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 Build code for vacuous graphs. |
31 | */ |
32 | #include "ng_vacuous.h" |
33 | |
34 | #include "grey.h" |
35 | #include "ng.h" |
36 | #include "ng_util.h" |
37 | #include "compiler/compiler.h" |
38 | |
39 | using namespace std; |
40 | |
41 | namespace ue2 { |
42 | |
43 | static |
44 | ReportID getInternalId(ReportManager &rm, const ExpressionInfo &expr) { |
45 | Report ir = rm.getBasicInternalReport(expr); |
46 | |
47 | // Apply any extended params. |
48 | if (expr.min_offset || expr.max_offset != MAX_OFFSET) { |
49 | ir.minOffset = expr.min_offset; |
50 | ir.maxOffset = expr.max_offset; |
51 | } |
52 | |
53 | assert(!expr.min_length); // should be handled elsewhere. |
54 | |
55 | return rm.getInternalId(ir); |
56 | } |
57 | |
58 | static |
59 | void makeFirehose(BoundaryReports &boundary, ReportManager &rm, NGHolder &g, |
60 | const ExpressionInfo &expr) { |
61 | const ReportID r = getInternalId(rm, expr); |
62 | |
63 | boundary.report_at_0_eod.insert(r); |
64 | boundary.report_at_0.insert(r); |
65 | |
66 | // Replace the graph with a '.+'. |
67 | |
68 | clear_graph(g); |
69 | clearReports(g); |
70 | remove_edge(g.start, g.accept, g); |
71 | remove_edge(g.start, g.acceptEod, g); |
72 | remove_edge(g.startDs, g.accept, g); |
73 | remove_edge(g.startDs, g.acceptEod, g); |
74 | |
75 | NFAVertex v = add_vertex(g); |
76 | g[v].char_reach.setall(); |
77 | g[v].reports.insert(r); |
78 | add_edge(v, v, g); |
79 | add_edge(g.start, v, g); |
80 | add_edge(g.startDs, v, g); |
81 | add_edge(v, g.accept, g); |
82 | } |
83 | |
84 | static |
85 | void makeAnchoredAcceptor(BoundaryReports &boundary, ReportManager &rm, |
86 | NGHolder &g, const ExpressionInfo &expr) { |
87 | boundary.report_at_0.insert(getInternalId(rm, expr)); |
88 | remove_edge(g.start, g.accept, g); |
89 | remove_edge(g.start, g.acceptEod, g); |
90 | g[g.start].reports.clear(); |
91 | } |
92 | |
93 | static |
94 | void makeEndAnchoredAcceptor(BoundaryReports &boundary, ReportManager &rm, |
95 | NGHolder &g, const ExpressionInfo &expr) { |
96 | boundary.report_at_eod.insert(getInternalId(rm, expr)); |
97 | remove_edge(g.startDs, g.acceptEod, g); |
98 | remove_edge(g.start, g.acceptEod, g); |
99 | g[g.start].reports.clear(); |
100 | g[g.startDs].reports.clear(); |
101 | } |
102 | |
103 | static |
104 | void makeNothingAcceptor(BoundaryReports &boundary, ReportManager &rm, |
105 | NGHolder &g, const ExpressionInfo &expr) { |
106 | boundary.report_at_0_eod.insert(getInternalId(rm, expr)); |
107 | remove_edge(g.start, g.acceptEod, g); |
108 | g[g.start].reports.clear(); |
109 | } |
110 | |
111 | bool splitOffVacuous(BoundaryReports &boundary, ReportManager &rm, |
112 | NGHolder &g, const ExpressionInfo &expr) { |
113 | if (edge(g.startDs, g.accept, g).second) { |
114 | // e.g. '.*'; match "between" every byte |
115 | DEBUG_PRINTF("graph is firehose\n" ); |
116 | makeFirehose(boundary, rm, g, expr); |
117 | return true; |
118 | } |
119 | |
120 | bool work_done = false; |
121 | |
122 | if (edge(g.start, g.accept, g).second) { |
123 | DEBUG_PRINTF("creating anchored acceptor\n" ); |
124 | makeAnchoredAcceptor(boundary, rm, g, expr); |
125 | work_done = true; |
126 | } |
127 | |
128 | if (edge(g.startDs, g.acceptEod, g).second) { |
129 | DEBUG_PRINTF("creating end-anchored acceptor\n" ); |
130 | makeEndAnchoredAcceptor(boundary, rm, g, expr); |
131 | work_done = true; |
132 | } |
133 | |
134 | if (edge(g.start, g.acceptEod, g).second) { |
135 | DEBUG_PRINTF("creating nothing acceptor\n" ); |
136 | makeNothingAcceptor(boundary, rm, g, expr); |
137 | work_done = true; |
138 | } |
139 | |
140 | return work_done; |
141 | } |
142 | |
143 | } // namespace ue2 |
144 | |