<?php
 
 /*
  * This file is part of the Symfony package.
  *
  * (c) Fabien Potencier <fabien@symfony.com>
  *
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
 
 namespace Symfony\Component\Translation\Loader;
 
 use Symfony\Component\Translation\Exception\InvalidResourceException;
 
 /**
  * @copyright Copyright (c) 2010, Union of RAD http://union-of-rad.org (http://lithify.me/)
  */
 class MoFileLoader extends FileLoader
 {
     /**
      * Magic used for validating the format of a MO file as well as
      * detecting if the machine used to create that file was little endian.
      */
     const MO_LITTLE_ENDIAN_MAGIC = 0x950412de;
 
     /**
      * Magic used for validating the format of a MO file as well as
      * detecting if the machine used to create that file was big endian.
      */
     const MO_BIG_ENDIAN_MAGIC = 0xde120495;
 
     /**
      * The size of the header of a MO file in bytes.
      */
     const MO_HEADER_SIZE = 28;
 
     /**
      * Parses machine object (MO) format, independent of the machine's endian it
      * was created on. Both 32bit and 64bit systems are supported.
      *
      * {@inheritdoc}
      */
     protected function loadResource($resource)
     {
         $stream = fopen($resource, 'r');
 
         $stat = fstat($stream);
 
         if ($stat['size'] < self::MO_HEADER_SIZE) {
             throw new InvalidResourceException('MO stream content has an invalid format.');
         }
         $magic = unpack('V1', fread($stream, 4));
         $magic = hexdec(substr(dechex(current($magic)), -8));
 
         if (self::MO_LITTLE_ENDIAN_MAGIC == $magic) {
             $isBigEndian = false;
         } elseif (self::MO_BIG_ENDIAN_MAGIC == $magic) {
             $isBigEndian = true;
         } else {
             throw new InvalidResourceException('MO stream content has an invalid format.');
         }
 
         // formatRevision
         $this->readLong($stream, $isBigEndian);
         $count = $this->readLong($stream, $isBigEndian);
         $offsetId = $this->readLong($stream, $isBigEndian);
         $offsetTranslated = $this->readLong($stream, $isBigEndian);
         // sizeHashes
         $this->readLong($stream, $isBigEndian);
         // offsetHashes
         $this->readLong($stream, $isBigEndian);
 
         $messages = [];
 
         for ($i = 0; $i < $count; ++$i) {
             $pluralId = null;
             $translated = null;
 
             fseek($stream, $offsetId + $i * 8);
 
             $length = $this->readLong($stream, $isBigEndian);
             $offset = $this->readLong($stream, $isBigEndian);
 
             if ($length < 1) {
                 continue;
             }
 
             fseek($stream, $offset);
             $singularId = fread($stream, $length);
 
             if (false !== strpos($singularId, "\000")) {
                 list($singularId, $pluralId) = explode("\000", $singularId);
             }
 
             fseek($stream, $offsetTranslated + $i * 8);
             $length = $this->readLong($stream, $isBigEndian);
             $offset = $this->readLong($stream, $isBigEndian);
 
             if ($length < 1) {
                 continue;
             }
 
             fseek($stream, $offset);
             $translated = fread($stream, $length);
 
             if (false !== strpos($translated, "\000")) {
                 $translated = explode("\000", $translated);
             }
 
             $ids = ['singular' => $singularId, 'plural' => $pluralId];
             $item = compact('ids', 'translated');
 
             if (!empty($item['ids']['singular'])) {
                 $id = $item['ids']['singular'];
                 if (isset($item['ids']['plural'])) {
                     $id .= '|'.$item['ids']['plural'];
                 }
                 $messages[$id] = stripcslashes(implode('|', (array) $item['translated']));
             }
         }
 
         fclose($stream);
 
         return array_filter($messages);
     }
 
     /**
      * Reads an unsigned long from stream respecting endianness.
      *
      * @param resource $stream
      */
     private function readLong($stream, bool $isBigEndian): int
     {
         $result = unpack($isBigEndian ? 'N1' : 'V1', fread($stream, 4));
         $result = current($result);
 
         return (int) substr($result, -8);
     }
 }