refactor: improve no-std support

Cargo.toml

@@ -10,4 +10,8 @@ readme        = "README.md"
 license       = "MIT"
 description   = "An unsafe reference without explicit lifetime"
 keywords      = []
-categories    = []
+categories    = ["rust-patterns", "no-std", "no-std::no-alloc"]
+
+[features]
+default = ["alloc"]
+alloc   = []

README.md

@@ -3,8 +3,6 @@
     An unsafe reference without explicit lifetime
 </div>
 
-<br>
-
 <div align="right">
     <a href="https://github.com/ohkami-rs/unsaferef/blob/main/LICENSE"><img alt="License" src="https://img.shields.io/crates/l/unsaferef.svg" /></a>
     <a href="https://github.com/ohkami-rs/unsaferef/actions"><img alt="CI status" src="https://github.com/ohkami-rs/unsaferef/actions/workflows/CI.yml/badge.svg"/></a>
@@ -30,6 +28,12 @@ fn main() {
 }
 ```
 
+## no-std and cow
+
+`UnsafeRef` supports `no-std::no-alloc`.
+
+On `alloc` feature ( default ), unsaferef additionally provides `UnsafeCow`, an unsafe Clone-on-Write container without explicit lifetime.
+
 ## License
 
 unsaferef is licensed under MIT LICENSE ( [LICENSE](https://github.com/ohkami-rs/unsaferef/blob/main/LICENSE) or [https://opensource.org/licenses/MIT](https://opensource.org/licenses/MIT) ).

Taskfile.yaml

@@ -19,12 +19,14 @@ tasks:
   test:doc:
     cmds:
       - cargo test --doc
-      
+
   test:lib:
     cmds:
-      - cargo test --lib
+      - cargo test --lib --no-default-features
+      - cargo test --lib --features alloc
 
   ##### check #####
   check:lib:
     cmds:
-      - cargo check
+      - cargo check --no-default-features
+      - cargo check --features alloc

src/lib.rs

@@ -3,7 +3,9 @@
 mod test_readme {}
 
 mod unsafe_ref;
-mod unsafe_cow;
-
 pub use unsafe_ref::UnsafeRef;
+
+#[cfg(feature="alloc")]
+mod unsafe_cow;
+#[cfg(feature="alloc")]
 pub use unsafe_cow::UnsafeCow;

src/unsafe_cow.rs

@@ -1,3 +1,5 @@
+#![cfg(feature="alloc")]
+
 use crate::UnsafeRef;
 
 pub enum UnsafeCow<T: ?Sized + ToOwned> {

src/unsafe_ref.rs

@@ -1,4 +1,4 @@
-use std::ptr::NonNull;
+use core::ptr::NonNull;
 
 pub struct UnsafeRef<T: ?Sized>(NonNull<T>);
 
@@ -20,7 +20,7 @@ impl<T: ?Sized> Clone for UnsafeRef<T> {
 }
 impl<T: ?Sized> Copy for UnsafeRef<T> {}
 
-impl<T: ?Sized> std::ops::Deref for UnsafeRef<T> {
+impl<T: ?Sized> core::ops::Deref for UnsafeRef<T> {
     type Target = T;
 
     #[inline(always)]
@@ -30,24 +30,24 @@ impl<T: ?Sized> std::ops::Deref for UnsafeRef<T> {
     }
 }
 
-impl<T: ?Sized + std::hash::Hash> std::hash::Hash for UnsafeRef<T> {
+impl<T: ?Sized + core::hash::Hash> core::hash::Hash for UnsafeRef<T> {
     #[inline]
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
         (&**self).hash(state);
     }
 }
 
-impl<T: ?Sized + std::fmt::Debug> std::fmt::Debug for UnsafeRef<T> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+impl<T: ?Sized + core::fmt::Debug> core::fmt::Debug for UnsafeRef<T> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         f.debug_tuple("UnsafeRef")
             .field(&&**self)
             .finish()
     }
 }
-impl<T: ?Sized + std::fmt::Display> std::fmt::Display for UnsafeRef<T> {
+impl<T: ?Sized + core::fmt::Display> core::fmt::Display for UnsafeRef<T> {
     #[inline]
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        std::fmt::Display::fmt(&**self, f)
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        core::fmt::Display::fmt(&**self, f)
     }
 }