111 lines
3.9 KiB
C
111 lines
3.9 KiB
C
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/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
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* Use of this file is governed by the BSD 3-clause license that
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* can be found in the LICENSE.txt file in the project root.
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*/
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#pragma once
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#include "support/BitSet.h"
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#include "atn/PredictionContext.h"
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namespace antlr4 {
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namespace atn {
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/// Specialized set that can track info about the set, with support for combining similar configurations using a
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/// graph-structured stack.
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class ANTLR4CPP_PUBLIC ATNConfigSet {
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public:
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/// Track the elements as they are added to the set; supports get(i)
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std::vector<Ref<ATNConfig>> configs;
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// TODO: these fields make me pretty uncomfortable but nice to pack up info together, saves recomputation
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// TODO: can we track conflicts as they are added to save scanning configs later?
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size_t uniqueAlt;
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/** Currently this is only used when we detect SLL conflict; this does
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* not necessarily represent the ambiguous alternatives. In fact,
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* I should also point out that this seems to include predicated alternatives
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* that have predicates that evaluate to false. Computed in computeTargetState().
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*/
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antlrcpp::BitSet conflictingAlts;
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// Used in parser and lexer. In lexer, it indicates we hit a pred
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// while computing a closure operation. Don't make a DFA state from this.
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bool hasSemanticContext;
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bool dipsIntoOuterContext;
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/// Indicates that this configuration set is part of a full context
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/// LL prediction. It will be used to determine how to merge $. With SLL
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/// it's a wildcard whereas it is not for LL context merge.
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const bool fullCtx;
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ATNConfigSet(bool fullCtx = true);
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ATNConfigSet(const Ref<ATNConfigSet> &old);
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virtual ~ATNConfigSet();
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virtual bool add(const Ref<ATNConfig> &config);
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/// <summary>
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/// Adding a new config means merging contexts with existing configs for
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/// {@code (s, i, pi, _)}, where {@code s} is the
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/// <seealso cref="ATNConfig#state"/>, {@code i} is the <seealso cref="ATNConfig#alt"/>, and
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/// {@code pi} is the <seealso cref="ATNConfig#semanticContext"/>. We use
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/// {@code (s,i,pi)} as key.
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/// <p/>
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/// This method updates <seealso cref="#dipsIntoOuterContext"/> and
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/// <seealso cref="#hasSemanticContext"/> when necessary.
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/// </summary>
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virtual bool add(const Ref<ATNConfig> &config, PredictionContextMergeCache *mergeCache);
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virtual std::vector<ATNState *> getStates();
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/**
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* Gets the complete set of represented alternatives for the configuration
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* set.
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*
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* @return the set of represented alternatives in this configuration set
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*
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* @since 4.3
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*/
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antlrcpp::BitSet getAlts();
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virtual std::vector<Ref<SemanticContext>> getPredicates();
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virtual Ref<ATNConfig> get(size_t i) const;
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virtual void optimizeConfigs(ATNSimulator *interpreter);
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bool addAll(const Ref<ATNConfigSet> &other);
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bool operator == (const ATNConfigSet &other);
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virtual size_t hashCode();
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virtual size_t size();
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virtual bool isEmpty();
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virtual void clear();
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virtual bool isReadonly();
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virtual void setReadonly(bool readonly);
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virtual std::string toString();
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protected:
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/// Indicates that the set of configurations is read-only. Do not
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/// allow any code to manipulate the set; DFA states will point at
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/// the sets and they must not change. This does not protect the other
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/// fields; in particular, conflictingAlts is set after
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/// we've made this readonly.
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bool _readonly;
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virtual size_t getHash(ATNConfig *c); // Hash differs depending on set type.
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private:
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size_t _cachedHashCode;
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/// All configs but hashed by (s, i, _, pi) not including context. Wiped out
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/// when we go readonly as this set becomes a DFA state.
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std::unordered_map<size_t, ATNConfig *> _configLookup;
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void InitializeInstanceFields();
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};
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} // namespace atn
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} // namespace antlr4
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