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 Lookahead/lookbehind zero-width assertions.
31 */
32 #include "ComponentAssertion.h"
33 #include "buildstate.h"
34 #include "position.h"
35 #include "position_info.h"
36 #include "ue2common.h"
37
38 #include <cassert>
39 #include <algorithm>
40
41 using namespace std;
42
43 namespace ue2 {
44
ComponentAssertion(enum Direction dir,enum Sense sense)45 ComponentAssertion::ComponentAssertion(enum Direction dir, enum Sense sense)
46 : m_dir(dir), m_sense(sense) {}
47
~ComponentAssertion()48 ComponentAssertion::~ComponentAssertion() { }
49
clone() const50 ComponentAssertion *ComponentAssertion::clone() const {
51 return new ComponentAssertion(*this);
52 }
53
accept(ComponentVisitor & v)54 Component * ComponentAssertion::accept(ComponentVisitor &v) {
55 Component *c = v.visit(this);
56 if (c != this) {
57 v.post(this);
58 return c;
59 }
60
61 for (auto i = children.begin(), e = children.end(); i != e; ++i) {
62 Component *child = i->get();
63 c = (*i)->accept(v);
64 if (c != child) {
65 // Child has been replaced (new Component pointer) or we've been
66 // instructed to delete it (null).
67 i->reset(c);
68 }
69 }
70
71 // Remove deleted children.
72 children.erase(remove(children.begin(), children.end(), nullptr),
73 children.end());
74
75 v.post(this);
76 return this;
77 }
78
accept(ConstComponentVisitor & v) const79 void ComponentAssertion::accept(ConstComponentVisitor &v) const {
80 v.pre(*this);
81 for (auto i = children.begin(), e = children.end(); i != e; ++i) {
82 (*i)->accept(v);
83 if (i + 1 != e) {
84 v.during(*this);
85 }
86 }
87
88 v.post(*this);
89 }
90
first() const91 vector<PositionInfo> ComponentAssertion::first() const {
92 assert(0);
93 return vector<PositionInfo>();
94 }
95
last() const96 vector<PositionInfo> ComponentAssertion::last() const {
97 assert(0);
98 return vector<PositionInfo>();
99 }
100
empty() const101 bool ComponentAssertion::empty() const {
102 return true;
103 }
104
notePositions(GlushkovBuildState &)105 void ComponentAssertion::notePositions(GlushkovBuildState &) {
106 assert(0);
107 }
108
buildFollowSet(GlushkovBuildState &,const vector<PositionInfo> &)109 void ComponentAssertion::buildFollowSet(GlushkovBuildState &,
110 const vector<PositionInfo> &) {
111 assert(0);
112 }
113
repeatable() const114 bool ComponentAssertion::repeatable() const {
115 // If this assertion has no children (it's an empty sequence, like that
116 // produced by '(?!)') then PCRE would throw a "nothing to repeat" error.
117 // So we do as well.
118 return !children.empty();
119 }
120
121 } // namespace ue2
122