Magic.php

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<?php
 
/*
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
 
require "MagicConfig.php";
 
class Magic
{
    public function Magic()
    {
        $this->config = new MagicConfig();
    }
    
    public function load_file($filename)
    {
        if (!($filehandle = @fopen($filename, "rb"))) {
            return undef;
        }
        set_magic_quotes_runtime(0);
        $text = fread($filehandle, filesize($filename));
        set_magic_quotes_runtime(get_magic_quotes_gpc());
        fclose($filehandle);
        return $text;
    }
 
    public function _is_ascii($file)
    {
        $arr = unpack("C*", $file);
        for ($i=1; $i<sizeof($arr); $i++) {
            if ($arr[$i]<32 && $arr[$i]!=13 && $arr[$i]!=10) {
                return false;
            }
        }
        return true;
    }
    
    public function get_language($filename)
    {
        // First attempt a match with the filename extension.
        $extensionspl = explode($this->config->separator, $filename);
        $extension = $extensionspl[sizeof($extensionspl)-1];
        $langstr = $this->config->extensions[$extension];
        // We may have a choice of languages, so check.
        $langarr = explode("|", $langstr);
        
        // Got one language? Good!
        if (sizeof($langarr)==1 && $langarr[0]!="") {
            return $langstr;
        }
        
        // Now the real magic starts :o) We may have a narrowed-down set of options from
        // the tests above, which will speed things up a little.
        
        // Get one /big/ string.
        $this->config->file = $this->load_file($filename);
        if ($this->config->file == undef) {
            return "illegal";
        }
        $this->is_ascii = $this->_is_ascii($this->config->file);
 
        if (isset($langstr)) {
            // We don't know if all of the types are in our magic file, so filter out those that
            // aren't.
            
            $outarray = array();
            foreach ($langarr as $lang) {
                if ($this->is_ascii && in_array($lang, $this->config->langfunctions)) {
                    array_push($outarray, $lang);
                } elseif (in_array($lang, $this->config->binfunctions)) {
                    array_push($outarray, $lang);
                }
            }
            $testarray = $outarray;
        } else {
            if ($this->is_ascii) {
                $testarray = $this->config->langfunctions;
            } else {
                $testarray = $this->config->binfunctions;
            }
        }
        foreach ($testarray as $test) {
            $func = "detect_" . $test;
            if ($this->config->$func()) {
                return $test;
            }
        }
    }
}