public static PredictionContext GetCachedContext(PredictionContext context, PredictionContextCache contextCache, PredictionContext.IdentityHashMap visited)
{
if (context.IsEmpty)
{
return(context);
}
PredictionContext existing = visited.Get(context);
if (existing != null)
{
return(existing);
}
existing = contextCache.Get(context);
if (existing != null)
{
visited.Put(context, existing);
return(existing);
}
bool changed = false;
PredictionContext[] parents = new PredictionContext[context.Size];
for (int i = 0; i < parents.Length; i++)
{
PredictionContext parent = GetCachedContext(context.GetParent(i), contextCache, visited);
if (changed || parent != context.GetParent(i))
{
if (!changed)
{
parents = new PredictionContext[context.Size];
for (int j = 0; j < context.Size; j++)
{
parents[j] = context.GetParent(j);
}
changed = true;
}
parents[i] = parent;
}
}
if (!changed)
{
contextCache.Add(context);
visited.Put(context, context);
return(context);
}
PredictionContext updated;
if (parents.Length == 0)
{
updated = EMPTY;
}
else if (parents.Length == 1)
{
updated = SingletonPredictionContext.Create(parents[0], context.GetReturnState(0));
}
else
{
ArrayPredictionContext arrayPredictionContext = (ArrayPredictionContext)context;
updated = new ArrayPredictionContext(parents, arrayPredictionContext.returnStates);
}
contextCache.Add(updated);
visited.Put(updated, updated);
visited.Put(context, updated);
return(updated);
}
public virtual string[] ToStrings(IRecognizer recognizer, PredictionContext stop, int currentState)
{
List <string> result = new List <string>();
for (int perm = 0; ; perm++)
{
int offset = 0;
bool last = true;
PredictionContext p = this;
int stateNumber = currentState;
StringBuilder localBuffer = new StringBuilder();
localBuffer.Append("[");
while (!p.IsEmpty && p != stop)
{
int index = 0;
if (p.Size > 0)
{
int bits = 1;
while ((1 << bits) < p.Size)
{
bits++;
}
int mask = (1 << bits) - 1;
index = (perm >> offset) & mask;
last &= index >= p.Size - 1;
if (index >= p.Size)
{
goto outer_continue;
}
offset += bits;
}
if (recognizer != null)
{
if (localBuffer.Length > 1)
{
// first char is '[', if more than that this isn't the first rule
localBuffer.Append(' ');
}
ATN atn = recognizer.Atn;
ATNState s = atn.states[stateNumber];
string ruleName = recognizer.RuleNames[s.ruleIndex];
localBuffer.Append(ruleName);
}
else
{
if (p.GetReturnState(index) != EMPTY_RETURN_STATE)
{
if (!p.IsEmpty)
{
if (localBuffer.Length > 1)
{
// first char is '[', if more than that this isn't the first rule
localBuffer.Append(' ');
}
localBuffer.Append(p.GetReturnState(index));
}
}
}
stateNumber = p.GetReturnState(index);
p = p.GetParent(index);
}
localBuffer.Append("]");
result.Add(localBuffer.ToString());
if (last)
{
break;
}
outer_continue :;
}
return(result.ToArray());
}
/// <summary>
/// Compute set of tokens that can follow
/// <paramref name="s"/>
/// in the ATN in the
/// specified
/// <paramref name="ctx"/>
/// .
/// <p/>
/// If
/// <paramref name="ctx"/>
/// is
/// <see cref="PredictionContext.EMPTY"/>
/// and
/// <paramref name="stopState"/>
/// or the end of the rule containing
/// <paramref name="s"/>
/// is reached,
/// <see cref="TokenConstants.EPSILON"/>
/// is added to the result set. If
/// <paramref name="ctx"/>
/// is not
/// <see cref="PredictionContext.EMPTY"/>
/// and
/// <paramref name="addEOF"/>
/// is
/// <see langword="true"/>
/// and
/// <paramref name="stopState"/>
/// or the end of the outermost rule is reached,
/// <see cref="TokenConstants.EOF"/>
/// is added to the result set.
/// </summary>
/// <param name="s">the ATN state.</param>
/// <param name="stopState">
/// the ATN state to stop at. This can be a
/// <see cref="BlockEndState"/>
/// to detect epsilon paths through a closure.
/// </param>
/// <param name="ctx">
/// The outer context, or
/// <see cref="PredictionContext.EMPTY"/>
/// if
/// the outer context should not be used.
/// </param>
/// <param name="look">The result lookahead set.</param>
/// <param name="lookBusy">
/// A set used for preventing epsilon closures in the ATN
/// from causing a stack overflow. Outside code should pass
/// <c>new HashSet<ATNConfig></c>
/// for this argument.
/// </param>
/// <param name="calledRuleStack">
/// A set used for preventing left recursion in the
/// ATN from causing a stack overflow. Outside code should pass
/// <c>new BitSet()</c>
/// for this argument.
/// </param>
/// <param name="seeThruPreds">
///
/// <see langword="true"/>
/// to true semantic predicates as
/// implicitly
/// <see langword="true"/>
/// and "see through them", otherwise
/// <see langword="false"/>
/// to treat semantic predicates as opaque and add
/// <see cref="HitPred"/>
/// to the
/// result if one is encountered.
/// </param>
/// <param name="addEOF">
/// Add
/// <see cref="TokenConstants.EOF"/>
/// to the result if the end of the
/// outermost context is reached. This parameter has no effect if
/// <paramref name="ctx"/>
/// is
/// <see cref="PredictionContext.EMPTY"/>
/// .
/// </param>
protected internal virtual void Look(ATNState s, ATNState stopState, PredictionContext ctx, IntervalSet look, HashSet <ATNConfig> lookBusy, BitSet calledRuleStack, bool seeThruPreds, bool addEOF)
{
// System.out.println("_LOOK("+s.stateNumber+", ctx="+ctx);
ATNConfig c = new ATNConfig(s, 0, ctx);
if (!lookBusy.Add(c))
{
return;
}
if (s == stopState)
{
if (ctx == null)
{
look.Add(TokenConstants.EPSILON);
return;
}
else if (ctx.IsEmpty && addEOF)
{
look.Add(TokenConstants.EOF);
return;
}
}
if (s is RuleStopState)
{
if (ctx == null)
{
look.Add(TokenConstants.EPSILON);
return;
}
else if (ctx.IsEmpty && addEOF)
{
look.Add(TokenConstants.EOF);
return;
}
if (ctx != PredictionContext.EMPTY)
{
for (int i = 0; i < ctx.Size; i++)
{
ATNState returnState = atn.states[ctx.GetReturnState(i)];
bool removed = calledRuleStack.Get(returnState.ruleIndex);
try
{
calledRuleStack.Clear(returnState.ruleIndex);
Look(returnState, stopState, ctx.GetParent(i), look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
finally
{
if (removed)
{
calledRuleStack.Set(returnState.ruleIndex);
}
}
}
return;
}
}
int n = s.NumberOfTransitions;
for (int i_1 = 0; i_1 < n; i_1++)
{
Transition t = s.Transition(i_1);
if (t is RuleTransition)
{
RuleTransition ruleTransition = (RuleTransition)t;
if (calledRuleStack.Get(ruleTransition.ruleIndex))
{
continue;
}
PredictionContext newContext = SingletonPredictionContext.Create(ctx, ruleTransition.followState.stateNumber);
try
{
calledRuleStack.Set(ruleTransition.target.ruleIndex);
Look(t.target, stopState, newContext, look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
finally
{
calledRuleStack.Clear(ruleTransition.target.ruleIndex);
}
}
else
{
if (t is AbstractPredicateTransition)
{
if (seeThruPreds)
{
Look(t.target, stopState, ctx, look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
else
{
look.Add(HitPred);
}
}
else
{
if (t.IsEpsilon)
{
Look(t.target, stopState, ctx, look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
else
{
if (t is WildcardTransition)
{
look.AddAll(IntervalSet.Of(TokenConstants.MinUserTokenType, atn.maxTokenType));
}
else
{
IntervalSet set = t.Label;
if (set != null)
{
if (t is NotSetTransition)
{
set = set.Complement(IntervalSet.Of(TokenConstants.MinUserTokenType, atn.maxTokenType));
}
look.AddAll(set);
}
}
}
}
}
}
}