build/class.JavaScriptPacker.php

   1 <?php
   2 /* 7 December 2006. version 1.0
   3  *
   4  * This is the php version of the Dean Edwards JavaScript 's Packer,
   5  * Based on :
   6  *
   7  * ParseMaster, version 1.0.2 (2005-08-19) Copyright 2005, Dean Edwards
   8  * a multi-pattern parser.
   9  * KNOWN BUG: erroneous behavior when using escapeChar with a replacement
  10  * value that is a function
  11  *
  12  * packer, version 2.0.2 (2005-08-19) Copyright 2004-2005, Dean Edwards
  13  *
  14  * License: http://creativecommons.org/licenses/LGPL/2.1/
  15  *
  16  * Ported to PHP by Nicolas Martin.
  17  *
  18  * ----------------------------------------------------------------------
  19  *
  20  * examples of usage :
  21  * $myPacker = new JavaScriptPacker($script, 62, true, false);
  22  * $packed = $myPacker->pack();
  23  *
  24  * or
  25  *
  26  * $myPacker = new JavaScriptPacker($script, 'Normal', true, false);
  27  * $packed = $myPacker->pack();
  28  *
  29  * or (default values)
  30  *
  31  * $myPacker = new JavaScriptPacker($script);
  32  * $packed = $myPacker->pack();
  33  *
  34  *
  35  * params of the constructor :
  36  * $script:       the JavaScript to pack, string.
  37  * $encoding:     level of encoding, int or string :
  38  *                0,10,62,95 or 'None', 'Numeric', 'Normal', 'High ASCII'.
  39  *                default: 62.
  40  * $fastDecode:   include the fast decoder in the packed result, boolean.
  41  *                default : true.
  42  * $specialChars: if you are flagged your private and local variables
  43  *                in the script, boolean.
  44  *                default: false.
  45  *
  46  * The pack() method return the compressed JavasScript, as a string.
  47  *
  48  * see http://dean.edwards.name/packer/usage/ for more information.
  49  *
  50  * Notes :
  51  * # need PHP 5 . Tested with PHP 5.1.2
  52  *
  53  * # The packed result may be different than with the Dean Edwards
  54  *   version, but with the same length. The reason is that the PHP
  55  *   function usort to sort array don't necessarily preserve the
  56  *   original order of two equal member. The Javascript sort function
  57  *   in fact preserve this order (but that's not require by the
  58  *   ECMAScript standard). So the encoded keywords order can be
  59  *   different in the two results.
  60  *
  61  * # Be careful with the 'High ASCII' Level encoding if you use
  62  *   UTF-8 in your files...
  63  */
  64
  65
  66 class JavaScriptPacker {
  67         // constants
  68         const IGNORE = '$1';
  69
  70         // validate parameters
  71         private $_script = '';
  72         private $_encoding = 62;
  73         private $_fastDecode = true;
  74         private $_specialChars = false;
  75
  76         private $LITERAL_ENCODING = array(
  77                 'None' => 0,
  78                 'Numeric' => 10,
  79                 'Normal' => 62,
  80                 'High ASCII' => 95
  81         );
  82
  83         public function __construct($_script, $_encoding = 62, $_fastDecode = true, $_specialChars = false)
  84         {
  85                 $this->_script = $_script . "\n";
  86                 if (array_key_exists($_encoding, $this->LITERAL_ENCODING))
  87                         $_encoding = $this->LITERAL_ENCODING[$_encoding];
  88                 $this->_encoding = min((int)$_encoding, 95);
  89                 $this->_fastDecode = $_fastDecode;
  90                 $this->_specialChars = $_specialChars;
  91         }
  92
  93         public function pack() {
  94                 $this->_addParser('_basicCompression');
  95                 if ($this->_specialChars)
  96                         $this->_addParser('_encodeSpecialChars');
  97                 if ($this->_encoding)
  98                         $this->_addParser('_encodeKeywords');
  99
 100                 // go!
 101                 return $this->_pack($this->_script);
 102         }
 103
 104         // apply all parsing routines
 105         private function _pack($script) {
 106                 for ($i = 0; isset($this->_parsers[$i]); $i++) {
 107                         $script = call_user_func(array(&$this,$this->_parsers[$i]), $script);
 108                 }
 109                 return $script;
 110         }
 111
 112         // keep a list of parsing functions, they'll be executed all at once
 113         private $_parsers = array();
 114         private function _addParser($parser) {
 115                 $this->_parsers[] = $parser;
 116         }
 117
 118         // zero encoding - just removal of white space and comments
 119         private function _basicCompression($script) {
 120                 $parser = new ParseMaster();
 121                 // make safe
 122                 $parser->escapeChar = '\\';
 123                 // protect strings
 124                 $parser->add('/\'[^\'\\n\\r]*\'/', self::IGNORE);
 125                 $parser->add('/"[^"\\n\\r]*"/', self::IGNORE);
 126                 // remove comments
 127                 $parser->add('/\\/\\/[^\\n\\r]*[\\n\\r]/', ' ');
 128                 $parser->add('/\\/\\*[^*]*\\*+([^\\/][^*]*\\*+)*\\//', ' ');
 129                 // protect regular expressions
 130                 $parser->add('/\\s+(\\/[^\\/\\n\\r\\*][^\\/\\n\\r]*\\/g?i?)/', '$2'); // IGNORE
 131                 $parser->add('/[^\\w\\x24\\/\'"*)\\?:]\\/[^\\/\\n\\r\\*][^\\/\\n\\r]*\\/g?i?/', self::IGNORE);
 132                 // remove: ;;; doSomething();
 133                 if ($this->_specialChars) $parser->add('/;;;[^\\n\\r]+[\\n\\r]/');
 134                 // remove redundant semi-colons
 135                 $parser->add('/\\(;;\\)/', self::IGNORE); // protect for (;;) loops
 136                 $parser->add('/;+\\s*([};])/', '$2');
 137                 // apply the above
 138                 $script = $parser->exec($script);
 139
 140                 // remove white-space
 141                 $parser->add('/(\\b|\\x24)\\s+(\\b|\\x24)/', '$2 $3');
 142                 $parser->add('/([+\\-])\\s+([+\\-])/', '$2 $3');
 143                 $parser->add('/\\s+/', '');
 144                 // done
 145                 return $parser->exec($script);
 146         }
 147
 148         private function _encodeSpecialChars($script) {
 149                 $parser = new ParseMaster();
 150                 // replace: $name -> n, $$name -> na
 151                 $parser->add('/((\\x24+)([a-zA-Z$_]+))(\\d*)/',
 152                                          array('fn' => '_replace_name')
 153                 );
 154                 // replace: _name -> _0, double-underscore (__name) is ignored
 155                 $regexp = '/\\b_[A-Za-z\\d]\\w*/';
 156                 // build the word list
 157                 $keywords = $this->_analyze($script, $regexp, '_encodePrivate');
 158                 // quick ref
 159                 $encoded = $keywords['encoded'];
 160
 161                 $parser->add($regexp,
 162                         array(
 163                                 'fn' => '_replace_encoded',
 164                                 'data' => $encoded
 165                         )
 166                 );
 167                 return $parser->exec($script);
 168         }
 169
 170         private function _encodeKeywords($script) {
 171                 // escape high-ascii values already in the script (i.e. in strings)
 172                 if ($this->_encoding > 62)
 173                         $script = $this->_escape95($script);
 174                 // create the parser
 175                 $parser = new ParseMaster();
 176                 $encode = $this->_getEncoder($this->_encoding);
 177                 // for high-ascii, don't encode single character low-ascii
 178                 $regexp = ($this->_encoding > 62) ? '/\\w\\w+/' : '/\\w+/';
 179                 // build the word list
 180                 $keywords = $this->_analyze($script, $regexp, $encode);
 181                 $encoded = $keywords['encoded'];
 182
 183                 // encode
 184                 $parser->add($regexp,
 185                         array(
 186                                 'fn' => '_replace_encoded',
 187                                 'data' => $encoded
 188                         )
 189                 );
 190                 if (empty($script)) return $script;
 191                 else {
 192                         //$res = $parser->exec($script);
 193                         //$res = $this->_bootStrap($res, $keywords);
 194                         //return $res;
 195                         return $this->_bootStrap($parser->exec($script), $keywords);
 196                 }
 197         }
 198
 199         private function _analyze($script, $regexp, $encode) {
 200                 // analyse
 201                 // retreive all words in the script
 202                 $all = array();
 203                 preg_match_all($regexp, $script, $all);
 204                 $_sorted = array(); // list of words sorted by frequency
 205                 $_encoded = array(); // dictionary of word->encoding
 206                 $_protected = array(); // instances of "protected" words
 207                 $all = $all[0]; // simulate the javascript comportement of global match
 208                 if (!empty($all)) {
 209                         $unsorted = array(); // same list, not sorted
 210                         $protected = array(); // "protected" words (dictionary of word->"word")
 211                         $value = array(); // dictionary of charCode->encoding (eg. 256->ff)
 212                         $this->_count = array(); // word->count
 213                         $i = count($all); $j = 0; //$word = null;
 214                         // count the occurrences - used for sorting later
 215                         do {
 216                                 --$i;
 217                                 $word = '$' . $all[$i];
 218                                 if (!isset($this->_count[$word])) {
 219                                         $this->_count[$word] = 0;
 220                                         $unsorted[$j] = $word;
 221                                         // make a dictionary of all of the protected words in this script
 222                                         //  these are words that might be mistaken for encoding
 223                                         //if (is_string($encode) && method_exists($this, $encode))
 224                                         $values[$j] = call_user_func(array(&$this, $encode), $j);
 225                                         $protected['$' . $values[$j]] = $j++;
 226                                 }
 227                                 // increment the word counter
 228                                 $this->_count[$word]++;
 229                         } while ($i > 0);
 230                         // prepare to sort the word list, first we must protect
 231                         //  words that are also used as codes. we assign them a code
 232                         //  equivalent to the word itself.
 233                         // e.g. if "do" falls within our encoding range
 234                         //      then we store keywords["do"] = "do";
 235                         // this avoids problems when decoding
 236                         $i = count($unsorted);
 237                         do {
 238                                 $word = $unsorted[--$i];
 239                                 if (isset($protected[$word]) /*!= null*/) {
 240                                         $_sorted[$protected[$word]] = substr($word, 1);
 241                                         $_protected[$protected[$word]] = true;
 242                                         $this->_count[$word] = 0;
 243                                 }
 244                         } while ($i);
 245
 246                         // sort the words by frequency
 247                         // Note: the javascript and php version of sort can be different :
 248                         // in php manual, usort :
 249                         // " If two members compare as equal,
 250                         // their order in the sorted array is undefined."
 251                         // so the final packed script is different of the Dean's javascript version
 252                         // but equivalent.
 253                         // the ECMAscript standard does not guarantee this behaviour,
 254                         // and thus not all browsers (e.g. Mozilla versions dating back to at
 255                         // least 2003) respect this.
 256                         usort($unsorted, array(&$this, '_sortWords'));
 257                         $j = 0;
 258                         // because there are "protected" words in the list
 259                         //  we must add the sorted words around them
 260                         do {
 261                                 if (!isset($_sorted[$i]))
 262                                         $_sorted[$i] = substr($unsorted[$j++], 1);
 263                                 $_encoded[$_sorted[$i]] = $values[$i];
 264                         } while (++$i < count($unsorted));
 265                 }
 266                 return array(
 267                         'sorted'  => $_sorted,
 268                         'encoded' => $_encoded,
 269                         'protected' => $_protected);
 270         }
 271
 272         private $_count = array();
 273         private function _sortWords($match1, $match2) {
 274                 return $this->_count[$match2] - $this->_count[$match1];
 275         }
 276
 277         // build the boot function used for loading and decoding
 278         private function _bootStrap($packed, $keywords) {
 279                 $ENCODE = $this->_safeRegExp('$encode\\($count\\)');
 280
 281                 // $packed: the packed script
 282                 $packed = "'" . $this->_escape($packed) . "'";
 283
 284                 // $ascii: base for encoding
 285                 $ascii = min(count($keywords['sorted']), $this->_encoding);
 286                 if ($ascii == 0) $ascii = 1;
 287
 288                 // $count: number of words contained in the script
 289                 $count = count($keywords['sorted']);
 290
 291                 // $keywords: list of words contained in the script
 292                 foreach ($keywords['protected'] as $i=>$value) {
 293                         $keywords['sorted'][$i] = '';
 294                 }
 295                 // convert from a string to an array
 296                 ksort($keywords['sorted']);
 297                 $keywords = "'" . implode('|',$keywords['sorted']) . "'.split('|')";
 298
 299                 $encode = ($this->_encoding > 62) ? '_encode95' : $this->_getEncoder($ascii);
 300                 $encode = $this->_getJSFunction($encode);
 301                 $encode = preg_replace('/_encoding/','$ascii', $encode);
 302                 $encode = preg_replace('/arguments\\.callee/','$encode', $encode);
 303                 $inline = '\\$count' . ($ascii > 10 ? '.toString(\\$ascii)' : '');
 304
 305                 // $decode: code snippet to speed up decoding
 306                 if ($this->_fastDecode) {
 307                         // create the decoder
 308                         $decode = $this->_getJSFunction('_decodeBody');
 309                         if ($this->_encoding > 62)
 310                                 $decode = preg_replace('/\\\\w/', '[\\xa1-\\xff]', $decode);
 311                         // perform the encoding inline for lower ascii values
 312                         elseif ($ascii < 36)
 313                                 $decode = preg_replace($ENCODE, $inline, $decode);
 314                         // special case: when $count==0 there are no keywords. I want to keep
 315                         //  the basic shape of the unpacking funcion so i'll frig the code...
 316                         if ($count == 0)
 317                                 $decode = preg_replace($this->_safeRegExp('($count)\\s*=\\s*1'), '$1=0', $decode, 1);
 318                 }
 319
 320                 // boot function
 321                 $unpack = $this->_getJSFunction('_unpack');
 322                 if ($this->_fastDecode) {
 323                         // insert the decoder
 324                         $this->buffer = $decode;
 325                         $unpack = preg_replace_callback('/\\{/', array(&$this, '_insertFastDecode'), $unpack, 1);
 326                 }
 327                 $unpack = preg_replace('/"/', "'", $unpack);
 328                 if ($this->_encoding > 62) { // high-ascii
 329                         // get rid of the word-boundaries for regexp matches
 330                         $unpack = preg_replace('/\'\\\\\\\\b\'\s*\\+|\\+\s*\'\\\\\\\\b\'/', '', $unpack);
 331                 }
 332                 if ($ascii > 36 || $this->_encoding > 62 || $this->_fastDecode) {
 333                         // insert the encode function
 334                         $this->buffer = $encode;
 335                         $unpack = preg_replace_callback('/\\{/', array(&$this, '_insertFastEncode'), $unpack, 1);
 336                 } else {
 337                         // perform the encoding inline
 338                         $unpack = preg_replace($ENCODE, $inline, $unpack);
 339                 }
 340                 // pack the boot function too
 341                 $unpackPacker = new JavaScriptPacker($unpack, 0, false, true);
 342                 $unpack = $unpackPacker->pack();
 343
 344                 // arguments
 345                 $params = array($packed, $ascii, $count, $keywords);
 346                 if ($this->_fastDecode) {
 347                         $params[] = 0;
 348                         $params[] = '{}';
 349                 }
 350                 $params = implode(',', $params);
 351
 352                 // the whole thing
 353                 return 'eval(' . $unpack . '(' . $params . "))\n";
 354         }
 355
 356         private $buffer;
 357         private function _insertFastDecode($match) {
 358                 return '{' . $this->buffer . ';';
 359         }
 360         private function _insertFastEncode($match) {
 361                 return '{$encode=' . $this->buffer . ';';
 362         }
 363
 364         // mmm.. ..which one do i need ??
 365         private function _getEncoder($ascii) {
 366                 return $ascii > 10 ? $ascii > 36 ? $ascii > 62 ?
 367                        '_encode95' : '_encode62' : '_encode36' : '_encode10';
 368         }
 369
 370         // zero encoding
 371         // characters: 0123456789
 372         private function _encode10($charCode) {
 373                 return $charCode;
 374         }
 375
 376         // inherent base36 support
 377         // characters: 0123456789abcdefghijklmnopqrstuvwxyz
 378         private function _encode36($charCode) {
 379                 return base_convert($charCode, 10, 36);
 380         }
 381
 382         // hitch a ride on base36 and add the upper case alpha characters
 383         // characters: 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
 384         private function _encode62($charCode) {
 385                 $res = '';
 386                 if ($charCode >= $this->_encoding) {
 387                         $res = $this->_encode62((int)($charCode / $this->_encoding));
 388                 }
 389                 $charCode = $charCode % $this->_encoding;
 390
 391                 if ($charCode > 35)
 392                         return $res . chr($charCode + 29);
 393                 else
 394                         return $res . base_convert($charCode, 10, 36);
 395         }
 396
 397         // use high-ascii values
 398         // characters: ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþ
 399         private function _encode95($charCode) {
 400                 $res = '';
 401                 if ($charCode >= $this->_encoding)
 402                         $res = $this->_encode95($charCode / $this->_encoding);
 403
 404                 return $res . chr(($charCode % $this->_encoding) + 161);
 405         }
 406
 407         private function _safeRegExp($string) {
 408                 return '/'.preg_replace('/\$/', '\\\$', $string).'/';
 409         }
 410
 411         private function _encodePrivate($charCode) {
 412                 return "_" . $charCode;
 413         }
 414
 415         // protect characters used by the parser
 416         private function _escape($script) {
 417                 return preg_replace('/([\\\\\'])/', '\\\$1', $script);
 418         }
 419
 420         // protect high-ascii characters already in the script
 421         private function _escape95($script) {
 422                 return preg_replace_callback(
 423                         '/[\\xa1-\\xff]/',
 424                         array(&$this, '_escape95Bis'),
 425                         $script
 426                 );
 427         }
 428         private function _escape95Bis($match) {
 429                 return '\x'.((string)dechex(ord($match)));
 430         }
 431
 432
 433         private function _getJSFunction($aName) {
 434                 if (defined('self::JSFUNCTION'.$aName))
 435                         return constant('self::JSFUNCTION'.$aName);
 436                 else
 437                         return '';
 438         }
 439
 440         // JavaScript Functions used.
 441         // Note : In Dean's version, these functions are converted
 442         // with 'String(aFunctionName);'.
 443         // This internal conversion complete the original code, ex :
 444         // 'while (aBool) anAction();' is converted to
 445         // 'while (aBool) { anAction(); }'.
 446         // The JavaScript functions below are corrected.
 447
 448         // unpacking function - this is the boot strap function
 449         //  data extracted from this packing routine is passed to
 450         //  this function when decoded in the target
 451         // NOTE ! : without the ';' final.
 452         const JSFUNCTION_unpack =
 453
 454 'function($packed, $ascii, $count, $keywords, $encode, $decode) {
 455     while ($count--) {
 456         if ($keywords[$count]) {
 457             $packed = $packed.replace(new RegExp(\'\\\\b\' + $encode($count) + \'\\\\b\', \'g\'), $keywords[$count]);
 458         }
 459     }
 460     return $packed;
 461 }';
 462 /*
 463 'function($packed, $ascii, $count, $keywords, $encode, $decode) {
 464     while ($count--)
 465         if ($keywords[$count])
 466             $packed = $packed.replace(new RegExp(\'\\\\b\' + $encode($count) + \'\\\\b\', \'g\'), $keywords[$count]);
 467     return $packed;
 468 }';
 469 */
 470
 471         // code-snippet inserted into the unpacker to speed up decoding
 472         const JSFUNCTION_decodeBody =
 473 //_decode = function() {
 474 // does the browser support String.replace where the
 475 //  replacement value is a function?
 476
 477 '    if (!\'\'.replace(/^/, String)) {
 478         // decode all the values we need
 479         while ($count--) {
 480             $decode[$encode($count)] = $keywords[$count] || $encode($count);
 481         }
 482         // global replacement function
 483         $keywords = [function ($encoded) {return $decode[$encoded]}];
 484         // generic match
 485         $encode = function () {return \'\\\\w+\'};
 486         // reset the loop counter -  we are now doing a global replace
 487         $count = 1;
 488     }
 489 ';
 490 //};
 491 /*
 492 '       if (!\'\'.replace(/^/, String)) {
 493         // decode all the values we need
 494         while ($count--) $decode[$encode($count)] = $keywords[$count] || $encode($count);
 495         // global replacement function
 496         $keywords = [function ($encoded) {return $decode[$encoded]}];
 497         // generic match
 498         $encode = function () {return\'\\\\w+\'};
 499         // reset the loop counter -  we are now doing a global replace
 500         $count = 1;
 501     }';
 502 */
 503
 504          // zero encoding
 505          // characters: 0123456789
 506          const JSFUNCTION_encode10 =
 507 'function($charCode) {
 508     return $charCode;
 509 }';//;';
 510
 511          // inherent base36 support
 512          // characters: 0123456789abcdefghijklmnopqrstuvwxyz
 513          const JSFUNCTION_encode36 =
 514 'function($charCode) {
 515     return $charCode.toString(36);
 516 }';//;';
 517
 518         // hitch a ride on base36 and add the upper case alpha characters
 519         // characters: 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
 520         const JSFUNCTION_encode62 =
 521 'function($charCode) {
 522     return ($charCode < _encoding ? \'\' : arguments.callee(parseInt($charCode / _encoding))) +
 523     (($charCode = $charCode % _encoding) > 35 ? String.fromCharCode($charCode + 29) : $charCode.toString(36));
 524 }';
 525
 526         // use high-ascii values
 527         // characters: ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþ
 528         const JSFUNCTION_encode95 =
 529 'function($charCode) {
 530     return ($charCode < _encoding ? \'\' : arguments.callee($charCode / _encoding)) +
 531         String.fromCharCode($charCode % _encoding + 161);
 532 }';
 533
 534 }
 535
 536
 537 class ParseMaster {
 538         public $ignoreCase = false;
 539         public $escapeChar = '';
 540
 541         // constants
 542         const EXPRESSION = 0;
 543         const REPLACEMENT = 1;
 544         const LENGTH = 2;
 545
 546         // used to determine nesting levels
 547         private $GROUPS = '/\\(/';//g
 548         private $SUB_REPLACE = '/\\$\\d/';
 549         private $INDEXED = '/^\\$\\d+$/';
 550         private $TRIM = '/([\'"])\\1\\.(.*)\\.\\1\\1$/';
 551         private $ESCAPE = '/\\\./';//g
 552         private $QUOTE = '/\'/';
 553         private $DELETED = '/\\x01[^\\x01]*\\x01/';//g
 554
 555         public function add($expression, $replacement = '') {
 556                 // count the number of sub-expressions
 557                 //  - add one because each pattern is itself a sub-expression
 558                 $length = 1 + preg_match_all($this->GROUPS, $this->_internalEscape((string)$expression), $out);
 559
 560                 // treat only strings $replacement
 561                 if (is_string($replacement)) {
 562                         // does the pattern deal with sub-expressions?
 563                         if (preg_match($this->SUB_REPLACE, $replacement)) {
 564                                 // a simple lookup? (e.g. "$2")
 565                                 if (preg_match($this->INDEXED, $replacement)) {
 566                                         // store the index (used for fast retrieval of matched strings)
 567                                         $replacement = (int)(substr($replacement, 1)) - 1;
 568                                 } else { // a complicated lookup (e.g. "Hello $2 $1")
 569                                         // build a function to do the lookup
 570                                         $quote = preg_match($this->QUOTE, $this->_internalEscape($replacement))
 571                                                  ? '"' : "'";
 572                                         $replacement = array(
 573                                                 'fn' => '_backReferences',
 574                                                 'data' => array(
 575                                                         'replacement' => $replacement,
 576                                                         'length' => $length,
 577                                                         'quote' => $quote
 578                                                 )
 579                                         );
 580                                 }
 581                         }
 582                 }
 583                 // pass the modified arguments
 584                 if (!empty($expression)) $this->_add($expression, $replacement, $length);
 585                 else $this->_add('/^$/', $replacement, $length);
 586         }
 587
 588         public function exec($string) {
 589                 // execute the global replacement
 590                 $this->_escaped = array();
 591
 592                 // simulate the _patterns.toSTring of Dean
 593                 $regexp = '/';
 594                 foreach ($this->_patterns as $reg) {
 595                         $regexp .= '(' . substr($reg[self::EXPRESSION], 1, -1) . ')|';
 596                 }
 597                 $regexp = substr($regexp, 0, -1) . '/';
 598                 $regexp .= ($this->ignoreCase) ? 'i' : '';
 599
 600                 $string = $this->_escape($string, $this->escapeChar);
 601                 $string = preg_replace_callback(
 602                         $regexp,
 603                         array(
 604                                 &$this,
 605                                 '_replacement'
 606                         ),
 607                         $string
 608                 );
 609                 $string = $this->_unescape($string, $this->escapeChar);
 610
 611                 return preg_replace($this->DELETED, '', $string);
 612         }
 613
 614         public function reset() {
 615                 // clear the patterns collection so that this object may be re-used
 616                 $this->_patterns = array();
 617         }
 618
 619         // private
 620         private $_escaped = array();  // escaped characters
 621         private $_patterns = array(); // patterns stored by index
 622
 623         // create and add a new pattern to the patterns collection
 624         private function _add() {
 625                 $arguments = func_get_args();
 626                 $this->_patterns[] = $arguments;
 627         }
 628
 629         // this is the global replace function (it's quite complicated)
 630         private function _replacement($arguments) {
 631                 if (empty($arguments)) return '';
 632
 633                 $i = 1; $j = 0;
 634                 // loop through the patterns
 635                 while (isset($this->_patterns[$j])) {
 636                         $pattern = $this->_patterns[$j++];
 637                         // do we have a result?
 638                         if (isset($arguments[$i]) && ($arguments[$i] != '')) {
 639                                 $replacement = $pattern[self::REPLACEMENT];
 640
 641                                 if (is_array($replacement) && isset($replacement['fn'])) {
 642
 643                                         if (isset($replacement['data'])) $this->buffer = $replacement['data'];
 644                                         return call_user_func(array(&$this, $replacement['fn']), $arguments, $i);
 645
 646                                 } elseif (is_int($replacement)) {
 647                                         return $arguments[$replacement + $i];
 648
 649                                 }
 650                                 $delete = ($this->escapeChar == '' ||
 651                                            strpos($arguments[$i], $this->escapeChar) === false)
 652                                         ? '' : "\x01" . $arguments[$i] . "\x01";
 653                                 return $delete . $replacement;
 654
 655                         // skip over references to sub-expressions
 656                         } else {
 657                                 $i += $pattern[self::LENGTH];
 658                         }
 659                 }
 660         }
 661
 662         private function _backReferences($match, $offset) {
 663                 $replacement = $this->buffer['replacement'];
 664                 $quote = $this->buffer['quote'];
 665                 $i = $this->buffer['length'];
 666                 while ($i) {
 667                         $replacement = str_replace('$'.$i--, $match[$offset + $i], $replacement);
 668                 }
 669                 return $replacement;
 670         }
 671
 672         private function _replace_name($match, $offset){
 673                 $length = strlen($match[$offset + 2]);
 674                 $start = $length - max($length - strlen($match[$offset + 3]), 0);
 675                 return substr($match[$offset + 1], $start, $length) . $match[$offset + 4];
 676         }
 677
 678         private function _replace_encoded($match, $offset) {
 679                 return $this->buffer[$match[$offset]];
 680         }
 681
 682
 683         // php : we cannot pass additional data to preg_replace_callback,
 684         // and we cannot use &$this in create_function, so let's go to lower level
 685         private $buffer;
 686
 687         // encode escaped characters
 688         private function _escape($string, $escapeChar) {
 689                 if ($escapeChar) {
 690                         $this->buffer = $escapeChar;
 691                         return preg_replace_callback(
 692                                 '/\\' . $escapeChar . '(.)' .'/',
 693                                 array(&$this, '_escapeBis'),
 694                                 $string
 695                         );
 696
 697                 } else {
 698                         return $string;
 699                 }
 700         }
 701         private function _escapeBis($match) {
 702                 $this->_escaped[] = $match[1];
 703                 return $this->buffer;
 704         }
 705
 706         // decode escaped characters
 707         private function _unescape($string, $escapeChar) {
 708                 if ($escapeChar) {
 709                         $regexp = '/'.'\\'.$escapeChar.'/';
 710                         $this->buffer = array('escapeChar'=> $escapeChar, 'i' => 0);
 711                         return preg_replace_callback
 712                         (
 713                                 $regexp,
 714                                 array(&$this, '_unescapeBis'),
 715                                 $string
 716                         );
 717
 718                 } else {
 719                         return $string;
 720                 }
 721         }
 722         private function _unescapeBis() {
 723                 if (!empty($this->_escaped[$this->buffer['i']])) {
 724                          $temp = $this->_escaped[$this->buffer['i']];
 725                 } else {
 726                         $temp = '';
 727                 }
 728                 $this->buffer['i']++;
 729                 return $this->buffer['escapeChar'] . $temp;
 730         }
 731
 732         private function _internalEscape($string) {
 733                 return preg_replace($this->ESCAPE, '', $string);
 734         }
 735 }
 736 ?>