diff --git a/Tests/xdiffTest.php b/Tests/xdiffTest.php
index 9c2907b..77b1ef7 100644
--- a/Tests/xdiffTest.php
+++ b/Tests/xdiffTest.php
@@ -290,4 +290,50 @@ to this document.
 +\n");
   }
 
+  public function test_diffFile_unified_1 ()
+  {
+    file_put_contents ("/tmp/test_xdiff1", $this->string1);
+    file_put_contents ("/tmp/test_xdiff2", $this->string2);
+    $xdiff = new xdiff ("unified");
+    $res = $xdiff->diffFile ("/tmp/test_xdiff1", "/tmp/test_xdiff2");
+    $this->assertSame ($res, "--- /tmp/test_xdiff1 ".date ("Y-m-d H:i:s.u000 O")."
++++ /tmp/test_xdiff2 ".date ("Y-m-d H:i:s.u001 O")."
+@@ -0,0 +1,6 @@
++This is an important
++notice! It should
++therefore be located at
++the beginning of this
++document!
++
+@@ -11,5 +16,0 @@
+-This paragraph contains
+-text that is outdated.
+-It will be deleted in the
+-near future.
+-
+@@ -17 +18 @@
+-check this dokument. On
++check this document. On
+@@ -24,0 +26,4 @@
++
++This paragraph contains
++important new additions
++to this document.
+");
+
+  }
+
+  public function test_diffFile_unified_2 ()
+  {
+    $xdiff = new xdiff ("unified");
+    $this->setExpectedException ();
+    $res = $xdiff->diffFile ("/tmp/test_xdiffNOTEXISTS", "/tmp/test_xdiff2");
+  }
+
+  public function test_diffFile_unified_3 ()
+  {
+    $xdiff = new xdiff ("unified");
+    $this->setExpectedException ();
+    $res = $xdiff->diffFile ("/tmp/test_xdiff1", "/tmp/test_xdiffNOTEXISTS");
+  }
 }
diff --git a/xdiff.php b/xdiff.php
index 9510618..6ee2ec0 100644
--- a/xdiff.php
+++ b/xdiff.php
@@ -196,13 +196,6 @@ class xdiff
       if (empty ($chunk1) && ! empty ($chunk2))
       {
         //   APPEND
-        while ($j < count ($array2))
-        {
-          if ($array2[$j] === $lcs)
-            break;
-          $chunk2[] = $array2[$j];
-          $j++;
-        }
         $diff[] = array ("type"       => "Append",
                          "startLine1" => $i,
                          "endLine1"   => $i,
@@ -214,13 +207,6 @@ class xdiff
       elseif (! empty ($chunk1) && empty ($chunk2))
       {
         //   DELETE
-        while ($i < count ($array1))
-        {
-          if ($array1[$i] === $lcs)
-            break;
-          $chunk1[] = $array1[$i];
-          $i++;
-        }
         $diff[] = array ("type"       => "Delete",
                          "startLine1" => 1 + $i - count ($chunk1),
                          "endLine1"   => $i,
@@ -232,20 +218,6 @@ class xdiff
       else
       {
         //   CHANGE ON BOTH ARRAY
-        while ($i < count ($array1))
-        {
-          if ($array1[$i] === $lcs)
-            break;
-          $chunk1[] = $array1[$i];
-          $i++;
-        }
-        while ($j < count ($array2))
-        {
-          if ($array2[$j] === $lcs)
-            break;
-          $chunk2[] = $array2[$j];
-          $j++;
-        }
         $diff[] = array ("type"       => "Change",
                          "startLine1" => 1 + $i - count ($chunk1),
                          "endLine1"   => $i,