587 lines
18 KiB
PHP
587 lines
18 KiB
PHP
<?php
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/*
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* This file is part of the JShrink package.
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*
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* (c) Robert Hafner <tedivm@tedivm.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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/**
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* JShrink
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*
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*
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* @package JShrink
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* @author Robert Hafner <tedivm@tedivm.com>
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*/
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namespace JShrink;
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/**
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* Minifier
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*
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* Usage - Minifier::minify($js);
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* Usage - Minifier::minify($js, $options);
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* Usage - Minifier::minify($js, array('flaggedComments' => false));
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*
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* @package JShrink
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* @author Robert Hafner <tedivm@tedivm.com>
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* @license http://www.opensource.org/licenses/bsd-license.php BSD License
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*/
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class Minifier
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{
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/**
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* The input javascript to be minified.
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*
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* @var string
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*/
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protected $input;
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/**
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* The location of the character (in the input string) that is next to be
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* processed.
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*
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* @var int
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*/
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protected $index = 0;
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/**
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* The first of the characters currently being looked at.
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*
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* @var string
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*/
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protected $a = '';
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/**
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* The next character being looked at (after a);
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*
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* @var string
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*/
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protected $b = '';
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/**
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* This character is only active when certain look ahead actions take place.
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*
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* @var string
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*/
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protected $c;
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/**
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* Contains the options for the current minification process.
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*
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* @var array
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*/
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protected $options;
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/**
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* Contains the default options for minification. This array is merged with
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* the one passed in by the user to create the request specific set of
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* options (stored in the $options attribute).
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*
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* @var array
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*/
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protected static $defaultOptions = array('flaggedComments' => true);
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/**
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* Contains lock ids which are used to replace certain code patterns and
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* prevent them from being minified
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*
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* @var array
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*/
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protected $locks = array();
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/**
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* Takes a string containing javascript and removes unneeded characters in
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* order to shrink the code without altering it's functionality.
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*
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* @param string $js The raw javascript to be minified
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* @param array $options Various runtime options in an associative array
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* @throws \Exception
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* @return bool|string
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*/
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public static function minify($js, $options = array())
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{
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try {
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ob_start();
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$jshrink = new Minifier();
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$js = $jshrink->lock($js);
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$jshrink->minifyDirectToOutput($js, $options);
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// Sometimes there's a leading new line, so we trim that out here.
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$js = ltrim(ob_get_clean());
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$js = $jshrink->unlock($js);
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unset($jshrink);
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return $js;
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} catch (\Exception $e) {
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if (isset($jshrink)) {
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// Since the breakdownScript function probably wasn't finished
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// we clean it out before discarding it.
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$jshrink->clean();
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unset($jshrink);
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}
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// without this call things get weird, with partially outputted js.
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ob_end_clean();
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throw $e;
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}
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}
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/**
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* Processes a javascript string and outputs only the required characters,
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* stripping out all unneeded characters.
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*
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* @param string $js The raw javascript to be minified
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* @param array $options Various runtime options in an associative array
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*/
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protected function minifyDirectToOutput($js, $options)
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{
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$this->initialize($js, $options);
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$this->loop();
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$this->clean();
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}
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/**
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* Initializes internal variables, normalizes new lines,
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*
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* @param string $js The raw javascript to be minified
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* @param array $options Various runtime options in an associative array
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*/
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protected function initialize($js, $options)
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{
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$this->options = array_merge(static::$defaultOptions, $options);
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$js = str_replace("\r\n", "\n", $js);
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$js = str_replace('/**/', '', $js);
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$this->input = str_replace("\r", "\n", $js);
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// We add a newline to the end of the script to make it easier to deal
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// with comments at the bottom of the script- this prevents the unclosed
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// comment error that can otherwise occur.
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$this->input .= PHP_EOL;
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// Populate "a" with a new line, "b" with the first character, before
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// entering the loop
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$this->a = "\n";
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$this->b = $this->getReal();
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}
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/**
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* The primary action occurs here. This function loops through the input string,
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* outputting anything that's relevant and discarding anything that is not.
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*/
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protected function loop()
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{
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while ($this->a !== false && !is_null($this->a) && $this->a !== '') {
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switch ($this->a) {
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// new lines
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case "\n":
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// if the next line is something that can't stand alone preserve the newline
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if (strpos('(-+{[@', $this->b) !== false) {
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echo $this->a;
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$this->saveString();
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break;
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}
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// if B is a space we skip the rest of the switch block and go down to the
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// string/regex check below, resetting $this->b with getReal
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if($this->b === ' ')
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break;
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// otherwise we treat the newline like a space
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case ' ':
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if(static::isAlphaNumeric($this->b))
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echo $this->a;
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$this->saveString();
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break;
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default:
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switch ($this->b) {
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case "\n":
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if (strpos('}])+-"\'', $this->a) !== false) {
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echo $this->a;
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$this->saveString();
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break;
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} else {
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if (static::isAlphaNumeric($this->a)) {
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echo $this->a;
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$this->saveString();
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}
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}
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break;
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case ' ':
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if(!static::isAlphaNumeric($this->a))
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break;
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default:
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// check for some regex that breaks stuff
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if ($this->a === '/' && ($this->b === '\'' || $this->b === '"')) {
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$this->saveRegex();
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continue;
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}
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echo $this->a;
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$this->saveString();
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break;
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}
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}
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// do reg check of doom
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$this->b = $this->getReal();
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if(($this->b == '/' && strpos('(,=:[!&|?', $this->a) !== false))
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$this->saveRegex();
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}
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}
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/**
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* Resets attributes that do not need to be stored between requests so that
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* the next request is ready to go. Another reason for this is to make sure
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* the variables are cleared and are not taking up memory.
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*/
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protected function clean()
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{
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unset($this->input);
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$this->index = 0;
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$this->a = $this->b = '';
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unset($this->c);
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unset($this->options);
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}
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/**
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* Returns the next string for processing based off of the current index.
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*
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* @return string
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*/
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protected function getChar()
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{
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// Check to see if we had anything in the look ahead buffer and use that.
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if (isset($this->c)) {
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$char = $this->c;
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unset($this->c);
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// Otherwise we start pulling from the input.
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} else {
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$char = substr($this->input, $this->index, 1);
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// If the next character doesn't exist return false.
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if (isset($char) && $char === false) {
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return false;
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}
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// Otherwise increment the pointer and use this char.
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$this->index++;
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}
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// Normalize all whitespace except for the newline character into a
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// standard space.
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if($char !== "\n" && ord($char) < 32)
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return ' ';
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return $char;
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}
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/**
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* This function gets the next "real" character. It is essentially a wrapper
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* around the getChar function that skips comments. This has significant
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* performance benefits as the skipping is done using native functions (ie,
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* c code) rather than in script php.
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*
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*
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* @return string Next 'real' character to be processed.
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* @throws \RuntimeException
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*/
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protected function getReal()
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{
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$startIndex = $this->index;
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$char = $this->getChar();
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// Check to see if we're potentially in a comment
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if ($char !== '/') {
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return $char;
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}
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$this->c = $this->getChar();
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if ($this->c === '/') {
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return $this->processOneLineComments($startIndex);
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} elseif ($this->c === '*') {
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return $this->processMultiLineComments($startIndex);
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}
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return $char;
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}
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/**
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* Removed one line comments, with the exception of some very specific types of
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* conditional comments.
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*
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* @param int $startIndex The index point where "getReal" function started
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* @return string
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*/
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protected function processOneLineComments($startIndex)
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{
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$thirdCommentString = substr($this->input, $this->index, 1);
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// kill rest of line
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$this->getNext("\n");
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if ($thirdCommentString == '@') {
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$endPoint = $this->index - $startIndex;
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unset($this->c);
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$char = "\n" . substr($this->input, $startIndex, $endPoint);
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} else {
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// first one is contents of $this->c
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$this->getChar();
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$char = $this->getChar();
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}
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return $char;
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}
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/**
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* Skips multiline comments where appropriate, and includes them where needed.
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* Conditional comments and "license" style blocks are preserved.
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*
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* @param int $startIndex The index point where "getReal" function started
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* @return bool|string False if there's no character
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* @throws \RuntimeException Unclosed comments will throw an error
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*/
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protected function processMultiLineComments($startIndex)
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{
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$this->getChar(); // current C
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$thirdCommentString = $this->getChar();
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// kill everything up to the next */ if it's there
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if ($this->getNext('*/')) {
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$this->getChar(); // get *
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$this->getChar(); // get /
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$char = $this->getChar(); // get next real character
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// Now we reinsert conditional comments and YUI-style licensing comments
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if (($this->options['flaggedComments'] && $thirdCommentString === '!')
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|| ($thirdCommentString === '@') ) {
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// If conditional comments or flagged comments are not the first thing in the script
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// we need to echo a and fill it with a space before moving on.
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if ($startIndex > 0) {
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echo $this->a;
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$this->a = " ";
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// If the comment started on a new line we let it stay on the new line
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if ($this->input[($startIndex - 1)] === "\n") {
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echo "\n";
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}
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}
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$endPoint = ($this->index - 1) - $startIndex;
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echo substr($this->input, $startIndex, $endPoint);
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return $char;
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}
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} else {
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$char = false;
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}
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if($char === false)
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throw new \RuntimeException('Unclosed multiline comment at position: ' . ($this->index - 2));
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// if we're here c is part of the comment and therefore tossed
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if(isset($this->c))
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unset($this->c);
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return $char;
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}
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/**
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* Pushes the index ahead to the next instance of the supplied string. If it
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* is found the first character of the string is returned and the index is set
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* to it's position.
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*
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* @param string $string
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* @return string|false Returns the first character of the string or false.
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*/
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protected function getNext($string)
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{
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// Find the next occurrence of "string" after the current position.
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$pos = strpos($this->input, $string, $this->index);
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// If it's not there return false.
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if($pos === false)
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return false;
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// Adjust position of index to jump ahead to the asked for string
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$this->index = $pos;
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// Return the first character of that string.
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return substr($this->input, $this->index, 1);
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}
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/**
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* When a javascript string is detected this function crawls for the end of
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* it and saves the whole string.
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*
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* @throws \RuntimeException Unclosed strings will throw an error
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*/
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protected function saveString()
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{
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$startpos = $this->index;
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// saveString is always called after a gets cleared, so we push b into
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// that spot.
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$this->a = $this->b;
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// If this isn't a string we don't need to do anything.
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if ($this->a !== "'" && $this->a !== '"') {
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return;
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}
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// String type is the quote used, " or '
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$stringType = $this->a;
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// Echo out that starting quote
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echo $this->a;
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// Loop until the string is done
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while (true) {
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// Grab the very next character and load it into a
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$this->a = $this->getChar();
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switch ($this->a) {
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// If the string opener (single or double quote) is used
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// output it and break out of the while loop-
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// The string is finished!
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case $stringType:
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break 2;
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// New lines in strings without line delimiters are bad- actual
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// new lines will be represented by the string \n and not the actual
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// character, so those will be treated just fine using the switch
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// block below.
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case "\n":
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throw new \RuntimeException('Unclosed string at position: ' . $startpos );
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break;
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// Escaped characters get picked up here. If it's an escaped new line it's not really needed
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case '\\':
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// a is a slash. We want to keep it, and the next character,
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// unless it's a new line. New lines as actual strings will be
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// preserved, but escaped new lines should be reduced.
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$this->b = $this->getChar();
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// If b is a new line we discard a and b and restart the loop.
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if ($this->b === "\n") {
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break;
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}
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// echo out the escaped character and restart the loop.
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echo $this->a . $this->b;
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break;
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// Since we're not dealing with any special cases we simply
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// output the character and continue our loop.
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default:
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echo $this->a;
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}
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}
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}
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/**
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* When a regular expression is detected this function crawls for the end of
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* it and saves the whole regex.
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*
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* @throws \RuntimeException Unclosed regex will throw an error
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*/
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protected function saveRegex()
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{
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echo $this->a . $this->b;
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while (($this->a = $this->getChar()) !== false) {
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if($this->a === '/')
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break;
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if ($this->a === '\\') {
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echo $this->a;
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$this->a = $this->getChar();
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}
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if($this->a === "\n")
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throw new \RuntimeException('Unclosed regex pattern at position: ' . $this->index);
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echo $this->a;
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}
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$this->b = $this->getReal();
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}
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/**
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* Checks to see if a character is alphanumeric.
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*
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* @param string $char Just one character
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* @return bool
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*/
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protected static function isAlphaNumeric($char)
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{
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return preg_match('/^[\w\$\pL]$/', $char) === 1 || $char == '/';
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}
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/**
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* Replace patterns in the given string and store the replacement
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*
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* @param string $js The string to lock
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* @return bool
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*/
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protected function lock($js)
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{
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/* lock things like <code>"asd" + ++x;</code> */
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$lock = '"LOCK---' . crc32(time()) . '"';
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$matches = array();
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preg_match('/([+-])(\s+)([+-])/S', $js, $matches);
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if (empty($matches)) {
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return $js;
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}
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$this->locks[$lock] = $matches[2];
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$js = preg_replace('/([+-])\s+([+-])/S', "$1{$lock}$2", $js);
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/* -- */
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return $js;
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}
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/**
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* Replace "locks" with the original characters
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*
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* @param string $js The string to unlock
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* @return bool
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*/
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protected function unlock($js)
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{
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if (empty($this->locks)) {
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return $js;
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}
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foreach ($this->locks as $lock => $replacement) {
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$js = str_replace($lock, $replacement, $js);
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}
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return $js;
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}
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}
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