diff --git a/src/url-state-machine.js b/src/url-state-machine.js
index 047052f..a9494f7 100644
--- a/src/url-state-machine.js
+++ b/src/url-state-machine.js
@@ -323,10 +323,10 @@ function parseIPv6(input) {
         } else {
           value = value * 10 + number;
         }
-        ++pointer;
         if (value > 255) {
           return failure;
         }
+        ++pointer;
       }
 
       ip[piecePtr] = ip[piecePtr] * 0x100 + value;
@@ -336,10 +336,9 @@ function parseIPv6(input) {
       if (numbersSeen === 2 || numbersSeen === 4) {
         ++piecePtr;
       }
-
-      if (input[pointer] === undefined && numbersSeen !== 4) {
-        return failure;
-      }
+    }
+    if (numbersSeen !== 4) {
+      return failure;
     }
   }