1 /*
2  * Copyright (c) 2015-2016, Intel Corporation
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are met:
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8  *    this list of conditions and the following disclaimer.
9  *  * Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *  * Neither the name of Intel Corporation nor the names of its contributors
13  *    may be used to endorse or promote products derived from this software
14  *    without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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27  */
28 
29 /** \file
30  * \brief NFA graph merging ("uncalc")
31  */
32 
33 #ifndef NG_UNCALC_COMPONENTS_H
34 #define NG_UNCALC_COMPONENTS_H
35 
36 #include <map>
37 #include <vector>
38 
39 namespace ue2 {
40 
41 struct CompileContext;
42 struct Grey;
43 class NGHolder;
44 class ReportManager;
45 
46 /**
47  * \brief Returns the common prefix length for a pair of graphs.
48  *
49  * The CPL is calculated based the topological ordering given by the state
50  * indices for each graph.
51  */
52 u32 commonPrefixLength(const NGHolder &ga, const NGHolder &gb);
53 
54 /**
55  * \brief Merge the group of graphs in \p cluster where possible.
56  *
57  * The (from, to) mapping of merged graphs is returned.
58  */
59 std::map<NGHolder *, NGHolder *>
60 mergeNfaCluster(const std::vector<NGHolder *> &cluster, const ReportManager *rm,
61                 const CompileContext &cc);
62 
63 /**
64  * \brief Merge graph \p ga into graph \p gb.
65  *
66  * Returns false on failure. On success, \p gb is reduced via \ref
67  * reduceImplementableGraph and renumbered.
68  */
69 bool mergeNfaPair(const NGHolder &ga, NGHolder &gb, const ReportManager *rm,
70                   const CompileContext &cc);
71 
72 } // namespace ue2
73 
74 #endif
75