Rule::__construct()   A
last analyzed

Complexity

Conditions 1
Paths 1

Size

Total Lines 4
Code Lines 2

Duplication

Lines 0
Ratio 0 %

Importance

Changes 1
Bugs 0 Features 0
Metric Value
cc 1
eloc 2
c 1
b 0
f 0
nc 1
nop 1
dl 0
loc 4
rs 10
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<?php
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namespace Trapdirector;
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use Exception;
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class Rule
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{
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    use \RuleUtils;
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    /** @var Logging $logging logging class*/
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    protected $logging;
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    /** @var Trap $trapClass */
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    protected $trapClass;
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    /**
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     * Setup Rule Class
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     * @param Trap $trapClass : To get logging class & plugin class
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     */
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    function __construct($trapClass)
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    {
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        $this->trapClass=$trapClass;
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        $this->logging=$trapClass->logging;
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    }
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    protected function eval_getElement($rule,&$item)
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    {
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        if ($item >= strlen($rule))
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        {
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            throw new Exception("Early end of string ".$rule ." at " .$item );
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        }
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        while ($rule[$item]==' ') $item++;
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        if (preg_match('/[\-0-9\.]/',$rule[$item]))
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        { // number
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            return $this->get_number($rule, $item);
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        }
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        if ($rule[$item] == '"')
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        { // string
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            return $this->get_string($rule, $item);
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        }
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        if ($rule[$item] == '(')
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        { // grouping
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            return $this->get_group($rule, $item);
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        }
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        if ($rule[$item] == '_')
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        { // function
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            return $this->get_function($rule, $item);
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        }
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        throw new Exception("number/string not found in ".$rule ." at " .$item . ' : ' .$rule[$item]);
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    }
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    protected function eval_getOper($rule,&$item)
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    {
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        while ($rule[$item]==' ') $item++;
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        switch ($rule[$item])
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        {
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            case '<':
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                if ($rule[$item+1]=='=') { $item+=2; return array(0,"<=");}
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                $item++; return array(0,"<");
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            case '>':
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                if ($rule[$item+1]=='=') { $item+=2; return array(0,">=");}
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                $item++; return array(0,">");
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            case '=':
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                $item++; return array(0,"=");
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            case '!':
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                if ($rule[$item+1]=='=') { $item+=2; return array(0,"!=");}
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                throw new Exception("Erreur in expr - incorrect operator '!'  found in ".$rule ." at " .$item);
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            case '~':
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                $item++; return array(0,"~");
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            case '|':
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                $item++; return array(1,"|");
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            case '&':
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                $item++; return array(1,"&");
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            default	:
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                throw new Exception("Erreur in expr - operator not found in ".$rule ." at " .$item);
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        }
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    }
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    private function do_compare($val1,$val2,$comp,$negate)
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    {
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        switch ($comp){
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            case '<':	$retVal= ($val1 < $val2); break;
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            case '<=':	$retVal= ($val1 <= $val2); break;
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            case '>':	$retVal= ($val1 > $val2); break;
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            case '>=':	$retVal= ($val1 >= $val2); break;
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            case '=':	$retVal= ($val1 == $val2); break;
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            case '!=':	$retVal= ($val1 != $val2); break;
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            case '~':	$retVal= (preg_match('/'.preg_replace('/"/','',$val2).'/',$val1)); break;
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            case '|':	$retVal= ($val1 || $val2); break;
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            case '&':	$retVal= ($val1 && $val2); break;
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            default:  throw new Exception("Error in expression - unknown comp : ".$comp);
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        }
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        if ($negate === true) $retVal = ! $retVal; // Inverse result if negate before expression
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        return $retVal;
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    }
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    /** Evaluation : makes token and evaluate.
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     *	Public function for expressions testing
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     *	accepts : < > = <= >= !=  (typec = 0)
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     *	operators : & | (typec=1)
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     *	with : integers/float  (type 0) or strings "" (type 1) or results (type 2)
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     *   comparison int vs strings will return null (error)
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     *	return : bool or null on error
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     */
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    public function evaluation($rule,&$item)
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    {
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        //echo "Evaluation of ".substr($rule,$item)."\n";
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        $negate=$this->check_negate_first($rule, $item);
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        // First element : number, string or ()
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        list($type1,$val1) = $this->eval_getElement($rule,$item);
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        //echo "Elmt1: ".$val1."/".$type1." : ".substr($rule,$item)."\n";
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        if ($item==strlen($rule)) // If only element, return value, but only boolean
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        {
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            if ($type1 != 2) throw new Exception("Cannot use num/string as boolean : ".$rule);
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            if ($negate === true) $val1= ! $val1;
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            return $val1;
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        }
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        // Second element : operator
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        list($typec,$comp) = $this->eval_getOper($rule,$item);
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        //echo "Comp : ".$comp." : ".substr($rule,$item)."\n";
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        // Third element : number, string or ()
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        if ( $rule[$item] == '!') // starts with a ! so evaluate whats next
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        {
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            $item++;
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            if ($typec != 1) throw new Exception("Mixing boolean and comparison : ".$rule);
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            $val2= ! $this->evaluation($rule,$item);
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            $type2=2; // result is a boolean
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        }
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        else
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        {
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            list($type2,$val2) = $this->eval_getElement($rule,$item);
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        }
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        //echo "Elmt2: ".$val2."/".$type2." : ".substr($rule,$item)."\n";
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        if ($type1!=$type2)  // cannot compare different types
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        {
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            throw new Exception("Cannot compare string & number : ".$rule);
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        }
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        if ($typec==1 && $type1 !=2) // cannot use & or | with string/number
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        {
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            throw new Exception("Cannot use boolean operators with string & number : ".$rule);
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        }
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        $retVal = $this->do_compare($val1, $val2, $comp, $negate);
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        if ($item==strlen($rule)) return $retVal; // End of string : return evaluation
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        // check for logical operator :
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        switch ($rule[$item])
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        {
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            case '|':	$item++; return ($retVal || $this->evaluation($rule,$item) );
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            case '&':	$item++; return ($retVal && $this->evaluation($rule,$item) );
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            default:  throw new Exception("Erreur in expr - garbadge at end of expression : ".$rule[$item]);
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        }
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    }
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    /**
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     * Get '*' or '**' and transform in [0-9]+ or .* in return string
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     * @param string $oid OID in normal or regexp format. '*' will be escaped ('\*')
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     * @return string correct regexp format
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     */
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    public function regexp_eval(string &$oid)
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    {
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        // ** replaced by .*
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        $oidR=preg_replace('/\*\*/', '.*', $oid);
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        // * replaced by [0-9]+
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        $oidR=preg_replace('/\*/', '[0-9]+', $oidR);
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        // replace * with \* in oid for preg_replace
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        $oid=preg_replace('/\*/', '\*', $oid);
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        $this->logging->log('Regexp eval : '.$oid.' / '.$oidR,DEBUG );
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        return $oidR;
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    }
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    /** Evaluation rule (uses eval_* functions recursively)
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     *	@param string $rule : rule ( _OID(.1.3.6.1.4.1.8072.2.3.2.1)=_OID(.1.3.6.1.2.1.1.3.0) )
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     *  @param array $oidList : OIDs values to sustitute.
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     *	@return bool : true : rule match, false : rule don't match , throw exception on error.
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     */   
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    public function eval_rule($rule,$oidList)
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    {
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        if ($rule==null || $rule == '') // Empty rule is always true
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        {
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            return true;
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        }
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        $matches=array();
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        while (preg_match('/_OID\(([0-9\.\*]+)\)/',$rule,$matches) == 1)
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        {
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            $oid=$matches[1];
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            $found=0;
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            // Test and transform regexp
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            $oidR = $this->regexp_eval($oid);
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            foreach($oidList as $val)
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            {
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                if (preg_match("/^$oidR$/",$val->oid) == 1)
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                {
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                    if (!preg_match('/^-?[0-9]*\.?[0-9]+$/',$val->value))
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                    { // If not a number, change " to ' and put " around it
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                        $val->value=preg_replace('/"/',"'",$val->value);
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                        $val->value='"'.$val->value.'"';
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                    }
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                    $rep=0;
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                    $rule=preg_replace('/_OID\('.$oid.'\)/',$val->value,$rule,-1,$rep);
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                    if ($rep==0)
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                    {
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                        $this->logging->log("Error in rule_eval",WARN,'');
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                        return false;
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                    }
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                    $found=1;
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                    break;
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                }
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            }
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            if ($found==0)
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            {	// OID not found : throw error
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                throw new Exception('OID '.$oid.' not found in trap');
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            }
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        }
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        $item=0;
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        $rule=$this->eval_cleanup($rule);
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        $this->logging->log('Rule after clenup: '.$rule,INFO );
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        return  $this->evaluation($rule,$item);
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    }
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}