feat: add core-net feature (#30)

* feat: add core-net feature

* chore: rustfmt

crates/rlp/Cargo.toml

@@ -33,6 +33,9 @@ hex-literal.workspace = true
 default = ["std"]
 std = ["bytes/std", "arrayvec?/std"]
 derive = ["dep:alloy-rlp-derive"]
+# Enables `core::net::` implementations always instead of conditionally through `std`.
+# Requires Rust 1.77 or newer.
+core-net = []
 
 arrayvec = ["dep:arrayvec"]
 

crates/rlp/src/decode.rs

@@ -142,9 +142,12 @@ where
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", feature = "core-net"))]
 mod std_impl {
     use super::*;
+    #[cfg(all(feature = "core-net", not(feature = "std")))]
+    use core::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+    #[cfg(feature = "std")]
     use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 
     impl Decodable for IpAddr {
@@ -175,6 +178,11 @@ mod std_impl {
             slice_to_array::<16>(bytes).map(Self::from)
         }
     }
+
+    #[inline]
+    fn slice_to_array<const N: usize>(slice: &[u8]) -> Result<[u8; N]> {
+        slice.try_into().map_err(|_| Error::UnexpectedLength)
+    }
 }
 
 /// Decodes the entire input, ensuring no trailing bytes remain.
@@ -223,12 +231,6 @@ pub(crate) fn static_left_pad<const N: usize>(data: &[u8]) -> Result<[u8; N]> {
     Ok(v)
 }
 
-#[cfg(feature = "std")]
-#[inline]
-fn slice_to_array<const N: usize>(slice: &[u8]) -> Result<[u8; N]> {
-    slice.try_into().map_err(|_| Error::UnexpectedLength)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

crates/rlp/src/encode.rs

@@ -237,9 +237,12 @@ deref_impl! {
     [T: ?Sized + Encodable] alloc::sync::Arc<T>,
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", feature = "core-net"))]
 mod std_support {
     use super::*;
+    #[cfg(all(feature = "core-net", not(feature = "std")))]
+    use core::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+    #[cfg(feature = "std")]
     use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 
     impl Encodable for IpAddr {