// // SetDomain.cs // // Authors: // Alexander Chebaturkin (chebaturkin@gmail.com) // // Copyright (C) 2011 Alexander Chebaturkin // // Permission is hereby granted, free of charge, to any person obtaining // a copy of this software and associated documentation files (the // "Software"), to deal in the Software without restriction, including // without limitation the rights to use, copy, modify, merge, publish, // distribute, sublicense, and/or sell copies of the Software, and to // permit persons to whom the Software is furnished to do so, subject to // the following conditions: // // The above copyright notice and this permission notice shall be // included in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. // using System; using System.IO; using Mono.CodeContracts.Static.DataStructures; namespace Mono.CodeContracts.Static.Lattices { struct SetDomain<T> : IAbstractDomain<SetDomain<T>> where T : IEquatable<T> { public static readonly SetDomain<T> TopValue = new SetDomain<T> (ImmutableSet<T>.Empty ()); public static readonly SetDomain<T> BottomValue = new SetDomain<T> ((IImmutableSet<T>) null); readonly IImmutableSet<T> set; SetDomain (IImmutableSet<T> set) { this.set = set; } public SetDomain (Func<T, int> keyConverter) { set = ImmutableSet<T>.Empty (keyConverter); } public SetDomain<T> Top { get { return TopValue; } } public SetDomain<T> Bottom { get { return BottomValue; } } public bool IsTop { get { return set != null && set.Count == 0; } } public bool IsBottom { get { return set == null; } } public SetDomain<T> Join (SetDomain<T> that) { SetDomain<T> result; if (this.TryTrivialJoin (that, out result)) return result; return new SetDomain<T> (set.Intersect (that.set)); } public SetDomain<T> Join (SetDomain<T> that, bool widening, out bool weaker) { if (set == that.set) { weaker = false; return this; } if (IsBottom) { weaker = !that.IsBottom; return that; } if (that.IsBottom || IsTop) { weaker = false; return this; } if (that.IsTop) { weaker = !IsTop; return that; } var join = set.Intersect (that.set); weaker = join.Count < set.Count; return new SetDomain<T> (join); } public SetDomain<T> Widen (SetDomain<T> that) { //no widening - finite lattice return Join (that); } public SetDomain<T> Meet (SetDomain<T> that) { SetDomain<T> result; if (this.TryTrivialMeet (that, out result)) return result; return new SetDomain<T> (set.Union (that.set)); } public bool LessEqual (SetDomain<T> that) { if (IsBottom) return true; if (that.IsBottom) return false; return that.set.IsContainedIn (set); } public SetDomain<T> ImmutableVersion () { return this; } public SetDomain<T> Clone () { return this; } public SetDomain<T> With (T elem) { return new SetDomain<T> (set.Add (elem)); } public SetDomain<T> Without (T elem) { return new SetDomain<T> (set.Remove (elem)); } public bool Contains (T item) { return set.Contains (item); } public void Dump (TextWriter tw) { if (IsBottom) tw.WriteLine ("Bot"); else if (IsTop) tw.WriteLine ("Top"); else set.Dump (tw); } } }