Merge pull request #340 from xgroleau/feat/add-bytes-support

Add support for `Bytes`

Author: reitermarkus

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Added `bytes::Buf` and `bytes::BufMut` implementations for `Vec`.
 - Added `format` macro.
 - Added `String::from_utf16`.
 - Added `is_full`, `recent_index`, `oldest`, and `oldest_index` to `HistoryBuffer`

Cargo.toml

@@ -15,6 +15,8 @@ repository = "https://github.com/rust-embedded/heapless"
 version = "0.8.0"
 
 [features]
+bytes = ["dep:bytes"]
+
 # Enable polyfilling of atomics via `portable-atomic`.
 # `portable-atomic` polyfills some functionality by default, but to get full atomics you must
 # enable one of its features to tell it how to do it. See `portable-atomic` documentation for details.
@@ -42,6 +44,7 @@ mpmc_large = []
 nightly = []
 
 [dependencies]
+bytes = { version = "1", default-features = false, optional = true }
 portable-atomic = { version = "1.0", optional = true }
 hash32 = "0.3.0"
 serde = { version = "1", optional = true, default-features = false }
@@ -58,6 +61,7 @@ static_assertions = "1.1.0"
 
 [package.metadata.docs.rs]
 features = [
+  "bytes",
   "ufmt",
   "serde",
   "defmt",

src/bytes.rs

@@ -0,0 +1,107 @@
+//! Bytes implementations for heapless types
+
+use crate::Vec;
+use bytes::{buf::UninitSlice, Buf, BufMut};
+
+unsafe impl<const N: usize> Buf for Vec<u8, N> {
+    #[inline]
+    fn remaining(&self) -> usize {
+        self.len()
+    }
+
+    #[inline]
+    fn chunk(&mut self) -> &[u8] {
+        self.as_slice()
+    }
+
+    #[inline]
+    unsafe fn advance(&mut self, cnt: usize) {
+        assert!(
+            cnt <= self.remaining(),
+            "cannot advance past `remaining`: {:?} <= {:?}",
+            cnt,
+            self.remaining(),
+        );
+        unsafe {
+            // SAFETY: We've checked that `cnt` <= `self.remaining()` and we know that
+            // `self.remaining()` <= `self.cap`.
+            self.advance_unchecked(cnt);
+        }
+    }
+}
+
+unsafe impl<const N: usize> BufMut for Vec<u8, N> {
+    #[inline]
+    fn remaining_mut(&self) -> usize {
+        N - self.len()
+    }
+
+    #[inline]
+    unsafe fn advance_mut(&mut self, cnt: usize) {
+        let len = self.len();
+        let pos = len + cnt;
+        if pos >= N {
+            panic!("Advance out of range");
+        }
+        self.set_len(pos);
+    }
+
+    #[inline]
+    fn chunk_mut(&mut self) -> &mut UninitSlice {
+        let len = self.len();
+        let ptr = self.as_mut_ptr();
+        unsafe { &mut UninitSlice::from_raw_parts_mut(ptr, N)[len..] }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::Vec;
+    use bytes::BufMut;
+
+    #[test]
+    #[should_panic]
+    fn buf_advance_out_of_bounds() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        vec.advance(9)
+    }
+
+    #[test]
+    fn buf_remaining() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        assert_eq!(vec.remaining(), 8);
+        vec.push(42).unwrap();
+        assert_eq!(vec.remaining(), 7);
+    }
+
+    #[test]
+    fn buf_chunk() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        assert_eq!(vec.chunk().len(), 8);
+        unsafe { vec.advance_mut(1) };
+        assert_eq!(vec.chunk().len(), 7);
+    }
+
+    #[test]
+    #[should_panic]
+    fn buf_mut_advance_mut_out_of_bounds() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        unsafe { vec.advance_mut(9) };
+    }
+
+    #[test]
+    fn buf_mut_remaining_mut() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        assert_eq!(vec.remaining_mut(), 8);
+        vec.push(42).unwrap();
+        assert_eq!(vec.remaining_mut(), 7);
+    }
+
+    #[test]
+    fn buf_mut_chunk_mut() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        assert_eq!(vec.chunk_mut().len(), 8);
+        unsafe { vec.advance_mut(1) };
+        assert_eq!(vec.chunk_mut().len(), 7);
+    }
+}

src/lib.rs

@@ -192,6 +192,8 @@ mod de;
 mod ser;
 
 pub mod binary_heap;
+#[cfg(feature = "bytes")]
+mod bytes;
 #[cfg(feature = "defmt")]
 mod defmt;
 #[cfg(any(