diff --git a/lib/random_bytes_dev_urandom.php b/lib/random_bytes_dev_urandom.php
index 5a5b370..8bf7034 100644
--- a/lib/random_bytes_dev_urandom.php
+++ b/lib/random_bytes_dev_urandom.php
@@ -1,22 +1,22 @@
 <?php
 /**
- * Random_* Compatibility Library
+ * Random_* Compatibility Library 
  * for using the new PHP 7 random_* API in PHP 5 projects
- *
+ * 
  * The MIT License (MIT)
- *
- * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises
- *
+ * 
+ * Copyright (c) 2015 Paragon Initiative Enterprises
+ * 
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
- *
+ * 
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
- *
+ * 
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -67,16 +67,16 @@ function random_bytes($bytes)
             if (!empty($fp)) {
                 /**
                  * stream_set_read_buffer() does not exist in HHVM
-                 *
+                 * 
                  * If we don't set the stream's read buffer to 0, PHP will
                  * internally buffer 8192 bytes, which can waste entropy
-                 *
+                 * 
                  * stream_set_read_buffer returns 0 on success
                  */
-                if (is_callable('stream_set_read_buffer')) {
+                if (function_exists('stream_set_read_buffer')) {
                     stream_set_read_buffer($fp, RANDOM_COMPAT_READ_BUFFER);
                 }
-                if (is_callable('stream_set_chunk_size')) {
+                if (function_exists('stream_set_chunk_size')) {
                     stream_set_chunk_size($fp, RANDOM_COMPAT_READ_BUFFER);
                 }
             }
@@ -104,50 +104,33 @@ function random_bytes($bytes)
          * page load.
          */
         if (!empty($fp)) {
-            /**
-             * @var int
-             */
             $remaining = $bytes;
-
-            /**
-             * @var string|bool
-             */
             $buf = '';
 
             /**
              * We use fread() in a loop to protect against partial reads
              */
             do {
-                /**
-                 * @var string|bool
-                 */
                 $read = fread($fp, $remaining);
-                if (!is_string($read)) {
-                    if ($read === false) {
-                        /**
-                         * We cannot safely read from the file. Exit the
-                         * do-while loop and trigger the exception condition
-                         *
-                         * @var string|bool
-                         */
-                        $buf = false;
-                        break;
-                    }
+                if ($read === false) {
+                    /**
+                     * We cannot safely read from the file. Exit the
+                     * do-while loop and trigger the exception condition
+                     */
+                    $buf = false;
+                    break;
                 }
                 /**
                  * Decrease the number of bytes returned from remaining
                  */
                 $remaining -= RandomCompat_strlen($read);
-                /**
-                 * @var string|bool
-                 */
-                $buf = $buf . $read;
+                $buf .= $read;
             } while ($remaining > 0);
 
             /**
              * Is our result valid?
              */
-            if (is_string($buf)) {
+            if ($buf !== false) {
                 if (RandomCompat_strlen($buf) === $bytes) {
                     /**
                      * Return our random entropy buffer here: