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<?php
/*
* The RandomLib library for securely generating random numbers and strings in PHP
*
* @author Anthony Ferrara <ircmaxell@ircmaxell.com>
* @copyright 2011 The Authors
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @version Build @@version@@
*/
/**
* The Random Factory
*
* Use this factory to instantiate random number generators, sources and mixers.
*
* PHP version 5.3
*
* @category PHPPasswordLib
* @package Random
*
* @author Anthony Ferrara <ircmaxell@ircmaxell.com>
* @copyright 2011 The Authors
* @license http://www.opensource.org/licenses/mit-license.html MIT License
*
* @version Build @@version@@
*/
namespace RandomLib;
use SecurityLib\Strength;
/**
* The Random Factory
*
* Use this factory to instantiate random number generators, sources and mixers.
*
* @category PHPPasswordLib
* @package Random
*
* @author Anthony Ferrara <ircmaxell@ircmaxell.com>
*/
class Factory extends \SecurityLib\AbstractFactory
{
/**
* @var array A list of available random number mixing strategies
*/
protected $mixers = array();
/**
* @var array A list of available random number sources
*/
protected $sources = array();
/**
* Build a new instance of the factory, loading core mixers and sources
*
* @return void
*/
public function __construct()
{
$this->loadMixers();
$this->loadSources();
}
/**
* Get a generator for the requested strength
*
* @param Strength $strength The requested strength of the random number
*
* @throws RuntimeException If an appropriate mixing strategy isn't found
*
* @return Generator The instantiated generator
*/
public function getGenerator(\SecurityLib\Strength $strength)
{
$sources = $this->findSources($strength);
$mixer = $this->findMixer($strength);
return new Generator($sources, $mixer);
}
/**
* Get a high strength random number generator
*
* High Strength keys should ONLY be used for generating extremely strong
* cryptographic keys. Generating them is very resource intensive and may
* take several minutes or more depending on the requested size.
*
* @return Generator The instantiated generator
*/
public function getHighStrengthGenerator()
{
return $this->getGenerator(new Strength(Strength::HIGH));
}
/**
* Get a low strength random number generator
*
* Low Strength should be used anywhere that random strings are needed in a
* non-cryptographical setting. They are not strong enough to be used as
* keys or salts. They are however useful for one-time use tokens.
*
* @return Generator The instantiated generator
*/
public function getLowStrengthGenerator()
{
return $this->getGenerator(new Strength(Strength::LOW));
}
/**
* Get a medium strength random number generator
*
* Medium Strength should be used for most needs of a cryptographic nature.
* They are strong enough to be used as keys and salts. However, they do
* take some time and resources to generate, so they should not be over-used
*
* @return Generator The instantiated generator
*/
public function getMediumStrengthGenerator()
{
return $this->getGenerator(new Strength(Strength::MEDIUM));
}
/**
* Get all loaded mixing strategies
*
* @return array An array of mixers
*/
public function getMixers()
{
return $this->mixers;
}
/**
* Get all loaded random number sources
*
* @return array An array of sources
*/
public function getSources()
{
return $this->sources;
}
/**
* Register a mixing strategy for this factory instance
*
* @param string $name The name of the stategy
* @param string $class The class name of the implementation
*
* @return Factory $this The current factory instance
*/
public function registerMixer($name, $class)
{
$this->registerType(
'mixers',
__NAMESPACE__ . '\\Mixer',
$name,
$class
);
return $this;
}
/**
* Register a random number source for this factory instance
*
* Note that this class must implement the Source interface
*
* @param string $name The name of the stategy
* @param string $class The class name of the implementation
*
* @return Factory $this The current factory instance
*/
public function registerSource($name, $class)
{
$this->registerType(
'sources',
__NAMESPACE__ . '\\Source',
$name,
$class
);
return $this;
}
/**
* Find a sources based upon the requested strength
*
* @param Strength $strength The strength mixer to find
*
* @throws RuntimeException if a valid source cannot be found
*
* @return Source The found source
*/
protected function findSources(\SecurityLib\Strength $strength)
{
$sources = array();
foreach ($this->getSources() as $source) {
if ($strength->compare($source::getStrength()) <= 0 && $source::isSupported()) {
$sources[] = new $source();
}
}
if (0 === count($sources)) {
throw new \RuntimeException('Could not find sources');
}
return $sources;
}
/**
* Find a mixer based upon the requested strength
*
* @param Strength $strength The strength mixer to find
*
* @throws RuntimeException if a valid mixer cannot be found
*
* @return Mixer The found mixer
*/
protected function findMixer(\SecurityLib\Strength $strength)
{
$newMixer = null;
$fallback = null;
foreach ($this->getMixers() as $mixer) {
if (!$mixer::test()) {
continue;
}
if ($strength->compare($mixer::getStrength()) == 0) {
$newMixer = new $mixer();
} elseif ($strength->compare($mixer::getStrength()) == 1) {
$fallback = new $mixer();
}
}
if (is_null($newMixer)) {
if (is_null($fallback)) {
throw new \RuntimeException('Could not find mixer');
}
return $fallback;
}
return $newMixer;
}
/**
* Load all core mixing strategies
*
* @return void
*/
protected function loadMixers()
{
$this->loadFiles(
__DIR__ . '/Mixer',
__NAMESPACE__ . '\\Mixer\\',
array($this, 'registerMixer')
);
}
/**
* Load all core random number sources
*
* @return void
*/
protected function loadSources()
{
$this->loadFiles(
__DIR__ . '/Source',
__NAMESPACE__ . '\\Source\\',
array($this, 'registerSource')
);
}
}
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