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<?php
/**
* PHP_ParserGenerator, a php 5 parser generator.
*
* This is a direct port of the Lemon parser generator, found at
* {@link http://www.hwaci.com/sw/lemon/}
*
* PHP version 5
*
* LICENSE: This source file is subject to version 3.01 of the PHP license
* that is available through the world-wide-web at the following URI:
* http://www.php.net/license/3_01.txt. If you did not receive a copy of
* the PHP License and are unable to obtain it through the web, please
* send a note to license@php.net so we can mail you a copy immediately.
*
* @category php
* @package PHP_ParserGenerator
* @author Gregory Beaver <cellog@php.net>
* @copyright 2006 Gregory Beaver
* @license http://www.php.net/license/3_01.txt PHP License 3.01
* @version CVS: $Id$
* @since File available since Release 0.1.0
*/
/**
* The structure used to represent a state in the associative array
* for a PHP_ParserGenerator_Config.
* @package PHP_ParserGenerator
* @author Gregory Beaver <cellog@php.net>
* @copyright 2006 Gregory Beaver
* @license http://www.php.net/license/3_01.txt PHP License 3.01
* @version 0.1.0
* @since Class available since Release 0.1.0
*/
class PHP_ParserGenerator_StateNode
{
public $key;
public $data;
public $from = 0;
public $next = 0;
}
/**
* Each state of the generated parser's finite state machine
* is encoded as an instance of this class
*
* @package PHP_ParserGenerator
* @author Gregory Beaver <cellog@php.net>
* @copyright 2006 Gregory Beaver
* @license http://www.php.net/license/3_01.txt PHP License 3.01
* @version 0.1.0
* @since Class available since Release 0.1.0
*/
class PHP_ParserGenerator_State {
/**
* The basis configurations for this state
* @var PHP_ParserGenerator_Config
*/
public $bp;
/**
* All configurations in this state
* @var PHP_ParserGenerator_Config
*/
public $cfp;
/**
* Sequential number for this state
*
* @var int
*/
public $statenum;
/**
* Linked list of actions for this state.
* @var PHP_ParserGenerator_Action
*/
public $ap;
/**
* Number of terminal (token) actions
*
* @var int
*/
public $nTknAct,
/**
* Number of non-terminal actions
*
* @var int
*/
$nNtAct;
/**
* The offset into the $yy_action table for terminal tokens.
*
* @var int
*/
public $iTknOfst,
/**
* The offset into the $yy_action table for non-terminals.
*
* @var int
*/
$iNtOfst;
/**
* Default action
*
* @var int
*/
public $iDflt;
/**
* Associative array of PHP_ParserGenerator_State objects
*
* @var array
*/
public static $x3a = array();
/**
* Array of PHP_ParserGenerator_State objects
*
* @var array
*/
public static $states = array();
/**
* Compare two states for sorting purposes. The smaller state is the
* one with the most non-terminal actions. If they have the same number
* of non-terminal actions, then the smaller is the one with the most
* token actions.
*/
static function stateResortCompare($a, $b)
{
$n = $b->nNtAct - $a->nNtAct;
if ($n === 0) {
$n = $b->nTknAct - $a->nTknAct;
}
return $n;
}
/**
* Compare two states based on their configurations
*
* @param PHP_ParserGenerator_Config|0 $a
* @param PHP_ParserGenerator_Config|0 $b
* @return int
*/
static function statecmp($a, $b)
{
for ($rc = 0; $rc == 0 && $a && $b; $a = $a->bp, $b = $b->bp) {
$rc = $a->rp->index - $b->rp->index;
if ($rc === 0) {
$rc = $a->dot - $b->dot;
}
}
if ($rc == 0) {
if ($a) {
$rc = 1;
}
if ($b) {
$rc = -1;
}
}
return $rc;
}
/**
* Hash a state based on its configuration
* @return int
*/
private static function statehash(PHP_ParserGenerator_Config $a)
{
$h = 0;
while ($a) {
$h = $h * 571 + $a->rp->index * 37 + $a->dot;
$a = $a->bp;
}
return (int) $h;
}
/**
* Return a pointer to data assigned to the given key. Return NULL
* if no such key.
* @param PHP_ParserGenerator_Config
* @return null|PHP_ParserGenerator_State
*/
static function State_find(PHP_ParserGenerator_Config $key)
{
if (!count(self::$x3a)) {
return 0;
}
$h = self::statehash($key);
if (!isset(self::$x3a[$h])) {
return 0;
}
$np = self::$x3a[$h];
while ($np) {
if (self::statecmp($np->key, $key) == 0) {
break;
}
$np = $np->next;
}
return $np ? $np->data : 0;
}
/**
* Insert a new record into the array. Return TRUE if successful.
* Prior data with the same key is NOT overwritten
*
* @param PHP_ParserGenerator_State $state
* @param PHP_ParserGenerator_Config $key
* @return unknown
*/
static function State_insert(PHP_ParserGenerator_State $state,
PHP_ParserGenerator_Config $key)
{
$h = self::statehash($key);
if (isset(self::$x3a[$h])) {
$np = self::$x3a[$h];
} else {
$np = 0;
}
while ($np) {
if (self::statecmp($np->key, $key) == 0) {
/* An existing entry with the same key is found. */
/* Fail because overwrite is not allows. */
return 0;
}
$np = $np->next;
}
/* Insert the new data */
$np = new PHP_ParserGenerator_StateNode;
$np->key = $key;
$np->data = $state;
self::$states[] = $np;
// the original lemon code sets the from link always to itself
// setting up a faulty double-linked list
// however, the from links are never used, so I suspect a copy/paste
// error from a standard algorithm that was never caught
if (isset(self::$x3a[$h])) {
self::$x3a[$h]->from = $np; // lemon has $np->next here
} else {
self::$x3a[$h] = 0; // dummy to avoid notice
}
$np->next = self::$x3a[$h];
self::$x3a[$h] = $np;
$np->from = self::$x3a[$h];
return 1;
}
/**
* Get an array indexed by state number
*
* @return array
*/
static function State_arrayof()
{
return self::$states;
}
}