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//-----------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All Rights Reserved.
//
//-----------------------------------------------------------------------------
using System;
using System.Text;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.Contracts;
using Microsoft.Basetypes;
// Visitor that establishes unique variable (or constant) names in a VCExpr.
// This is done by adding a counter as suffix if name clashes occur
// TODO: also handle type variables here
namespace Microsoft.Boogie.VCExprAST {
using TEHelperFuns = Microsoft.Boogie.TypeErasure.HelperFuns;
public class UniqueNamer : ICloneable {
public UniqueNamer() {
GlobalNames = new Dictionary<Object, string>();
LocalNames = TEHelperFuns.ToList(new Dictionary<Object/*!*/, string/*!*/>()
as IDictionary<Object/*!*/, string/*!*/>);
UsedNames = new Dictionary<string, bool>();
CurrentCounters = new Dictionary<string, int>();
GlobalPlusLocalNames = new Dictionary<Object, string>();
}
private UniqueNamer(UniqueNamer namer) {
Contract.Requires(namer != null);
GlobalNames = new Dictionary<Object, string>(namer.GlobalNames);
List<IDictionary<Object/*!*/, string/*!*/>/*!*/>/*!*/ localNames =
new List<IDictionary<Object, string>>();
LocalNames = localNames;
foreach (IDictionary<Object/*!*/, string/*!*/>/*!*/ d in namer.LocalNames)
localNames.Add(new Dictionary<Object/*!*/, string/*!*/>(d));
UsedNames = new Dictionary<string, bool>(namer.UsedNames);
CurrentCounters = new Dictionary<string, int>(namer.CurrentCounters);
GlobalPlusLocalNames = new Dictionary<Object, string>(namer.GlobalPlusLocalNames);
}
public Object Clone() {
Contract.Ensures(Contract.Result<Object>() != null);
return new UniqueNamer(this);
}
////////////////////////////////////////////////////////////////////////////
private readonly IDictionary<Object/*!*/, string/*!*/>/*!*/ GlobalNames;
[ContractInvariantMethod]
void GlobalNamesInvariantMethod() {
Contract.Invariant(cce.NonNullElements(GlobalNames));
}
private readonly List<IDictionary<Object/*!*/, string/*!*/>/*!*/>/*!*/ LocalNames;
[ContractInvariantMethod]
void LocalNamesInvariantMethod() {
Contract.Invariant(Contract.ForAll(LocalNames, i => i != null && cce.NonNullElements(i)));
}
// dictionary of all names that have already been used
// (locally or globally)
private readonly IDictionary<string/*!*/, bool/*!*/>/*!*/ UsedNames;
[ContractInvariantMethod]
void UsedNamesInvariantMethod() {
Contract.Invariant(cce.NonNullElements(UsedNames));
}
private readonly IDictionary<string/*!*/, int/*!*/>/*!*/ CurrentCounters;
[ContractInvariantMethod]
void CurrentCountersInvariantMethod() {
Contract.Invariant(cce.NonNullElements(CurrentCounters));
}
private readonly IDictionary<Object/*!*/, string/*!*/>/*!*/ GlobalPlusLocalNames;
[ContractInvariantMethod]
void GlobalPlusLocalNamesInvariantMethod() {
Contract.Invariant(cce.NonNullElements(GlobalPlusLocalNames));
}
////////////////////////////////////////////////////////////////////////////
public void PushScope() {
LocalNames.Add(new Dictionary<Object/*!*/, string/*!*/>());
}
public void PopScope() {
LocalNames.RemoveAt(LocalNames.Count - 1);
}
////////////////////////////////////////////////////////////////////////////
private string NextFreeName(Object thingie, string baseName) {
Contract.Requires(baseName != null);
Contract.Requires(thingie != null);
Contract.Ensures(Contract.Result<string>() != null);
string/*!*/ candidate;
int counter;
if (CurrentCounters.TryGetValue(baseName, out counter)) {
candidate = baseName + "@@" + counter;
counter = counter + 1;
} else {
candidate = baseName;
counter = 0;
}
bool dummy;
while (UsedNames.TryGetValue(candidate, out dummy)) {
candidate = baseName + "@@" + counter;
counter = counter + 1;
}
UsedNames.Add(candidate, true);
CurrentCounters[baseName] = counter;
GlobalPlusLocalNames[thingie] = candidate;
return candidate;
}
// retrieve the name of a thingie; if it does not have a name yet,
// generate a unique name for it (as close as possible to its inherent
// name) and register it globally
public string GetName(Object thingie, string inherentName) {
Contract.Requires(inherentName != null);
Contract.Requires(thingie != null);
Contract.Ensures(Contract.Result<string>() != null);
string res = this[thingie];
if (res != null)
return res;
// if the object is not yet registered, create a name for it
res = NextFreeName(thingie, inherentName);
GlobalNames.Add(thingie, res);
return res;
}
[Pure]
public string this[Object/*!*/ thingie] {
get {
Contract.Requires(thingie != null);
Contract.Ensures(Contract.Result<String>() != null);
string res;
for (int i = LocalNames.Count - 1; i >= 0; --i) {
if (LocalNames[i].TryGetValue(thingie, out res))
return res;
}
GlobalNames.TryGetValue(thingie, out res);
return res;
}
}
public string GetLocalName(Object thingie, string inherentName) {
Contract.Requires(inherentName != null);
Contract.Requires(thingie != null);
Contract.Ensures(Contract.Result<string>() != null);
string res = NextFreeName(thingie, inherentName);
LocalNames[LocalNames.Count - 1][thingie] = res;
return res;
}
public string Lookup(Object thingie) {
Contract.Requires(thingie != null);
Contract.Ensures(Contract.Result<string>() != null);
return GlobalPlusLocalNames[thingie];
}
}
}
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