 128                 public void Visit (Action<T> action)
 129                 {
 130                         foreach (T value in Values)
 131                                 action (value);
 132                 }
 133
 134                 public void Visit (Action<int, T> action)
 135                 {
 136                         foreach (int key in Keys)
 137                                 action (key, this [key]);
 138                 }
 139                 #endregion
 140
 141                 public static IImmutableIntMap<T> Empty ()
 142                 {
 143                         return new ImmutableIntMap<T> (null);
 144                 }
 145         }
 146 }