1/****************************************************************************
2**
3** Copyright (C) 2016 The Qt Company Ltd.
4** Contact: https://www.qt.io/licensing/
5**
6** This file is part of the QtXmlPatterns module of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:LGPL$
9** Commercial License Usage
10** Licensees holding valid commercial Qt licenses may use this file in
11** accordance with the commercial license agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and The Qt Company. For licensing terms
14** and conditions see https://www.qt.io/terms-conditions. For further
15** information use the contact form at https://www.qt.io/contact-us.
16**
17** GNU Lesser General Public License Usage
18** Alternatively, this file may be used under the terms of the GNU Lesser
19** General Public License version 3 as published by the Free Software
20** Foundation and appearing in the file LICENSE.LGPL3 included in the
21** packaging of this file. Please review the following information to
22** ensure the GNU Lesser General Public License version 3 requirements
23** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
24**
25** GNU General Public License Usage
26** Alternatively, this file may be used under the terms of the GNU
27** General Public License version 2.0 or (at your option) the GNU General
28** Public license version 3 or any later version approved by the KDE Free
29** Qt Foundation. The licenses are as published by the Free Software
30** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
31** included in the packaging of this file. Please review the following
32** information to ensure the GNU General Public License requirements will
33** be met: https://www.gnu.org/licenses/gpl-2.0.html and
34** https://www.gnu.org/licenses/gpl-3.0.html.
35**
36** $QT_END_LICENSE$
37**
38****************************************************************************/
39
40//
41// W A R N I N G
42// -------------
43//
44// This file is not part of the Qt API. It exists purely as an
45// implementation detail. This header file may change from version to
46// version without notice, or even be removed.
47//
48// We mean it.
49
50#ifndef Patternist_AtomicComparator_H
51#define Patternist_AtomicComparator_H
52
53#include <QFlags>
54
55#include <private/qitem_p.h>
56#include <private/qatomictypedispatch_p.h>
57
58QT_BEGIN_NAMESPACE
59
60class QString;
61
62namespace QPatternist
63{
64
65 /**
66 * @short Base class for classes responsible of comparing two atomic values.
67 *
68 * This class is also known as the AtomicParrot.
69 *
70 * @ingroup Patternist_xdm
71 * @author Frans Englich <frans.englich@nokia.com>
72 */
73 class Q_AUTOTEST_EXPORT AtomicComparator : public AtomicTypeVisitorResult
74 {
75 public:
76 AtomicComparator();
77 virtual ~AtomicComparator();
78
79 typedef QExplicitlySharedDataPointer<AtomicComparator> Ptr;
80
81 /**
82 * Identifies operators used in value comparisons.
83 *
84 * The enum values are bit-significant.
85 *
86 * @see <a href="http://www.w3.org/TR/xpath20/#id-value-comparisons">W3C XML Path
87 * Language (XPath) 2.0, 3.5.1 Value Comparisons</a>
88 */
89 enum Operator
90 {
91 /**
92 * Operator <tt>eq</tt> and <tt>=</tt>.
93 */
94 OperatorEqual = 1,
95
96 /**
97 * Operator <tt>ne</tt> and <tt>!=</tt>.
98 */
99 OperatorNotEqual = 1 << 1,
100
101 /**
102 * Operator <tt>gt</tt> and <tt>\></tt>.
103 */
104 OperatorGreaterThan = 1 << 2,
105
106 /**
107 * Operator <tt>lt</tt> and <tt>\<</tt>.
108 */
109 OperatorLessThan = 1 << 3,
110
111 /**
112 * One of the operators we use for sorting. The only difference from
113 * OperatorLessThan is that it sees NaN as ordered and smaller than
114 * other numbers.
115 */
116 OperatorLessThanNaNLeast = 1 << 4,
117
118 /**
119 * One of the operators we use for sorting. The only difference from
120 * OperatorLessThanLeast is that it sees NaN as ordered and larger than
121 * other numbers.
122 */
123 OperatorLessThanNaNGreatest = 1 << 5,
124
125 /**
126 * Operator <tt>ge</tt> and <tt>\>=</tt>.
127 */
128 OperatorGreaterOrEqual = OperatorEqual | OperatorGreaterThan,
129
130 /**
131 * Operator <tt>le</tt> and <tt>\<=</tt>.
132 */
133 OperatorLessOrEqual = OperatorEqual | OperatorLessThan
134 };
135
136 typedef QFlags<Operator> Operators;
137
138 /**
139 * Signifies the result of a value comparison. This is used for value comparisons,
140 * and in the future likely also for sorting.
141 *
142 * @see <a href="http://www.w3.org/TR/xpath20/#id-value-comparisons">W3C XML Path
143 * Language (XPath) 2.0, 3.5.1 Value Comparisons</a>
144 */
145 enum ComparisonResult
146 {
147 LessThan = 1,
148 Equal = 2,
149 GreaterThan = 4,
150 Incomparable = 8
151 };
152
153 /**
154 * Compares @p op1 and @p op2 and determines the relationship between the two. This
155 * is used for sorting and comparisons. The implementation performs an assert crash,
156 * and must therefore be re-implemented if comparing the relevant values should be
157 * possible.
158 *
159 * @param op1 the first operand
160 * @param op the operator. How a comparison is carried out shouldn't depend on what the
161 * operator is, but in some cases it is of interest.
162 * @param op2 the second operand
163 */
164 virtual ComparisonResult compare(const Item &op1,
165 const AtomicComparator::Operator op,
166 const Item &op2) const;
167
168 /**
169 * Determines whether @p op1 and @p op2 are equal. It is the same as calling compare()
170 * and checking whether the return value is Equal, but since comparison testing is such
171 * a common operation, this specialized function exists.
172 *
173 * @returns true if @p op1 and @p op2 are equal.
174 *
175 * @param op1 the first operand
176 * @param op2 the second operand
177 */
178 virtual bool equals(const Item &op1,
179 const Item &op2) const = 0;
180
181 /**
182 * Identifies the kind of comparison.
183 */
184 enum ComparisonType
185 {
186 /**
187 * Identifies a general comparison; operator @c =, @c >, @c <=, and so on.
188 */
189 AsGeneralComparison = 1,
190
191 /**
192 * Identifies a value comparison; operator @c eq, @c lt, @c le, and so on.
193 */
194 AsValueComparison
195 };
196
197 /**
198 * Utility function for getting the lexical representation for
199 * the comparison operator @p op. Depending on the @p type argument,
200 * the string returned is either a general comparison or a value comparison
201 * operator.
202 *
203 * @param op the operator which the display name should be determined for.
204 * @param type signifies whether the returned display name should be for
205 * a value comparison or a general comparison. For example, if @p op is
206 * OperatorEqual and @p type is AsValueComparision, "eq" is returned.
207 */
208 static QString displayName(const AtomicComparator::Operator op,
209 const ComparisonType type);
210
211 };
212 Q_DECLARE_OPERATORS_FOR_FLAGS(AtomicComparator::Operators)
213}
214
215QT_END_NAMESPACE
216
217#endif
218

source code of qtxmlpatterns/src/xmlpatterns/data/qatomiccomparator_p.h