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<?php

/* 25 October 2011. version 1.1-FF4

 *

 * This is the php version of the Dean Edwards JavaScript's Packer,

 * Based on :

 *

 * ParseMaster, version 1.0.2 (2005-08-19) Copyright 2005, Dean Edwards

 * a multi-pattern parser.

 * KNOWN BUG: erroneous behavior when using escapeChar with a replacement

 * value that is a function

 *

 * packer, version 2.0.2 (2005-08-19) Copyright 2004-2005, Dean Edwards

 *

 * License: http://creativecommons.org/licenses/LGPL/2.1/

 *

 * Ported to PHP by Nicolas Martin.

 *

 * ----------------------------------------------------------------------

 * changelog:

 * 1.1 : correct a bug, '\0' packed then unpacked becomes '\'.

 * 1.1-FF4 : Firefox 4 fix, Copyright 2011, Mieczyslaw Nalewaj

 * ----------------------------------------------------------------------

 *

 * examples of usage :

 * $myPacker = new JavaScriptPacker($script, 62, true, false);

 * $packed = $myPacker->pack();

 *

 * or

 *

 * $myPacker = new JavaScriptPacker($script, 'Normal', true, false);

 * $packed = $myPacker->pack();

 *

 * or (default values)

 *

 * $myPacker = new JavaScriptPacker($script);

 * $packed = $myPacker->pack();

 *

 *

 * params of the constructor :

 * $script:       the JavaScript to pack, string.

 * $encoding:     level of encoding, int or string :

 *                0,10,62,95 or 'None', 'Numeric', 'Normal', 'High ASCII'.

 *                default: 62.

 * $fastDecode:   include the fast decoder in the packed result, boolean.

 *                default : true.

 * $specialChars: if you are flagged your private and local variables

 *                in the script, boolean.

 *                default: false.

 *

 * The pack() method return the compressed JavasScript, as a string.

 *

 * see http://dean.edwards.name/packer/usage/ for more information.

 *

 * Notes :

 * # need PHP 5 . Tested with PHP 5.1.2, 5.1.3, 5.1.4, 5.2.3

 *

 * # The packed result may be different than with the Dean Edwards

 *   version, but with the same length. The reason is that the PHP

 *   function usort to sort array don't necessarily preserve the

 *   original order of two equal member. The Javascript sort function

 *   in fact preserve this order (but that's not require by the

 *   ECMAScript standard). So the encoded keywords order can be

 *   different in the two results.

 *

 * # Be careful with the 'High ASCII' Level encoding if you use

 *   UTF-8 in your files...

 */

class JavaScriptPacker

{

    // constants

    const IGNORE = '$1';

    // validate parameters

    private $_script = '';

    private $_encoding = 62;

    private $_fastDecode = true;

    private $_specialChars = false;

    private $LITERAL_ENCODING = array(

        'None' => 0,

        'Numeric' => 10,

        'Normal' => 62,

        'High ASCII' => 95

    );

    public function __construct($_script, $_encoding = 62, $_fastDecode = true, $_specialChars = false)

    {

        $this->_script = $_script . "\n";

        if (array_key_exists($_encoding, $this->LITERAL_ENCODING))

            $_encoding = $this->LITERAL_ENCODING[$_encoding];

        $this->_encoding = min((int) $_encoding, 95);

        $this->_fastDecode = $_fastDecode;

        $this->_specialChars = $_specialChars;

    }

    public function pack()

    {

        $this->_addParser('_basicCompression');

        if ($this->_specialChars)

            $this->_addParser('_encodeSpecialChars');

        if ($this->_encoding)

            $this->_addParser('_encodeKeywords');

        // go!

        return $this->_pack($this->_script);

    }

    // apply all parsing routines

    private function _pack($script)

    {

        for ($i = 0; isset($this->_parsers[$i]); $i++) {

            $script = call_user_func(array(&$this, $this->_parsers[$i]), $script);

        }

        return $script;

    }

    // keep a list of parsing functions, they'll be executed all at once

    private $_parsers = array();

    private function _addParser($parser)

    {

        $this->_parsers[] = $parser;

    }

    // zero encoding - just removal of white space and comments

    private function _basicCompression($script)

    {

        $parser = new ParseMaster();

        // make safe

        $parser->escapeChar = '\\';

        // protect strings

        $parser->add('/\'[^\'\\n\\r]*\'/', self::IGNORE);

        $parser->add('/"[^"\\n\\r]*"/', self::IGNORE);

        // remove comments

        $parser->add('/\\/\\/[^\\n\\r]*[\\n\\r]/', ' ');

        $parser->add('/\\/\\*[^*]*\\*+([^\\/][^*]*\\*+)*\\//', ' ');

        // protect regular expressions

        $parser->add('/\\s+(\\/[^\\/\\n\\r\\*][^\\/\\n\\r]*\\/g?i?)/', '$2'); // IGNORE

        $parser->add('/[^\\w\\x24\\/\'"*)\\?:]\\/[^\\/\\n\\r\\*][^\\/\\n\\r]*\\/g?i?/', self::IGNORE);

        // remove: ;;; doSomething();

        if ($this->_specialChars) $parser->add('/;;;[^\\n\\r]+[\\n\\r]/');

        // remove redundant semi-colons

        $parser->add('/\\(;;\\)/', self::IGNORE); // protect for (;;) loops

        $parser->add('/;+\\s*([};])/', '$2');

        // apply the above

        $script = $parser->exec($script);

        // remove white-space

        $parser->add('/(\\b|\\x24)\\s+(\\b|\\x24)/', '$2 $3');

        $parser->add('/([+\\-])\\s+([+\\-])/', '$2 $3');

        $parser->add('/\\s+/', '');

        // done

        return $parser->exec($script);

    }

    private function _encodeSpecialChars($script)

    {

        $parser = new ParseMaster();

        // replace: $name -> n, $$name -> na

        $parser->add('/((\\x24+)([a-zA-Z$_]+))(\\d*)/',

                     array('fn' => '_replace_name')

        );

        // replace: _name -> _0, double-underscore (__name) is ignored

        $regexp = '/\\b_[A-Za-z\\d]\\w*/';

        // build the word list

        $keywords = $this->_analyze($script, $regexp, '_encodePrivate');

        // quick ref

        $encoded = $keywords['encoded'];

        $parser->add($regexp,

            array(

                'fn' => '_replace_encoded',

                'data' => $encoded

            )

        );

        return $parser->exec($script);

    }

    private function _encodeKeywords($script)

    {

        // escape high-ascii values already in the script (i.e. in strings)

        if ($this->_encoding > 62)

            $script = $this->_escape95($script);

        // create the parser

        $parser = new ParseMaster();

        $encode = $this->_getEncoder($this->_encoding);

        // for high-ascii, don't encode single character low-ascii

        $regexp = ($this->_encoding > 62) ? '/\\w\\w+/' : '/\\w+/';

        // build the word list

        $keywords = $this->_analyze($script, $regexp, $encode);

        $encoded = $keywords['encoded'];

        // encode

        $parser->add($regexp,

            array(

                'fn' => '_replace_encoded',

                'data' => $encoded

            )

        );

        if (empty($script)) return $script;

        else {

            //$res = $parser->exec($script);

            //$res = $this->_bootStrap($res, $keywords);

            //return $res;

            return $this->_bootStrap($parser->exec($script), $keywords);

        }

    }

    private function _analyze($script, $regexp, $encode)

    {

        // analyse

        // retreive all words in the script

        $all = array();

        preg_match_all($regexp, $script, $all);

        $_sorted = array(); // list of words sorted by frequency

        $_encoded = array(); // dictionary of word->encoding

        $_protected = array(); // instances of "protected" words

        $all = $all[0]; // simulate the javascript comportement of global match

        if (!empty($all)) {

            $unsorted = array(); // same list, not sorted

            $protected = array(); // "protected" words (dictionary of word->"word")

            $value = array(); // dictionary of charCode->encoding (eg. 256->ff)

            $this->_count = array(); // word->count

            $i = count($all); $j = 0; //$word = null;

            // count the occurrences - used for sorting later

            do {

                --$i;

                $word = '$' . $all[$i];

                if (!isset($this->_count[$word])) {

                    $this->_count[$word] = 0;

                    $unsorted[$j] = $word;

                    // make a dictionary of all of the protected words in this script

                    //  these are words that might be mistaken for encoding

                    //if (is_string($encode) && method_exists($this, $encode))

                    $values[$j] = call_user_func(array(&$this, $encode), $j);

                    $protected['$' . $values[$j]] = $j++;

                }

                // increment the word counter

                $this->_count[$word]++;

            } while ($i > 0);

            // prepare to sort the word list, first we must protect

            //  words that are also used as codes. we assign them a code

            //  equivalent to the word itself.

            // e.g. if "do" falls within our encoding range

            //      then we store keywords["do"] = "do";

            // this avoids problems when decoding

            $i = count($unsorted);

            do {

                $word = $unsorted[--$i];

                if (isset($protected[$word]) /*!= null*/) {

                    $_sorted[$protected[$word]] = substr($word, 1);

                    $_protected[$protected[$word]] = true;

                    $this->_count[$word] = 0;

                }

            } while ($i);

            // sort the words by frequency

            // Note: the javascript and php version of sort can be different :

            // in php manual, usort :

            // " If two members compare as equal,

            // their order in the sorted array is undefined."

            // so the final packed script is different of the Dean's javascript version

            // but equivalent.

            // the ECMAscript standard does not guarantee this behaviour,

            // and thus not all browsers (e.g. Mozilla versions dating back to at

            // least 2003) respect this.

            usort($unsorted, array(&$this, '_sortWords'));

            $j = 0;

            // because there are "protected" words in the list

            //  we must add the sorted words around them

            do {

                if (!isset($_sorted[$i]))

                    $_sorted[$i] = substr($unsorted[$j++], 1);

                $_encoded[$_sorted[$i]] = $values[$i];

            } while (++$i < count($unsorted));

        }

        return array(

            'sorted'  => $_sorted,

            'encoded' => $_encoded,

            'protected' => $_protected);

    }

    private $_count = array();

    private function _sortWords($match1, $match2)

    {

        return $this->_count[$match2] - $this->_count[$match1];

    }

    // build the boot function used for loading and decoding

    private function _bootStrap($packed, $keywords)

    {

        $ENCODE = $this->_safeRegExp('$encode\\($count\\)');

        // $packed: the packed script

        $packed = "'" . $this->_escape($packed) . "'";

        // $ascii: base for encoding

        $ascii = min(count($keywords['sorted']), $this->_encoding);

        if ($ascii == 0) $ascii = 1;

        // $count: number of words contained in the script

        $count = count($keywords['sorted']);

        // $keywords: list of words contained in the script

        foreach ($keywords['protected'] as $i=>$value) {

            $keywords['sorted'][$i] = '';

        }

        // convert from a string to an array

        ksort($keywords['sorted']);

        $keywords = "'" . implode('|', $keywords['sorted']) . "'.split('|')";

        $encode = ($this->_encoding > 62) ? '_encode95' : $this->_getEncoder($ascii);

        $encode = $this->_getJSFunction($encode);

        $encode = preg_replace('/_encoding/', '$ascii', $encode);

        $encode = preg_replace('/arguments\\.callee/', '$encode', $encode);

        $inline = '\\$count' . ($ascii > 10 ? '.toString(\\$ascii)' : '');

        // $decode: code snippet to speed up decoding

        if ($this->_fastDecode) {

            // create the decoder

            $decode = $this->_getJSFunction('_decodeBody');

            if ($this->_encoding > 62)

                $decode = preg_replace('/\\\\w/', '[\\xa1-\\xff]', $decode);

            // perform the encoding inline for lower ascii values

            elseif ($ascii < 36)

                $decode = preg_replace($ENCODE, $inline, $decode);

            // special case: when $count==0 there are no keywords. I want to keep

            //  the basic shape of the unpacking funcion so i'll frig the code...

            if ($count == 0)

                $decode = preg_replace($this->_safeRegExp('($count)\\s*=\\s*1'), '$1=0', $decode, 1);

        }

        // boot function

        $unpack = $this->_getJSFunction('_unpack');

        if ($this->_fastDecode) {

            // insert the decoder

            $this->buffer = $decode;

            $unpack = preg_replace_callback('/\\{/', array(&$this, '_insertFastDecode'), $unpack, 1);

        }

        $unpack = preg_replace('/"/', "'", $unpack);

        if ($this->_encoding > 62) { // high-ascii

            // get rid of the word-boundaries for regexp matches

            $unpack = preg_replace('/\'\\\\\\\\b\'\s*\\+|\\+\s*\'\\\\\\\\b\'/', '', $unpack);

        }

        if ($ascii > 36 || $this->_encoding > 62 || $this->_fastDecode) {

            // insert the encode function

            $this->buffer = $encode;

            $unpack = preg_replace_callback('/\\{/', array(&$this, '_insertFastEncode'), $unpack, 1);

        } else {

            // perform the encoding inline

            $unpack = preg_replace($ENCODE, $inline, $unpack);

        }

        // pack the boot function too

        $unpackPacker = new JavaScriptPacker($unpack, 0, false, true);

        $unpack = $unpackPacker->pack();

        // arguments

        $params = array($packed, $ascii, $count, $keywords);

        if ($this->_fastDecode) {

            $params[] = 0;

            $params[] = '{}';

        }

        $params = implode(',', $params);

        // the whole thing

        //Firefox 4 fix, old: return 'eval(' . $unpack . '(' . $params . "))\n";

        return "(typeof setTimeout=='function'?setTimeout:eval)(" . $unpack . "(" . $params . "));\n";

    }

    private $buffer;

    private function _insertFastDecode($match)

    {

        return '{' . $this->buffer . ';';

    }

    private function _insertFastEncode($match)

    {

        return '{$encode=' . $this->buffer . ';';

    }

    // mmm.. ..which one do i need ??

    private function _getEncoder($ascii)

    {

        return $ascii > 10 ? $ascii > 36 ? $ascii > 62 ?

               '_encode95' : '_encode62' : '_encode36' : '_encode10';

    }

    // zero encoding

    // characters: 0123456789

    private function _encode10($charCode)

    {

        return $charCode;

    }

    // inherent base36 support

    // characters: 0123456789abcdefghijklmnopqrstuvwxyz

    private function _encode36($charCode)

    {

        return base_convert($charCode, 10, 36);

    }

    // hitch a ride on base36 and add the upper case alpha characters

    // characters: 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ

    private function _encode62($charCode)

    {

        $res = '';

        if ($charCode >= $this->_encoding) {

            $res = $this->_encode62((int) ($charCode / $this->_encoding));

        }

        $charCode = $charCode % $this->_encoding;

        if ($charCode > 35)

            return $res . chr($charCode + 29);

        else

            return $res . base_convert($charCode, 10, 36);

    }

    // use high-ascii values

    // characters: ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþ

    private function _encode95($charCode)

    {

        $res = '';

        if ($charCode >= $this->_encoding)

            $res = $this->_encode95($charCode / $this->_encoding);

        return $res . chr(($charCode % $this->_encoding) + 161);

    }

    private function _safeRegExp($string)

    {

        return '/'.preg_replace('/\$/', '\\\$', $string).'/';

    }

    private function _encodePrivate($charCode)

    {

        return "_" . $charCode;

    }

    // protect characters used by the parser

    private function _escape($script)

    {

        return preg_replace('/([\\\\\'])/', '\\\$1', $script);

    }

    // protect high-ascii characters already in the script

    private function _escape95($script)

    {

        return preg_replace_callback(

            '/[\\xa1-\\xff]/',

            array(&$this, '_escape95Bis'),

            $script

        );

    }

    private function _escape95Bis($match)

    {

        return '\x'.((string) dechex(ord($match)));

    }

    private function _getJSFunction($aName)

    {

        if (defined('self::JSFUNCTION'.$aName))

            return constant('self::JSFUNCTION'.$aName);

        else

            return '';

    }

    // JavaScript Functions used.

    // Note : In Dean's version, these functions are converted

    // with 'String(aFunctionName);'.

    // This internal conversion complete the original code, ex :

    // 'while (aBool) anAction();' is converted to

    // 'while (aBool) { anAction(); }'.

    // The JavaScript functions below are corrected.

    // unpacking function - this is the boot strap function

    //  data extracted from this packing routine is passed to

    //  this function when decoded in the target

    // NOTE ! : without the ';' final.

    const JSFUNCTION_unpack =

'function ($packed, $ascii, $count, $keywords, $encode, $decode) {

    while ($count--) {

        if ($keywords[$count]) {

            $packed = $packed.replace(new RegExp(\'\\\\b\' + $encode($count) + \'\\\\b\', \'g\'), $keywords[$count]);

        }

    }

    return $packed;

}';

/*

'function ($packed, $ascii, $count, $keywords, $encode, $decode) {

    while ($count--)

        if ($keywords[$count])

            $packed = $packed.replace(new RegExp(\'\\\\b\' + $encode($count) + \'\\\\b\', \'g\'), $keywords[$count]);

    return $packed;

}';

*/

    // code-snippet inserted into the unpacker to speed up decoding

    const JSFUNCTION_decodeBody =

//_decode = function () {

// does the browser support String.replace where the

//  replacement value is a function?

'    if (!\'\'.replace(/^/, String)) {

        // decode all the values we need

        while ($count--) {

            $decode[$encode($count)] = $keywords[$count] || $encode($count);

        }

        // global replacement function

        $keywords = [function ($encoded) {return $decode[$encoded]}];

        // generic match

        $encode = function () {return \'\\\\w+\'};

        // reset the loop counter -  we are now doing a global replace

        $count = 1;

    }

';

//};

/*

'	if (!\'\'.replace(/^/, String)) {

        // decode all the values we need

        while ($count--) $decode[$encode($count)] = $keywords[$count] || $encode($count);

        // global replacement function

        $keywords = [function ($encoded) {return $decode[$encoded]}];

        // generic match

        $encode = function () {return\'\\\\w+\'};

        // reset the loop counter -  we are now doing a global replace

        $count = 1;

    }';

*/

     // zero encoding

     // characters: 0123456789

     const JSFUNCTION_encode10 =

'function ($charCode) {

    return $charCode;

}';//;';

     // inherent base36 support

     // characters: 0123456789abcdefghijklmnopqrstuvwxyz

     const JSFUNCTION_encode36 =

'function ($charCode) {

    return $charCode.toString(36);

}';//;';

    // hitch a ride on base36 and add the upper case alpha characters

    // characters: 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ

    const JSFUNCTION_encode62 =

'function ($charCode) {

    return ($charCode < _encoding ? \'\' : arguments.callee(parseInt($charCode / _encoding))) +

    (($charCode = $charCode % _encoding) > 35 ? String.fromCharCode($charCode + 29) : $charCode.toString(36));

}';

    // use high-ascii values

    // characters: ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþ

    const JSFUNCTION_encode95 =

'function ($charCode) {

    return ($charCode < _encoding ? \'\' : arguments.callee($charCode / _encoding)) +

        String.fromCharCode($charCode % _encoding + 161);

}';

}

class ParseMaster

{

    public $ignoreCase = false;

    public $escapeChar = '';

    // constants

    const EXPRESSION = 0;

    const REPLACEMENT = 1;

    const LENGTH = 2;

    // used to determine nesting levels

    private $GROUPS = '/\\(/';//g

    private $SUB_REPLACE = '/\\$\\d/';

    private $INDEXED = '/^\\$\\d+$/';

    private $TRIM = '/([\'"])\\1\\.(.*)\\.\\1\\1$/';

    private $ESCAPE = '/\\\./';//g

    private $QUOTE = '/\'/';

    private $DELETED = '/\\x01[^\\x01]*\\x01/';//g

    public function add($expression, $replacement = '')

    {

        // count the number of sub-expressions

        //  - add one because each pattern is itself a sub-expression

        $length = 1 + preg_match_all($this->GROUPS, $this->_internalEscape((string) $expression), $out);

        // treat only strings $replacement

        if (is_string($replacement)) {

            // does the pattern deal with sub-expressions?

            if (preg_match($this->SUB_REPLACE, $replacement)) {

                // a simple lookup? (e.g. "$2")

                if (preg_match($this->INDEXED, $replacement)) {

                    // store the index (used for fast retrieval of matched strings)

                    $replacement = (int) (substr($replacement, 1)) - 1;

                } else { // a complicated lookup (e.g. "Hello $2 $1")

                    // build a function to do the lookup

                    $quote = preg_match($this->QUOTE, $this->_internalEscape($replacement))

                             ? '"' : "'";

                    $replacement = array(

                        'fn' => '_backReferences',

                        'data' => array(

                            'replacement' => $replacement,

                            'length' => $length,

                            'quote' => $quote

                        )

                    );

                }

            }

        }

        // pass the modified arguments

        if (!empty($expression)) $this->_add($expression, $replacement, $length);

        else $this->_add('/^$/', $replacement, $length);

    }

    public function exec($string)

    {

        // execute the global replacement

        $this->_escaped = array();

        // simulate the _patterns.toSTring of Dean

        $regexp = '/';

        foreach ($this->_patterns as $reg) {

            $regexp .= '(' . substr($reg[self::EXPRESSION], 1, -1) . ')|';

        }

        $regexp = substr($regexp, 0, -1) . '/';

        $regexp .= ($this->ignoreCase) ? 'i' : '';

        $string = $this->_escape($string, $this->escapeChar);

        $string = preg_replace_callback(

            $regexp,

            array(

                &$this,

                '_replacement'

            ),

            $string

        );

        $string = $this->_unescape($string, $this->escapeChar);

        return preg_replace($this->DELETED, '', $string);

    }

    public function reset()

    {

        // clear the patterns collection so that this object may be re-used

        $this->_patterns = array();

    }

    // private

    private $_escaped = array();  // escaped characters

    private $_patterns = array(); // patterns stored by index

    // create and add a new pattern to the patterns collection

    private function _add()

    {

        $arguments = func_get_args();

        $this->_patterns[] = $arguments;

    }

    // this is the global replace function (it's quite complicated)

    private function _replacement($arguments)

    {

        if (empty($arguments)) return '';

        $i = 1; $j = 0;

        // loop through the patterns

        while (isset($this->_patterns[$j])) {

            $pattern = $this->_patterns[$j++];

            // do we have a result?

            if (isset($arguments[$i]) && ($arguments[$i] != '')) {

                $replacement = $pattern[self::REPLACEMENT];

                if (is_array($replacement) && isset($replacement['fn'])) {

                    if (isset($replacement['data'])) $this->buffer = $replacement['data'];

                    return call_user_func(array(&$this, $replacement['fn']), $arguments, $i);

                } elseif (is_int($replacement)) {

                    return $arguments[$replacement + $i];

                }

                $delete = ($this->escapeChar == '' ||

                           strpos($arguments[$i], $this->escapeChar) === false)

                        ? '' : "\x01" . $arguments[$i] . "\x01";

                return $delete . $replacement;

            // skip over references to sub-expressions

            } else {

                $i += $pattern[self::LENGTH];

            }

        }

    }

    private function _backReferences($match, $offset)

    {

        $replacement = $this->buffer['replacement'];

        $quote = $this->buffer['quote'];

        $i = $this->buffer['length'];

        while ($i) {

            $replacement = str_replace('$'.$i--, $match[$offset + $i], $replacement);

        }

        return $replacement;

    }

    private function _replace_name($match, $offset)

    {

        $length = strlen($match[$offset + 2]);

        $start = $length - max($length - strlen($match[$offset + 3]), 0);

        return substr($match[$offset + 1], $start, $length) . $match[$offset + 4];

    }

    private function _replace_encoded($match, $offset)

    {

        return $this->buffer[$match[$offset]];

    }

    // php : we cannot pass additional data to preg_replace_callback,

    // and we cannot use &$this in create_function, so let's go to lower level

    private $buffer;

    // encode escaped characters

    private function _escape($string, $escapeChar)

    {

        if ($escapeChar) {

            $this->buffer = $escapeChar;

            return preg_replace_callback(

                '/\\' . $escapeChar . '(.)' .'/',

                array(&$this, '_escapeBis'),

                $string

            );

        } else {

            return $string;

        }

    }

    private function _escapeBis($match)

    {

        $this->_escaped[] = $match[1];

        return $this->buffer;

    }

    // decode escaped characters

    private function _unescape($string, $escapeChar)

    {

        if ($escapeChar) {

            $regexp = '/'.'\\'.$escapeChar.'/';

            $this->buffer = array('escapeChar'=> $escapeChar, 'i' => 0);

            return preg_replace_callback(

                $regexp,

                array(&$this, '_unescapeBis'),

                $string

            );

        } else {

            return $string;

        }

    }

    private function _unescapeBis()

    {

        if (isset($this->_escaped[$this->buffer['i']])

            && $this->_escaped[$this->buffer['i']] != '')

        {

             $temp = $this->_escaped[$this->buffer['i']];

        } else {

            $temp = '';

        }

        $this->buffer['i']++;

        return $this->buffer['escapeChar'] . $temp;

    }

    private function _internalEscape($string)

    {

        return preg_replace($this->ESCAPE, '', $string);

    }

}