/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved. * Use of this file is governed by the BSD 3-clause license that * can be found in the LICENSE.txt file in the project root. */ #pragma once #include "dfa/DFAState.h" namespace antlr4 { namespace dfa { class ANTLR4CPP_PUBLIC DFA final { private: struct DFAStateHasher final { size_t operator()(const DFAState *dfaState) const { return dfaState->hashCode(); } }; struct DFAStateComparer final { bool operator()(const DFAState *lhs, const DFAState *rhs) const { return lhs == rhs || *lhs == *rhs; } }; public: /// A set of all DFA states. Use a map so we can get old state back. /// Set only allows you to see if it's there. /// From which ATN state did we create this DFA? atn::DecisionState *atnStartState; std::unordered_set states; // States are owned by this class. DFAState *s0; size_t decision; explicit DFA(atn::DecisionState *atnStartState); DFA(atn::DecisionState *atnStartState, size_t decision); DFA(const DFA &other) = delete; DFA(DFA &&other); ~DFA(); /** * Gets whether this DFA is a precedence DFA. Precedence DFAs use a special * start state {@link #s0} which is not stored in {@link #states}. The * {@link DFAState#edges} array for this start state contains outgoing edges * supplying individual start states corresponding to specific precedence * values. * * @return {@code true} if this is a precedence DFA; otherwise, * {@code false}. * @see Parser#getPrecedence() */ bool isPrecedenceDfa() const; /** * Get the start state for a specific precedence value. * * @param precedence The current precedence. * @return The start state corresponding to the specified precedence, or * {@code null} if no start state exists for the specified precedence. * * @throws IllegalStateException if this is not a precedence DFA. * @see #isPrecedenceDfa() */ DFAState* getPrecedenceStartState(int precedence) const; /** * Set the start state for a specific precedence value. * * @param precedence The current precedence. * @param startState The start state corresponding to the specified * precedence. * * @throws IllegalStateException if this is not a precedence DFA. * @see #isPrecedenceDfa() */ void setPrecedenceStartState(int precedence, DFAState *startState); /// Return a list of all states in this DFA, ordered by state number. std::vector getStates() const; std::string toString(const Vocabulary &vocabulary) const; std::string toLexerString() const; private: /** * {@code true} if this DFA is for a precedence decision; otherwise, * {@code false}. This is the backing field for {@link #isPrecedenceDfa}. */ bool _precedenceDfa; }; } // namespace atn } // namespace antlr4