Ejemplo n.º 1
0
        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);
        }
Ejemplo n.º 2
0
        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());
        }
Ejemplo n.º 3
0
        /// <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&lt;ATNConfig&gt;</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);
                                }
                            }
                        }
                    }
                }
            }
        }