Release shared reference on zero truncate (#842)

Co-authored-by: JSap0914 <[email protected]>

.github/workflows/ci.yml

@@ -7,10 +7,13 @@ on:
   push:
     branches:
       - master
+  schedule:
+    - cron: '0 2 * * 0'
 
 env:
   RUSTFLAGS: -Dwarnings
   RUST_BACKTRACE: 1
+  nightly: nightly-2024-09-15
 
 defaults:
   run:
@@ -22,11 +25,11 @@ jobs:
     name: rustfmt
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Install Rust
-      run: rustup update stable && rustup default stable
+      run: rustup update stable
     - name: Check formatting
-      run: cargo fmt --all -- --check
+      run: cargo fmt --all --check
 
   # TODO
   # # Apply clippy lints
@@ -34,7 +37,7 @@ jobs:
   #   name: clippy
   #   runs-on: ubuntu-latest
   #   steps:
-  #   - uses: actions/checkout@v2
+  #   - uses: actions/checkout@v4
   #   - name: Apply clippy lints
   #     run: cargo clippy --all-features
 
@@ -47,11 +50,11 @@ jobs:
     name: minrust
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install Rust
-        run: rustup update 1.39.0 && rustup default 1.39.0
+      - uses: actions/checkout@v4
+      - name: Install cargo-hack
+        uses: taiki-e/install-action@cargo-hack
       - name: Check
-        run: . ci/test-stable.sh check
+        run: cargo hack check --feature-powerset --optional-deps --rust-version
 
   # Stable
   stable:
@@ -60,83 +63,120 @@ jobs:
       matrix:
         os:
           - ubuntu-latest
+          - ubuntu-22.04-arm # TODO: update to 24.04 when https://github.com/rust-lang/rust/issues/135867 solved
           - macos-latest
           - windows-latest
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install Rust
         # --no-self-update is necessary because the windows environment cannot self-update rustup.exe.
-        run: rustup update stable --no-self-update && rustup default stable
+        run: rustup update stable --no-self-update
+      - name: Install cargo-hack
+        uses: taiki-e/install-action@cargo-hack
       - name: Test
-        run: . ci/test-stable.sh test
+        run: ci/test-stable.sh test
 
   # Nightly
   nightly:
     name: nightly
-    env:
-      # Pin nightly to avoid being impacted by breakage
-      RUST_VERSION: nightly-2019-09-25
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install Rust
-        run: rustup update $RUST_VERSION && rustup default $RUST_VERSION
+        run: rustup update $nightly && rustup default $nightly
+      - name: Install cargo-hack
+        uses: taiki-e/install-action@cargo-hack
       - name: Test
-        run: . ci/test-stable.sh test
+        run: ci/test-stable.sh test
+
+  panic-abort:
+    name: panic=abort tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust
+        run: rustup update $nightly && rustup default $nightly
+      - name: Run tests with -Cpanic=abort
+        run: ci/panic-abort.sh
 
   # Run tests on some extra platforms
   cross:
     name: cross
     strategy:
       matrix:
-        target:
-          - i686-unknown-linux-gnu
-          - armv7-unknown-linux-gnueabihf
-          - powerpc-unknown-linux-gnu
-          - powerpc64-unknown-linux-gnu
-          - wasm32-unknown-unknown
-    runs-on: ubuntu-16.04
+        include:
+          - target: i686-unknown-linux-gnu
+            os: ubuntu-latest
+          - target: armv7-unknown-linux-gnueabihf
+            os: ubuntu-22.04-arm # TODO: update to 24.04 when https://github.com/rust-lang/rust/issues/135867 solved
+          - target: powerpc-unknown-linux-gnu
+            os: ubuntu-latest
+          - target: powerpc64-unknown-linux-gnu
+            os: ubuntu-latest
+          - target: wasm32-wasip1
+            os: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install Rust
-        run: rustup update stable && rustup default stable
-      - name: cross build --target ${{ matrix.target }}
-        run: |
-          cargo install cross
-          cross build --target ${{ matrix.target }}
-        if: matrix.target != 'wasm32-unknown-unknown'
-      # WASM support
-      - name: cargo build --target ${{ matrix.target }}
-        run: |
-          rustup target add ${{ matrix.target }}
-          cargo build --target ${{ matrix.target }}
-        if: matrix.target == 'wasm32-unknown-unknown'
+        run: rustup update stable
+      - uses: taiki-e/setup-cross-toolchain-action@v1
+        with:
+          target: ${{ matrix.target }}
+      - name: Test
+        run: cargo test --target ${{ matrix.target }}
+
+  # Build for no_std environment.
+  no-std:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust
+        run: rustup update stable
+      - name: Install cargo-hack
+        uses: taiki-e/install-action@cargo-hack
+      # thumbv6m-none-eabi supports atomic, but not atomic CAS.
+      # thumbv7m-none-eabi supports atomic CAS.
+      - run: rustup target add thumbv6m-none-eabi thumbv7m-none-eabi
+      # * --optional-deps is needed for serde feature
+      # * --no-dev-deps is needed to avoid https://github.com/rust-lang/cargo/issues/4866
+      - run: cargo hack build --target thumbv7m-none-eabi --feature-powerset --skip std,default --optional-deps --no-dev-deps
+      # A sound way to provide atomic CAS on platforms without native atomic CAS is system-dependent.
+      # portable-atomic provides major ways via cfgs and accepts user-defined implementations via critical-section feature.
+      - run: cargo hack build --target thumbv6m-none-eabi --feature-powerset --skip std,default --optional-deps --no-dev-deps --features extra-platforms,extra-platforms/critical-section
 
   # Sanitizers
   tsan:
     name: tsan
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install Rust
-        run: rustup update nightly && rustup default nightly
+        run: rustup update $nightly && rustup default $nightly
       - name: Install rust-src
         run: rustup component add rust-src
       - name: ASAN / TSAN
-        run: . ci/tsan.sh
+        run: ci/tsan.sh
+
+  miri:
+    name: miri
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust
+        run: rustup update $nightly && rustup default $nightly
+      - name: Miri
+        run: ci/miri.sh
 
   # Loom
   loom:
     name: loom
-    env:
-      # Pin nightly to avoid being impacted by breakage
-      RUST_VERSION: nightly-2020-05-19
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install Rust
-        run: rustup update $RUST_VERSION && rustup default $RUST_VERSION
+        run: rustup update $nightly && rustup default $nightly
       - name: Loom tests
         run: RUSTFLAGS="--cfg loom -Dwarnings" cargo test --lib
 
@@ -149,13 +189,18 @@ jobs:
       - nightly
       - minrust
       - cross
+      - tsan
+      - miri
+      - loom
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - 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:
+          RUSTDOCFLAGS: --cfg docsrs
       - name: Publish documentation
         run: |
           cd target/doc

CHANGELOG.md

@@ -1,3 +1,291 @@
+# 1.12.1 (July 8th, 2026)
+
+### Fixed
+- Properly handle when `Box::new` panics (#837)
+
+# 1.12.0 (June 18th, 2026)
+
+### Added
+- Add `BytesMut::extend_from_within()` (#818)
+- Add `BytesMut::try_unsplit()` (#746)
+
+### Fixed
+- Fix panic in `get_int` if `nbytes` is zero (#806)
+
+### Changed
+- Pass vtable data by value (#826)
+- Exclude development scripts from published package (#810)
+
+### Documented
+- Document that `BytesMut::{reserve,try_reserve}` doesn't preserve unused capacity (#808)
+
+# 1.11.1 (February 3rd, 2026)
+
+- Fix integer overflow in `BytesMut::reserve`
+
+# 1.11.0 (November 14th, 2025)
+
+- Bump MSRV to 1.57 (#788)
+
+### Fixed
+
+- fix: `BytesMut` only reuse if src has remaining (#803)
+- Specialize `BytesMut::put::<Bytes>` (#793)
+- Reserve capacity in `BytesMut::put` (#794)
+- Change `BytesMut::remaining_mut` to use `isize::MAX` instead of `usize::MAX` (#795)
+
+### Internal changes
+
+- Guarantee address in `slice()` for empty slices. (#780)
+- Rename `Vtable::to_*` -> `Vtable::into_*` (#776)
+- Fix latest clippy warnings (#787)
+- Ignore `BytesMut::freeze` doctest on wasm (#790)
+- Move `drop_fn` of `from_owner` into vtable (#801)
+
+# 1.10.1 (March 5th, 2025)
+
+### Fixed
+
+- Fix memory leak when using `to_vec` with `Bytes::from_owner` (#773)
+
+# 1.10.0 (February 3rd, 2025)
+
+### Added
+
+- Add feature to support platforms without atomic CAS (#467)
+- `try_get_*` methods for `Buf` trait (#753)
+- Implement `Buf::chunks_vectored` for `Take` (#617)
+- Implement `Buf::chunks_vectored` for `VecDeque<u8>` (#708)
+
+### Fixed
+
+- Remove incorrect guarantee for `chunks_vectored` (#754)
+- Ensure that tests pass under `panic=abort` (#749)
+
+# 1.9.0 (November 27, 2024)
+
+### Added
+
+- Add `Bytes::from_owner` to enable externally-allocated memory (#742)
+
+### Documented
+
+- Fix typo in Buf::chunk() comment (#744)
+
+### Internal changes
+
+- Replace BufMut::put with BufMut::put_slice in Writer impl (#745)
+- Rename hex_impl! to fmt_impl! and reuse it for fmt::Debug (#743)
+
+# 1.8.0 (October 21, 2024)
+
+- Guarantee address in `split_off`/`split_to` for empty slices (#740)
+
+# 1.7.2 (September 17, 2024)
+
+### Fixed
+
+- Fix default impl of `Buf::{get_int, get_int_le}` (#732)
+
+### Documented
+
+- Fix double spaces in comments and doc comments (#731)
+
+### Internal changes
+
+- Ensure BytesMut::advance reduces capacity (#728)
+
+# 1.7.1 (August 1, 2024)
+
+This release reverts the following change due to a regression:
+
+- Reuse capacity when possible in `<BytesMut as Buf>::advance` impl (#698)
+
+The revert can be found at #726.
+
+# 1.7.0 (July 31, 2024)
+
+### Added
+
+- Add conversion from `Bytes` to `BytesMut` (#695, #710)
+- Add reclaim method without additional allocation (#686)
+
+### Documented
+
+- Clarify how `BytesMut::zeroed` works (#714)
+- Clarify the behavior of `Buf::chunk` (#717)
+
+### Changed
+
+- Change length condition of `BytesMut::truncate`
+- Reuse capacity when possible in `<BytesMut as Buf>::advance` impl (#698)
+- Improve `must_use` suggestion of `BytesMut::split` (#699)
+
+### Internal changes
+
+- Use `ManuallyDrop` instead of `mem::forget` (#678)
+- Don't set `len` in `BytesMut::reserve` (#682)
+- Optimize `Bytes::copy_to_bytes` (#688)
+- Refactor `BytesMut::truncate` (#694)
+- Refactor `BytesMut::resize` (#696)
+- Reorder assertion in `Bytes::split_to`, `Bytes::split_off` (#689, #693)
+- Use `offset_from` in more places (#705)
+- Correct the wrong usage of `IntoIter` (#707)
+
+# 1.6.1 (July 13, 2024)
+
+This release fixes a bug where `Bytes::is_unique` returns incorrect values when
+the `Bytes` originates from a shared `BytesMut`. (#718)
+
+# 1.6.0 (March 22, 2024)
+
+### Added
+
+- Add `Bytes::is_unique` (#643)
+
+### Documented
+
+- Fix changelog typo (#628)
+- Fix some spelling mistakes (#633)
+- Typo fix (#637)
+- Fix broken links (#639)
+- Add security policy (#649)
+
+### Internal changes
+
+- Move comment to correct constant (#629)
+- Various cleanup (#635)
+- Simplify `UninitSlice::as_uninit_slice_mut()` logic (#644)
+- Use `self.` instead of `Self::` (#642)
+- `BytesMut`: Assert alignment of `Shared` (#652)
+- Remove unnecessary namespace qualifier (#660)
+- Remove an unnecessary else branch (#662)
+- Remove unreachable else branch (#661)
+- make parameter mut in `From<Vec>` (#667)
+- Restore commented tests (#665)
+- Use `sub` instead of `offset` (#668)
+- Calculate original capacity only if necessary (#666)
+- `set_vec_pos` does not need a second parameter (#672)
+- `get_vec_pos`: use `&self` instead of `&mut self` (#670)
+- Refactor `split_at`/`split_to` (#663)
+- Use `Iterator` from the prelude (#673)
+- `copy_to_bytes`: Add panic section to docs (#676)
+- Remove redundant reserve call (#674)
+- Use `ManuallyDrop` instead of `mem::forget` (#675)
+
+
+# 1.5.0 (September 7, 2023)
+
+### Added
+
+- Add `UninitSlice::{new,uninit}` (#598, #599)
+- Implement `BufMut` for `&mut [MaybeUninit<u8>]` (#597)
+
+### Changed
+
+- Mark `BytesMut::extend_from_slice` as inline (#595)
+
+# 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
+
+- Fix unbounded memory growth when using `reserve` (#560)
+
+# 1.2.0 (July 19, 2022)
+
+### Added
+
+- Add `BytesMut::zeroed` (#517)
+- Implement `Extend<Bytes>` for `BytesMut` (#527)
+- Add conversion from `BytesMut` to `Vec<u8>` (#543, #554)
+- Add conversion from `Bytes` to `Vec<u8>` (#547)
+- Add `UninitSlice::as_uninit_slice_mut()` (#548)
+- Add const to `Bytes::{len,is_empty}` (#514)
+
+### Changed
+
+- Reuse vector in `BytesMut::reserve` (#539, #544)
+
+### Fixed
+
+- Make miri happy (#515, #523, #542, #545, #553)
+- Make tsan happy (#541)
+- Fix `remaining_mut()` on chain (#488)
+- Fix amortized asymptotics of `BytesMut` (#555)
+
+### Documented
+
+- Redraw layout diagram with box drawing characters (#539)
+- Clarify `BytesMut::unsplit` docs (#535)
+
+# 1.1.0 (August 25, 2021)
+
+### Added
+
+- `BufMut::put_bytes(self, val, cnt)` (#487)
+- Implement `From<Box<[u8]>>` for `Bytes` (#504)
+
+### Changed
+
+- Override `put_slice` for `&mut [u8]` (#483)
+- Panic on integer overflow in `Chain::remaining` (#482)
+- Add inline tags to `UninitSlice` methods (#443)
+- Override `copy_to_bytes` for Chain and Take (#481)
+- Keep capacity when unsplit on empty other buf (#502)
+
+### Documented
+
+- Clarify `BufMut` allocation guarantees (#501)
+- Clarify `BufMut::put_int` behavior (#486)
+- Clarify actions of `clear` and `truncate`. (#508)
+
+# 1.0.1 (January 11, 2021)
+
+### Changed
+- mark `Vec::put_slice` with `#[inline]` (#459)
+
+### Fixed
+- Fix deprecation warning (#457)
+- use `Box::into_raw` instead of `mem::forget`-in-disguise (#458)
+
+# 1.0.0 (December 22, 2020)
+
+### Changed
+- Rename `Buf`/`BufMut` methods `bytes()` and `bytes_mut()` to `chunk()` and `chunk_mut()` (#450)
+
+### Removed
+- remove unused Buf implementation. (#449)
+
 # 0.6.0 (October 21, 2020)
 
 API polish in preparation for a 1.0 release.

Cargo.toml

@@ -2,23 +2,22 @@
 
 name = "bytes"
 # When releasing to crates.io:
-# - Update html_root_url.
 # - Update CHANGELOG.md.
-# - Update doc URL.
-# - Create "v0.6.x" git tag.
-version = "0.6.0"
+# - Create "v1.x.y" git tag.
+version = "1.12.1"
+edition = "2021"
+rust-version = "1.57"
 license = "MIT"
 authors = [
     "Carl Lerche <[email protected]>",
     "Sean McArthur <[email protected]>",
 ]
 description = "Types and traits for working with bytes"
-documentation = "https://docs.rs/bytes/0.6.0/bytes/"
 repository = "https://github.com/tokio-rs/bytes"
 readme = "README.md"
 keywords = ["buffers", "zero-copy", "io"]
 categories = ["network-programming", "data-structures"]
-edition = "2018"
+include = ["CHANGELOG.md", "LICENSE", "README.md", "SECURITY.md", "Cargo.toml", "src/**/*.rs", "tests/**/*.rs", "clippy.toml"]
 
 [features]
 default = ["std"]
@@ -26,9 +25,22 @@ std = []
 
 [dependencies]
 serde = { version = "1.0.60", optional = true, default-features = false, features = ["alloc"] }
+# Use portable-atomic crate to support platforms without atomic CAS.
+# See "no_std support" section in readme for more information.
+#
+# Enable require-cas feature to provide a better error message if the end user forgets to use the cfg or feature.
+extra-platforms = { package = "portable-atomic", version = "1.3", optional = true, default-features = false, features = ["require-cas"] }
 
 [dev-dependencies]
 serde_test = "1.0"
 
 [target.'cfg(loom)'.dev-dependencies]
-loom = "0.3"
+loom = "0.7"
+
+[package.metadata.docs.rs]
+rustdoc-args = ["--cfg", "docsrs"]
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = [
+  'cfg(loom)',
+] }

README.md

@@ -18,7 +18,7 @@ To use `bytes`, first add this to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-bytes = "0.5"
+bytes = "1"
 ```
 
 Next, add this to your crate:
@@ -27,13 +27,39 @@ Next, add this to your crate:
 use bytes::{Bytes, BytesMut, Buf, BufMut};
 ```
 
+## no_std support
+
+To use `bytes` with no_std environment, disable the (enabled by default) `std` feature.
+
+```toml
+[dependencies]
+bytes = { version = "1", default-features = false }
+```
+
+To use `bytes` with no_std environment without atomic CAS, such as thumbv6m, you also need to enable
+the `extra-platforms` feature. See the [documentation for the `portable-atomic`
+crate](https://docs.rs/portable-atomic) for more information.
+
+The MSRV when `extra-platforms` feature is enabled depends on the MSRV of `portable-atomic`.
+
 ## Serde support
 
 Serde support is optional and disabled by default. To enable use the feature `serde`.
 
 ```toml
 [dependencies]
-bytes = { version = "0.5", features = ["serde"] }
+bytes = { version = "1", features = ["serde"] }
+```
+
+The MSRV when `serde` feature is enabled depends on the MSRV of `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

SECURITY.md

@@ -0,0 +1,9 @@
+# Security Policy
+
+Bytes is part of the Tokio project and uses the same security policy as [Tokio][tokio-security].
+
+## Report a security issue
+
+The process for reporting an issue is the same as for [Tokio][tokio-security]. This includes private reporting via security@tokio.rs.
+
+[tokio-security]: https://github.com/tokio-rs/tokio/security/policy

benches/buf.rs

@@ -46,14 +46,14 @@ impl TestBuf {
 }
 impl Buf for TestBuf {
     fn remaining(&self) -> usize {
-        return self.buf.len() - self.pos;
+        self.buf.len() - self.pos
     }
     fn advance(&mut self, cnt: usize) {
         self.pos += cnt;
         assert!(self.pos <= self.buf.len());
         self.next_readlen();
     }
-    fn bytes(&self) -> &[u8] {
+    fn chunk(&self) -> &[u8] {
         if self.readlen == 0 {
             Default::default()
         } else {
@@ -87,8 +87,8 @@ impl Buf for TestBufC {
         self.inner.advance(cnt)
     }
     #[inline(never)]
-    fn bytes(&self) -> &[u8] {
-        self.inner.bytes()
+    fn chunk(&self) -> &[u8] {
+        self.inner.chunk()
     }
 }
 
@@ -159,7 +159,6 @@ macro_rules! bench_group {
 mod get_u8 {
     use super::*;
     bench_group!(get_u8);
-    bench!(option, option);
 }
 mod get_u16 {
     use super::*;

benches/bytes.rs

@@ -47,7 +47,7 @@ fn clone_static(b: &mut Bencher) {
 
     b.iter(|| {
         for _ in 0..1024 {
-            test::black_box(&bytes.clone());
+            test::black_box(test::black_box(&bytes).clone());
         }
     })
 }
@@ -58,7 +58,7 @@ fn clone_shared(b: &mut Bencher) {
 
     b.iter(|| {
         for _ in 0..1024 {
-            test::black_box(&bytes.clone());
+            test::black_box(test::black_box(&bytes).clone());
         }
     })
 }
@@ -70,7 +70,7 @@ fn clone_arc_vec(b: &mut Bencher) {
 
     b.iter(|| {
         for _ in 0..1024 {
-            test::black_box(&bytes.clone());
+            test::black_box(test::black_box(&bytes).clone());
         }
     })
 }
@@ -88,6 +88,7 @@ fn from_long_slice(b: &mut Bencher) {
 #[bench]
 fn slice_empty(b: &mut Bencher) {
     b.iter(|| {
+        // `clone` is to convert to ARC
         let b = Bytes::from(vec![17; 1024]).clone();
         for i in 0..1000 {
             test::black_box(b.slice(i % 100..i % 100));

ci/miri.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -e
+
+rustup component add miri
+cargo miri setup
+
+export MIRIFLAGS="-Zmiri-strict-provenance"
+
+cargo miri test
+cargo miri test --target mips64-unknown-linux-gnuabi64
+
+# run with wrapping integer overflow instead of panic
+cargo miri test --release

ci/panic-abort.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+set -ex
+RUSTFLAGS="$RUSTFLAGS -Cpanic=abort -Zpanic-abort-tests" cargo test --all-features --test '*'

ci/test-stable.sh

@@ -4,9 +4,6 @@ set -ex
 
 cmd="${1:-test}"
 
-# Install cargo-hack for feature flag test
-cargo install cargo-hack
-
 # Run with each feature
 # * --each-feature includes both default/no-default features
 # * --optional-deps is needed for serde feature
@@ -14,14 +11,15 @@ cargo hack "${cmd}" --each-feature --optional-deps
 # Run with all features
 cargo "${cmd}" --all-features
 
-cargo doc --no-deps --all-features
-
 if [[ "${RUST_VERSION}" == "nightly"* ]]; then
     # Check benchmarks
     cargo check --benches
 
     # Check minimal versions
-    cargo clean
-    cargo update -Zminimal-versions
+    # Remove dev-dependencies from Cargo.toml to prevent the next `cargo update`
+    # from determining minimal versions based on dev-dependencies.
+    cargo hack --remove-dev-deps --workspace
+    # Update Cargo.lock to minimal version dependencies.
+    cargo update -Z minimal-versions
     cargo check --all-features
 fi

clippy.toml

@@ -0,0 +1 @@
+msrv = "1.57"

src/buf/chain.rs

@@ -25,9 +25,7 @@ use std::io::IoSlice;
 /// assert_eq!(full[..], b"hello world"[..]);
 /// ```
 ///
-/// [`Buf::chain`]: trait.Buf.html#method.chain
-/// [`Buf`]: trait.Buf.html
-/// [`BufMut`]: trait.BufMut.html
+/// [`Buf::chain`]: Buf::chain
 #[derive(Debug)]
 pub struct Chain<T, U> {
     a: T,
@@ -135,14 +133,14 @@ where
     U: Buf,
 {
     fn remaining(&self) -> usize {
-        self.a.remaining() + self.b.remaining()
+        self.a.remaining().saturating_add(self.b.remaining())
     }
 
-    fn bytes(&self) -> &[u8] {
+    fn chunk(&self) -> &[u8] {
         if self.a.has_remaining() {
-            self.a.bytes()
+            self.a.chunk()
         } else {
-            self.b.bytes()
+            self.b.chunk()
         }
     }
 
@@ -165,11 +163,29 @@ where
     }
 
     #[cfg(feature = "std")]
-    fn bytes_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize {
-        let mut n = self.a.bytes_vectored(dst);
-        n += self.b.bytes_vectored(&mut dst[n..]);
+    fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize {
+        let mut n = self.a.chunks_vectored(dst);
+        n += self.b.chunks_vectored(&mut dst[n..]);
         n
     }
+
+    fn copy_to_bytes(&mut self, len: usize) -> crate::Bytes {
+        let a_rem = self.a.remaining();
+        if a_rem >= len {
+            self.a.copy_to_bytes(len)
+        } else if a_rem == 0 {
+            self.b.copy_to_bytes(len)
+        } else {
+            assert!(
+                len - a_rem <= self.b.remaining(),
+                "`len` greater than remaining"
+            );
+            let mut ret = crate::BytesMut::with_capacity(len);
+            ret.put(&mut self.a);
+            ret.put((&mut self.b).take(len - a_rem));
+            ret.freeze()
+        }
+    }
 }
 
 unsafe impl<T, U> BufMut for Chain<T, U>
@@ -178,14 +194,16 @@ where
     U: BufMut,
 {
     fn remaining_mut(&self) -> usize {
-        self.a.remaining_mut() + self.b.remaining_mut()
+        self.a
+            .remaining_mut()
+            .saturating_add(self.b.remaining_mut())
     }
 
-    fn bytes_mut(&mut self) -> &mut UninitSlice {
+    fn chunk_mut(&mut self) -> &mut UninitSlice {
         if self.a.has_remaining_mut() {
-            self.a.bytes_mut()
+            self.a.chunk_mut()
         } else {
-            self.b.bytes_mut()
+            self.b.chunk_mut()
         }
     }
 

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:
@@ -19,9 +17,6 @@ use crate::Buf;
 /// assert_eq!(iter.next(), Some(b'c'));
 /// assert_eq!(iter.next(), None);
 /// ```
-///
-/// [`iter`]: trait.Buf.html#method.iter
-/// [`Buf`]: trait.Buf.html
 #[derive(Debug)]
 pub struct IntoIter<T> {
     inner: T,
@@ -43,7 +38,7 @@ 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 }
     }
 
@@ -117,7 +112,7 @@ impl<T: Buf> Iterator for IntoIter<T> {
             return None;
         }
 
-        let b = self.inner.bytes()[0];
+        let b = self.inner.chunk()[0];
         self.inner.advance(1);
 
         Some(b)

src/buf/limit.rs

@@ -61,8 +61,8 @@ unsafe impl<T: BufMut> BufMut for Limit<T> {
         cmp::min(self.inner.remaining_mut(), self.limit)
     }
 
-    fn bytes_mut(&mut self) -> &mut UninitSlice {
-        let bytes = self.inner.bytes_mut();
+    fn chunk_mut(&mut self) -> &mut UninitSlice {
+        let bytes = self.inner.chunk_mut();
         let end = cmp::min(bytes.len(), self.limit);
         &mut bytes[..end]
     }

src/buf/mod.rs

@@ -13,8 +13,6 @@
 //! See [`Buf`] and [`BufMut`] for more details.
 //!
 //! [rope]: https://en.wikipedia.org/wiki/Rope_(data_structure)
-//! [`Buf`]: trait.Buf.html
-//! [`BufMut`]: trait.BufMut.html
 
 mod buf_impl;
 mod buf_mut;

src/buf/reader.rs

@@ -5,7 +5,7 @@ use std::{cmp, io};
 /// A `Buf` adapter which implements `io::Read` for the inner value.
 ///
 /// This struct is generally created by calling `reader()` on `Buf`. See
-/// documentation of [`reader()`](trait.Buf.html#method.reader) for more
+/// documentation of [`reader()`](Buf::reader) for more
 /// details.
 #[derive(Debug)]
 pub struct Reader<B> {
@@ -73,7 +73,7 @@ impl<B: Buf + Sized> io::Read for Reader<B> {
 
 impl<B: Buf + Sized> io::BufRead for Reader<B> {
     fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        Ok(self.buf.bytes())
+        Ok(self.buf.chunk())
     }
     fn consume(&mut self, amt: usize) {
         self.buf.advance(amt)

src/buf/take.rs

@@ -2,10 +2,13 @@ use crate::Buf;
 
 use core::cmp;
 
+#[cfg(feature = "std")]
+use std::io::IoSlice;
+
 /// A `Buf` adapter which limits the bytes read from an underlying buffer.
 ///
 /// This struct is generally created by calling `take()` on `Buf`. See
-/// documentation of [`take()`](trait.BufExt.html#method.take) for more details.
+/// documentation of [`take()`](Buf::take) for more details.
 #[derive(Debug)]
 pub struct Take<T> {
     inner: T,
@@ -134,8 +137,8 @@ impl<T: Buf> Buf for Take<T> {
         cmp::min(self.inner.remaining(), self.limit)
     }
 
-    fn bytes(&self) -> &[u8] {
-        let bytes = self.inner.bytes();
+    fn chunk(&self) -> &[u8] {
+        let bytes = self.inner.chunk();
         &bytes[..cmp::min(bytes.len(), self.limit)]
     }
 
@@ -144,4 +147,41 @@ impl<T: Buf> Buf for Take<T> {
         self.inner.advance(cnt);
         self.limit -= cnt;
     }
+
+    fn copy_to_bytes(&mut self, len: usize) -> crate::Bytes {
+        assert!(len <= self.remaining(), "`len` greater than remaining");
+
+        let r = self.inner.copy_to_bytes(len);
+        self.limit -= len;
+        r
+    }
+
+    #[cfg(feature = "std")]
+    fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize {
+        if self.limit == 0 {
+            return 0;
+        }
+
+        const LEN: usize = 16;
+        let mut slices: [IoSlice<'a>; LEN] = [IoSlice::new(&[]); LEN];
+
+        let cnt = self
+            .inner
+            .chunks_vectored(&mut slices[..dst.len().min(LEN)]);
+        let mut limit = self.limit;
+        for (i, (dst, slice)) in dst[..cnt].iter_mut().zip(slices.iter()).enumerate() {
+            if let Some(buf) = slice.get(..limit) {
+                // SAFETY: We could do this safely with `IoSlice::advance` if we had a larger MSRV.
+                let buf = unsafe { std::mem::transmute::<&[u8], &'a [u8]>(buf) };
+                *dst = IoSlice::new(buf);
+                return i + 1;
+            } else {
+                // SAFETY: We could do this safely with `IoSlice::advance` if we had a larger MSRV.
+                let buf = unsafe { std::mem::transmute::<&[u8], &'a [u8]>(slice) };
+                *dst = IoSlice::new(buf);
+                limit -= slice.len();
+            }
+        }
+        cnt
+    }
 }

src/buf/uninit_slice.rs

@@ -6,7 +6,7 @@ use core::ops::{
 
 /// Uninitialized byte slice.
 ///
-/// Returned by `BufMut::bytes_mut()`, the referenced byte slice may be
+/// Returned by `BufMut::chunk_mut()`, the referenced byte slice may be
 /// uninitialized. The wrapper provides safe access without introducing
 /// undefined behavior.
 ///
@@ -22,6 +22,44 @@ use core::ops::{
 pub struct UninitSlice([MaybeUninit<u8>]);
 
 impl UninitSlice {
+    /// Creates a `&mut UninitSlice` wrapping a slice of initialised memory.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::buf::UninitSlice;
+    ///
+    /// let mut buffer = [0u8; 64];
+    /// let slice = UninitSlice::new(&mut buffer[..]);
+    /// ```
+    #[inline]
+    pub fn new(slice: &mut [u8]) -> &mut UninitSlice {
+        unsafe { &mut *(slice as *mut [u8] as *mut [MaybeUninit<u8>] as *mut UninitSlice) }
+    }
+
+    /// Creates a `&mut UninitSlice` wrapping a slice of uninitialised memory.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::buf::UninitSlice;
+    /// use core::mem::MaybeUninit;
+    ///
+    /// let mut buffer = [MaybeUninit::uninit(); 64];
+    /// let slice = UninitSlice::uninit(&mut buffer[..]);
+    ///
+    /// let mut vec = Vec::with_capacity(1024);
+    /// let spare: &mut UninitSlice = vec.spare_capacity_mut().into();
+    /// ```
+    #[inline]
+    pub fn uninit(slice: &mut [MaybeUninit<u8>]) -> &mut UninitSlice {
+        unsafe { &mut *(slice as *mut [MaybeUninit<u8>] as *mut UninitSlice) }
+    }
+
+    fn uninit_ref(slice: &[MaybeUninit<u8>]) -> &UninitSlice {
+        unsafe { &*(slice as *const [MaybeUninit<u8>] as *const UninitSlice) }
+    }
+
     /// Create a `&mut UninitSlice` from a pointer and a length.
     ///
     /// # Safety
@@ -40,10 +78,11 @@ impl UninitSlice {
     ///
     /// let slice = unsafe { UninitSlice::from_raw_parts_mut(ptr, len) };
     /// ```
+    #[inline]
     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::uninit(maybe_init)
     }
 
     /// Write a single byte at the specified offset.
@@ -64,13 +103,14 @@ impl UninitSlice {
     ///
     /// assert_eq!(b"boo", &data[..]);
     /// ```
+    #[inline]
     pub fn write_byte(&mut self, index: usize, byte: u8) {
         assert!(index < self.len());
 
         unsafe { self[index..].as_mut_ptr().write(byte) }
     }
 
-    /// Copies bytes  from `src` into `self`.
+    /// Copies bytes from `src` into `self`.
     ///
     /// The length of `src` must be the same as `self`.
     ///
@@ -90,6 +130,7 @@ impl UninitSlice {
     ///
     /// assert_eq!(b"bar", &data[..]);
     /// ```
+    #[inline]
     pub fn copy_from_slice(&mut self, src: &[u8]) {
         use core::ptr;
 
@@ -114,12 +155,39 @@ impl UninitSlice {
     ///
     /// let mut data = [0, 1, 2];
     /// let mut slice = &mut data[..];
-    /// let ptr = BufMut::bytes_mut(&mut slice).as_mut_ptr();
+    /// let ptr = BufMut::chunk_mut(&mut slice).as_mut_ptr();
     /// ```
+    #[inline]
     pub fn as_mut_ptr(&mut self) -> *mut u8 {
         self.0.as_mut_ptr() as *mut _
     }
 
+    /// Return a `&mut [MaybeUninit<u8>]` to this slice's buffer.
+    ///
+    /// # Safety
+    ///
+    /// The caller **must not** read from the referenced memory and **must not** write
+    /// **uninitialized** bytes to the slice either. This is because `BufMut` implementation
+    /// that created the `UninitSlice` knows which parts are initialized. Writing uninitialized
+    /// bytes to the slice may cause the `BufMut` to read those bytes and trigger undefined
+    /// behavior.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytes::BufMut;
+    ///
+    /// let mut data = [0, 1, 2];
+    /// let mut slice = &mut data[..];
+    /// unsafe {
+    ///     let uninit_slice = BufMut::chunk_mut(&mut slice).as_uninit_slice_mut();
+    /// };
+    /// ```
+    #[inline]
+    pub unsafe fn as_uninit_slice_mut(&mut self) -> &mut [MaybeUninit<u8>] {
+        &mut self.0
+    }
+
     /// Returns the number of bytes in the slice.
     ///
     /// # Examples
@@ -129,10 +197,11 @@ impl UninitSlice {
     ///
     /// let mut data = [0, 1, 2];
     /// let mut slice = &mut data[..];
-    /// let len = BufMut::bytes_mut(&mut slice).len();
+    /// let len = BufMut::chunk_mut(&mut slice).len();
     ///
     /// assert_eq!(len, 3);
     /// ```
+    #[inline]
     pub fn len(&self) -> usize {
         self.0.len()
     }
@@ -144,22 +213,34 @@ impl fmt::Debug for UninitSlice {
     }
 }
 
+impl<'a> From<&'a mut [u8]> for &'a mut UninitSlice {
+    fn from(slice: &'a mut [u8]) -> Self {
+        UninitSlice::new(slice)
+    }
+}
+
+impl<'a> From<&'a mut [MaybeUninit<u8>]> for &'a mut UninitSlice {
+    fn from(slice: &'a mut [MaybeUninit<u8>]) -> Self {
+        UninitSlice::uninit(slice)
+    }
+}
+
 macro_rules! impl_index {
     ($($t:ty),*) => {
         $(
             impl Index<$t> for UninitSlice {
                 type Output = UninitSlice;
 
+                #[inline]
                 fn index(&self, index: $t) -> &UninitSlice {
-                    let maybe_uninit: &[MaybeUninit<u8>] = &self.0[index];
-                    unsafe { &*(maybe_uninit as *const [MaybeUninit<u8>] as *const UninitSlice) }
+                    UninitSlice::uninit_ref(&self.0[index])
                 }
             }
 
             impl IndexMut<$t> for UninitSlice {
+                #[inline]
                 fn index_mut(&mut self, index: $t) -> &mut UninitSlice {
-                    let maybe_uninit: &mut [MaybeUninit<u8>] = &mut self.0[index];
-                    unsafe { &mut *(maybe_uninit as *mut [MaybeUninit<u8>] as *mut UninitSlice) }
+                    UninitSlice::uninit(&mut self.0[index])
                 }
             }
         )*

src/buf/vec_deque.rs

@@ -1,4 +1,6 @@
 use alloc::collections::VecDeque;
+#[cfg(feature = "std")]
+use std::io;
 
 use super::Buf;
 
@@ -7,7 +9,7 @@ impl Buf for VecDeque<u8> {
         self.len()
     }
 
-    fn bytes(&self) -> &[u8] {
+    fn chunk(&self) -> &[u8] {
         let (s1, s2) = self.as_slices();
         if s1.is_empty() {
             s2
@@ -16,6 +18,22 @@ impl Buf for VecDeque<u8> {
         }
     }
 
+    #[cfg(feature = "std")]
+    fn chunks_vectored<'a>(&'a self, dst: &mut [io::IoSlice<'a>]) -> usize {
+        if self.is_empty() || dst.is_empty() {
+            return 0;
+        }
+
+        let (s1, s2) = self.as_slices();
+        dst[0] = io::IoSlice::new(s1);
+        if s2.is_empty() || dst.len() == 1 {
+            return 1;
+        }
+
+        dst[1] = io::IoSlice::new(s2);
+        2
+    }
+
     fn advance(&mut self, cnt: usize) {
         self.drain(..cnt);
     }

src/buf/writer.rs

@@ -5,7 +5,7 @@ use std::{cmp, io};
 /// A `BufMut` adapter which implements `io::Write` for the inner value.
 ///
 /// This struct is generally created by calling `writer()` on `BufMut`. See
-/// documentation of [`writer()`](trait.BufMut.html#method.writer) for more
+/// documentation of [`writer()`](BufMut::writer) for more
 /// details.
 #[derive(Debug)]
 pub struct Writer<B> {
@@ -78,7 +78,7 @@ impl<B: BufMut + Sized> io::Write for Writer<B> {
     fn write(&mut self, src: &[u8]) -> io::Result<usize> {
         let n = cmp::min(self.buf.remaining_mut(), src.len());
 
-        self.buf.put(&src[0..n]);
+        self.buf.put_slice(&src[..n]);
         Ok(n)
     }
 

src/fmt/debug.rs

@@ -25,7 +25,7 @@ impl Debug for BytesRef<'_> {
             } else if b == b'\0' {
                 write!(f, "\\0")?;
             // ASCII printable
-            } else if b >= 0x20 && b < 0x7f {
+            } else if (0x20..0x7f).contains(&b) {
                 write!(f, "{}", b as char)?;
             } else {
                 write!(f, "\\x{:02x}", b)?;
@@ -36,14 +36,5 @@ impl Debug for BytesRef<'_> {
     }
 }
 
-impl Debug for Bytes {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
-        Debug::fmt(&BytesRef(&self.as_ref()), f)
-    }
-}
-
-impl Debug for BytesMut {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
-        Debug::fmt(&BytesRef(&self.as_ref()), f)
-    }
-}
+fmt_impl!(Debug, Bytes);
+fmt_impl!(Debug, BytesMut);

src/fmt/hex.rs

@@ -21,17 +21,7 @@ impl UpperHex for BytesRef<'_> {
     }
 }
 
-macro_rules! hex_impl {
-    ($tr:ident, $ty:ty) => {
-        impl $tr for $ty {
-            fn fmt(&self, f: &mut Formatter<'_>) -> Result {
-                $tr::fmt(&BytesRef(self.as_ref()), f)
-            }
-        }
-    };
-}
-
-hex_impl!(LowerHex, Bytes);
-hex_impl!(LowerHex, BytesMut);
-hex_impl!(UpperHex, Bytes);
-hex_impl!(UpperHex, BytesMut);
+fmt_impl!(LowerHex, Bytes);
+fmt_impl!(LowerHex, BytesMut);
+fmt_impl!(UpperHex, Bytes);
+fmt_impl!(UpperHex, BytesMut);

src/fmt/mod.rs

@@ -1,3 +1,13 @@
+macro_rules! fmt_impl {
+    ($tr:ident, $ty:ty) => {
+        impl $tr for $ty {
+            fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+                $tr::fmt(&BytesRef(self.as_ref()), f)
+            }
+        }
+    };
+}
+
 mod debug;
 mod hex;
 

src/lib.rs

@@ -3,18 +3,15 @@
     no_crate_inject,
     attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
 ))]
-#![doc(html_root_url = "https://docs.rs/bytes/0.6.0")]
 #![no_std]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 //! Provides abstractions for working with bytes.
 //!
 //! The `bytes` crate provides an efficient byte buffer structure
-//! ([`Bytes`](struct.Bytes.html)) and traits for working with buffer
+//! ([`Bytes`]) and traits for working with buffer
 //! implementations ([`Buf`], [`BufMut`]).
 //!
-//! [`Buf`]: trait.Buf.html
-//! [`BufMut`]: trait.BufMut.html
-//!
 //! # `Bytes`
 //!
 //! `Bytes` is an efficient container for storing and operating on contiguous
@@ -52,9 +49,7 @@
 //! `a` and `b` will share the underlying buffer and maintain indices tracking
 //! the view into the buffer represented by the handle.
 //!
-//! See the [struct docs] for more details.
-//!
-//! [struct docs]: struct.Bytes.html
+//! See the [struct docs](`Bytes`) for more details.
 //!
 //! # `Buf`, `BufMut`
 //!
@@ -70,7 +65,7 @@
 //! ## Relation with `Read` and `Write`
 //!
 //! At first glance, it may seem that `Buf` and `BufMut` overlap in
-//! functionality with `std::io::Read` and `std::io::Write`. However, they
+//! functionality with [`std::io::Read`] and [`std::io::Write`]. However, they
 //! serve different purposes. A buffer is the value that is provided as an
 //! argument to `Read::read` and `Write::write`. `Read` and `Write` may then
 //! perform a syscall, which has the potential of failing. Operations on `Buf`
@@ -115,3 +110,110 @@ fn abort() -> ! {
         panic!("abort");
     }
 }
+
+#[inline(always)]
+#[cfg(feature = "std")]
+fn saturating_sub_usize_u64(a: usize, b: u64) -> usize {
+    match usize::try_from(b) {
+        Ok(b) => a.saturating_sub(b),
+        Err(_) => 0,
+    }
+}
+
+#[inline(always)]
+#[cfg(feature = "std")]
+fn min_u64_usize(a: u64, b: usize) -> usize {
+    match usize::try_from(a) {
+        Ok(a) => usize::min(a, b),
+        Err(_) => b,
+    }
+}
+
+/// Performs bounds checking of a range.
+///
+/// This is a spiritual copy of [core::slice::index::range] because that
+/// function is currently unstable.
+#[inline(always)]
+#[track_caller]
+fn range(range: impl core::ops::RangeBounds<usize>, len: usize) -> (usize, usize) {
+    use core::ops::Bound;
+
+    let begin = match range.start_bound() {
+        Bound::Included(&n) => n,
+        Bound::Excluded(&n) => n.checked_add(1).expect("out of range"),
+        Bound::Unbounded => 0,
+    };
+
+    let end = match range.end_bound() {
+        Bound::Included(&n) => n.checked_add(1).expect("out of range"),
+        Bound::Excluded(&n) => n,
+        Bound::Unbounded => len,
+    };
+
+    assert!(
+        begin <= end,
+        "range start must not be greater than end: {:?} <= {:?}",
+        begin,
+        end,
+    );
+    assert!(
+        end <= len,
+        "range end out of bounds: {:?} <= {:?}",
+        end,
+        len,
+    );
+
+    (begin, end)
+}
+
+/// Error type for the `try_get_` methods of [`Buf`].
+/// Indicates that there were not enough remaining
+/// bytes in the buffer while attempting
+/// to get a value from a [`Buf`] with one
+/// of the `try_get_` methods.
+#[derive(Debug, PartialEq, Eq)]
+pub struct TryGetError {
+    /// The number of bytes necessary to get the value
+    pub requested: usize,
+
+    /// The number of bytes available in the buffer
+    pub available: usize,
+}
+
+impl core::fmt::Display for TryGetError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {
+        write!(
+            f,
+            "Not enough bytes remaining in buffer to read value (requested {} but only {} available)",
+            self.requested,
+            self.available
+        )
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for TryGetError {}
+
+#[cfg(feature = "std")]
+impl From<TryGetError> for std::io::Error {
+    fn from(error: TryGetError) -> Self {
+        std::io::Error::new(std::io::ErrorKind::Other, error)
+    }
+}
+
+/// Panic with a nice error message.
+#[cold]
+fn panic_advance(error_info: &TryGetError) -> ! {
+    panic!(
+        "advance out of bounds: the len is {} but advancing by {}",
+        error_info.available, error_info.requested
+    );
+}
+
+#[cold]
+fn panic_does_not_fit(size: usize, nbytes: usize) -> ! {
+    panic!(
+        "size too large: the integer type can fit {} bytes, but nbytes is {}",
+        size, nbytes
+    );
+}

src/loom.rs

@@ -1,7 +1,10 @@
 #[cfg(not(all(test, loom)))]
 pub(crate) mod sync {
     pub(crate) mod atomic {
-        pub(crate) use core::sync::atomic::{fence, AtomicPtr, AtomicUsize, Ordering};
+        #[cfg(not(feature = "extra-platforms"))]
+        pub(crate) use core::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
+        #[cfg(feature = "extra-platforms")]
+        pub(crate) use extra_platforms::{AtomicPtr, AtomicUsize, Ordering};
 
         pub(crate) trait AtomicMut<T> {
             fn with_mut<F, R>(&mut self, f: F) -> R
@@ -23,7 +26,7 @@ pub(crate) mod sync {
 #[cfg(all(test, loom))]
 pub(crate) mod sync {
     pub(crate) mod atomic {
-        pub(crate) use loom::sync::atomic::{fence, AtomicPtr, AtomicUsize, Ordering};
+        pub(crate) use loom::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
 
         pub(crate) trait AtomicMut<T> {}
     }

tests/test_buf.rs

@@ -1,77 +1,424 @@
 #![warn(rust_2018_idioms)]
 
-use bytes::Buf;
+use ::bytes::{Buf, Bytes, BytesMut};
+use core::{cmp, mem};
+use std::collections::VecDeque;
 #[cfg(feature = "std")]
 use std::io::IoSlice;
 
-#[test]
-fn test_fresh_cursor_vec() {
-    let mut buf = &b"hello"[..];
+// A random 64-byte ascii string, with the first 8 bytes altered to
+// give valid representations of f32 and f64 (making them easier to compare)
+// and negative signed numbers when interpreting as big endian
+// (testing Sign Extension for `Buf::get_int' and `Buf::get_int_ne`).
+const INPUT: &[u8] = b"\xffFqrjrDqPhvTc45vvq33f6bJrUtyHESuTeklWKgYd64xgzxJwvAkpYYnpNJyZSRn";
 
-    assert_eq!(buf.remaining(), 5);
-    assert_eq!(buf.bytes(), b"hello");
-
-    buf.advance(2);
-
-    assert_eq!(buf.remaining(), 3);
-    assert_eq!(buf.bytes(), b"llo");
-
-    buf.advance(3);
-
-    assert_eq!(buf.remaining(), 0);
-    assert_eq!(buf.bytes(), b"");
+macro_rules! e {
+    ($big_endian_val:expr, $little_endian_val:expr) => {
+        if cfg!(target_endian = "big") {
+            $big_endian_val
+        } else {
+            $little_endian_val
+        }
+    };
 }
 
-#[test]
-fn test_get_u8() {
-    let mut buf = &b"\x21zomg"[..];
-    assert_eq!(0x21, buf.get_u8());
+macro_rules! buf_tests {
+    ($make_input:ident) => {
+        buf_tests!($make_input, true);
+    };
+    ($make_input:ident, $checks_vectored_is_complete:expr) => {
+        use super::*;
+
+        #[test]
+        fn empty_state() {
+            let buf = $make_input(&[]);
+            assert_eq!(buf.remaining(), 0);
+            assert!(!buf.has_remaining());
+            assert!(buf.chunk().is_empty());
+        }
+
+        #[test]
+        fn fresh_state() {
+            let buf = $make_input(INPUT);
+            assert_eq!(buf.remaining(), 64);
+            assert!(buf.has_remaining());
+
+            let chunk = buf.chunk();
+            assert!(chunk.len() <= 64);
+            assert!(INPUT.starts_with(chunk));
+        }
+
+        #[test]
+        fn advance() {
+            let mut buf = $make_input(INPUT);
+            buf.advance(8);
+            assert_eq!(buf.remaining(), 64 - 8);
+            assert!(buf.has_remaining());
+
+            let chunk = buf.chunk();
+            assert!(chunk.len() <= 64 - 8);
+            assert!(INPUT[8..].starts_with(chunk));
+        }
+
+        #[test]
+        fn advance_to_end() {
+            let mut buf = $make_input(INPUT);
+            buf.advance(64);
+            assert_eq!(buf.remaining(), 0);
+            assert!(!buf.has_remaining());
+
+            let chunk = buf.chunk();
+            assert!(chunk.is_empty());
+        }
+
+        #[test]
+        #[should_panic]
+        fn advance_past_end() {
+            let  mut buf = $make_input(INPUT);
+            buf.advance(65);
+        }
+
+        #[test]
+        #[cfg(feature = "std")]
+        fn chunks_vectored_empty() {
+            let  buf = $make_input(&[]);
+            let mut bufs = [IoSlice::new(&[]); 16];
+
+            let n = buf.chunks_vectored(&mut bufs);
+            assert_eq!(n, 0);
+            assert!(bufs.iter().all(|buf| buf.is_empty()));
+        }
+
+        #[test]
+        #[cfg(feature = "std")]
+        fn chunks_vectored_is_complete() {
+            let buf = $make_input(INPUT);
+            let mut bufs = [IoSlice::new(&[]); 16];
+
+            let n = buf.chunks_vectored(&mut bufs);
+            assert!(n > 0);
+            assert!(n <= 16);
+
+            let bufs_concat = bufs[..n]
+                .iter()
+                .flat_map(|b| b.iter().copied())
+                .collect::<Vec<u8>>();
+            if $checks_vectored_is_complete {
+                assert_eq!(bufs_concat, INPUT);
+            } else {
+                // If this panics then `buf` implements `chunks_vectored`.
+                // Remove the `false` argument from `buf_tests!` for that type.
+                assert!(bufs_concat.len() < INPUT.len());
+                assert!(INPUT.starts_with(&bufs_concat));
+            }
+
+            for i in n..16 {
+                assert!(bufs[i].is_empty());
+            }
+        }
+
+        #[test]
+        fn copy_to_slice() {
+            let mut buf = $make_input(INPUT);
+
+            let mut chunk = [0u8; 8];
+            buf.copy_to_slice(&mut chunk);
+            assert_eq!(buf.remaining(), 64 - 8);
+            assert!(buf.has_remaining());
+            assert_eq!(chunk, INPUT[..8]);
+
+            let chunk = buf.chunk();
+            assert!(chunk.len() <= 64 - 8);
+            assert!(INPUT[8..].starts_with(chunk));
+        }
+
+        #[test]
+        fn copy_to_slice_big() {
+            let mut buf = $make_input(INPUT);
+
+            let mut chunk = [0u8; 56];
+            buf.copy_to_slice(&mut chunk);
+            assert_eq!(buf.remaining(), 64 - 56);
+            assert!(buf.has_remaining());
+            assert_eq!(chunk, INPUT[..56]);
+
+            let chunk = buf.chunk();
+            assert!(chunk.len() <= 64 - 56);
+            assert!(INPUT[56..].starts_with(chunk));
+        }
+
+        #[test]
+        fn copy_to_slice_to_end() {
+            let mut buf = $make_input(INPUT);
+
+            let mut chunk = [0u8; 64];
+            buf.copy_to_slice(&mut chunk);
+            assert_eq!(buf.remaining(), 0);
+            assert!(!buf.has_remaining());
+            assert_eq!(chunk, INPUT);
+
+            assert!(buf.chunk().is_empty());
+        }
+
+        #[test]
+        #[should_panic]
+        fn copy_to_slice_overflow() {
+            let mut buf = $make_input(INPUT);
+
+            let mut chunk = [0u8; 65];
+            buf.copy_to_slice(&mut chunk);
+        }
+
+        #[test]
+        fn copy_to_bytes() {
+            let mut buf = $make_input(INPUT);
+
+            let chunk = buf.copy_to_bytes(8);
+            assert_eq!(buf.remaining(), 64 - 8);
+            assert!(buf.has_remaining());
+            assert_eq!(chunk, INPUT[..8]);
+
+            let chunk = buf.chunk();
+            assert!(chunk.len() <= 64 - 8);
+            assert!(INPUT[8..].starts_with(chunk));
+        }
+
+        #[test]
+        fn copy_to_bytes_big() {
+            let mut buf = $make_input(INPUT);
+
+            let chunk = buf.copy_to_bytes(56);
+            assert_eq!(buf.remaining(), 64 - 56);
+            assert!(buf.has_remaining());
+            assert_eq!(chunk, INPUT[..56]);
+
+            let chunk = buf.chunk();
+            assert!(chunk.len() <= 64 - 56);
+            assert!(INPUT[56..].starts_with(chunk));
+        }
+
+        #[test]
+        fn copy_to_bytes_to_end() {
+            let mut buf = $make_input(INPUT);
+
+            let chunk = buf.copy_to_bytes(64);
+            assert_eq!(buf.remaining(), 0);
+            assert!(!buf.has_remaining());
+            assert_eq!(chunk, INPUT);
+
+            assert!(buf.chunk().is_empty());
+        }
+
+        #[test]
+        #[should_panic]
+        fn copy_to_bytes_overflow() {
+            let mut buf = $make_input(INPUT);
+
+            let _ = buf.copy_to_bytes(65);
+        }
+
+        buf_tests!(number $make_input, get_u8, get_u8_overflow, u8, get_u8, 0xff);
+        buf_tests!(number $make_input, get_i8, get_i8_overflow, i8, get_i8, 0xffu8 as i8);
+        buf_tests!(number $make_input, get_u16_be, get_u16_be_overflow, u16, get_u16, 0xff46);
+        buf_tests!(number $make_input, get_u16_le, get_u16_le_overflow, u16, get_u16_le, 0x46ff);
+        buf_tests!(number $make_input, get_u16_ne, get_u16_ne_overflow, u16, get_u16_ne, e!(0xff46, 0x46ff));
+        buf_tests!(number $make_input, get_i16_be, get_i16_be_overflow, i16, get_i16, 0xff46u16 as i16);
+        buf_tests!(number $make_input, get_i16_le, get_i16_le_overflow, i16, get_i16_le, 0x46ff);
+        buf_tests!(number $make_input, get_i16_ne, get_i16_ne_overflow, i16, get_i16_ne, e!(0xff46u16 as i16, 0x46ff));
+        buf_tests!(number $make_input, get_u32_be, get_u32_be_overflow, u32, get_u32, 0xff467172);
+        buf_tests!(number $make_input, get_u32_le, get_u32_le_overflow, u32, get_u32_le, 0x727146ff);
+        buf_tests!(number $make_input, get_u32_ne, get_u32_ne_overflow, u32, get_u32_ne, e!(0xff467172, 0x727146ff));
+        buf_tests!(number $make_input, get_i32_be, get_i32_be_overflow, i32, get_i32, 0xff467172u32 as i32);
+        buf_tests!(number $make_input, get_i32_le, get_i32_le_overflow, i32, get_i32_le, 0x727146ff);
+        buf_tests!(number $make_input, get_i32_ne, get_i32_ne_overflow, i32, get_i32_ne, e!(0xff467172u32 as i32, 0x727146ff));
+        buf_tests!(number $make_input, get_u64_be, get_u64_be_overflow, u64, get_u64, 0xff4671726a724471);
+        buf_tests!(number $make_input, get_u64_le, get_u64_le_overflow, u64, get_u64_le, 0x7144726a727146ff);
+        buf_tests!(number $make_input, get_u64_ne, get_u64_ne_overflow, u64, get_u64_ne, e!(0xff4671726a724471, 0x7144726a727146ff));
+        buf_tests!(number $make_input, get_i64_be, get_i64_be_overflow, i64, get_i64, 0xff4671726a724471u64 as i64);
+        buf_tests!(number $make_input, get_i64_le, get_i64_le_overflow, i64, get_i64_le, 0x7144726a727146ff);
+        buf_tests!(number $make_input, get_i64_ne, get_i64_ne_overflow, i64, get_i64_ne, e!(0xff4671726a724471u64 as i64, 0x7144726a727146ff));
+        buf_tests!(number $make_input, get_u128_be, get_u128_be_overflow, u128, get_u128, 0xff4671726a7244715068765463343576);
+        buf_tests!(number $make_input, get_u128_le, get_u128_le_overflow, u128, get_u128_le, 0x76353463547668507144726a727146ff);
+        buf_tests!(number $make_input, get_u128_ne, get_u128_ne_overflow, u128, get_u128_ne, e!(0xff4671726a7244715068765463343576, 0x76353463547668507144726a727146ff));
+        buf_tests!(number $make_input, get_i128_be, get_i128_be_overflow, i128, get_i128, 0xff4671726a7244715068765463343576u128 as i128);
+        buf_tests!(number $make_input, get_i128_le, get_i128_le_overflow, i128, get_i128_le, 0x76353463547668507144726a727146ff);
+        buf_tests!(number $make_input, get_i128_ne, get_i128_ne_overflow, i128, get_i128_ne, e!(0xff4671726a7244715068765463343576u128 as i128, 0x76353463547668507144726a727146ff));
+        buf_tests!(number $make_input, get_f32_be, get_f32_be_overflow, f32, get_f32, f32::from_bits(0xff467172));
+        buf_tests!(number $make_input, get_f32_le, get_f32_le_overflow, f32, get_f32_le, f32::from_bits(0x727146ff));
+        buf_tests!(number $make_input, get_f32_ne, get_f32_ne_overflow, f32, get_f32_ne, f32::from_bits(e!(0xff467172, 0x727146ff)));
+        buf_tests!(number $make_input, get_f64_be, get_f64_be_overflow, f64, get_f64, f64::from_bits(0xff4671726a724471));
+        buf_tests!(number $make_input, get_f64_le, get_f64_le_overflow, f64, get_f64_le, f64::from_bits(0x7144726a727146ff));
+        buf_tests!(number $make_input, get_f64_ne, get_f64_ne_overflow, f64, get_f64_ne, f64::from_bits(e!(0xff4671726a724471, 0x7144726a727146ff)));
+
+        buf_tests!(var_number $make_input, get_uint_be, get_uint_be_zero, get_uint_be_overflow, u64, get_uint, 3, 0xff4671);
+        buf_tests!(var_number $make_input, get_uint_le, get_uint_le_zero, get_uint_le_overflow, u64, get_uint_le, 3, 0x7146ff);
+        buf_tests!(var_number $make_input, get_uint_ne, get_uint_ne_zero, get_uint_ne_overflow, u64, get_uint_ne, 3, e!(0xff4671, 0x7146ff));
+        buf_tests!(var_number $make_input, get_int_be, get_int_be_zero, get_int_be_overflow, i64, get_int, 3, 0xffffffffffff4671u64 as i64);
+        buf_tests!(var_number $make_input, get_int_le, get_int_le_zero, get_int_le_overflow, i64, get_int_le, 3, 0x7146ff);
+        buf_tests!(var_number $make_input, get_int_ne, get_int_ne_zero, get_int_ne_overflow, i64, get_int_ne, 3, e!(0xffffffffffff4671u64 as i64, 0x7146ff));
+    };
+    (number $make_input:ident, $ok_name:ident, $panic_name:ident, $number:ty, $method:ident, $value:expr) => {
+        #[test]
+        fn $ok_name() {
+            let mut buf = $make_input(INPUT);
+
+            let value = buf.$method();
+            assert_eq!(buf.remaining(), 64 - mem::size_of::<$number>());
+            assert!(buf.has_remaining());
+            assert_eq!(value, $value);
+        }
+
+        #[test]
+        #[should_panic]
+        fn $panic_name() {
+            let mut buf = $make_input(&[]);
+
+            let _ = buf.$method();
+        }
+    };
+    (var_number $make_input:ident, $ok_name:ident, $ok_zero_name:ident, $panic_name:ident, $number:ty, $method:ident, $len:expr, $value:expr) => {
+        #[test]
+        fn $ok_name() {
+            let mut buf = $make_input(INPUT);
+
+            let value = buf.$method($len);
+            assert_eq!(buf.remaining(), 64 - $len);
+            assert!(buf.has_remaining());
+            assert_eq!(value, $value);
+        }
+
+        // Regression test for https://github.com/tokio-rs/bytes/issues/798
+        #[test]
+        fn $ok_zero_name() {
+            let mut buf = $make_input(INPUT);
+
+            let value = buf.$method(0);
+            assert_eq!(buf.remaining(), 64);
+            assert!(buf.has_remaining());
+            assert_eq!(value, 0);
+        }
+
+        #[test]
+        #[should_panic]
+        fn $panic_name() {
+            let mut buf = $make_input(&[]);
+
+            let _ = buf.$method($len);
+        }
+    };
 }
 
-#[test]
-fn test_get_u16() {
-    let mut buf = &b"\x21\x54zomg"[..];
-    assert_eq!(0x2154, buf.get_u16());
-    let mut buf = &b"\x21\x54zomg"[..];
-    assert_eq!(0x5421, buf.get_u16_le());
+mod u8_slice {
+    fn make_input(buf: &'static [u8]) -> &'static [u8] {
+        buf
+    }
+
+    buf_tests!(make_input);
 }
 
-#[test]
-#[should_panic]
-fn test_get_u16_buffer_underflow() {
-    let mut buf = &b"\x21"[..];
-    buf.get_u16();
+mod bytes {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        Bytes::from_static(buf)
+    }
+
+    buf_tests!(make_input);
+}
+
+mod bytes_mut {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        BytesMut::from(buf)
+    }
+
+    buf_tests!(make_input);
+}
+
+mod vec_deque {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        let mut deque = VecDeque::new();
+
+        if !buf.is_empty() {
+            // Construct |b|some bytes|a| `VecDeque`
+            let mid = buf.len() / 2;
+            let (a, b) = buf.split_at(mid);
+
+            deque.reserve_exact(buf.len() + 1);
+
+            let extra_space = deque.capacity() - b.len() - 1;
+            deque.resize(extra_space, 0);
+
+            deque.extend(a);
+            deque.drain(..extra_space);
+            deque.extend(b);
+
+            let (a, b) = deque.as_slices();
+            assert!(
+                !a.is_empty(),
+                "could not setup test - attempt to create discontiguous VecDeque failed"
+            );
+            assert!(
+                !b.is_empty(),
+                "could not setup test - attempt to create discontiguous VecDeque failed"
+            );
+        }
+
+        deque
+    }
+
+    buf_tests!(make_input, true);
 }
 
 #[cfg(feature = "std")]
-#[test]
-fn test_bufs_vec() {
-    let buf = &b"hello world"[..];
+mod cursor {
+    use std::io::Cursor;
 
-    let b1: &[u8] = &mut [];
-    let b2: &[u8] = &mut [];
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        Cursor::new(buf)
+    }
 
-    let mut dst = [IoSlice::new(b1), IoSlice::new(b2)];
-
-    assert_eq!(1, buf.bytes_vectored(&mut dst[..]));
+    buf_tests!(make_input);
 }
 
-#[test]
-fn test_vec_deque() {
-    use std::collections::VecDeque;
+mod box_bytes {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        Box::new(Bytes::from_static(buf))
+    }
 
-    let mut buffer: VecDeque<u8> = VecDeque::new();
-    buffer.extend(b"hello world");
-    assert_eq!(11, buffer.remaining());
-    assert_eq!(b"hello world", buffer.bytes());
-    buffer.advance(6);
-    assert_eq!(b"world", buffer.bytes());
-    buffer.extend(b" piece");
-    let mut out = [0; 11];
-    buffer.copy_to_slice(&mut out);
-    assert_eq!(b"world piece", &out[..]);
+    buf_tests!(make_input);
 }
 
+mod chain_u8_slice {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        let (a, b) = buf.split_at(buf.len() / 2);
+        Buf::chain(a, b)
+    }
+
+    buf_tests!(make_input);
+}
+
+mod chain_small_big_u8_slice {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        let mid = cmp::min(1, buf.len());
+        let (a, b) = buf.split_at(mid);
+        Buf::chain(a, b)
+    }
+
+    buf_tests!(make_input);
+}
+
+mod chain_limited_slices {
+    fn make_input(buf: &'static [u8]) -> impl Buf {
+        let buf3 = &buf[cmp::min(buf.len(), 3)..];
+        let a = Buf::take(buf3, 0);
+        let b = Buf::take(buf, 3);
+        let c = Buf::take(buf3, usize::MAX);
+        let d = buf;
+        Buf::take(Buf::chain(Buf::chain(a, b), Buf::chain(c, d)), buf.len())
+    }
+
+    buf_tests!(make_input, true);
+}
+
+#[allow(unused_allocation)] // This is intentional.
 #[test]
 fn test_deref_buf_forwards() {
     struct Special;
@@ -81,8 +428,8 @@ fn test_deref_buf_forwards() {
             unreachable!("remaining");
         }
 
-        fn bytes(&self) -> &[u8] {
-            unreachable!("bytes");
+        fn chunk(&self) -> &[u8] {
+            unreachable!("chunk");
         }
 
         fn advance(&mut self, _: usize) {
@@ -103,18 +450,12 @@ fn test_deref_buf_forwards() {
 }
 
 #[test]
-fn copy_to_bytes_less() {
-    let mut buf = &b"hello world"[..];
-
-    let bytes = buf.copy_to_bytes(5);
-    assert_eq!(bytes, &b"hello"[..]);
-    assert_eq!(buf, &b" world"[..])
-}
-
-#[test]
-#[should_panic]
-fn copy_to_bytes_overflow() {
-    let mut buf = &b"hello world"[..];
-
-    let _bytes = buf.copy_to_bytes(12);
+fn copy_to_bytes_mut() {
+    let mut bytes_mut = BytesMut::from(b"foobar".as_slice());
+    let ptr = bytes_mut.as_ptr();
+    let ret = bytes_mut.copy_to_bytes(bytes_mut.len());
+    assert_eq!(ret.as_ptr(), ptr);
+    drop(bytes_mut);
+    let bytes_mut2 = BytesMut::from(ret);
+    assert_eq!(bytes_mut2.as_ptr(), ptr);
 }

tests/test_buf_mut.rs

@@ -3,21 +3,21 @@
 use bytes::buf::UninitSlice;
 use bytes::{BufMut, BytesMut};
 use core::fmt::Write;
-use core::usize;
+use core::mem::MaybeUninit;
 
 #[test]
 fn test_vec_as_mut_buf() {
     let mut buf = Vec::with_capacity(64);
 
-    assert_eq!(buf.remaining_mut(), usize::MAX);
+    assert_eq!(buf.remaining_mut(), isize::MAX as usize);
 
-    assert!(buf.bytes_mut().len() >= 64);
+    assert!(buf.chunk_mut().len() >= 64);
 
     buf.put(&b"zomg"[..]);
 
     assert_eq!(&buf, b"zomg");
 
-    assert_eq!(buf.remaining_mut(), usize::MAX - 4);
+    assert_eq!(buf.remaining_mut(), isize::MAX as usize - 4);
     assert_eq!(buf.capacity(), 64);
 
     for _ in 0..16 {
@@ -27,6 +27,14 @@ fn test_vec_as_mut_buf() {
     assert_eq!(buf.len(), 68);
 }
 
+#[test]
+fn test_vec_put_bytes() {
+    let mut buf = Vec::new();
+    buf.push(17);
+    buf.put_bytes(19, 2);
+    assert_eq!([17, 19, 19], &buf[..]);
+}
+
 #[test]
 fn test_put_u8() {
     let mut buf = Vec::with_capacity(8);
@@ -46,7 +54,35 @@ fn test_put_u16() {
 }
 
 #[test]
-#[should_panic(expected = "cannot advance")]
+fn test_put_int() {
+    let mut buf = Vec::with_capacity(8);
+    buf.put_int(0x1020304050607080, 3);
+    assert_eq!(b"\x60\x70\x80", &buf[..]);
+}
+
+#[test]
+#[should_panic]
+fn test_put_int_nbytes_overflow() {
+    let mut buf = Vec::with_capacity(8);
+    buf.put_int(0x1020304050607080, 9);
+}
+
+#[test]
+fn test_put_int_le() {
+    let mut buf = Vec::with_capacity(8);
+    buf.put_int_le(0x1020304050607080, 3);
+    assert_eq!(b"\x80\x70\x60", &buf[..]);
+}
+
+#[test]
+#[should_panic]
+fn test_put_int_le_nbytes_overflow() {
+    let mut buf = Vec::with_capacity(8);
+    buf.put_int_le(0x1020304050607080, 9);
+}
+
+#[test]
+#[should_panic(expected = "advance out of bounds: the len is 8 but advancing by 12")]
 fn test_vec_advance_mut() {
     // Verify fix for #354
     let mut buf = Vec::with_capacity(8);
@@ -65,13 +101,123 @@ fn test_clone() {
     assert!(buf != buf2);
 }
 
-#[test]
-fn test_mut_slice() {
-    let mut v = vec![0, 0, 0, 0];
-    let mut s = &mut v[..];
-    s.put_u32(42);
+fn do_test_slice_small<T: ?Sized>(make: impl Fn(&mut [u8]) -> &mut T)
+where
+    for<'r> &'r mut T: BufMut,
+{
+    let mut buf = [b'X'; 8];
+
+    let mut slice = make(&mut buf[..]);
+    slice.put_bytes(b'A', 2);
+    slice.put_u8(b'B');
+    slice.put_slice(b"BCC");
+    assert_eq!(2, slice.remaining_mut());
+    assert_eq!(b"AABBCCXX", &buf[..]);
+
+    let mut slice = make(&mut buf[..]);
+    slice.put_u32(0x61626364);
+    assert_eq!(4, slice.remaining_mut());
+    assert_eq!(b"abcdCCXX", &buf[..]);
+
+    let mut slice = make(&mut buf[..]);
+    slice.put_u32_le(0x30313233);
+    assert_eq!(4, slice.remaining_mut());
+    assert_eq!(b"3210CCXX", &buf[..]);
 }
 
+fn do_test_slice_large<T: ?Sized>(make: impl Fn(&mut [u8]) -> &mut T)
+where
+    for<'r> &'r mut T: BufMut,
+{
+    const LEN: usize = 100;
+    const FILL: [u8; LEN] = [b'Y'; LEN];
+
+    let test = |fill: &dyn Fn(&mut &mut T, usize)| {
+        for buf_len in 0..LEN {
+            let mut buf = [b'X'; LEN];
+            for fill_len in 0..=buf_len {
+                let mut slice = make(&mut buf[..buf_len]);
+                fill(&mut slice, fill_len);
+                assert_eq!(buf_len - fill_len, slice.remaining_mut());
+                let (head, tail) = buf.split_at(fill_len);
+                assert_eq!(&FILL[..fill_len], head);
+                assert!(tail.iter().all(|b| *b == b'X'));
+            }
+        }
+    };
+
+    test(&|slice, fill_len| slice.put_slice(&FILL[..fill_len]));
+    test(&|slice, fill_len| slice.put_bytes(FILL[0], fill_len));
+}
+
+fn do_test_slice_put_slice_panics<T: ?Sized>(make: impl Fn(&mut [u8]) -> &mut T)
+where
+    for<'r> &'r mut T: BufMut,
+{
+    let mut buf = [b'X'; 4];
+    let mut slice = make(&mut buf[..]);
+    slice.put_slice(b"12345");
+}
+
+fn do_test_slice_put_bytes_panics<T: ?Sized>(make: impl Fn(&mut [u8]) -> &mut T)
+where
+    for<'r> &'r mut T: BufMut,
+{
+    let mut buf = [b'X'; 4];
+    let mut slice = make(&mut buf[..]);
+    slice.put_bytes(b'1', 5);
+}
+
+#[test]
+fn test_slice_buf_mut_small() {
+    do_test_slice_small(|x| x);
+}
+
+#[test]
+fn test_slice_buf_mut_large() {
+    do_test_slice_large(|x| x);
+}
+
+#[test]
+#[should_panic]
+fn test_slice_buf_mut_put_slice_overflow() {
+    do_test_slice_put_slice_panics(|x| x);
+}
+
+#[test]
+#[should_panic]
+fn test_slice_buf_mut_put_bytes_overflow() {
+    do_test_slice_put_bytes_panics(|x| x);
+}
+
+fn make_maybe_uninit_slice(slice: &mut [u8]) -> &mut [MaybeUninit<u8>] {
+    // SAFETY: [u8] has the same layout as [MaybeUninit<u8>].
+    unsafe { core::mem::transmute(slice) }
+}
+
+#[test]
+fn test_maybe_uninit_buf_mut_small() {
+    do_test_slice_small(make_maybe_uninit_slice);
+}
+
+#[test]
+fn test_maybe_uninit_buf_mut_large() {
+    do_test_slice_large(make_maybe_uninit_slice);
+}
+
+#[test]
+#[should_panic]
+fn test_maybe_uninit_buf_mut_put_slice_overflow() {
+    do_test_slice_put_slice_panics(make_maybe_uninit_slice);
+}
+
+#[test]
+#[should_panic]
+fn test_maybe_uninit_buf_mut_put_bytes_overflow() {
+    do_test_slice_put_bytes_panics(make_maybe_uninit_slice);
+}
+
+#[allow(unused_allocation)] // This is intentional.
 #[test]
 fn test_deref_bufmut_forwards() {
     struct Special;
@@ -81,8 +227,8 @@ fn test_deref_bufmut_forwards() {
             unreachable!("remaining_mut");
         }
 
-        fn bytes_mut(&mut self) -> &mut UninitSlice {
-            unreachable!("bytes_mut");
+        fn chunk_mut(&mut self) -> &mut UninitSlice {
+            unreachable!("chunk_mut");
         }
 
         unsafe fn advance_mut(&mut self, _: usize) {
@@ -127,3 +273,12 @@ fn copy_from_slice_panics_if_different_length_2() {
     let slice = unsafe { UninitSlice::from_raw_parts_mut(data.as_mut_ptr(), 3) };
     slice.copy_from_slice(b"abcd");
 }
+
+/// Test if with zero capacity BytesMut does not infinitely recurse in put from Buf
+#[test]
+fn test_bytes_mut_reuse() {
+    let mut buf = BytesMut::new();
+    buf.put(&[] as &[u8]);
+    let mut buf = BytesMut::new();
+    buf.put(&[1u8, 2, 3] as &[u8]);
+}

tests/test_bytes_odd_alloc.rs

@@ -1,10 +1,12 @@
 //! Test using `Bytes` with an allocator that hands out "odd" pointers for
 //! vectors (pointers where the LSB is set).
 
+#![cfg(not(miri))] // Miri does not support custom allocators (also, Miri is "odd" by default with 50% chance)
+
 use std::alloc::{GlobalAlloc, Layout, System};
 use std::ptr;
 
-use bytes::Bytes;
+use bytes::{Bytes, BytesMut};
 
 #[global_allocator]
 static ODD: Odd = Odd;
@@ -22,8 +24,7 @@ unsafe impl GlobalAlloc for Odd {
             };
             let ptr = System.alloc(new_layout);
             if !ptr.is_null() {
-                let ptr = ptr.offset(1);
-                ptr
+                ptr.offset(1)
             } else {
                 ptr
             }
@@ -65,3 +66,82 @@ fn test_bytes_clone_drop() {
     let b1 = Bytes::from(vec);
     let _b2 = b1.clone();
 }
+
+#[test]
+fn test_bytes_into_vec() {
+    let vec = vec![33u8; 1024];
+
+    // Test cases where kind == KIND_VEC
+    let b1 = Bytes::from(vec.clone());
+    assert_eq!(Vec::from(b1), vec);
+
+    // Test cases where kind == KIND_ARC, ref_cnt == 1
+    let b1 = Bytes::from(vec.clone());
+    drop(b1.clone());
+    assert_eq!(Vec::from(b1), vec);
+
+    // Test cases where kind == KIND_ARC, ref_cnt == 2
+    let b1 = Bytes::from(vec.clone());
+    let b2 = b1.clone();
+    assert_eq!(Vec::from(b1), vec);
+
+    // Test cases where vtable = SHARED_VTABLE, kind == KIND_ARC, ref_cnt == 1
+    assert_eq!(Vec::from(b2), vec);
+
+    // Test cases where offset != 0
+    let mut b1 = Bytes::from(vec.clone());
+    let b2 = b1.split_off(20);
+
+    assert_eq!(Vec::from(b2), vec[20..]);
+    assert_eq!(Vec::from(b1), vec[..20]);
+}
+
+#[test]
+fn test_bytesmut_from_bytes_vec() {
+    let vec = vec![33u8; 1024];
+
+    // Test case where kind == KIND_VEC
+    let b1 = Bytes::from(vec.clone());
+    let b1m = BytesMut::from(b1);
+    assert_eq!(b1m, vec);
+}
+
+#[test]
+fn test_bytesmut_from_bytes_arc_1() {
+    let vec = vec![33u8; 1024];
+
+    // Test case where kind == KIND_ARC, ref_cnt == 1
+    let b1 = Bytes::from(vec.clone());
+    drop(b1.clone());
+    let b1m = BytesMut::from(b1);
+    assert_eq!(b1m, vec);
+}
+
+#[test]
+fn test_bytesmut_from_bytes_arc_2() {
+    let vec = vec![33u8; 1024];
+
+    // Test case where kind == KIND_ARC, ref_cnt == 2
+    let b1 = Bytes::from(vec.clone());
+    let b2 = b1.clone();
+    let b1m = BytesMut::from(b1);
+    assert_eq!(b1m, vec);
+
+    // Test case where vtable = SHARED_VTABLE, kind == KIND_ARC, ref_cnt == 1
+    let b2m = BytesMut::from(b2);
+    assert_eq!(b2m, vec);
+}
+
+#[test]
+fn test_bytesmut_from_bytes_arc_offset() {
+    let vec = vec![33u8; 1024];
+
+    // Test case where offset != 0
+    let mut b1 = Bytes::from(vec.clone());
+    let b2 = b1.split_off(20);
+    let b1m = BytesMut::from(b1);
+    let b2m = BytesMut::from(b2);
+
+    assert_eq!(b2m, vec[20..]);
+    assert_eq!(b1m, vec[..20]);
+}

tests/test_bytes_vec_alloc.rs

@@ -1,61 +1,90 @@
+#![cfg(not(miri))]
 use std::alloc::{GlobalAlloc, Layout, System};
-use std::{mem, ptr};
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
 
 use bytes::{Buf, Bytes};
 
 #[global_allocator]
-static LEDGER: Ledger = Ledger;
+static LEDGER: Ledger = Ledger::new();
 
-struct Ledger;
+const LEDGER_LENGTH: usize = 1024 * 1024;
 
-const USIZE_SIZE: usize = mem::size_of::<usize>();
+struct Ledger {
+    alloc_table: [(AtomicPtr<u8>, AtomicUsize); LEDGER_LENGTH],
+}
+
+impl Ledger {
+    const fn new() -> Self {
+        const ELEM: (AtomicPtr<u8>, AtomicUsize) =
+            (AtomicPtr::new(null_mut()), AtomicUsize::new(0));
+        let alloc_table = [ELEM; LEDGER_LENGTH];
+
+        Self { alloc_table }
+    }
+
+    /// Iterate over our table until we find an open entry, then insert into said entry
+    fn insert(&self, ptr: *mut u8, size: usize) {
+        for (entry_ptr, entry_size) in self.alloc_table.iter() {
+            // SeqCst is good enough here, we don't care about perf, i just want to be correct!
+            if entry_ptr
+                .compare_exchange(null_mut(), ptr, Ordering::SeqCst, Ordering::SeqCst)
+                .is_ok()
+            {
+                entry_size.store(size, Ordering::SeqCst);
+                return;
+            }
+        }
+
+        panic!("Ledger ran out of space.");
+    }
+
+    fn remove(&self, ptr: *mut u8) -> usize {
+        for (entry_ptr, entry_size) in self.alloc_table.iter() {
+            // set the value to be something that will never try and be deallocated, so that we
+            // don't have any chance of a race condition
+            //
+            // dont worry, LEDGER_LENGTH is really long to compensate for us not reclaiming space
+            if entry_ptr
+                .compare_exchange(
+                    ptr,
+                    invalid_ptr(usize::MAX),
+                    Ordering::SeqCst,
+                    Ordering::SeqCst,
+                )
+                .is_ok()
+            {
+                return entry_size.load(Ordering::SeqCst);
+            }
+        }
+
+        panic!("Couldn't find a matching entry for {:x?}", ptr);
+    }
+}
 
 unsafe impl GlobalAlloc for Ledger {
     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        if layout.align() == 1 && layout.size() > 0 {
-            // Allocate extra space to stash a record of
-            // how much space there was.
-            let orig_size = layout.size();
-            let size = orig_size + USIZE_SIZE;
-            let new_layout = match Layout::from_size_align(size, 1) {
-                Ok(layout) => layout,
-                Err(_err) => return ptr::null_mut(),
-            };
-            let ptr = System.alloc(new_layout);
-            if !ptr.is_null() {
-                (ptr as *mut usize).write(orig_size);
-                let ptr = ptr.offset(USIZE_SIZE as isize);
-                ptr
-            } else {
-                ptr
-            }
-        } else {
-            System.alloc(layout)
-        }
+        let size = layout.size();
+        let ptr = System.alloc(layout);
+        self.insert(ptr, size);
+        ptr
     }
 
     unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
-        if layout.align() == 1 && layout.size() > 0 {
-            let off_ptr = (ptr as *mut usize).offset(-1);
-            let orig_size = off_ptr.read();
-            if orig_size != layout.size() {
-                panic!(
-                    "bad dealloc: alloc size was {}, dealloc size is {}",
-                    orig_size,
-                    layout.size()
-                );
-            }
+        let orig_size = self.remove(ptr);
 
-            let new_layout = match Layout::from_size_align(layout.size() + USIZE_SIZE, 1) {
-                Ok(layout) => layout,
-                Err(_err) => std::process::abort(),
-            };
-            System.dealloc(off_ptr as *mut u8, new_layout);
+        if orig_size != layout.size() {
+            panic!(
+                "bad dealloc: alloc size was {}, dealloc size is {}",
+                orig_size,
+                layout.size()
+            );
         } else {
             System.dealloc(ptr, layout);
         }
     }
 }
+
 #[test]
 fn test_bytes_advance() {
     let mut bytes = Bytes::from(vec![10, 20, 30]);
@@ -77,3 +106,41 @@ fn test_bytes_truncate_and_advance() {
     bytes.advance(1);
     drop(bytes);
 }
+
+/// Returns a dangling pointer with the given address. This is used to store
+/// integer data in pointer fields.
+#[inline]
+fn invalid_ptr<T>(addr: usize) -> *mut T {
+    let ptr = std::ptr::null_mut::<u8>().wrapping_add(addr);
+    debug_assert_eq!(ptr as usize, addr);
+    ptr.cast::<T>()
+}
+
+#[test]
+fn test_bytes_into_vec() {
+    let vec = vec![33u8; 1024];
+
+    // Test cases where kind == KIND_VEC
+    let b1 = Bytes::from(vec.clone());
+    assert_eq!(Vec::from(b1), vec);
+
+    // Test cases where kind == KIND_ARC, ref_cnt == 1
+    let b1 = Bytes::from(vec.clone());
+    drop(b1.clone());
+    assert_eq!(Vec::from(b1), vec);
+
+    // Test cases where kind == KIND_ARC, ref_cnt == 2
+    let b1 = Bytes::from(vec.clone());
+    let b2 = b1.clone();
+    assert_eq!(Vec::from(b1), vec);
+
+    // Test cases where vtable = SHARED_VTABLE, kind == KIND_ARC, ref_cnt == 1
+    assert_eq!(Vec::from(b2), vec);
+
+    // Test cases where offset != 0
+    let mut b1 = Bytes::from(vec.clone());
+    let b2 = b1.split_off(20);
+
+    assert_eq!(Vec::from(b2), vec[20..]);
+    assert_eq!(Vec::from(b1), vec[..20]);
+}

tests/test_chain.rs

@@ -62,7 +62,7 @@ fn vectored_read() {
             IoSlice::new(b4),
         ];
 
-        assert_eq!(2, buf.bytes_vectored(&mut iovecs));
+        assert_eq!(2, buf.chunks_vectored(&mut iovecs));
         assert_eq!(iovecs[0][..], b"hello"[..]);
         assert_eq!(iovecs[1][..], b"world"[..]);
         assert_eq!(iovecs[2][..], b""[..]);
@@ -83,7 +83,7 @@ fn vectored_read() {
             IoSlice::new(b4),
         ];
 
-        assert_eq!(2, buf.bytes_vectored(&mut iovecs));
+        assert_eq!(2, buf.chunks_vectored(&mut iovecs));
         assert_eq!(iovecs[0][..], b"llo"[..]);
         assert_eq!(iovecs[1][..], b"world"[..]);
         assert_eq!(iovecs[2][..], b""[..]);
@@ -104,7 +104,7 @@ fn vectored_read() {
             IoSlice::new(b4),
         ];
 
-        assert_eq!(1, buf.bytes_vectored(&mut iovecs));
+        assert_eq!(1, buf.chunks_vectored(&mut iovecs));
         assert_eq!(iovecs[0][..], b"world"[..]);
         assert_eq!(iovecs[1][..], b""[..]);
         assert_eq!(iovecs[2][..], b""[..]);
@@ -125,10 +125,53 @@ fn vectored_read() {
             IoSlice::new(b4),
         ];
 
-        assert_eq!(1, buf.bytes_vectored(&mut iovecs));
+        assert_eq!(1, buf.chunks_vectored(&mut iovecs));
         assert_eq!(iovecs[0][..], b"ld"[..]);
         assert_eq!(iovecs[1][..], b""[..]);
         assert_eq!(iovecs[2][..], b""[..]);
         assert_eq!(iovecs[3][..], b""[..]);
     }
 }
+
+#[test]
+fn chain_growing_buffer() {
+    let mut buff = [b' '; 10];
+    let mut vec = b"wassup".to_vec();
+
+    let mut chained = (&mut buff[..]).chain_mut(&mut vec).chain_mut(Vec::new()); // Required for potential overflow because remaining_mut for Vec is isize::MAX - vec.len(), but for chain_mut is usize::MAX
+
+    chained.put_slice(b"hey there123123");
+
+    assert_eq!(&buff, b"hey there1");
+    assert_eq!(&vec, b"wassup23123");
+}
+
+#[test]
+fn chain_overflow_remaining_mut() {
+    let mut chained = Vec::<u8>::new().chain_mut(Vec::new()).chain_mut(Vec::new());
+
+    assert_eq!(chained.remaining_mut(), usize::MAX);
+    chained.put_slice(&[0; 256]);
+    assert_eq!(chained.remaining_mut(), usize::MAX);
+}
+
+#[test]
+fn chain_get_bytes() {
+    let mut ab = Bytes::copy_from_slice(b"ab");
+    let mut cd = Bytes::copy_from_slice(b"cd");
+    let ab_ptr = ab.as_ptr();
+    let cd_ptr = cd.as_ptr();
+    let mut chain = (&mut ab).chain(&mut cd);
+    let a = chain.copy_to_bytes(1);
+    let bc = chain.copy_to_bytes(2);
+    let d = chain.copy_to_bytes(1);
+
+    assert_eq!(Bytes::copy_from_slice(b"a"), a);
+    assert_eq!(Bytes::copy_from_slice(b"bc"), bc);
+    assert_eq!(Bytes::copy_from_slice(b"d"), d);
+
+    // assert `get_bytes` did not allocate
+    assert_eq!(ab_ptr, a.as_ptr());
+    // assert `get_bytes` did not allocate
+    assert_eq!(cd_ptr.wrapping_offset(1), d.as_ptr());
+}

tests/test_iter.rs

@@ -1,11 +1,11 @@
 #![warn(rust_2018_idioms)]
 
-use bytes::Bytes;
+use bytes::{buf::IntoIter, Bytes};
 
 #[test]
 fn iter_len() {
     let buf = Bytes::from_static(b"hello world");
-    let iter = buf.iter();
+    let iter = IntoIter::new(buf);
 
     assert_eq!(iter.size_hint(), (11, Some(11)));
     assert_eq!(iter.len(), 11);
@@ -13,8 +13,8 @@ fn iter_len() {
 
 #[test]
 fn empty_iter_len() {
-    let buf = Bytes::from_static(b"");
-    let iter = buf.iter();
+    let buf = Bytes::new();
+    let iter = IntoIter::new(buf);
 
     assert_eq!(iter.size_hint(), (0, Some(0)));
     assert_eq!(iter.len(), 0);

tests/test_limit.rs

@@ -0,0 +1,86 @@
+#![warn(rust_2018_idioms)]
+
+use bytes::{buf::Limit, BufMut};
+
+#[test]
+fn long_limit() {
+    let buf = &mut [0u8; 10];
+    let limit = buf.limit(100);
+    assert_eq!(10, limit.remaining_mut());
+    assert_eq!(&[0u8; 10], &limit.get_ref()[..]);
+}
+
+#[test]
+fn limit_get_mut() {
+    let buf = &mut [0u8; 128];
+    let mut limit = buf.limit(10);
+    assert_eq!(10, limit.remaining_mut());
+    assert_eq!(&mut [0u8; 128], &limit.get_mut()[..]);
+}
+
+#[test]
+fn limit_set_limit() {
+    let buf = &mut [0u8; 128];
+    let mut limit = buf.limit(10);
+    assert_eq!(10, Limit::limit(&limit));
+    limit.set_limit(5);
+    assert_eq!(5, Limit::limit(&limit));
+}
+
+#[test]
+fn limit_chunk_mut() {
+    let buf = &mut [0u8; 20];
+    let mut limit = buf.limit(10);
+    assert_eq!(10, limit.chunk_mut().len());
+
+    let buf = &mut [0u8; 10];
+    let mut limit = buf.limit(20);
+    assert_eq!(10, limit.chunk_mut().len());
+}
+
+#[test]
+#[should_panic = "advance out of bounds"]
+fn limit_advance_mut_panic_1() {
+    let buf = &mut [0u8; 10];
+    let mut limit = buf.limit(100);
+    unsafe {
+        limit.advance_mut(50);
+    }
+}
+
+#[test]
+#[should_panic = "cnt <= self.limit"]
+fn limit_advance_mut_panic_2() {
+    let buf = &mut [0u8; 100];
+    let mut limit = buf.limit(10);
+    unsafe {
+        limit.advance_mut(50);
+    }
+}
+
+#[test]
+fn limit_advance_mut() {
+    let buf = &mut [0u8; 100];
+    let mut limit = buf.limit(10);
+    unsafe {
+        limit.advance_mut(5);
+    }
+    assert_eq!(5, limit.remaining_mut());
+    assert_eq!(5, limit.chunk_mut().len());
+}
+
+#[test]
+fn limit_into_inner() {
+    let buf_arr = *b"hello world";
+    let buf: &mut [u8] = &mut buf_arr.clone();
+    let mut limit = buf.limit(4);
+    let mut dst = vec![];
+
+    unsafe {
+        limit.advance_mut(2);
+    }
+
+    let buf = limit.into_inner();
+    dst.put(&buf[..]);
+    assert_eq!(*dst, b"llo world"[..]);
+}

tests/test_reader.rs

@@ -27,3 +27,12 @@ fn buf_read() {
     reader.read_line(&mut line).unwrap();
     assert_eq!("world", &line);
 }
+
+#[test]
+fn get_mut() {
+    let buf = &b"hello world"[..];
+    let mut reader = buf.reader();
+    let buf_mut = reader.get_mut();
+    assert_eq!(11, buf_mut.remaining());
+    assert_eq!(b"hello world", buf_mut);
+}

tests/test_take.rs

@@ -1,6 +1,7 @@
 #![warn(rust_2018_idioms)]
 
 use bytes::buf::Buf;
+use bytes::Bytes;
 
 #[test]
 fn long_take() {
@@ -8,5 +9,76 @@ fn long_take() {
     // overrun the buffer. Regression test for #138.
     let buf = b"hello world".take(100);
     assert_eq!(11, buf.remaining());
-    assert_eq!(b"hello world", buf.bytes());
+    assert_eq!(b"hello world", buf.chunk());
+}
+
+#[test]
+fn take_copy_to_bytes() {
+    let mut abcd = Bytes::copy_from_slice(b"abcd");
+    let abcd_ptr = abcd.as_ptr();
+    let mut take = (&mut abcd).take(2);
+    let a = take.copy_to_bytes(1);
+    assert_eq!(Bytes::copy_from_slice(b"a"), a);
+    // assert `to_bytes` did not allocate
+    assert_eq!(abcd_ptr, a.as_ptr());
+    assert_eq!(Bytes::copy_from_slice(b"bcd"), abcd);
+}
+
+#[test]
+#[should_panic]
+fn take_copy_to_bytes_panics() {
+    let abcd = Bytes::copy_from_slice(b"abcd");
+    abcd.take(2).copy_to_bytes(3);
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn take_chunks_vectored() {
+    fn chain() -> impl Buf {
+        Bytes::from([1, 2, 3].to_vec()).chain(Bytes::from([4, 5, 6].to_vec()))
+    }
+
+    {
+        let mut dst = [std::io::IoSlice::new(&[]); 2];
+        let take = chain().take(0);
+        assert_eq!(take.chunks_vectored(&mut dst), 0);
+    }
+
+    {
+        let mut dst = [std::io::IoSlice::new(&[]); 2];
+        let take = chain().take(1);
+        assert_eq!(take.chunks_vectored(&mut dst), 1);
+        assert_eq!(&*dst[0], &[1]);
+    }
+
+    {
+        let mut dst = [std::io::IoSlice::new(&[]); 2];
+        let take = chain().take(3);
+        assert_eq!(take.chunks_vectored(&mut dst), 1);
+        assert_eq!(&*dst[0], &[1, 2, 3]);
+    }
+
+    {
+        let mut dst = [std::io::IoSlice::new(&[]); 2];
+        let take = chain().take(4);
+        assert_eq!(take.chunks_vectored(&mut dst), 2);
+        assert_eq!(&*dst[0], &[1, 2, 3]);
+        assert_eq!(&*dst[1], &[4]);
+    }
+
+    {
+        let mut dst = [std::io::IoSlice::new(&[]); 2];
+        let take = chain().take(6);
+        assert_eq!(take.chunks_vectored(&mut dst), 2);
+        assert_eq!(&*dst[0], &[1, 2, 3]);
+        assert_eq!(&*dst[1], &[4, 5, 6]);
+    }
+
+    {
+        let mut dst = [std::io::IoSlice::new(&[]); 2];
+        let take = chain().take(7);
+        assert_eq!(take.chunks_vectored(&mut dst), 2);
+        assert_eq!(&*dst[0], &[1, 2, 3]);
+        assert_eq!(&*dst[1], &[4, 5, 6]);
+    }
 }