diff --git a/src/util/macros.rs b/src/util/macros.rs
new file mode 100644
index 0000000..c5be1d8
--- /dev/null
+++ b/src/util/macros.rs
@@ -0,0 +1,5 @@
+#[macro_export] macro_rules! static_assert {
+    ($ex:expr) => {
+	const _: &[bool; ((($ex) == true) as usize)] = &[true];
+    }
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
new file mode 100644
index 0000000..02b5fd3
--- /dev/null
+++ b/src/util/mod.rs
@@ -0,0 +1,17 @@
+#[allow(unused_imports)]
+use std::{
+    ops::{
+	Drop,
+	Deref,
+	DerefMut,
+    },
+    mem::{
+	replace,
+	MaybeUninit,
+    },
+    fmt,
+};
+
+#[macro_use] mod macros; pub use macros::*;
+mod opaque; pub use opaque::*;
+mod phantom_drop; pub use phantom_drop::*;
diff --git a/src/util/opaque.rs b/src/util/opaque.rs
new file mode 100644
index 0000000..73b658f
--- /dev/null
+++ b/src/util/opaque.rs
@@ -0,0 +1,58 @@
+use super::*;
+
+/// Enabled `#[derive(Debug)]` on types with fields that are not `Debug`.
+pub struct Opaque<T>(T);
+
+impl<T> Opaque<T>
+{
+    /// Create a new `Opaque` wrapper around `value`.
+    #[inline]
+    pub const fn new(value: T) -> Self
+    {
+	Self(value)
+    }
+
+    /// Consume `Opaque` and get back the inner value.
+    #[inline]
+    pub fn into(self) -> T
+    {
+	self.0
+    }
+}
+
+impl<T> From<T> for Opaque<T>
+{
+    fn from(from: T) -> Self
+    {
+	Self(from)
+    }
+}
+
+impl<T> std::fmt::Debug for Opaque<T>
+{
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	write!(f, "<opaque type>")
+    }
+}
+
+impl<T> Deref for Opaque<T>
+{
+    type Target = T;
+    #[inline]
+    fn deref(&self) -> &Self::Target
+    {
+	&self.0
+    }
+}
+
+
+impl<T> DerefMut for Opaque<T>
+{
+    #[inline]
+    fn deref_mut(&mut self) -> &mut <Self as Deref>::Target
+    {
+	&mut self.0
+    }
+}
diff --git a/src/util.rs b/src/util/phantom_drop.rs
similarity index 70%
rename from src/util.rs
rename to src/util/phantom_drop.rs
index c4bdb85..86c7244 100644
--- a/src/util.rs
+++ b/src/util/phantom_drop.rs
@@ -1,19 +1,6 @@
-#[allow(unused_imports)]
-use std::{
-    ops::{
-	Drop,
-	Deref,
-	DerefMut,
-    },
-    mem::{
-	replace,
-	MaybeUninit,
-    },
-    fmt,
-};
+use super::*;
 use cfg_if::cfg_if;
 
-
 #[cfg(not(debug_assertions))]
 type OptFn<T,F> = MaybeUninit<(T,F)>;
 #[cfg(debug_assertions)]
@@ -165,68 +152,3 @@ where F:FnOnce(T)
 	
     }
 }
-
-/// Enabled `#[derive(Debug)]` on types with fields that are not `Debug`.
-pub struct Opaque<T>(T);
-
-impl<T> Opaque<T>
-{
-    /// Create a new `Opaque` wrapper around `value`.
-    #[inline]
-    pub const fn new(value: T) -> Self
-    {
-	Self(value)
-    }
-
-    /// Consume `Opaque` and get back the inner value.
-    #[inline]
-    pub fn into(self) -> T
-    {
-	self.0
-    }
-}
-
-impl<T> From<T> for Opaque<T>
-{
-    fn from(from: T) -> Self
-    {
-	Self(from)
-    }
-}
-
-impl<T> std::fmt::Debug for Opaque<T>
-{
-    #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
-    {
-	write!(f, "<opaque type>")
-    }
-}
-
-impl<T> Deref for Opaque<T>
-{
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &Self::Target
-    {
-	&self.0
-    }
-}
-
-
-impl<T> DerefMut for Opaque<T>
-{
-    #[inline]
-    fn deref_mut(&mut self) -> &mut <Self as Deref>::Target
-    {
-	&mut self.0
-    }
-}
-
-// static assert
-
-#[macro_export] macro_rules! static_assert {
-    ($ex:expr) => {
-	const _: &[bool; ((($ex) == true) as usize)] = &[true];
-    }
-}