1 | /* |
2 | * Copyright (c) 2015, 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 Represents an empty regex element, like (?m) |
31 | */ |
32 | #include <cassert> |
33 | |
34 | #include "ComponentEmpty.h" |
35 | #include "position.h" |
36 | #include "position_info.h" |
37 | #include "buildstate.h" |
38 | #include "ue2common.h" |
39 | |
40 | using namespace std; |
41 | |
42 | namespace ue2 { |
43 | |
44 | ComponentEmpty::ComponentEmpty() { |
45 | // Surprise, it's EMPTY! |
46 | } |
47 | |
48 | ComponentEmpty::~ComponentEmpty() { |
49 | // Surprise, it's EMPTY! |
50 | } |
51 | |
52 | ComponentEmpty *ComponentEmpty::clone() const { return new ComponentEmpty(); } |
53 | |
54 | bool ComponentEmpty::empty() const { |
55 | return true; |
56 | } |
57 | |
58 | bool ComponentEmpty::vacuous_everywhere(void) const { |
59 | return true; |
60 | } |
61 | |
62 | bool ComponentEmpty::repeatable() const { |
63 | // This is the whole point of this class. Empty constructs like '(?m)' are |
64 | // not repeatable. |
65 | return false; |
66 | } |
67 | |
68 | vector<PositionInfo> ComponentEmpty::first() const { |
69 | return vector<PositionInfo>(1, GlushkovBuildState::POS_EPSILON); |
70 | } |
71 | |
72 | vector<PositionInfo> ComponentEmpty::last() const { |
73 | return vector<PositionInfo>(); |
74 | } |
75 | |
76 | void ComponentEmpty::notePositions(GlushkovBuildState &) { |
77 | // Nothing to do. |
78 | } |
79 | |
80 | void ComponentEmpty::buildFollowSet(GlushkovBuildState &, |
81 | const vector<PositionInfo> &) { |
82 | // Nothing to do. |
83 | } |
84 | |
85 | bool ComponentEmpty::checkEmbeddedStartAnchor(bool at_start) const { |
86 | return at_start; |
87 | } |
88 | |
89 | bool ComponentEmpty::checkEmbeddedEndAnchor(bool at_end) const { |
90 | return at_end; |
91 | } |
92 | |
93 | } // namespace ue2 |
94 | |