Merge pull request #28 from sgued/byte-array

Add support for `[u8; N]`

Author: dtolnay

Cargo.toml

@@ -9,7 +9,7 @@ edition = "2018"
 keywords = ["serde", "serialization", "no_std", "bytes"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/serde-rs/bytes"
-rust-version = "1.31"
+rust-version = "1.53"
 
 [features]
 default = ["std"]

src/bytearray.rs

@@ -0,0 +1,225 @@
+use crate::Bytes;
+use core::borrow::{Borrow, BorrowMut};
+use core::cmp::Ordering;
+use core::convert::TryInto;
+use core::fmt::{self, Debug};
+use core::hash::{Hash, Hasher};
+use core::ops::{Deref, DerefMut};
+
+use serde::de::{Deserialize, Deserializer, Error, SeqAccess, Visitor};
+use serde::ser::{Serialize, Serializer};
+
+/// Wrapper around `[u8; N]` to serialize and deserialize efficiently.
+///
+/// ```
+/// use std::collections::HashMap;
+/// use std::io;
+///
+/// use serde_bytes::ByteArray;
+///
+/// fn deserialize_bytearrays() -> bincode::Result<()> {
+///     let example_data = [
+///         2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 116,
+///         119, 111, 1, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 111, 110, 101
+///     ];
+///
+///     let map: HashMap<u32, ByteArray<3>> = bincode::deserialize(&example_data[..])?;
+///
+///     println!("{:?}", map);
+///
+///     Ok(())
+/// }
+/// #
+/// # fn main() {
+/// #     deserialize_bytearrays().unwrap();
+/// # }
+/// ```
+#[derive(Clone, Eq, Ord)]
+pub struct ByteArray<const N: usize> {
+    bytes: [u8; N],
+}
+
+impl<const N: usize> ByteArray<N> {
+    /// Transform an [array](https://doc.rust-lang.org/stable/std/primitive.array.html) to the equivalent `ByteArray`
+    pub fn new(bytes: [u8; N]) -> Self {
+        Self { bytes }
+    }
+
+    /// Wrap existing bytes into a `ByteArray`
+    pub fn from<T: Into<[u8; N]>>(bytes: T) -> Self {
+        Self {
+            bytes: bytes.into(),
+        }
+    }
+
+    /// Unwraps the byte array underlying this `ByteArray`
+    pub fn into_array(self) -> [u8; N] {
+        self.bytes
+    }
+}
+
+impl<const N: usize> Debug for ByteArray<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        Debug::fmt(&self.bytes, f)
+    }
+}
+
+impl<const N: usize> AsRef<[u8; N]> for ByteArray<N> {
+    fn as_ref(&self) -> &[u8; N] {
+        &self.bytes
+    }
+}
+impl<const N: usize> AsMut<[u8; N]> for ByteArray<N> {
+    fn as_mut(&mut self) -> &mut [u8; N] {
+        &mut self.bytes
+    }
+}
+
+impl<const N: usize> Borrow<[u8; N]> for ByteArray<N> {
+    fn borrow(&self) -> &[u8; N] {
+        &self.bytes
+    }
+}
+impl<const N: usize> BorrowMut<[u8; N]> for ByteArray<N> {
+    fn borrow_mut(&mut self) -> &mut [u8; N] {
+        &mut self.bytes
+    }
+}
+
+impl<const N: usize> Deref for ByteArray<N> {
+    type Target = [u8; N];
+
+    fn deref(&self) -> &Self::Target {
+        &self.bytes
+    }
+}
+
+impl<const N: usize> DerefMut for ByteArray<N> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.bytes
+    }
+}
+
+impl<const N: usize> Borrow<Bytes> for ByteArray<N> {
+    fn borrow(&self) -> &Bytes {
+        Bytes::new(&self.bytes)
+    }
+}
+
+impl<const N: usize> BorrowMut<Bytes> for ByteArray<N> {
+    fn borrow_mut(&mut self) -> &mut Bytes {
+        unsafe { &mut *(&mut self.bytes as &mut [u8] as *mut [u8] as *mut Bytes) }
+    }
+}
+
+impl<Rhs, const N: usize> PartialEq<Rhs> for ByteArray<N>
+where
+    Rhs: ?Sized + Borrow<[u8; N]>,
+{
+    fn eq(&self, other: &Rhs) -> bool {
+        self.as_ref().eq(other.borrow())
+    }
+}
+
+impl<Rhs, const N: usize> PartialOrd<Rhs> for ByteArray<N>
+where
+    Rhs: ?Sized + Borrow<[u8; N]>,
+{
+    fn partial_cmp(&self, other: &Rhs) -> Option<Ordering> {
+        self.as_ref().partial_cmp(other.borrow())
+    }
+}
+
+impl<const N: usize> Hash for ByteArray<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.bytes.hash(state);
+    }
+}
+
+impl<const N: usize> IntoIterator for ByteArray<N> {
+    type Item = u8;
+    type IntoIter = <[u8; N] as IntoIterator>::IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIterator::into_iter(self.bytes)
+    }
+}
+
+impl<'a, const N: usize> IntoIterator for &'a ByteArray<N> {
+    type Item = &'a u8;
+    type IntoIter = <&'a [u8; N] as IntoIterator>::IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.bytes.iter()
+    }
+}
+
+impl<'a, const N: usize> IntoIterator for &'a mut ByteArray<N> {
+    type Item = &'a mut u8;
+    type IntoIter = <&'a mut [u8; N] as IntoIterator>::IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.bytes.iter_mut()
+    }
+}
+
+impl<const N: usize> Serialize for ByteArray<N> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(&self.bytes)
+    }
+}
+
+struct ByteArrayVisitor<const N: usize>;
+
+impl<'de, const N: usize> Visitor<'de> for ByteArrayVisitor<N> {
+    type Value = ByteArray<N>;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        write!(formatter, "a byte array of length {}", N)
+    }
+
+    fn visit_seq<V>(self, mut seq: V) -> Result<ByteArray<N>, V::Error>
+    where
+        V: SeqAccess<'de>,
+    {
+        let mut bytes = [0; N];
+
+        for (idx, byte) in bytes.iter_mut().enumerate() {
+            *byte = seq
+                .next_element()?
+                .ok_or_else(|| V::Error::invalid_length(idx, &self))?;
+        }
+
+        Ok(ByteArray::from(bytes))
+    }
+
+    fn visit_bytes<E>(self, v: &[u8]) -> Result<ByteArray<N>, E>
+    where
+        E: Error,
+    {
+        Ok(ByteArray {
+            bytes: v
+                .try_into()
+                .map_err(|_| E::invalid_length(v.len(), &self))?,
+        })
+    }
+
+    fn visit_str<E>(self, v: &str) -> Result<ByteArray<N>, E>
+    where
+        E: Error,
+    {
+        self.visit_bytes(v.as_bytes())
+    }
+}
+
+impl<'de, const N: usize> Deserialize<'de> for ByteArray<N> {
+    fn deserialize<D>(deserializer: D) -> Result<ByteArray<N>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_bytes(ByteArrayVisitor::<N>)
+    }
+}

src/de.rs

@@ -1,4 +1,4 @@
-use crate::Bytes;
+use crate::{ByteArray, Bytes};
 use core::fmt;
 use core::marker::PhantomData;
 use serde::de::{Error, Visitor};
@@ -63,6 +63,26 @@ impl<'de: 'a, 'a> Deserialize<'de> for &'a Bytes {
     }
 }
 
+impl<'de, const N: usize> Deserialize<'de> for [u8; N] {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let arr: ByteArray<N> = serde::Deserialize::deserialize(deserializer)?;
+        Ok(*arr)
+    }
+}
+
+impl<'de, const N: usize> Deserialize<'de> for ByteArray<N> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        // Via the serde::Deserialize impl for ByteArray
+        serde::Deserialize::deserialize(deserializer)
+    }
+}
+
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'de> Deserialize<'de> for ByteBuf {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

src/lib.rs

@@ -24,6 +24,9 @@
 //!
 //!     #[serde(with = "serde_bytes")]
 //!     byte_buf: Vec<u8>,
+//!
+//!     #[serde(with = "serde_bytes")]
+//!     byte_array: [u8; 314],
 //! }
 //! ```
 
@@ -37,6 +40,7 @@
     clippy::needless_doctest_main
 )]
 
+mod bytearray;
 mod bytes;
 mod de;
 mod ser;
@@ -52,6 +56,7 @@ use serde::Deserializer;
 
 use serde::Serializer;
 
+pub use crate::bytearray::ByteArray;
 pub use crate::bytes::Bytes;
 pub use crate::de::Deserialize;
 pub use crate::ser::Serialize;
@@ -77,6 +82,9 @@ pub use crate::bytebuf::ByteBuf;
 ///
 ///     #[serde(with = "serde_bytes")]
 ///     byte_buf: Vec<u8>,
+///
+///     #[serde(with = "serde_bytes")]
+///     byte_array: [u8; 314],
 /// }
 /// ```
 pub fn serialize<T, S>(bytes: &T, serializer: S) -> Result<S::Ok, S::Error>
@@ -102,6 +110,9 @@ where
 /// struct Packet {
 ///     #[serde(with = "serde_bytes")]
 ///     payload: Vec<u8>,
+///
+///     #[serde(with = "serde_bytes")]
+///     byte_array: [u8; 314],
 /// }
 /// ```
 #[cfg(any(feature = "std", feature = "alloc"))]

src/ser.rs

@@ -1,4 +1,4 @@
-use crate::Bytes;
+use crate::{ByteArray, Bytes};
 use serde::Serializer;
 
 #[cfg(any(feature = "std", feature = "alloc"))]
@@ -51,6 +51,24 @@ impl Serialize for Bytes {
     }
 }
 
+impl<const N: usize> Serialize for [u8; N] {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+impl<const N: usize> Serialize for ByteArray<N> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(&**self)
+    }
+}
+
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl Serialize for ByteBuf {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>