1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2025, Ben Burton *
* For further details contact Ben Burton (bab@debian.org). *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 2 of the *
* License, or (at your option) any later version. *
* *
* As an exception, when this program is distributed through (i) the *
* App Store by Apple Inc.; (ii) the Mac App Store by Apple Inc.; or *
* (iii) Google Play by Google Inc., then that store may impose any *
* digital rights management, device limits and/or redistribution *
* restrictions that are required by its terms of service. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <https://www.gnu.org/licenses/>. *
* *
**************************************************************************/
#include "file/xml/xmlalgebrareader.h"
#include "utilities/stringutils.h"
namespace regina {
/**
* A unique namespace containing various task-specific packet readers.
*/
namespace {
/**
* Reads a single relation in a group presentation.
*/
class ExpressionReader : public XMLElementReader {
private:
std::optional<GroupExpression> exp;
long nGens;
public:
ExpressionReader(long newNGens) : exp(GroupExpression()),
nGens(newNGens) {
}
std::optional<GroupExpression>& expression() {
return exp;
}
void initialChars(const std::string& chars) override {
std::vector<std::string> tokens = basicTokenise(chars);
std::string genStr, powStr;
long gen, pow;
std::string::size_type split;
for (const std::string& t : tokens) {
split = t.find('^');
if (split == t.length()) {
exp.reset();
break;
}
genStr = t.substr(0, split);
powStr = t.substr(split + 1, t.length() - split - 1);
if ((! valueOf(genStr, gen)) || (! valueOf(powStr, pow))) {
exp.reset();
break;
}
if (gen < 0 || gen >= nGens) {
exp.reset();
break;
}
exp->addTermLast(gen, pow);
}
}
};
}
void XMLAbelianGroupReader::startElement(const std::string&,
const regina::xml::XMLPropertyDict& tagProps, XMLElementReader*) {
long rank;
if (valueOf(tagProps.lookup("rank"), rank))
if (rank >= 0) {
group_ = AbelianGroup(rank);
}
}
void XMLAbelianGroupReader::initialChars(const std::string& chars) {
if (group_) {
std::vector<std::string> tokens = basicTokenise(chars);
try {
for (const std::string& t : tokens)
group_->addTorsion(Integer(t));
} catch (const regina::InvalidArgument&) {
// Unparseable.
group_.reset();
}
}
}
void XMLGroupPresentationReader::startElement(const std::string&,
const regina::xml::XMLPropertyDict& tagProps, XMLElementReader*) {
long nGen;
if (valueOf(tagProps.lookup("generators"), nGen))
if (nGen >= 0) {
group_ = GroupPresentation();
if (nGen)
group_->addGenerator(nGen);
}
}
XMLElementReader* XMLGroupPresentationReader::startSubElement(
const std::string& subTagName,
const regina::xml::XMLPropertyDict& /* subTagProps */) {
if (group_)
if (subTagName == "reln")
return new ExpressionReader(group_->countGenerators());
return new XMLElementReader();
}
void XMLGroupPresentationReader::endSubElement(const std::string& subTagName,
XMLElementReader* subReader) {
if (group_)
if (subTagName == "reln") {
auto& exp = static_cast<ExpressionReader*>(subReader)->expression();
if (exp)
group_->addRelation(std::move(*exp));
}
}
} // namespace regina
|
