H:/Workspace/php-axiom/www/php-axiom/libraries/axiom/axCaptcha.class.php

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<?php
class axCaptcha {
    
    protected $_options;
    
    protected $_dictionnary_struct;
    
    protected $_session;
    
    public function __construct (array $options = array()) {
        $default = array(
            'dictionnaries_path' => null,
            'dictionnary'        => 'static.dictionary.ini',
            'dictionnary_type'   => 'static',
        );
        
        $this->_config = $config + $default;
    }
    
    protected function _parseDictionnary ($path) {
        if (!$this->_dictionnary_struct = parse_ini_file($path, true))
            throw new RuntimeException("Cannot parse {$path}");
    }
    
    public function generate ($lang) {
        if (empty($this->_dictionnary_struct)) {
            if (!is_file($path = realpath($this->_config['dictionnaries_path']) . '/' . $this->_config['dictionnary']))
                throw new axMissingFileException($path);
                
            $this->_parseDictionnary($path);
        }
        
        if (empty($this->_session)) {
            $this->_session = new axSession;
            $this->_session->start();
        }
        
        if (empty($this->_dictionnary_struct[$lang]))
            throw new RuntimeException("Dictionnary does not provide any data for {$lang} language");
            
        $question = array_rand($this->_dictionnary_struct[$lang]);
        
        if ($this->_config['dictionnary_type'] == 'static') {
            $answer = array_map('strtolower', array_map('trim', explode(',', $this->_dictionnary_struct[$lang][$question])));
        }
        elseif ($this->_config['dictionnary_type'] == 'dynamic') {
            if (!$alpha = callback($this->_dictionnary_struct[$lang][$question]))
                throw new RuntimeException("Cannot understand alpha function definition");
            
            $argc = substr_count($question, '%d');
            $argv = array();
            for ($i=0; $i<$argc; $i++)
                $argv[] = rand(0,9);

            $answer   = array(call_user_func_array($alpha, $argv));
            array_unshift($argv, $question);
            $question = call_user_func_array('sprintf', $argv);
        }
        else {
            throw new RuntimeException("Unrecognized dictionnary type " . $this->_config['dictionnary_type']);
        }
            
        $this->_session->captcha_ans = $answer;
        return $question;
    }
    
    public function verify ($answer) {
        if (empty($this->_session)) {
            $this->_session = new axSession;
            $this->_session->start();
        }
        
        return in_array(strtolower(trim($answer)), $this->_session->captcha_ans);
    }
}

if (!function_exists('callback')) {
                function callback ($fct) {
                    if (!preg_match('~(function)?\s*\((?P<args>[^\)]*)\)\s*\{(?P<code>.*)\}~', $fct, $matches))
                        return false;
                
                    $args = $matches['args'];
                    $code = $matches['code'];
                    return create_function($args, $code);
                }
}