269 lines
9.4 KiB
PHP
269 lines
9.4 KiB
PHP
<?php
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/**
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* PHP_ParserGenerator, a php 5 parser generator.
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*
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* This is a direct port of the Lemon parser generator, found at
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* {@link http://www.hwaci.com/sw/lemon/}
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*
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* PHP version 5
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*
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* LICENSE: This source file is subject to version 3.01 of the PHP license
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* that is available through the world-wide-web at the following URI:
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* http://www.php.net/license/3_01.txt. If you did not receive a copy of
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* the PHP License and are unable to obtain it through the web, please
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* send a note to license@php.net so we can mail you a copy immediately.
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*
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* @category php
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* @package PHP_ParserGenerator
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* @author Gregory Beaver <cellog@php.net>
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* @copyright 2006 Gregory Beaver
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* @license http://www.php.net/license/3_01.txt PHP License 3.01
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* @version CVS: $Id$
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* @since File available since Release 0.1.0
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*/
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/**
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* The state of the yy_action table under construction is an instance of
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* the following structure
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* @package PHP_ParserGenerator
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* @author Gregory Beaver <cellog@php.net>
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* @copyright 2006 Gregory Beaver
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* @license http://www.php.net/license/3_01.txt PHP License 3.01
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* @version 0.1.0
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* @since Class available since Release 0.1.0
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*/
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class PHP_ParserGenerator_ActionTable
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{
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/**
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* Number of used slots in {@link $aAction}
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* @var int
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*/
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public $nAction = 0;
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/**
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* The $yy_action table under construction.
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*
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* Each entry is of format:
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* <code>
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* array(
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* 'lookahead' => -1, // Value of the lookahead token (symbol index)
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* 'action' => -1 // Action to take on the given lookahead (action index)
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* );
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* </code>
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* @see PHP_ParserGenerator_Data::compute_action()
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* @var array
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*/
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public $aAction =
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array(array(
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'lookahead' => -1,
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'action' => -1
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));
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/**
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* A single new transaction set.
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*
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* @see $aAction format of the internal array is described here
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* @var array
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*/
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public $aLookahead =
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array(array(
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'lookahead' => 0,
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'action' => 0
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));
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/**
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* The smallest (minimum) value of any lookahead token in {@link $aLookahead}
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*
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* The lowest non-terminal is always introduced earlier in the parser file,
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* and is therefore a more significant token.
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* @var int
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*/
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public $mnLookahead = 0;
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/**
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* The action associated with the smallest lookahead token.
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* @see $mnLookahead
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* @var int
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*/
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public $mnAction = 0;
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/**
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* The largest (maximum) value of any lookahead token in {@link $aLookahead}
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* @var int
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*/
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public $mxLookahead = 0;
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/**
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* The number of slots used in {@link $aLookahead}.
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*
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* This is the same as count($aLookahead), but there was no pressing reason
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* to change this when porting from C.
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* @see $mnLookahead
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* @var int
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*/
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public $nLookahead = 0;
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/**
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* Add a new action to the current transaction set
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* @param int
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* @param int
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*/
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function acttab_action($lookahead, $action)
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{
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if ($this->nLookahead === 0) {
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$this->aLookahead = array();
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$this->mxLookahead = $lookahead;
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$this->mnLookahead = $lookahead;
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$this->mnAction = $action;
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} else {
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if ($this->mxLookahead < $lookahead) {
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$this->mxLookahead = $lookahead;
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}
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if ($this->mnLookahead > $lookahead) {
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$this->mnLookahead = $lookahead;
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$this->mnAction = $action;
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}
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}
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$this->aLookahead[$this->nLookahead] = array(
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'lookahead' => $lookahead,
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'action' => $action);
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$this->nLookahead++;
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}
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/**
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* Add the transaction set built up with prior calls to acttab_action()
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* into the current action table. Then reset the transaction set back
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* to an empty set in preparation for a new round of acttab_action() calls.
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*
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* Return the offset into the action table of the new transaction.
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* @return int Return the offset that should be added to the lookahead in
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* order to get the index into $yy_action of the action. This will be used
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* in generation of $yy_ofst tables (reduce and shift)
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* @throws Exception
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*/
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function acttab_insert()
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{
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if ($this->nLookahead <= 0) {
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throw new Exception('nLookahead is not set up?');
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}
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/* Scan the existing action table looking for an offset where we can
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** insert the current transaction set. Fall out of the loop when that
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** offset is found. In the worst case, we fall out of the loop when
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** i reaches $this->nAction, which means we append the new transaction set.
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**
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** i is the index in $this->aAction[] where $this->mnLookahead is inserted.
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*/
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for ($i = 0; $i < $this->nAction + $this->mnLookahead; $i++) {
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if (!isset($this->aAction[$i])) {
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$this->aAction[$i] = array(
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'lookahead' => -1,
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'action' => -1,
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);
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}
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if ($this->aAction[$i]['lookahead'] < 0) {
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for ($j = 0; $j < $this->nLookahead; $j++) {
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if (!isset($this->aLookahead[$j])) {
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$this->aLookahead[$j] = array(
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'lookahead' => 0,
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'action' => 0,
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);
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}
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$k = $this->aLookahead[$j]['lookahead'] -
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$this->mnLookahead + $i;
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if ($k < 0) {
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break;
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}
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if (!isset($this->aAction[$k])) {
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$this->aAction[$k] = array(
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'lookahead' => -1,
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'action' => -1,
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);
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}
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if ($this->aAction[$k]['lookahead'] >= 0) {
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break;
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}
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}
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if ($j < $this->nLookahead ) {
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continue;
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}
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for ($j = 0; $j < $this->nAction; $j++) {
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if (!isset($this->aAction[$j])) {
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$this->aAction[$j] = array(
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'lookahead' => -1,
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'action' => -1,
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);
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}
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if ($this->aAction[$j]['lookahead'] == $j +
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$this->mnLookahead - $i) {
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break;
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}
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}
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if ($j == $this->nAction) {
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break; /* Fits in empty slots */
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}
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} elseif ($this->aAction[$i]['lookahead'] == $this->mnLookahead) {
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if ($this->aAction[$i]['action'] != $this->mnAction) {
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continue;
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}
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for ($j = 0; $j < $this->nLookahead; $j++) {
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$k = $this->aLookahead[$j]['lookahead'] -
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$this->mnLookahead + $i;
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if ($k < 0 || $k >= $this->nAction) {
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break;
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}
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if (!isset($this->aAction[$k])) {
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$this->aAction[$k] = array(
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'lookahead' => -1,
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'action' => -1,
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);
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}
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if ($this->aLookahead[$j]['lookahead'] !=
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$this->aAction[$k]['lookahead']) {
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break;
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}
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if ($this->aLookahead[$j]['action'] !=
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$this->aAction[$k]['action']) {
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break;
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}
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}
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if ($j < $this->nLookahead) {
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continue;
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}
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$n = 0;
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for ($j = 0; $j < $this->nAction; $j++) {
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if (!isset($this->aAction[$j])) {
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$this->aAction[$j] = array(
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'lookahead' => -1,
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'action' => -1,
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);
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}
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if ($this->aAction[$j]['lookahead'] < 0) {
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continue;
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}
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if ($this->aAction[$j]['lookahead'] == $j +
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$this->mnLookahead - $i) {
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$n++;
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}
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}
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if ($n == $this->nLookahead) {
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break; /* Same as a prior transaction set */
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}
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}
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}
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/* Insert transaction set at index i. */
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for ($j = 0; $j < $this->nLookahead; $j++) {
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if (!isset($this->aLookahead[$j])) {
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$this->aLookahead[$j] = array(
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'lookahead' => 0,
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'action' => 0,
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);
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}
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$k = $this->aLookahead[$j]['lookahead'] - $this->mnLookahead + $i;
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$this->aAction[$k] = $this->aLookahead[$j];
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if ($k >= $this->nAction) {
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$this->nAction = $k + 1;
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}
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}
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$this->nLookahead = 0;
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$this->aLookahead = array();
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/* Return the offset that is added to the lookahead in order to get the
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** index into yy_action of the action */
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return $i - $this->mnLookahead;
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}
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}
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?>
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