444 lines
14 KiB
PHP
444 lines
14 KiB
PHP
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<?php
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/**
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* Zend Framework
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*
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* LICENSE
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*
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* This source file is subject to the new BSD license that is bundled
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* with this package in the file LICENSE.txt.
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* It is also available through the world-wide-web at this URL:
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* http://framework.zend.com/license/new-bsd
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* If you did not receive a copy of the license and are unable to
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* obtain it through the world-wide-web, please send an email
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* to license@zend.com so we can send you a copy immediately.
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*
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* @category Zend
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* @package Zend_Search_Lucene
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* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
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* @license http://framework.zend.com/license/new-bsd New BSD License
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* @version $Id: FSM.php 16971 2009-07-22 18:05:45Z mikaelkael $
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*/
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/** Zend_Search_Lucene_FSMAction */
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require_once 'Zend/Search/Lucene/FSMAction.php';
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/**
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* Abstract Finite State Machine
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*
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* Take a look on Wikipedia state machine description: http://en.wikipedia.org/wiki/Finite_state_machine
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*
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* Any type of Transducers (Moore machine or Mealy machine) also may be implemented by using this abstract FSM.
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* process() methods invokes a specified actions which may construct FSM output.
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* Actions may be also used to signal, that we have reached Accept State
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*
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* @category Zend
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* @package Zend_Search_Lucene
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* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
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* @license http://framework.zend.com/license/new-bsd New BSD License
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*/
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abstract class Zend_Search_Lucene_FSM
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{
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/**
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* Machine States alphabet
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*
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* @var array
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*/
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private $_states = array();
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/**
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* Current state
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*
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* @var integer|string
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*/
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private $_currentState = null;
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/**
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* Input alphabet
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*
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* @var array
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*/
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private $_inputAphabet = array();
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/**
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* State transition table
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*
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* [sourceState][input] => targetState
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*
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* @var array
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*/
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private $_rules = array();
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/**
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* List of entry actions
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* Each action executes when entering the state
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*
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* [state] => action
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*
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* @var array
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*/
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private $_entryActions = array();
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/**
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* List of exit actions
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* Each action executes when exiting the state
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*
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* [state] => action
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*
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* @var array
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*/
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private $_exitActions = array();
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/**
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* List of input actions
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* Each action executes when entering the state
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*
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* [state][input] => action
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*
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* @var array
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*/
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private $_inputActions = array();
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/**
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* List of input actions
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* Each action executes when entering the state
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*
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* [state1][state2] => action
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*
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* @var array
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*/
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private $_transitionActions = array();
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/**
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* Finite State machine constructor
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*
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* $states is an array of integers or strings with a list of possible machine states
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* constructor treats fist list element as a sturt state (assignes it to $_current state).
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* It may be reassigned by setState() call.
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* States list may be empty and can be extended later by addState() or addStates() calls.
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*
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* $inputAphabet is the same as $states, but represents input alphabet
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* it also may be extended later by addInputSymbols() or addInputSymbol() calls.
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*
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* $rules parameter describes FSM transitions and has a structure:
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* array( array(sourseState, input, targetState[, inputAction]),
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* array(sourseState, input, targetState[, inputAction]),
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* array(sourseState, input, targetState[, inputAction]),
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* ...
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* )
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* Rules also can be added later by addRules() and addRule() calls.
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*
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* FSM actions are very flexible and may be defined by addEntryAction(), addExitAction(),
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* addInputAction() and addTransitionAction() calls.
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*
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* @param array $states
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* @param array $inputAphabet
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* @param array $rules
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*/
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public function __construct($states = array(), $inputAphabet = array(), $rules = array())
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{
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$this->addStates($states);
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$this->addInputSymbols($inputAphabet);
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$this->addRules($rules);
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}
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/**
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* Add states to the state machine
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*
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* @param array $states
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*/
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public function addStates($states)
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{
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foreach ($states as $state) {
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$this->addState($state);
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}
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}
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/**
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* Add state to the state machine
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*
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* @param integer|string $state
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*/
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public function addState($state)
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{
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$this->_states[$state] = $state;
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if ($this->_currentState === null) {
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$this->_currentState = $state;
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}
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}
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/**
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* Set FSM state.
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* No any action is invoked
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*
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* @param integer|string $state
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* @throws Zend_Search_Exception
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*/
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public function setState($state)
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{
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if (!isset($this->_states[$state])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('State \'' . $state . '\' is not on of the possible FSM states.');
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}
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$this->_currentState = $state;
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}
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/**
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* Get FSM state.
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*
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* @return integer|string $state|null
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*/
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public function getState()
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{
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return $this->_currentState;
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}
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/**
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* Add symbols to the input alphabet
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*
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* @param array $inputAphabet
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*/
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public function addInputSymbols($inputAphabet)
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{
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foreach ($inputAphabet as $inputSymbol) {
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$this->addInputSymbol($inputSymbol);
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}
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}
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/**
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* Add symbol to the input alphabet
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*
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* @param integer|string $inputSymbol
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*/
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public function addInputSymbol($inputSymbol)
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{
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$this->_inputAphabet[$inputSymbol] = $inputSymbol;
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}
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/**
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* Add transition rules
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*
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* array structure:
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* array( array(sourseState, input, targetState[, inputAction]),
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* array(sourseState, input, targetState[, inputAction]),
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* array(sourseState, input, targetState[, inputAction]),
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* ...
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* )
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*
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* @param array $rules
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*/
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public function addRules($rules)
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{
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foreach ($rules as $rule) {
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$this->addrule($rule[0], $rule[1], $rule[2], isset($rule[3])?$rule[3]:null);
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}
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}
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/**
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* Add symbol to the input alphabet
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*
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* @param integer|string $sourceState
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* @param integer|string $input
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* @param integer|string $targetState
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* @param Zend_Search_Lucene_FSMAction|null $inputAction
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* @throws Zend_Search_Exception
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*/
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public function addRule($sourceState, $input, $targetState, $inputAction = null)
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{
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if (!isset($this->_states[$sourceState])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined source state (' . $sourceState . ').');
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}
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if (!isset($this->_states[$targetState])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined target state (' . $targetState . ').');
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}
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if (!isset($this->_inputAphabet[$input])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined input symbol (' . $input . ').');
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}
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if (!isset($this->_rules[$sourceState])) {
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$this->_rules[$sourceState] = array();
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}
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if (isset($this->_rules[$sourceState][$input])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Rule for {state,input} pair (' . $sourceState . ', '. $input . ') is already defined.');
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}
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$this->_rules[$sourceState][$input] = $targetState;
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if ($inputAction !== null) {
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$this->addInputAction($sourceState, $input, $inputAction);
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}
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}
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/**
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* Add state entry action.
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* Several entry actions are allowed.
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* Action execution order is defined by addEntryAction() calls
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*
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* @param integer|string $state
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* @param Zend_Search_Lucene_FSMAction $action
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*/
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public function addEntryAction($state, Zend_Search_Lucene_FSMAction $action)
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{
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if (!isset($this->_states[$state])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined state (' . $state. ').');
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}
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if (!isset($this->_entryActions[$state])) {
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$this->_entryActions[$state] = array();
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}
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$this->_entryActions[$state][] = $action;
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}
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/**
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* Add state exit action.
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* Several exit actions are allowed.
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* Action execution order is defined by addEntryAction() calls
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*
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* @param integer|string $state
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* @param Zend_Search_Lucene_FSMAction $action
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*/
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public function addExitAction($state, Zend_Search_Lucene_FSMAction $action)
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{
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if (!isset($this->_states[$state])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined state (' . $state. ').');
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}
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if (!isset($this->_exitActions[$state])) {
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$this->_exitActions[$state] = array();
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}
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$this->_exitActions[$state][] = $action;
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}
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/**
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* Add input action (defined by {state, input} pair).
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* Several input actions are allowed.
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* Action execution order is defined by addInputAction() calls
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*
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* @param integer|string $state
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* @param integer|string $input
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* @param Zend_Search_Lucene_FSMAction $action
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*/
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public function addInputAction($state, $inputSymbol, Zend_Search_Lucene_FSMAction $action)
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{
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if (!isset($this->_states[$state])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined state (' . $state. ').');
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}
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if (!isset($this->_inputAphabet[$inputSymbol])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined input symbol (' . $inputSymbol. ').');
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}
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if (!isset($this->_inputActions[$state])) {
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$this->_inputActions[$state] = array();
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}
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if (!isset($this->_inputActions[$state][$inputSymbol])) {
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$this->_inputActions[$state][$inputSymbol] = array();
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}
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$this->_inputActions[$state][$inputSymbol][] = $action;
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}
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/**
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* Add transition action (defined by {state, input} pair).
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* Several transition actions are allowed.
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* Action execution order is defined by addTransitionAction() calls
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*
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* @param integer|string $sourceState
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* @param integer|string $targetState
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* @param Zend_Search_Lucene_FSMAction $action
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*/
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public function addTransitionAction($sourceState, $targetState, Zend_Search_Lucene_FSMAction $action)
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{
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if (!isset($this->_states[$sourceState])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined source state (' . $sourceState. ').');
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}
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if (!isset($this->_states[$targetState])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('Undefined source state (' . $targetState. ').');
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}
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if (!isset($this->_transitionActions[$sourceState])) {
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$this->_transitionActions[$sourceState] = array();
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}
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if (!isset($this->_transitionActions[$sourceState][$targetState])) {
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$this->_transitionActions[$sourceState][$targetState] = array();
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}
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$this->_transitionActions[$sourceState][$targetState][] = $action;
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}
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/**
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* Process an input
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*
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* @param mixed $input
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* @throws Zend_Search_Exception
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*/
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public function process($input)
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{
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if (!isset($this->_rules[$this->_currentState])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('There is no any rule for current state (' . $this->_currentState . ').');
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}
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if (!isset($this->_rules[$this->_currentState][$input])) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('There is no any rule for {current state, input} pair (' . $this->_currentState . ', ' . $input . ').');
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}
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$sourceState = $this->_currentState;
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$targetState = $this->_rules[$this->_currentState][$input];
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if ($sourceState != $targetState && isset($this->_exitActions[$sourceState])) {
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foreach ($this->_exitActions[$sourceState] as $action) {
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$action->doAction();
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}
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}
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if (isset($this->_inputActions[$sourceState]) &&
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isset($this->_inputActions[$sourceState][$input])) {
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foreach ($this->_inputActions[$sourceState][$input] as $action) {
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$action->doAction();
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}
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}
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$this->_currentState = $targetState;
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if (isset($this->_transitionActions[$sourceState]) &&
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isset($this->_transitionActions[$sourceState][$targetState])) {
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foreach ($this->_transitionActions[$sourceState][$targetState] as $action) {
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$action->doAction();
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}
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}
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if ($sourceState != $targetState && isset($this->_entryActions[$targetState])) {
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foreach ($this->_entryActions[$targetState] as $action) {
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$action->doAction();
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}
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}
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}
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public function reset()
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{
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if (count($this->_states) == 0) {
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require_once 'Zend/Search/Exception.php';
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throw new Zend_Search_Exception('There is no any state defined for FSM.');
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}
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$this->_currentState = $this->_states[0];
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}
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}
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