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
ComponentEmpty()44 ComponentEmpty::ComponentEmpty() {
45 // Surprise, it's EMPTY!
46 }
47
~ComponentEmpty()48 ComponentEmpty::~ComponentEmpty() {
49 // Surprise, it's EMPTY!
50 }
51
clone() const52 ComponentEmpty *ComponentEmpty::clone() const { return new ComponentEmpty(); }
53
empty() const54 bool ComponentEmpty::empty() const {
55 return true;
56 }
57
vacuous_everywhere(void) const58 bool ComponentEmpty::vacuous_everywhere(void) const {
59 return true;
60 }
61
repeatable() const62 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
first() const68 vector<PositionInfo> ComponentEmpty::first() const {
69 return vector<PositionInfo>(1, GlushkovBuildState::POS_EPSILON);
70 }
71
last() const72 vector<PositionInfo> ComponentEmpty::last() const {
73 return vector<PositionInfo>();
74 }
75
notePositions(GlushkovBuildState &)76 void ComponentEmpty::notePositions(GlushkovBuildState &) {
77 // Nothing to do.
78 }
79
buildFollowSet(GlushkovBuildState &,const vector<PositionInfo> &)80 void ComponentEmpty::buildFollowSet(GlushkovBuildState &,
81 const vector<PositionInfo> &) {
82 // Nothing to do.
83 }
84
checkEmbeddedStartAnchor(bool at_start) const85 bool ComponentEmpty::checkEmbeddedStartAnchor(bool at_start) const {
86 return at_start;
87 }
88
checkEmbeddedEndAnchor(bool at_end) const89 bool ComponentEmpty::checkEmbeddedEndAnchor(bool at_end) const {
90 return at_end;
91 }
92
93 } // namespace ue2
94