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//-----------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All Rights Reserved.
//
//-----------------------------------------------------------------------------
namespace Microsoft.Boogie {
using System;
using System.IO;
using System.Collections;
using System.Diagnostics.Contracts;
/// <summary>
/// A class representing a mathematical set.
/// </summary>
public class Set : ICloneable, IEnumerable {
/*[Own]*/
Hashtable ht;
[ContractInvariantMethod]
void ObjectInvariant() {
Contract.Invariant(ht != null);
}
public Set() {
ht = new Hashtable();
//:base();
}
private Set(Hashtable/*!*/ ht) {
Contract.Requires(ht != null);
this.ht = ht;
//:base();
}
public Set(int capacity) {
ht = new Hashtable(capacity);
//:base();
}
public readonly static Set/*!*/ Empty = new Set();
public void Clear() {
ht.Clear();
}
/// <summary>
/// This method idempotently adds "o" to the set.
/// In notation:
/// this.SetElements = this.SetElements_old \union {o};
/// </summary>
public void Add(object/*!*/ o) {
Contract.Requires(o != null);
ht[o] = o;
}
/// <summary>
/// this.SetElements = this.SetElements_old \union s.SetElements;
/// </summary>
public void AddRange(Set/*!*/ s) {
Contract.Requires(s != null);
foreach (object/*!*/ o in s) {
Contract.Assert(o != null);
Add(o);
}
}
/// <summary>
/// this.SetElements = this.SetElements_old \setminus {o};
/// </summary>
public void Remove(object/*!*/ o) {
Contract.Requires(o != null);
ht.Remove(o);
}
/// <summary>
/// this.SetElements = this.SetElements_old \setminus s.SetElements;
/// </summary>
public void RemoveRange(Set/*!*/ s) {
Contract.Requires(s != null);
if (s == this) {
ht.Clear();
} else {
foreach (object/*!*/ o in s) {
Contract.Assert(o != null);
ht.Remove(o);
}
}
}
/// <summary>
/// Returns an arbitrary element from the set.
/// </summary>
public object/*!*/ Choose() {
Contract.Requires((Count > 0));
Contract.Ensures(Contract.Result<object>() != null);
IEnumerator iter = GetEnumerator();
iter.MoveNext();
return cce.NonNull(iter.Current);
}
/// <summary>
/// Picks an arbitrary element from the set, removes it, and returns it.
/// </summary>
public object/*!*/ Take() {
Contract.Requires((Count > 0));
Contract.Ensures(Contract.Result<object>() != null);
Contract.Ensures(Count == Contract.OldValue(Count) - 1);
object r = Choose();
Remove(r);
return r;
}
public void Intersect(Set/*!*/ s) {
Contract.Requires(s != null);
Hashtable h = new Hashtable(ht.Count);
foreach (object/*!*/ key in ht.Keys) {
Contract.Assert(key != null);
if (s.ht.ContainsKey(key)) {
h.Add(key, key);
}
}
ht = h;
}
/// <summary>
/// The getter returns true iff "o" is in the set.
/// The setter adds the value "o" (for "true") or removes "o" (for "false")
/// </summary>
public bool this[object/*!*/ o] {
get {
Contract.Requires(o != null);
return ht.ContainsKey(o);
}
set {
if (value) {
Add(o);
} else {
Remove(o);
}
}
}
/// <summary>
/// Returns true iff "o" is an element of "this".
/// </summary>
/// <param name="o"></param>
/// <returns></returns>
[Pure]
public bool Contains(object/*!*/ o) {
Contract.Requires(o != null);
if (!this.ht.ContainsKey(o)) {
return false;
}
return true;
}
/// <summary>
/// Returns true iff every element of "s" is an element of "this", that is, if
/// "s" is a subset of "this".
/// </summary>
/// <param name="s"></param>
/// <returns></returns>
public bool ContainsRange(Set/*!*/ s) {
Contract.Requires(s != null);
if (s != this) {
foreach (object/*!*/ key in s.ht.Keys) {
Contract.Assert(key != null);
if (!this.ht.ContainsKey(key)) {
return false;
}
}
}
return true;
}
public object/*!*/ Clone() {
Contract.Ensures(Contract.Result<object>() != null);
return new Set((Hashtable/*!*/)cce.NonNull(ht.Clone()));
}
public virtual int Count {
get {
return ht.Count;
}
}
[Pure]
public IEnumerator/*!*/ GetEnumerator() {
Contract.Ensures(Contract.Result<IEnumerator>() != null);
return ht.Keys.GetEnumerator();
}
[Pure]
public override string/*!*/ ToString() {
Contract.Ensures(Contract.Result<string>() != null);
string s = null;
foreach (object/*!*/ key in ht.Keys) {
Contract.Assert(key != null);
if (s == null) {
s = "{";
} else {
s += ", ";
}
s += key.ToString();
}
if (s == null) {
return "{}";
} else {
return s + "}";
}
}
public bool AddAll(IEnumerable/*!*/ objs) {
Contract.Requires(objs != null);
foreach (object/*!*/ o in objs) {
Contract.Assert(o != null);
this.Add(o);
}
return true;
}
//----------------------------- Static Methods ---------------------------------
// Functional Intersect
public static Set/*!*/ Intersect(Set/*!*/ a, Set/*!*/ b) {
Contract.Requires(b != null);
Contract.Requires(a != null);
Contract.Ensures(Contract.Result<Set>() != null);
//Contract.Ensures(Contract.ForAll(result, x => a[x] && b[x] ));
Set/*!*/ res = (Set/*!*/)cce.NonNull(a.Clone());
res.Intersect(b);
return res;
}
// Functional Union
public static Set/*!*/ Union(Set/*!*/ a, Set/*!*/ b) {
Contract.Requires(a != null);
Contract.Requires(b != null);
Contract.Ensures(Contract.Result<Set>() != null);
// Contract.Ensures(Contract.ForAll(result, x => a[x] || b[x] ));
Set/*!*/ res = (Set/*!*/)cce.NonNull(a.Clone());
res.AddRange(b);
return res;
}
public delegate bool SetFilter(object/*!*/ obj);
public static Set/*!*/ Filter(Set/*!*/ a, SetFilter/*!*/ filter) {
Contract.Requires(filter != null);
Contract.Requires(a != null);
Contract.Ensures(Contract.Result<Set>() != null);
Set inter = new Set();
foreach (object/*!*/ elem in a) {
Contract.Assert(elem != null);
if (filter(elem)) {
inter.Add(elem);
}
}
return inter;
}
}
public interface IWorkList : ICollection {
bool Add(object o);
bool AddAll(IEnumerable objs);
bool IsEmpty();
object Pull();
}
}
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