source: trunk/src/xmlpatterns/expr/qoptimizationpasses.cpp@ 439

Last change on this file since 439 was 2, checked in by Dmitry A. Kuminov, 16 years ago

Initially imported qt-all-opensource-src-4.5.1 from Trolltech.
File size: 8.5 KB
Line 
1/****************************************************************************
2**
3** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
4** Contact: Qt Software Information ([email protected])
5**
6** This file is part of the QtXmlPatterns module of the Qt Toolkit.
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15** GNU Lesser General Public License Usage
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41
42#include "qcommonsequencetypes_p.h"
43#include "qoptimizerblocks_p.h"
44
45#include "qoptimizationpasses_p.h"
46
47QT_BEGIN_NAMESPACE
48
49using namespace QPatternist;
50
51OptimizationPass::List OptimizationPasses::comparisonPasses;
52OptimizationPass::List OptimizationPasses::forPasses;
53OptimizationPass::List OptimizationPasses::ifThenPasses;
54OptimizationPass::List OptimizationPasses::notFN;
55
56void OptimizationPasses::Coordinator::init()
57{
58 static bool isInitialized = false; // STATIC DATA
59
60 if(isInitialized)
61 return;
62
63 isInitialized = true;
64
65 /* Note, below is many of the building blocks re-used in several passes
66 * in order to reduce memory use. Thus, when changing one building block
67 * it potentially affects many passes. */
68
69 /* ****************************************************** */
70 /* Rewrite "count(<expr>) ge 1" into "exists(<expr>)" */
71 OptimizationPass::ExpressionMarker firstFirstChild;
72 firstFirstChild.append(0);
73 firstFirstChild.append(0);
74
75 ExpressionIdentifier::List geOpIDs;
76 const ExpressionIdentifier::Ptr countFN(new ByIDIdentifier(Expression::IDCountFN));
77 geOpIDs.append(countFN);
78 geOpIDs.append(ExpressionIdentifier::Ptr(new IntegerIdentifier(1)));
79
80 QVector<Expression::ID> geMatcher;
81 geMatcher.append(Expression::IDValueComparison);
82 geMatcher.append(Expression::IDGeneralComparison);
83
84 const ExpressionIdentifier::Ptr ge(new ComparisonIdentifier(geMatcher,
85 AtomicComparator::OperatorGreaterOrEqual));
86
87 const ExpressionCreator::Ptr existsFN(new ByIDCreator(Expression::IDExistsFN));
88 const OptimizationPass::Ptr geToExists(new OptimizationPass(ge, geOpIDs, firstFirstChild, existsFN));
89 comparisonPasses.append(geToExists);
90 /* ****************************************************** */
91
92 /* ****************************************************** */
93 /* Rewrite "count(<expr>) gt 0" into "exists(<expr>)" */
94 ExpressionIdentifier::List countAndIntZero;
95 countAndIntZero.append(countFN);
96 const ExpressionIdentifier::Ptr zeroInteger(new IntegerIdentifier(0));
97 countAndIntZero.append(zeroInteger);
98
99 const ExpressionIdentifier::Ptr gt(new ComparisonIdentifier(geMatcher,
100 AtomicComparator::OperatorGreaterThan));
101
102 const OptimizationPass::Ptr gtToExists(new OptimizationPass(gt, countAndIntZero,
103 firstFirstChild, existsFN));
104 comparisonPasses.append(gtToExists);
105 /* ****************************************************** */
106
107 /* ****************************************************** */
108 /* Rewrite "count(<expr>) ne 0" into "exists(<expr>)" */
109
110 const ExpressionIdentifier::Ptr ne(new ComparisonIdentifier(geMatcher,
111 AtomicComparator::OperatorNotEqual));
112 const OptimizationPass::Ptr neToExists(new OptimizationPass(ne, countAndIntZero, firstFirstChild,
113 existsFN,
114 OptimizationPass::AnyOrder));
115 comparisonPasses.append(neToExists);
116 /* ****************************************************** */
117
118 /* ****************************************************** */
119 /* Rewrite "count(<expr>) eq 0" into "empty(<expr>)" */
120 ExpressionIdentifier::List eqOpIDs;
121 eqOpIDs.append(countFN);
122 eqOpIDs.append(zeroInteger);
123 const ExpressionCreator::Ptr emptyFN(new ByIDCreator(Expression::IDEmptyFN));
124 const ExpressionIdentifier::Ptr eq(new ComparisonIdentifier(geMatcher,
125 AtomicComparator::OperatorEqual));
126 const OptimizationPass::Ptr eqToEmpty(new OptimizationPass(eq, eqOpIDs, firstFirstChild,
127 emptyFN,
128 OptimizationPass::AnyOrder));
129 comparisonPasses.append(eqToEmpty);
130
131 /* ****************************************************** */
132
133 /* ****************************************************** */
134 /* Rewrite "for $var in <expr> return $var" into "<expr>" */
135 ExpressionIdentifier::List forOps;
136 OptimizationPass::ExpressionMarker firstChild;
137 firstChild.append(0);
138
139 forOps.append(ExpressionIdentifier::Ptr());
140 forOps.append(ExpressionIdentifier::Ptr(new ByIDIdentifier(Expression::IDRangeVariableReference)));
141 const OptimizationPass::Ptr simplifyFor(new OptimizationPass(ExpressionIdentifier::Ptr(), forOps,
142 firstChild, ExpressionCreator::Ptr()));
143 forPasses.append(simplifyFor);
144 /* ****************************************************** */
145
146 /* ****************************************************** */
147 /* Rewrite "if(<expr>) then true() else false()" to "<expr>" */
148 OptimizationPass::ExpressionMarker marker;
149 marker.append(0);
150
151 ExpressionIdentifier::List opIDs;
152 opIDs.append(ExpressionIdentifier::Ptr(new BySequenceTypeIdentifier(
153 CommonSequenceTypes::ExactlyOneBoolean)));
154 opIDs.append(ExpressionIdentifier::Ptr(new BooleanIdentifier(true)));
155 opIDs.append(ExpressionIdentifier::Ptr(new BooleanIdentifier(false)));
156
157 const OptimizationPass::Ptr pass(new OptimizationPass(ExpressionIdentifier::Ptr(), opIDs, marker));
158 ifThenPasses.append(pass);
159 /* ****************************************************** */
160
161 /* ****************************************************** */
162 /* Rewrite "not(exists(X))" into "empty(X)" */
163 ExpressionIdentifier::List idExistsFN;
164 idExistsFN.append(ExpressionIdentifier::Ptr(new ByIDIdentifier(Expression::IDExistsFN)));
165
166 notFN.append(OptimizationPass::Ptr(new OptimizationPass(ExpressionIdentifier::Ptr(),
167 idExistsFN,
168 firstFirstChild,
169 emptyFN)));
170
171 /* Rewrite "not(empty(X))" into "exists(X)" */
172 ExpressionIdentifier::List idEmptyFN;
173 idEmptyFN.append(ExpressionIdentifier::Ptr(new ByIDIdentifier(Expression::IDEmptyFN)));
174
175 notFN.append(OptimizationPass::Ptr(new OptimizationPass(ExpressionIdentifier::Ptr(),
176 idEmptyFN,
177 firstFirstChild,
178 existsFN)));
179 /* ****************************************************** */
180}
181
182QT_END_NAMESPACE
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