1/*
2 * Copyright (c) 2015-2017, Intel Corporation
3 *
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5 * modification, are permitted provided that the following conditions are met:
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15 *
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27 */
28
29/** \file
30 * \brief Glushkov construction.
31 */
32
33#ifndef BUILDSTATE_H
34#define BUILDSTATE_H
35
36#include "ue2common.h"
37#include "position.h"
38#include "util/noncopyable.h"
39
40#include <memory>
41#include <vector>
42
43namespace ue2 {
44
45class NFABuilder;
46class PositionInfo;
47
48/** \brief Machinery for Glushkov construction.
49 *
50 * Abstract base class; use \ref makeGlushkovBuildState to get one of these you
51 * can use. */
52class GlushkovBuildState : noncopyable {
53public:
54 /** \brief Represents an uninitialized state. */
55 static const Position POS_UNINITIALIZED;
56
57 /** \brief Represents an epsilon transition in the firsts of a component. */
58 static const Position POS_EPSILON;
59
60 virtual ~GlushkovBuildState();
61
62 /** \brief Returns a reference to the NFABuilder being used. */
63 virtual NFABuilder &getBuilder() = 0;
64
65 /** \brief Returns a const reference to the NFABuilder being used. */
66 virtual const NFABuilder &getBuilder() const = 0;
67
68 /** \brief Wire up edges from the lasts of one component to the firsts of
69 * another. */
70 virtual void connectRegions(const std::vector<PositionInfo> &lasts,
71 const std::vector<PositionInfo> &firsts) = 0;
72
73 /** \brief Wire the lasts of the main sequence to accepts. */
74 virtual void connectAccepts(const std::vector<PositionInfo> &lasts) = 0;
75
76 /** \brief Wire up a pair of positions. */
77 virtual void addSuccessor(Position from, Position to) = 0;
78
79 /** \brief Clone the vertex properties and edges of all vertices between
80 * two positions. */
81 virtual void cloneFollowSet(Position from, Position to, u32 offset) = 0;
82
83 /** \brief Build the prioritised list of edges out of our successor map. */
84 virtual void buildEdges() = 0;
85};
86
87/** \brief Returns a new GlushkovBuildState object. */
88std::unique_ptr<GlushkovBuildState> makeGlushkovBuildState(NFABuilder &b,
89 bool prefilter);
90
91/** \brief Replace all epsilons with the given positions. */
92void replaceEpsilons(std::vector<PositionInfo> &target,
93 const std::vector<PositionInfo> &source);
94
95/** \brief Eliminate lower-priority duplicate PositionInfo entries.
96 *
97 * Scans through a list of positions and retains only the highest priority
98 * version of a given (position, flags) entry. */
99void cleanupPositions(std::vector<PositionInfo> &a);
100
101} // namespace ue2
102
103#endif
104