From a92e777f38fda6d4d055339d0d300119065e8e37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?xgroleau=F0=9F=90=A2?= <xavgroleau@gmail.com>
Date: Wed, 25 Jan 2023 17:59:05 -0500
Subject: [PATCH] Added support for Bytes

---
 Cargo.toml   |  5 +++++
 src/bytes.rs | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs   |  2 ++
 3 files changed, 65 insertions(+)
 create mode 100644 src/bytes.rs

diff --git a/Cargo.toml b/Cargo.toml
index 292bc35175..b13c8267da 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -71,3 +71,8 @@ rustc_version = "0.4.0"
 
 [package.metadata.docs.rs]
 all-features = true
+
+[dependencies.bytes]
+version = "1"
+optional = true
+default-features = false
diff --git a/src/bytes.rs b/src/bytes.rs
new file mode 100644
index 0000000000..437903a164
--- /dev/null
+++ b/src/bytes.rs
@@ -0,0 +1,58 @@
+//! Bytes implementations for heapless types
+
+use crate::Vec;
+use bytes::buf::UninitSlice;
+use bytes::BufMut;
+
+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 advance_out_of_bound() {
+        let mut vec: Vec<u8, 8> = Vec::new();
+        unsafe { vec.advance_mut(9) };
+    }
+
+    #[test]
+    fn 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 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);
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index b6ca41ff9e..67fe63946e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -110,6 +110,8 @@ mod de;
 mod ser;
 
 pub mod binary_heap;
+#[cfg(feature = "bytes")]
+mod bytes;
 #[cfg(feature = "defmt-impl")]
 mod defmt;
 #[cfg(all(has_cas, feature = "cas"))]