1 files changed, 1 insertions, 1 deletions
diff --git a/src/bytes_mut.rs b/src/bytes_mut.rs
index 88d7f00..cc1a3ba 100644
--- a/src/bytes_mut.rs
+++ b/src/bytes_mut.rs
@@ -646,7 +646,7 @@ impl BytesMut {
                     self.cap = v.capacity();
                 } else {
                     // calculate offset
-                    let off = v.capacity() - self.cap;
+                    let off = (self.ptr.as_ptr() as usize) - (v.as_ptr() as usize);
 
                     // new_cap is calculated in terms of `BytesMut`, not the underlying
                     // `Vec`, so it does not take the offset into account.