diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -82,7 +82,7 @@
 {-# LANGUAGE OverloadedStrings, RecordWildCards #-}
 
 import qualified Jsonifier as J
-import qualified Data.ByteString.Char8 as Char8ByteString
+import qualified Data.ByteString.Char8
 
 
 {-|
@@ -91,7 +91,7 @@
 > {"name":"Metallica","genres":[{"name":"Metal"},{"name":"Rock"},{"name":"Blues"}]}
 -}
 main =
-  Char8ByteString.putStrLn (J.toByteString (artistJson metallica))
+  Data.ByteString.Char8.putStrLn (J.toByteString (artistJson metallica))
 
 metallica :: Artist
 metallica =
diff --git a/cbits/json_allocation.c b/cbits/json_allocation.c
--- a/cbits/json_allocation.c
+++ b/cbits/json_allocation.c
@@ -14,13 +14,9 @@
 int count_string_allocation
 (
   const uint16_t *src_ptr,
-  size_t src_off,
-  size_t src_len
+  const uint16_t *end_ptr
 )
 {
-  src_ptr += src_off;
-  const uint16_t *end_ptr = src_ptr + src_len;
-
   size_t allocation = 0;
 
   while (src_ptr < end_ptr) {
@@ -44,4 +40,17 @@
   }
 
   return allocation;
+}
+
+int count_string_allocation_off_len
+(
+  const uint16_t *src_ptr,
+  size_t src_off,
+  size_t src_len
+)
+{
+  src_ptr += src_off;
+  const uint16_t *end_ptr = src_ptr + src_len;
+
+  return count_string_allocation(src_ptr, end_ptr);
 }
diff --git a/demo/Main.hs b/demo/Main.hs
--- a/demo/Main.hs
+++ b/demo/Main.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE OverloadedStrings, RecordWildCards #-}
 
 import qualified Jsonifier as J
-import qualified Data.ByteString.Char8 as Char8ByteString
+import qualified Data.ByteString.Char8
 
 
 {-|
@@ -10,7 +10,7 @@
 > {"name":"Metallica","genres":[{"name":"Metal"},{"name":"Rock"},{"name":"Blues"}]}
 -}
 main =
-  Char8ByteString.putStrLn (J.toByteString (artistJson metallica))
+  Data.ByteString.Char8.putStrLn (J.toByteString (artistJson metallica))
 
 metallica :: Artist
 metallica =
diff --git a/jsonifier.cabal b/jsonifier.cabal
--- a/jsonifier.cabal
+++ b/jsonifier.cabal
@@ -1,5 +1,5 @@
 name: jsonifier
-version: 0.1.0.5
+version: 0.1.0.6
 synopsis: Fast and simple JSON encoding toolkit
 description:
   Minimalistic library for encoding JSON directly to strict bytestring,
@@ -42,7 +42,7 @@
   build-depends:
     base >=4.11 && <5,
     bytestring >=0.10.10 && <0.12,
-    ptr-poker >=0.1 && <0.2,
+    ptr-poker >=0.1.1.3 && <0.2,
     scientific >=0.3.6.2 && <0.4,
     text >=1 && <2
 
diff --git a/library/Jsonifier/Ffi.hs b/library/Jsonifier/Ffi.hs
--- a/library/Jsonifier/Ffi.hs
+++ b/library/Jsonifier/Ffi.hs
@@ -7,7 +7,7 @@
 import GHC.Base (ByteArray#, MutableByteArray#)
 
 
-foreign import ccall unsafe "static count_string_allocation"
+foreign import ccall unsafe "static count_string_allocation_off_len"
   countStringAllocationSize :: ByteArray# -> CSize -> CSize -> IO CInt
 
 foreign import ccall unsafe "static encode_utf16_as_string"