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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 // |
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43 // W A R N I N G |
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44 // ------------- |
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45 // |
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46 // This file is not part of the Qt API. It exists purely as an |
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47 // implementation detail. This header file may change from version to |
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48 // version without notice, or even be removed. |
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49 // |
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50 // We mean it. |
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51 |
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52 #ifndef Patternist_XsdStateMachine_H |
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53 #define Patternist_XsdStateMachine_H |
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54 |
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55 #include "qnamepool_p.h" |
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56 |
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57 #include <QtCore/QHash> |
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58 #include <QtCore/QSet> |
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59 #include <QtCore/QTextStream> |
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60 |
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61 class QIODevice; |
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62 |
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63 QT_BEGIN_HEADER |
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64 |
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65 QT_BEGIN_NAMESPACE |
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66 |
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67 namespace QPatternist |
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68 { |
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69 /** |
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70 * @short A state machine used for evaluation. |
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71 * |
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72 * @ingroup Patternist_schema |
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73 * @author Tobias Koenig <tobias.koenig@nokia.com> |
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74 */ |
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75 template <typename TransitionType> |
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76 class XsdStateMachine |
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77 { |
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78 public: |
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79 typedef qint32 StateId; |
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80 |
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81 /** |
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82 * Describes the type of state. |
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83 */ |
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84 enum StateType |
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85 { |
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86 StartState, ///< The state the machine will start with. |
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87 StartEndState, ///< The state the machine will start with, can be end state as well. |
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88 InternalState, ///< Any state that is not start or end state. |
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89 EndState ///< Any state where the machine is allowed to stop. |
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90 }; |
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91 |
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92 /** |
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93 * Creates a new state machine object. |
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94 */ |
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95 XsdStateMachine(); |
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96 |
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97 /** |
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98 * Creates a new state machine object. |
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99 * |
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100 * The name pool to use for accessing object names. |
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101 */ |
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102 XsdStateMachine(const NamePool::Ptr &namePool); |
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103 |
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104 /** |
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105 * Adds a new state of the given @p type to the state machine. |
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106 * |
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107 * @return The id of the new state. |
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108 */ |
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109 StateId addState(StateType type); |
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110 |
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111 /** |
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112 * Adds a new @p transition to the state machine. |
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113 * |
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114 * @param start The start state. |
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115 * @param transition The transition to come from the start to the end state. |
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116 * @param end The end state. |
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117 */ |
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118 void addTransition(StateId start, TransitionType transition, StateId end); |
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119 |
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120 /** |
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121 * Adds a new epsilon @p transition to the state machine. |
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122 * |
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123 * @param start The start state. |
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124 * @param end The end state. |
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125 */ |
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126 void addEpsilonTransition(StateId start, StateId end); |
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127 |
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128 /** |
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129 * Resets the machine to the start state. |
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130 */ |
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131 void reset(); |
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132 |
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133 /** |
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134 * Removes all states and transitions from the state machine. |
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135 */ |
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136 void clear(); |
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137 |
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138 /** |
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139 * Continues execution of the machine with the given input @p transition. |
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140 * |
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141 * @return @c true if the transition was successfull, @c false otherwise. |
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142 */ |
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143 bool proceed(TransitionType transition); |
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144 |
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145 /** |
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146 * Returns the list of transitions that are reachable from the current |
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147 * state. |
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148 */ |
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149 QList<TransitionType> possibleTransitions() const; |
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150 |
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151 /** |
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152 * Continues execution of the machine with the given @p input. |
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153 * |
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154 * @note To use this method, inputEqualsTransition must be implemented |
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155 * to find the right transition to use. |
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156 * |
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157 * @return @c true if the transition was successfull, @c false otherwise. |
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158 */ |
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159 template <typename InputType> |
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160 bool proceed(InputType input); |
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161 |
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162 /** |
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163 * Returns whether the given @p input matches the given @p transition. |
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164 */ |
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165 template <typename InputType> |
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166 bool inputEqualsTransition(InputType input, TransitionType transition) const; |
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167 |
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168 /** |
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169 * Returns whether the machine is in an allowed end state. |
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170 */ |
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171 bool inEndState() const; |
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172 |
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173 /** |
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174 * Returns the last transition that was taken. |
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175 */ |
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176 TransitionType lastTransition() const; |
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177 |
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178 /** |
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179 * Returns the start state of the machine. |
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180 */ |
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181 StateId startState() const; |
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182 |
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183 /** |
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184 * This method should be redefined by template specialization for every |
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185 * concret TransitionType. |
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186 */ |
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187 QString transitionTypeToString(TransitionType type) const; |
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188 |
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189 /** |
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190 * Outputs the state machine in DOT format to the given |
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191 * output @p device. |
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192 */ |
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193 bool outputGraph(QIODevice *device, const QString &graphName) const; |
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194 |
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195 /** |
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196 * Returns a DFA that is equal to the NFA of the state machine. |
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197 */ |
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198 XsdStateMachine<TransitionType> toDFA() const; |
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199 |
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200 /** |
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201 * Returns the information of all states of the state machine. |
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202 */ |
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203 QHash<StateId, StateType> states() const; |
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204 |
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205 /** |
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206 * Returns the information of all transitions of the state machine. |
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207 * |
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208 * The implementation is inlined in order to workaround a compiler |
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209 * bug on Symbian/winscw. |
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210 */ |
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211 QHash<StateId, QHash<TransitionType, QVector<StateId> > > transitions() const |
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212 { |
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213 return m_transitions; |
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214 } |
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215 |
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216 private: |
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217 /** |
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218 * Returns the DFA state for the given @p nfaStat from the given @p stateTable. |
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219 * If there is no corresponding DFA state yet, a new one is created. |
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220 */ |
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221 StateId dfaStateForNfaState(QSet<StateId> nfaState, QList< QPair< QSet<StateId>, StateId> > &stateTable, XsdStateMachine<TransitionType> &dfa) const; |
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222 |
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223 /** |
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224 * Returns the set of all states that can be reached from the set of @p input states |
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225 * by the epsilon transition. |
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226 * |
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227 * The implementation is inlined in order to workaround a compiler |
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228 * bug on Symbian/winscw. |
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229 */ |
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230 QSet<StateId> epsilonClosure(const QSet<StateId> &input) const |
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231 { |
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232 // every state can reach itself by epsilon transition, so include the input states |
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233 // in the result as well |
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234 QSet<StateId> result = input; |
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235 |
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236 // add the input states to the list of to be processed states |
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237 QList<StateId> workStates = input.toList(); |
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238 while (!workStates.isEmpty()) { // while there are states to be processed left... |
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239 |
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240 // dequeue one state from list |
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241 const StateId state = workStates.takeFirst(); |
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242 |
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243 // get the list of states that can be reached by the epsilon transition |
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244 // from the current 'state' |
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245 const QVector<StateId> targetStates = m_epsilonTransitions.value(state); |
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246 for (int i = 0; i < targetStates.count(); ++i) { |
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247 // if we have this target state not in our result set yet... |
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248 if (!result.contains(targetStates.at(i))) { |
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249 // ... add it to the result set |
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250 result.insert(targetStates.at(i)); |
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251 |
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252 // add the target state to the list of to be processed states as well, |
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253 // as we want to have the epsilon transitions not only for the first |
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254 // level of following states |
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255 workStates.append(targetStates.at(i)); |
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256 } |
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257 } |
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258 } |
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259 |
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260 return result; |
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261 } |
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262 |
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263 /** |
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264 * Returns the set of all states that can be reached from the set of given @p states |
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265 * by the given @p input. |
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266 * |
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267 * The implementation is inlined in order to workaround a compiler |
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268 * bug on Symbian/winscw. |
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269 */ |
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270 QSet<StateId> move(const QSet<StateId> &states, TransitionType input) const |
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271 { |
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272 QSet<StateId> result; |
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273 |
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274 QSetIterator<StateId> it(states); |
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275 while (it.hasNext()) { // iterate over all given states |
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276 const StateId state = it.next(); |
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277 |
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278 // get the transition table for the current state |
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279 const QHash<TransitionType, QVector<StateId> > transitions = m_transitions.value(state); |
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280 |
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281 // get the target states for the given input |
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282 const QVector<StateId> targetStates = transitions.value(input); |
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283 |
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284 // add all target states to the result |
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285 for (int i = 0; i < targetStates.size(); ++i) |
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286 result.insert(targetStates.at(i)); |
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287 } |
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288 |
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289 return result; |
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290 } |
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291 |
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292 NamePool::Ptr m_namePool; |
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293 QHash<StateId, StateType> m_states; |
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294 QHash<StateId, QHash<TransitionType, QVector<StateId> > > m_transitions; |
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295 QHash<StateId, QVector<StateId> > m_epsilonTransitions; |
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296 StateId m_currentState; |
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297 qint32 m_counter; |
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298 TransitionType m_lastTransition; |
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299 }; |
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300 |
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301 #include "qxsdstatemachine.cpp" |
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302 } |
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303 |
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304 QT_END_NAMESPACE |
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305 |
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306 QT_END_HEADER |
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307 |
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308 #endif |