chore: prepare bytes v1.4.0 (#593)

When we freeze a BytesMut, we turn it into a Vec, and then convert that
to a Bytes.  Currently, this happen using Vec::into_boxed_slice, which
reallocates to a slice of the same length as the Vev if the length and
the capacity are not equal.  This can pose a performance problem if the
Vec is large or if this happens many times in a loop.

Instead, let's compare the length and capacity, and if they're the same,
continue to handle this using into_boxed_slice.  Otherwise, since we
have a type of vtable which can handle a separate capacity, the shared
vtable, let's turn our Vec into that kind of Bytes.  While this does not
avoid allocation altogether, it performs a fixed size allocation and
avoids any need to memcpy.

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ on:
 env:
   RUSTFLAGS: -Dwarnings
   RUST_BACKTRACE: 1
-  nightly: nightly-2021-11-05
+  nightly: nightly-2022-11-12
 
 defaults:
   run:
@@ -157,7 +157,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Install Rust
-        run: rustup update stable && rustup default stable
+        run: rustup update $nightly && rustup default $nightly
       - name: Build documentation
         run: cargo doc --no-deps --all-features
         env:

CHANGELOG.md

@@ -1,3 +1,33 @@
+# 1.4.0 (January 31, 2023)
+
+### Added
+
+- Make `IntoIter` constructor public (#581)
+
+### Fixed
+
+- Avoid large reallocations when freezing `BytesMut` (#592)
+
+### Documented
+
+- Document which functions require `std` (#591)
+- Fix duplicate "the the" typos (#585)
+
+# 1.3.0 (November 20, 2022)
+
+### Added
+
+- Rename and expose `BytesMut::spare_capacity_mut` (#572)
+- Implement native-endian get and put functions for `Buf` and `BufMut` (#576)
+
+### Fixed
+
+- Don't have important data in unused capacity when calling reserve (#563)
+
+### Documented
+
+- `Bytes::new` etc should return `Self` not `Bytes` (#568)
+
 # 1.2.1 (July 30, 2022)
 
 ### Fixed

Cargo.toml

@@ -4,7 +4,7 @@ name = "bytes"
 # When releasing to crates.io:
 # - Update CHANGELOG.md.
 # - Create "v1.x.y" git tag.
-version = "1.2.1"
+version = "1.4.0"
 license = "MIT"
 authors = [
     "Carl Lerche <[email protected]>",

README.md

@@ -36,6 +36,15 @@ Serde support is optional and disabled by default. To enable use the feature `se
 bytes = { version = "1", features = ["serde"] }
 ```
 
+## Building documentation
+
+When building the `bytes` documentation the `docsrs` option should be used, otherwise
+feature gates will not be shown. This requires a nightly toolchain:
+
+```
+RUSTDOCFLAGS="--cfg docsrs" cargo +nightly doc
+```
+
 ## License
 
 This project is licensed under the [MIT license](LICENSE).

src/buf/buf_impl.rs

@@ -160,6 +160,7 @@ pub trait Buf {
     ///
     /// [`writev`]: http://man7.org/linux/man-pages/man2/readv.2.html
     #[cfg(feature = "std")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
     fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize {
         if dst.is_empty() {
             return 0;
@@ -354,6 +355,29 @@ pub trait Buf {
         buf_get_impl!(self, u16::from_le_bytes);
     }
 
+    /// Gets an unsigned 16 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 2.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x08\x09 hello",
+    ///     false => b"\x09\x08 hello",
+    /// };
+    /// assert_eq!(0x0809, buf.get_u16_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_u16_ne(&mut self) -> u16 {
+        buf_get_impl!(self, u16::from_ne_bytes);
+    }
+
     /// Gets a signed 16 bit integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by 2.
@@ -394,6 +418,29 @@ pub trait Buf {
         buf_get_impl!(self, i16::from_le_bytes);
     }
 
+    /// Gets a signed 16 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 2.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x08\x09 hello",
+    ///     false => b"\x09\x08 hello",
+    /// };
+    /// assert_eq!(0x0809, buf.get_i16_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_i16_ne(&mut self) -> i16 {
+        buf_get_impl!(self, i16::from_ne_bytes);
+    }
+
     /// Gets an unsigned 32 bit integer from `self` in the big-endian byte order.
     ///
     /// The current position is advanced by 4.
@@ -434,6 +481,29 @@ pub trait Buf {
         buf_get_impl!(self, u32::from_le_bytes);
     }
 
+    /// Gets an unsigned 32 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 4.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x08\x09\xA0\xA1 hello",
+    ///     false => b"\xA1\xA0\x09\x08 hello",
+    /// };
+    /// assert_eq!(0x0809A0A1, buf.get_u32_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_u32_ne(&mut self) -> u32 {
+        buf_get_impl!(self, u32::from_ne_bytes);
+    }
+
     /// Gets a signed 32 bit integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by 4.
@@ -474,6 +544,29 @@ pub trait Buf {
         buf_get_impl!(self, i32::from_le_bytes);
     }
 
+    /// Gets a signed 32 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 4.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x08\x09\xA0\xA1 hello",
+    ///     false => b"\xA1\xA0\x09\x08 hello",
+    /// };
+    /// assert_eq!(0x0809A0A1, buf.get_i32_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_i32_ne(&mut self) -> i32 {
+        buf_get_impl!(self, i32::from_ne_bytes);
+    }
+
     /// Gets an unsigned 64 bit integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by 8.
@@ -514,6 +607,29 @@ pub trait Buf {
         buf_get_impl!(self, u64::from_le_bytes);
     }
 
+    /// Gets an unsigned 64 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x01\x02\x03\x04\x05\x06\x07\x08 hello",
+    ///     false => b"\x08\x07\x06\x05\x04\x03\x02\x01 hello",
+    /// };
+    /// assert_eq!(0x0102030405060708, buf.get_u64_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_u64_ne(&mut self) -> u64 {
+        buf_get_impl!(self, u64::from_ne_bytes);
+    }
+
     /// Gets a signed 64 bit integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by 8.
@@ -554,6 +670,29 @@ pub trait Buf {
         buf_get_impl!(self, i64::from_le_bytes);
     }
 
+    /// Gets a signed 64 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x01\x02\x03\x04\x05\x06\x07\x08 hello",
+    ///     false => b"\x08\x07\x06\x05\x04\x03\x02\x01 hello",
+    /// };
+    /// assert_eq!(0x0102030405060708, buf.get_i64_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_i64_ne(&mut self) -> i64 {
+        buf_get_impl!(self, i64::from_ne_bytes);
+    }
+
     /// Gets an unsigned 128 bit integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by 16.
@@ -594,6 +733,29 @@ pub trait Buf {
         buf_get_impl!(self, u128::from_le_bytes);
     }
 
+    /// Gets an unsigned 128 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 16.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16 hello",
+    ///     false => b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01 hello",
+    /// };
+    /// assert_eq!(0x01020304050607080910111213141516, buf.get_u128_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_u128_ne(&mut self) -> u128 {
+        buf_get_impl!(self, u128::from_ne_bytes);
+    }
+
     /// Gets a signed 128 bit integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by 16.
@@ -634,6 +796,29 @@ pub trait Buf {
         buf_get_impl!(self, i128::from_le_bytes);
     }
 
+    /// Gets a signed 128 bit integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 16.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16 hello",
+    ///     false => b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01 hello",
+    /// };
+    /// assert_eq!(0x01020304050607080910111213141516, buf.get_i128_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_i128_ne(&mut self) -> i128 {
+        buf_get_impl!(self, i128::from_ne_bytes);
+    }
+
     /// Gets an unsigned n-byte integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by `nbytes`.
@@ -674,6 +859,33 @@ pub trait Buf {
         buf_get_impl!(le => self, u64, nbytes);
     }
 
+    /// Gets an unsigned n-byte integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by `nbytes`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x01\x02\x03 hello",
+    ///     false => b"\x03\x02\x01 hello",
+    /// };
+    /// assert_eq!(0x010203, buf.get_uint_ne(3));
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_uint_ne(&mut self, nbytes: usize) -> u64 {
+        if cfg!(target_endian = "big") {
+            self.get_uint(nbytes)
+        } else {
+            self.get_uint_le(nbytes)
+        }
+    }
+
     /// Gets a signed n-byte integer from `self` in big-endian byte order.
     ///
     /// The current position is advanced by `nbytes`.
@@ -714,6 +926,33 @@ pub trait Buf {
         buf_get_impl!(le => self, i64, nbytes);
     }
 
+    /// Gets a signed n-byte integer from `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by `nbytes`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x01\x02\x03 hello",
+    ///     false => b"\x03\x02\x01 hello",
+    /// };
+    /// assert_eq!(0x010203, buf.get_int_ne(3));
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_int_ne(&mut self, nbytes: usize) -> i64 {
+        if cfg!(target_endian = "big") {
+            self.get_int(nbytes)
+        } else {
+            self.get_int_le(nbytes)
+        }
+    }
+
     /// Gets an IEEE754 single-precision (4 bytes) floating point number from
     /// `self` in big-endian byte order.
     ///
@@ -756,6 +995,30 @@ pub trait Buf {
         f32::from_bits(Self::get_u32_le(self))
     }
 
+    /// Gets an IEEE754 single-precision (4 bytes) floating point number from
+    /// `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 4.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x3F\x99\x99\x9A hello",
+    ///     false => b"\x9A\x99\x99\x3F hello",
+    /// };
+    /// assert_eq!(1.2f32, buf.get_f32_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_f32_ne(&mut self) -> f32 {
+        f32::from_bits(Self::get_u32_ne(self))
+    }
+
     /// Gets an IEEE754 double-precision (8 bytes) floating point number from
     /// `self` in big-endian byte order.
     ///
@@ -798,6 +1061,30 @@ pub trait Buf {
         f64::from_bits(Self::get_u64_le(self))
     }
 
+    /// Gets an IEEE754 double-precision (8 bytes) floating point number from
+    /// `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::Buf;
+    ///
+    /// let mut buf: &[u8] = match cfg!(target_endian = "big") {
+    ///     true => b"\x3F\xF3\x33\x33\x33\x33\x33\x33 hello",
+    ///     false => b"\x33\x33\x33\x33\x33\x33\xF3\x3F hello",
+    /// };
+    /// assert_eq!(1.2f64, buf.get_f64_ne());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining data in `self`.
+    fn get_f64_ne(&mut self) -> f64 {
+        f64::from_bits(Self::get_u64_ne(self))
+    }
+
     /// Consumes `len` bytes inside self and returns new instance of `Bytes`
     /// with this data.
     ///
@@ -897,6 +1184,7 @@ pub trait Buf {
     /// assert_eq!(&dst[..11], &b"hello world"[..]);
     /// ```
     #[cfg(feature = "std")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
     fn reader(self) -> Reader<Self>
     where
         Self: Sized,
@@ -948,6 +1236,10 @@ macro_rules! deref_forward_buf {
             (**self).get_u16_le()
         }
 
+        fn get_u16_ne(&mut self) -> u16 {
+            (**self).get_u16_ne()
+        }
+
         fn get_i16(&mut self) -> i16 {
             (**self).get_i16()
         }
@@ -956,6 +1248,10 @@ macro_rules! deref_forward_buf {
             (**self).get_i16_le()
         }
 
+        fn get_i16_ne(&mut self) -> i16 {
+            (**self).get_i16_ne()
+        }
+
         fn get_u32(&mut self) -> u32 {
             (**self).get_u32()
         }
@@ -964,6 +1260,10 @@ macro_rules! deref_forward_buf {
             (**self).get_u32_le()
         }
 
+        fn get_u32_ne(&mut self) -> u32 {
+            (**self).get_u32_ne()
+        }
+
         fn get_i32(&mut self) -> i32 {
             (**self).get_i32()
         }
@@ -972,6 +1272,10 @@ macro_rules! deref_forward_buf {
             (**self).get_i32_le()
         }
 
+        fn get_i32_ne(&mut self) -> i32 {
+            (**self).get_i32_ne()
+        }
+
         fn get_u64(&mut self) -> u64 {
             (**self).get_u64()
         }
@@ -980,6 +1284,10 @@ macro_rules! deref_forward_buf {
             (**self).get_u64_le()
         }
 
+        fn get_u64_ne(&mut self) -> u64 {
+            (**self).get_u64_ne()
+        }
+
         fn get_i64(&mut self) -> i64 {
             (**self).get_i64()
         }
@@ -988,6 +1296,10 @@ macro_rules! deref_forward_buf {
             (**self).get_i64_le()
         }
 
+        fn get_i64_ne(&mut self) -> i64 {
+            (**self).get_i64_ne()
+        }
+
         fn get_uint(&mut self, nbytes: usize) -> u64 {
             (**self).get_uint(nbytes)
         }
@@ -996,6 +1308,10 @@ macro_rules! deref_forward_buf {
             (**self).get_uint_le(nbytes)
         }
 
+        fn get_uint_ne(&mut self, nbytes: usize) -> u64 {
+            (**self).get_uint_ne(nbytes)
+        }
+
         fn get_int(&mut self, nbytes: usize) -> i64 {
             (**self).get_int(nbytes)
         }
@@ -1004,6 +1320,10 @@ macro_rules! deref_forward_buf {
             (**self).get_int_le(nbytes)
         }
 
+        fn get_int_ne(&mut self, nbytes: usize) -> i64 {
+            (**self).get_int_ne(nbytes)
+        }
+
         fn copy_to_bytes(&mut self, len: usize) -> crate::Bytes {
             (**self).copy_to_bytes(len)
         }

src/buf/buf_mut.rs

@@ -386,6 +386,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes an unsigned 16 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 2.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_u16_ne(0x0809);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x08\x09");
+    /// } else {
+    ///     assert_eq!(buf, b"\x09\x08");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_u16_ne(&mut self, n: u16) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes a signed 16 bit integer to `self` in big-endian byte order.
     ///
     /// The current position is advanced by 2.
@@ -430,6 +456,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes a signed 16 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 2.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_i16_ne(0x0809);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x08\x09");
+    /// } else {
+    ///     assert_eq!(buf, b"\x09\x08");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_i16_ne(&mut self, n: i16) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes an unsigned 32 bit integer to `self` in big-endian byte order.
     ///
     /// The current position is advanced by 4.
@@ -474,6 +526,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes an unsigned 32 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 4.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_u32_ne(0x0809A0A1);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x08\x09\xA0\xA1");
+    /// } else {
+    ///     assert_eq!(buf, b"\xA1\xA0\x09\x08");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_u32_ne(&mut self, n: u32) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes a signed 32 bit integer to `self` in big-endian byte order.
     ///
     /// The current position is advanced by 4.
@@ -518,6 +596,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes a signed 32 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 4.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_i32_ne(0x0809A0A1);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x08\x09\xA0\xA1");
+    /// } else {
+    ///     assert_eq!(buf, b"\xA1\xA0\x09\x08");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_i32_ne(&mut self, n: i32) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes an unsigned 64 bit integer to `self` in the big-endian byte order.
     ///
     /// The current position is advanced by 8.
@@ -562,6 +666,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes an unsigned 64 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_u64_ne(0x0102030405060708);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
+    /// } else {
+    ///     assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_u64_ne(&mut self, n: u64) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes a signed 64 bit integer to `self` in the big-endian byte order.
     ///
     /// The current position is advanced by 8.
@@ -606,6 +736,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes a signed 64 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_i64_ne(0x0102030405060708);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
+    /// } else {
+    ///     assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_i64_ne(&mut self, n: i64) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes an unsigned 128 bit integer to `self` in the big-endian byte order.
     ///
     /// The current position is advanced by 16.
@@ -650,6 +806,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes an unsigned 128 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 16.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_u128_ne(0x01020304050607080910111213141516);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
+    /// } else {
+    ///     assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_u128_ne(&mut self, n: u128) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes a signed 128 bit integer to `self` in the big-endian byte order.
     ///
     /// The current position is advanced by 16.
@@ -694,6 +876,32 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes())
     }
 
+    /// Writes a signed 128 bit integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 16.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_i128_ne(0x01020304050607080910111213141516);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
+    /// } else {
+    ///     assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_i128_ne(&mut self, n: i128) {
+        self.put_slice(&n.to_ne_bytes())
+    }
+
     /// Writes an unsigned n-byte integer to `self` in big-endian byte order.
     ///
     /// The current position is advanced by `nbytes`.
@@ -738,6 +946,36 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes()[0..nbytes]);
     }
 
+    /// Writes an unsigned n-byte integer to `self` in the native-endian byte order.
+    ///
+    /// The current position is advanced by `nbytes`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_uint_ne(0x010203, 3);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x01\x02\x03");
+    /// } else {
+    ///     assert_eq!(buf, b"\x03\x02\x01");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_uint_ne(&mut self, n: u64, nbytes: usize) {
+        if cfg!(target_endian = "big") {
+            self.put_uint(n, nbytes)
+        } else {
+            self.put_uint_le(n, nbytes)
+        }
+    }
+
     /// Writes low `nbytes` of a signed integer to `self` in big-endian byte order.
     ///
     /// The current position is advanced by `nbytes`.
@@ -782,6 +1020,36 @@ pub unsafe trait BufMut {
         self.put_slice(&n.to_le_bytes()[0..nbytes]);
     }
 
+    /// Writes low `nbytes` of a signed integer to `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by `nbytes`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_int_ne(0x010203, 3);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x01\x02\x03");
+    /// } else {
+    ///     assert_eq!(buf, b"\x03\x02\x01");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self` or if `nbytes` is greater than 8.
+    fn put_int_ne(&mut self, n: i64, nbytes: usize) {
+        if cfg!(target_endian = "big") {
+            self.put_int(n, nbytes)
+        } else {
+            self.put_int_le(n, nbytes)
+        }
+    }
+
     /// Writes  an IEEE754 single-precision (4 bytes) floating point number to
     /// `self` in big-endian byte order.
     ///
@@ -828,6 +1096,33 @@ pub unsafe trait BufMut {
         self.put_u32_le(n.to_bits());
     }
 
+    /// Writes an IEEE754 single-precision (4 bytes) floating point number to
+    /// `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 4.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_f32_ne(1.2f32);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x3F\x99\x99\x9A");
+    /// } else {
+    ///     assert_eq!(buf, b"\x9A\x99\x99\x3F");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_f32_ne(&mut self, n: f32) {
+        self.put_u32_ne(n.to_bits());
+    }
+
     /// Writes  an IEEE754 double-precision (8 bytes) floating point number to
     /// `self` in big-endian byte order.
     ///
@@ -874,6 +1169,33 @@ pub unsafe trait BufMut {
         self.put_u64_le(n.to_bits());
     }
 
+    /// Writes  an IEEE754 double-precision (8 bytes) floating point number to
+    /// `self` in native-endian byte order.
+    ///
+    /// The current position is advanced by 8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut buf = vec![];
+    /// buf.put_f64_ne(1.2f64);
+    /// if cfg!(target_endian = "big") {
+    ///     assert_eq!(buf, b"\x3F\xF3\x33\x33\x33\x33\x33\x33");
+    /// } else {
+    ///     assert_eq!(buf, b"\x33\x33\x33\x33\x33\x33\xF3\x3F");
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if there is not enough remaining capacity in
+    /// `self`.
+    fn put_f64_ne(&mut self, n: f64) {
+        self.put_u64_ne(n.to_bits());
+    }
+
     /// Creates an adaptor which can write at most `limit` bytes to `self`.
     ///
     /// # Examples
@@ -917,6 +1239,7 @@ pub unsafe trait BufMut {
     /// assert_eq!(*buf, b"hello world"[..]);
     /// ```
     #[cfg(feature = "std")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
     fn writer(self) -> Writer<Self>
     where
         Self: Sized,
@@ -986,6 +1309,10 @@ macro_rules! deref_forward_bufmut {
             (**self).put_u16_le(n)
         }
 
+        fn put_u16_ne(&mut self, n: u16) {
+            (**self).put_u16_ne(n)
+        }
+
         fn put_i16(&mut self, n: i16) {
             (**self).put_i16(n)
         }
@@ -994,6 +1321,10 @@ macro_rules! deref_forward_bufmut {
             (**self).put_i16_le(n)
         }
 
+        fn put_i16_ne(&mut self, n: i16) {
+            (**self).put_i16_ne(n)
+        }
+
         fn put_u32(&mut self, n: u32) {
             (**self).put_u32(n)
         }
@@ -1002,6 +1333,10 @@ macro_rules! deref_forward_bufmut {
             (**self).put_u32_le(n)
         }
 
+        fn put_u32_ne(&mut self, n: u32) {
+            (**self).put_u32_ne(n)
+        }
+
         fn put_i32(&mut self, n: i32) {
             (**self).put_i32(n)
         }
@@ -1010,6 +1345,10 @@ macro_rules! deref_forward_bufmut {
             (**self).put_i32_le(n)
         }
 
+        fn put_i32_ne(&mut self, n: i32) {
+            (**self).put_i32_ne(n)
+        }
+
         fn put_u64(&mut self, n: u64) {
             (**self).put_u64(n)
         }
@@ -1018,6 +1357,10 @@ macro_rules! deref_forward_bufmut {
             (**self).put_u64_le(n)
         }
 
+        fn put_u64_ne(&mut self, n: u64) {
+            (**self).put_u64_ne(n)
+        }
+
         fn put_i64(&mut self, n: i64) {
             (**self).put_i64(n)
         }
@@ -1025,6 +1368,10 @@ macro_rules! deref_forward_bufmut {
         fn put_i64_le(&mut self, n: i64) {
             (**self).put_i64_le(n)
         }
+
+        fn put_i64_ne(&mut self, n: i64) {
+            (**self).put_i64_ne(n)
+        }
     };
 }
 

src/buf/iter.rs

@@ -2,8 +2,6 @@ use crate::Buf;
 
 /// Iterator over the bytes contained by the buffer.
 ///
-/// This struct is created by the [`iter`] method on [`Buf`].
-///
 /// # Examples
 ///
 /// Basic usage:
@@ -43,7 +41,7 @@ impl<T> IntoIter<T> {
     /// assert_eq!(iter.next(), Some(b'c'));
     /// assert_eq!(iter.next(), None);
     /// ```
-    pub(crate) fn new(inner: T) -> IntoIter<T> {
+    pub fn new(inner: T) -> IntoIter<T> {
         IntoIter { inner }
     }
 

src/buf/uninit_slice.rs

@@ -22,6 +22,10 @@ use core::ops::{
 pub struct UninitSlice([MaybeUninit<u8>]);
 
 impl UninitSlice {
+    pub(crate) fn from_slice(slice: &mut [MaybeUninit<u8>]) -> &mut UninitSlice {
+        unsafe { &mut *(slice as *mut [MaybeUninit<u8>] as *mut UninitSlice) }
+    }
+
     /// Create a `&mut UninitSlice` from a pointer and a length.
     ///
     /// # Safety
@@ -44,7 +48,7 @@ impl UninitSlice {
     pub unsafe fn from_raw_parts_mut<'a>(ptr: *mut u8, len: usize) -> &'a mut UninitSlice {
         let maybe_init: &mut [MaybeUninit<u8>] =
             core::slice::from_raw_parts_mut(ptr as *mut _, len);
-        &mut *(maybe_init as *mut [MaybeUninit<u8>] as *mut UninitSlice)
+        Self::from_slice(maybe_init)
     }
 
     /// Write a single byte at the specified offset.

src/bytes.rs

@@ -32,7 +32,7 @@ use crate::Buf;
 /// All `Bytes` implementations must fulfill the following requirements:
 /// - They are cheaply cloneable and thereby shareable between an unlimited amount
 ///   of components, for example by modifying a reference count.
-/// - Instances can be sliced to refer to a subset of the the original buffer.
+/// - Instances can be sliced to refer to a subset of the original buffer.
 ///
 /// ```
 /// use bytes::Bytes;
@@ -71,7 +71,7 @@ use crate::Buf;
 ///
 /// For `Bytes` implementations which point to a reference counted shared storage
 /// (e.g. an `Arc<[u8]>`), sharing will be implemented by increasing the
-/// the reference count.
+/// reference count.
 ///
 /// Due to this mechanism, multiple `Bytes` instances may point to the same
 /// shared memory region.
@@ -131,7 +131,7 @@ impl Bytes {
     /// ```
     #[inline]
     #[cfg(not(all(loom, test)))]
-    pub const fn new() -> Bytes {
+    pub const fn new() -> Self {
         // Make it a named const to work around
         // "unsizing casts are not allowed in const fn"
         const EMPTY: &[u8] = &[];
@@ -139,7 +139,7 @@ impl Bytes {
     }
 
     #[cfg(all(loom, test))]
-    pub fn new() -> Bytes {
+    pub fn new() -> Self {
         const EMPTY: &[u8] = &[];
         Bytes::from_static(EMPTY)
     }
@@ -159,7 +159,7 @@ impl Bytes {
     /// ```
     #[inline]
     #[cfg(not(all(loom, test)))]
-    pub const fn from_static(bytes: &'static [u8]) -> Bytes {
+    pub const fn from_static(bytes: &'static [u8]) -> Self {
         Bytes {
             ptr: bytes.as_ptr(),
             len: bytes.len(),
@@ -169,7 +169,7 @@ impl Bytes {
     }
 
     #[cfg(all(loom, test))]
-    pub fn from_static(bytes: &'static [u8]) -> Bytes {
+    pub fn from_static(bytes: &'static [u8]) -> Self {
         Bytes {
             ptr: bytes.as_ptr(),
             len: bytes.len(),
@@ -235,7 +235,7 @@ impl Bytes {
     ///
     /// Requires that `begin <= end` and `end <= self.len()`, otherwise slicing
     /// will panic.
-    pub fn slice(&self, range: impl RangeBounds<usize>) -> Bytes {
+    pub fn slice(&self, range: impl RangeBounds<usize>) -> Self {
         use core::ops::Bound;
 
         let len = self.len();
@@ -302,7 +302,7 @@ impl Bytes {
     ///
     /// Requires that the given `sub` slice is in fact contained within the
     /// `Bytes` buffer; otherwise this function will panic.
-    pub fn slice_ref(&self, subset: &[u8]) -> Bytes {
+    pub fn slice_ref(&self, subset: &[u8]) -> Self {
         // Empty slice and empty Bytes may have their pointers reset
         // so explicitly allow empty slice to be a subslice of any slice.
         if subset.is_empty() {
@@ -359,7 +359,7 @@ impl Bytes {
     ///
     /// Panics if `at > len`.
     #[must_use = "consider Bytes::truncate if you don't need the other half"]
-    pub fn split_off(&mut self, at: usize) -> Bytes {
+    pub fn split_off(&mut self, at: usize) -> Self {
         assert!(
             at <= self.len(),
             "split_off out of bounds: {:?} <= {:?}",
@@ -408,7 +408,7 @@ impl Bytes {
     ///
     /// Panics if `at > len`.
     #[must_use = "consider Bytes::advance if you don't need the other half"]
-    pub fn split_to(&mut self, at: usize) -> Bytes {
+    pub fn split_to(&mut self, at: usize) -> Self {
         assert!(
             at <= self.len(),
             "split_to out of bounds: {:?} <= {:?}",
@@ -807,8 +807,36 @@ impl From<&'static str> for Bytes {
 
 impl From<Vec<u8>> for Bytes {
     fn from(vec: Vec<u8>) -> Bytes {
-        let slice = vec.into_boxed_slice();
-        slice.into()
+        let mut vec = vec;
+        let ptr = vec.as_mut_ptr();
+        let len = vec.len();
+        let cap = vec.capacity();
+
+        // Avoid an extra allocation if possible.
+        if len == cap {
+            return Bytes::from(vec.into_boxed_slice());
+        }
+
+        let shared = Box::new(Shared {
+            buf: ptr,
+            cap,
+            ref_cnt: AtomicUsize::new(1),
+        });
+        mem::forget(vec);
+
+        let shared = Box::into_raw(shared);
+        // The pointer should be aligned, so this assert should
+        // always succeed.
+        debug_assert!(
+            0 == (shared as usize & KIND_MASK),
+            "internal: Box<Shared> should have an aligned pointer",
+        );
+        Bytes {
+            ptr,
+            len,
+            data: AtomicPtr::new(shared as _),
+            vtable: &SHARED_VTABLE,
+        }
     }
 }
 

src/bytes_mut.rs

@@ -1,5 +1,5 @@
 use core::iter::{FromIterator, Iterator};
-use core::mem::{self, ManuallyDrop};
+use core::mem::{self, ManuallyDrop, MaybeUninit};
 use core::ops::{Deref, DerefMut};
 use core::ptr::{self, NonNull};
 use core::{cmp, fmt, hash, isize, slice, usize};
@@ -705,6 +705,15 @@ impl BytesMut {
                     new_cap = cmp::max(double, new_cap);
 
                     // No space - allocate more
+                    //
+                    // The length field of `Shared::vec` is not used by the `BytesMut`;
+                    // instead we use the `len` field in the `BytesMut` itself. However,
+                    // when calling `reserve`, it doesn't guarantee that data stored in
+                    // the unused capacity of the vector is copied over to the new
+                    // allocation, so we need to ensure that we don't have any data we
+                    // care about in the unused capacity before calling `reserve`.
+                    debug_assert!(off + len <= v.capacity());
+                    v.set_len(off + len);
                     v.reserve(new_cap - v.len());
 
                     // Update the info
@@ -757,11 +766,11 @@ impl BytesMut {
         self.reserve(cnt);
 
         unsafe {
-            let dst = self.uninit_slice();
+            let dst = self.spare_capacity_mut();
             // Reserved above
             debug_assert!(dst.len() >= cnt);
 
-            ptr::copy_nonoverlapping(extend.as_ptr(), dst.as_mut_ptr(), cnt);
+            ptr::copy_nonoverlapping(extend.as_ptr(), dst.as_mut_ptr().cast(), cnt);
         }
 
         unsafe {
@@ -983,13 +992,42 @@ impl BytesMut {
         self.data = invalid_ptr((pos << VEC_POS_OFFSET) | (prev & NOT_VEC_POS_MASK));
     }
 
+    /// Returns the remaining spare capacity of the buffer as a slice of `MaybeUninit<u8>`.
+    ///
+    /// The returned slice can be used to fill the buffer with data (e.g. by
+    /// reading from a file) before marking the data as initialized using the
+    /// [`set_len`] method.
+    ///
+    /// [`set_len`]: BytesMut::set_len
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BytesMut;
+    ///
+    /// // Allocate buffer big enough for 10 bytes.
+    /// let mut buf = BytesMut::with_capacity(10);
+    ///
+    /// // Fill in the first 3 elements.
+    /// let uninit = buf.spare_capacity_mut();
+    /// uninit[0].write(0);
+    /// uninit[1].write(1);
+    /// uninit[2].write(2);
+    ///
+    /// // Mark the first 3 bytes of the buffer as being initialized.
+    /// unsafe {
+    ///     buf.set_len(3);
+    /// }
+    ///
+    /// assert_eq!(&buf[..], &[0, 1, 2]);
+    /// ```
     #[inline]
-    fn uninit_slice(&mut self) -> &mut UninitSlice {
+    pub fn spare_capacity_mut(&mut self) -> &mut [MaybeUninit<u8>] {
         unsafe {
             let ptr = self.ptr.as_ptr().add(self.len);
             let len = self.cap - self.len;
 
-            UninitSlice::from_raw_parts_mut(ptr, len)
+            slice::from_raw_parts_mut(ptr.cast(), len)
         }
     }
 }
@@ -1063,7 +1101,7 @@ unsafe impl BufMut for BytesMut {
         if self.capacity() == self.len() {
             self.reserve(64);
         }
-        self.uninit_slice()
+        UninitSlice::from_slice(self.spare_capacity_mut())
     }
 
     // Specialize these methods so they can skip checking `remaining_mut`
@@ -1088,7 +1126,7 @@ unsafe impl BufMut for BytesMut {
     fn put_bytes(&mut self, val: u8, cnt: usize) {
         self.reserve(cnt);
         unsafe {
-            let dst = self.uninit_slice();
+            let dst = self.spare_capacity_mut();
             // Reserved above
             debug_assert!(dst.len() >= cnt);
 

src/lib.rs

@@ -4,6 +4,7 @@
     attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
 ))]
 #![no_std]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 //! Provides abstractions for working with bytes.
 //!

tests/test_bytes.rs

@@ -1163,3 +1163,48 @@ fn test_bytes_into_vec_promotable_even() {
     assert_eq!(Vec::from(b2), vec[20..]);
     assert_eq!(Vec::from(b1), vec[..20]);
 }
+
+#[test]
+fn test_bytes_vec_conversion() {
+    let mut vec = Vec::with_capacity(10);
+    vec.extend(b"abcdefg");
+    let b = Bytes::from(vec);
+    let v = Vec::from(b);
+    assert_eq!(v.len(), 7);
+    assert_eq!(v.capacity(), 10);
+
+    let mut b = Bytes::from(v);
+    b.advance(1);
+    let v = Vec::from(b);
+    assert_eq!(v.len(), 6);
+    assert_eq!(v.capacity(), 10);
+    assert_eq!(v.as_slice(), b"bcdefg");
+}
+
+#[test]
+fn test_bytes_mut_conversion() {
+    let mut b1 = BytesMut::with_capacity(10);
+    b1.extend(b"abcdefg");
+    let b2 = Bytes::from(b1);
+    let v = Vec::from(b2);
+    assert_eq!(v.len(), 7);
+    assert_eq!(v.capacity(), 10);
+
+    let mut b = Bytes::from(v);
+    b.advance(1);
+    let v = Vec::from(b);
+    assert_eq!(v.len(), 6);
+    assert_eq!(v.capacity(), 10);
+    assert_eq!(v.as_slice(), b"bcdefg");
+}
+
+#[test]
+fn test_bytes_capacity_len() {
+    for cap in 0..100 {
+        for len in 0..=cap {
+            let mut v = Vec::with_capacity(cap);
+            v.resize(len, 0);
+            let _ = Bytes::from(v);
+        }
+    }
+}