Add an ext/hash compatibility layer (just hash_pbkdf2(), for now)
diff --git a/system/core/compat/hash.php b/system/core/compat/hash.php
new file mode 100644
index 0000000..a9f59f1
--- /dev/null
+++ b/system/core/compat/hash.php
@@ -0,0 +1,144 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst. It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package CodeIgniter
+ * @author EllisLab Dev Team
+ * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
+ * @license http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link http://codeigniter.com
+ * @since Version 3.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PHP ext/hash compatibility package
+ *
+ * @package CodeIgniter
+ * @subpackage CodeIgniter
+ * @category Compatibility
+ * @author Andrey Andreev
+ * @link http://codeigniter.com/user_guide/
+ * @link http://php.net/hash
+ */
+
+// ------------------------------------------------------------------------
+
+if (is_php('5.5'))
+{
+ return;
+}
+
+// ------------------------------------------------------------------------
+
+if ( ! function_exists('hash_pbkdf2'))
+{
+ /**
+ * hash_pbkdf2()
+ *
+ * @link http://php.net/hash_pbkdf2
+ * @param string $algo
+ * @param string $password
+ * @param string $salt
+ * @param int $iterations
+ * @param int $length
+ * @param bool $raw_output
+ * @return string
+ */
+ function hash_pbkdf2($algo, $password, $salt, $iterations, $length = 0, $raw_output = FALSE)
+ {
+ if ( ! in_array($algo, hash_algos(), TRUE))
+ {
+ trigger_error('hash_pbkdf2(): Unknown hashing algorithm: '.$algo, E_USER_WARNING);
+ return FALSE;
+ }
+
+ if (($type = gettype($iterations)) !== 'integer')
+ {
+ if ($type === 'object' && method_exists($iterations, '__toString'))
+ {
+ $iterations = (string) $iterations;
+ }
+
+ if (is_string($iterations) && is_numeric($iterations))
+ {
+ $iterations = (int) $iterations;
+ }
+ else
+ {
+ trigger_error('hash_pbkdf2() expects parameter 4 to be long, '.$type.' given', E_USER_WARNING);
+ return NULL;
+ }
+ }
+
+ if ($iterations < 1)
+ {
+ trigger_error('hash_pbkdf2(): Iterations must be a positive integer: '.$iterations, E_USER_WARNING);
+ return FALSE;
+ }
+
+ if (($type = gettype($length)) !== 'integer')
+ {
+ if ($type === 'object' && method_exists($length, '__toString'))
+ {
+ $length = (string) $length;
+ }
+
+ if (is_string($length) && is_numeric($length))
+ {
+ $length = (int) $length;
+ }
+ else
+ {
+ trigger_error('hash_pbkdf2() expects parameter 5 to be long, '.$type.' given', E_USER_WARNING);
+ return NULL;
+ }
+ }
+
+ if ($length < 0)
+ {
+ trigger_error('hash_pbkdf2(): Length must be greater than or equal to 0: '.$length, E_USER_WARNING);
+ return FALSE;
+ }
+
+ $hash_length = strlen(hash($algo, NULL, TRUE));
+ if (empty($length))
+ {
+ $length = $hash_length;
+ }
+
+ $hash = '';
+ // Note: Blocks are NOT 0-indexed
+ for ($bc = ceil($length / $hash_length), $bi = 1; $bi <= $bc; $bi++)
+ {
+ $key = $derived_key = hash_hmac($algo, $salt.pack('N', $bi), $password, TRUE);
+ for ($i = 1; $i < $iterations; $i++)
+ {
+ $derived_key ^= $key = hash_hmac($algo, $key, $password, TRUE);
+ }
+
+ $hash .= $derived_key;
+ }
+
+ // This is not RFC-compatible, but we're aiming for natural PHP compatibility
+ return substr($raw_output ? $hash : bin2hex($hash), 0, $length);
+ }
+}
+
+/* End of file hash.php */
+/* Location: ./system/core/compat/hash.php */
\ No newline at end of file