1 | /* |
2 | * Copyright (c) 2015-2017, 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: |
6 | * |
7 | * * Redistributions of source code must retain the above copyright notice, |
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" |
17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | /** \file |
30 | * \brief Shared build code for DFAs (McClellan, Haig). |
31 | */ |
32 | |
33 | #ifndef NG_MCCLELLAN_INTERNAL_H |
34 | #define NG_MCCLELLAN_INTERNAL_H |
35 | |
36 | #include "ue2common.h" |
37 | #include "nfa/mcclellancompile.h" |
38 | #include "nfagraph/ng_holder.h" |
39 | #include "util/charreach.h" |
40 | #include "util/graph_range.h" |
41 | #include "util/flat_containers.h" |
42 | |
43 | #include <boost/dynamic_bitset.hpp> |
44 | |
45 | #include <map> |
46 | #include <vector> |
47 | |
48 | namespace ue2 { |
49 | |
50 | struct raw_dfa; |
51 | |
52 | /** Fills alpha, unalpha and returns alphabet size. */ |
53 | u16 buildAlphabetFromEquivSets(const std::vector<CharReach> &esets, |
54 | std::array<u16, ALPHABET_SIZE> &alpha, |
55 | std::array<u16, ALPHABET_SIZE> &unalpha); |
56 | |
57 | /** \brief Calculates an alphabet remapping based on the symbols which the |
58 | * graph discriminates on. Throws in some special DFA symbols as well. */ |
59 | void calculateAlphabet(const NGHolder &g, std::array<u16, ALPHABET_SIZE> &alpha, |
60 | std::array<u16, ALPHABET_SIZE> &unalpha, u16 *alphasize); |
61 | |
62 | void getFullTransitionFromState(const raw_dfa &n, u16 state, |
63 | u16 *out_table); |
64 | |
65 | /** produce a map of states on which it is valid to receive tops */ |
66 | void markToppableStarts(const NGHolder &g, const flat_set<NFAVertex> &unused, |
67 | bool single_trigger, |
68 | const std::vector<std::vector<CharReach>> &triggers, |
69 | boost::dynamic_bitset<> *out); |
70 | |
71 | /** |
72 | * \brief Returns a set of start vertices that will not participate in an |
73 | * implementation of this graph. These are either starts with no successors or |
74 | * starts which are redundant with startDs. |
75 | */ |
76 | flat_set<NFAVertex> getRedundantStarts(const NGHolder &g); |
77 | |
78 | template<typename autom> |
79 | void transition_graph(autom &nfa, const std::vector<NFAVertex> &vByStateId, |
80 | const typename autom::StateSet &in, |
81 | typename autom::StateSet *next) { |
82 | typedef typename autom::StateSet StateSet; |
83 | const NGHolder &graph = nfa.graph; |
84 | const auto &unused = nfa.unused; |
85 | const auto &alpha = nfa.alpha; |
86 | const StateSet &squash = nfa.squash; |
87 | const std::map<u32, StateSet> &squash_mask = nfa.squash_mask; |
88 | const std::vector<CharReach> &cr_by_index = nfa.cr_by_index; |
89 | |
90 | for (symbol_t s = 0; s < nfa.alphasize; s++) { |
91 | next[s].reset(); |
92 | } |
93 | |
94 | /* generate top transitions, false -> top = selfloop */ |
95 | bool top_allowed = is_triggered(graph); |
96 | |
97 | StateSet succ = nfa.dead; |
98 | for (size_t i = in.find_first(); i != in.npos; i = in.find_next(i)) { |
99 | NFAVertex u = vByStateId[i]; |
100 | |
101 | for (const auto &v : adjacent_vertices_range(u, graph)) { |
102 | if (contains(unused, v)) { |
103 | continue; |
104 | } |
105 | succ.set(graph[v].index); |
106 | } |
107 | |
108 | if (top_allowed && !nfa.toppable.test(i)) { |
109 | /* we don't need to generate a top at this location as we are in |
110 | * an nfa state which cannot be on when a trigger arrives. */ |
111 | top_allowed = false; |
112 | } |
113 | } |
114 | |
115 | StateSet active_squash = succ & squash; |
116 | if (active_squash.any()) { |
117 | for (size_t j = active_squash.find_first(); j != active_squash.npos; |
118 | j = active_squash.find_next(j)) { |
119 | succ &= squash_mask.find(j)->second; |
120 | } |
121 | } |
122 | |
123 | for (size_t j = succ.find_first(); j != succ.npos; j = succ.find_next(j)) { |
124 | const CharReach &cr = cr_by_index[j]; |
125 | for (size_t s = cr.find_first(); s != cr.npos; s = cr.find_next(s)) { |
126 | next[s].set(j); /* already alpha'ed */ |
127 | } |
128 | } |
129 | |
130 | next[alpha[TOP]] = in; |
131 | |
132 | if (top_allowed) { |
133 | /* we don't add in the anchored starts as the only case as the only |
134 | * time it is appropriate is if no characters have been consumed.*/ |
135 | next[alpha[TOP]] |= nfa.initDS; |
136 | |
137 | active_squash = next[alpha[TOP]] & squash; |
138 | if (active_squash.any()) { |
139 | for (size_t j = active_squash.find_first(); j != active_squash.npos; |
140 | j = active_squash.find_next(j)) { |
141 | next[alpha[TOP]] &= squash_mask.find(j)->second; |
142 | } |
143 | } |
144 | } |
145 | } |
146 | |
147 | } // namespace ue2 |
148 | |
149 | #endif |
150 | |