<?php
namespace Aws;
/**
* Incremental hashing using PHP's hash functions.
*/
class PhpHash implements HashInterface
{
/** @var resource|\HashContext */
private $context;
/** @var string */
private $algo;
/** @var array */
private $options;
/** @var string */
private $hash;
/**
* @param string $algo Hashing algorithm. One of PHP's hash_algos()
* return values (e.g. md5, sha1, etc...).
* @param array $options Associative array of hashing options:
* - key: Secret key used with the hashing algorithm.
* - base64: Set to true to base64 encode the value when complete.
*/
public function __construct($algo, array $options = [])
{
$this->algo = $algo;
$this->options = $options;
}
public function update($data)
{
if ($this->hash !== null) {
$this->reset();
}
hash_update($this->getContext(), $data);
}
public function complete()
{
if ($this->hash) {
return $this->hash;
}
$this->hash = hash_final($this->getContext(), true);
if (isset($this->options['base64']) && $this->options['base64']) {
$this->hash = base64_encode($this->hash);
}
return $this->hash;
}
public function reset()
{
$this->context = $this->hash = null;
}
/**
* Get a hash context or create one if needed
*
* @return resource|\HashContext
*/
private function getContext()
{
if (!$this->context) {
$key = isset($this->options['key']) ? $this->options['key'] : null;
$this->context = hash_init(
$this->algo,
$key ? HASH_HMAC : 0,
$key
);
}
return $this->context;
}
}