/**
* Loads RSA math wrapper with name $wrapper_name.
* Implemented wrappers can be found at Crypt/RSA/Math folder.
* Read docs/Crypt_RSA/docs/math_wrappers.txt for details
*
* This is a static function:
* // load BigInt wrapper
* $big_int_wrapper = &Crypt_RSA_MathLoader::loadWrapper('BigInt');
*
* // load BCMath wrapper
* $bcmath_wrapper = &Crypt_RSA_MathLoader::loadWrapper('BCMath');
*
* @param string $wrapper_name Name of wrapper
*
* @return object
* Reference to object of wrapper with name $wrapper_name on success
* or PEAR_Error object on error
*
* @access public
*/
function loadWrapper($wrapper_name = 'default')
{
static $math_objects = array();
// ordered by performance. GMP is the fastest math library, BCMath - the slowest.
static $math_wrappers = array('GMP', 'BigInt', 'BCMath');
if (isset($math_objects[$wrapper_name])) {
/*
wrapper with name $wrapper_name is already loaded and created.
Return reference to existing copy of wrapper
*/
return $math_objects[$wrapper_name];
}
$err_handler = new Crypt_RSA_ErrorHandler();
if ($wrapper_name === 'default') {
// try to load the most suitable wrapper
$n = sizeof($math_wrappers);
for ($i = 0; $i < $n; $i++) {
$obj = Crypt_RSA_MathLoader::loadWrapper($math_wrappers[$i]);
if (!$err_handler->isError($obj)) {
// wrapper for $math_wrappers[$i] successfully loaded
// register it as default wrapper and return reference to it
return $math_objects['default'] = $obj;
}
}
// can't load any wrapper
$err_handler->pushError("can't load any wrapper for existing math libraries", CRYPT_RSA_ERROR_NO_WRAPPERS);
return $err_handler->getLastError();
}
$class_name = 'Crypt_RSA_Math_' . $wrapper_name;
$class_filename = dirname(__FILE__) . '/Math/' . $wrapper_name . '.php';
if (!is_file($class_filename)) {
$err_handler->pushError("can't find file [{$class_filename}] for RSA math wrapper [{$wrapper_name}]", CRYPT_RSA_ERROR_NO_FILE);
return $err_handler->getLastError();
}
include_once $class_filename;
if (!class_exists($class_name)) {
$err_handler->pushError("can't find class [{$class_name}] in file [{$class_filename}]", CRYPT_RSA_ERROR_NO_CLASS);
return $err_handler->getLastError();
}
// create and return wrapper object on success or PEAR_Error object on error
$obj = new $class_name();
if ($obj->errstr) {
// cannot load required extension for math wrapper
$err_handler->pushError($obj->errstr, CRYPT_RSA_ERROR_NO_EXT);
return $err_handler->getLastError();
}
return $math_objects[$wrapper_name] = $obj;
}
