diff --git a/src/LTDBeget/stringstream/StringStream.php b/src/LTDBeget/stringstream/StringStream.php
index addc4c2..872e55b 100644
--- a/src/LTDBeget/stringstream/StringStream.php
+++ b/src/LTDBeget/stringstream/StringStream.php
@@ -30,11 +30,11 @@ public function __construct(string $string)
 
     /**
      * Current char of stream
-     * @return string
+     * @return string|null
      */
-    public function current() : string
+    public function current()
     {
-        return current($this->stream);
+        return $this->stream->current();
     }
 
     /**
@@ -62,7 +62,7 @@ public function currentAscii() : AsciiChar
      */
     public function position() : int
     {
-        return key($this->stream);
+        return $this->stream->key();
     }
 
     /**
@@ -71,7 +71,12 @@ public function position() : int
     public function next()
     {
         $this->pointerAtStart = false;
-        $this->pointerAtEnd = next($this->stream) === false;
+        if ($this->stream->key() === $this->stream->count() - 1) {
+            $this->pointerAtEnd = true;
+        } else {
+            $this->pointerAtEnd = false;
+            $this->stream->next();
+        }
     }
 
     /**
@@ -80,7 +85,13 @@ public function next()
     public function previous()
     {
         $this->pointerAtEnd = false;
-        $this->pointerAtStart = prev($this->stream) === false;
+        $this->pointerAtStart = false;
+        if ($this->stream->key() == 0) {
+            $this->pointerAtStart = true;
+        } else {
+            $prevPos = $this->stream->key() - 1;
+            $this->stream->seek($prevPos);
+        }
     }
 
     /**
@@ -88,7 +99,7 @@ public function previous()
      */
     public function start()
     {
-        reset($this->stream);
+        $this->stream->rewind();
     }
 
     /**
@@ -105,7 +116,7 @@ public function isStart() : bool
      */
     public function end()
     {
-        end($this->stream);
+        $this->stream->seek($this->stream->count() - 1);
     }
 
     /**
@@ -169,7 +180,7 @@ private function makeIterator(string $string) : ArrayIterator
     }
 
     /**
-     * @var array
+     * @var ArrayIterator
      */
     private $stream;