Merge #7

7: impl Index r=japaric a=japaric



Co-authored-by: Jorge Aparicio <jorge@japaric.io>

Author: bors[bot]

.travis.yml

@@ -3,16 +3,8 @@ language: rust
 matrix:
   include:
     - env: TARGET=x86_64-unknown-linux-gnu
-      rust: beta
 
     - env: TARGET=thumbv7m-none-eabi
-      rust: beta
-
-    - env: TARGET=x86_64-unknown-linux-gnu
-      rust: nightly
-
-    - env: TARGET=thumbv7m-none-eabi
-      rust: nightly
 
 before_install: set -e
 

CHANGELOG.md

@@ -5,6 +5,13 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+## [v0.3.2] - 2019-11-26
+
+### Added
+
+- `Aligned<_, [T]>` now implements the `Index<RangeTo<usize>>` trait; slicing
+  this value to end returns an `Aligned<_, [T]>` slice.
+
 ## [v0.3.1] - 2018-11-07
 
 ### Changed
@@ -48,7 +55,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 - Initial release
 
-[Unreleased]: https://github.com/japaric/aligned/compare/v0.3.0...HEAD
+[Unreleased]: https://github.com/japaric/aligned/compare/v0.3.2...HEAD
+[v0.3.2]: https://github.com/japaric/aligned/compare/v0.3.1...v0.3.2
+[v0.3.1]: https://github.com/japaric/aligned/compare/v0.3.0...v0.3.1
 [v0.3.0]: https://github.com/japaric/aligned/compare/v0.2.0...v0.3.0
 [v0.2.0]: https://github.com/japaric/aligned/compare/v0.1.2...v0.2.0
 [v0.1.2]: https://github.com/japaric/aligned/compare/v0.1.1...v0.1.2

Cargo.toml

@@ -8,7 +8,7 @@ keywords = ["alignment", "aligned", "array", "static"]
 license = "MIT OR Apache-2.0"
 name = "aligned"
 repository = "https://github.com/japaric/aligned"
-version = "0.3.1"
+version = "0.3.2"
 
 [dependencies]
 as-slice = "0.1.0"

ci/install.sh

@@ -1,9 +1,7 @@
 set -euxo pipefail
 
 main() {
-    if [ $TARGET != x86_64-unknown-linux-gnu ]; then
-        rustup target add $TARGET
-    fi
+    rustup target add $TARGET
 }
 
 main

ci/script.sh

@@ -1,9 +1,9 @@
 set -euxo pipefail
 
 main() {
-    cargo check --target $TARGET
-
-    if [ $TRAVIS_RUST_VERSION = nightly ]; then
+    if [ $TARGET = x86_64-unknown-linux-gnu ]; then
+        cargo test --target $TARGET
+    else
         cargo check --target $TARGET
     fi
 }

src/lib.rs

@@ -91,6 +91,17 @@ where
     }
 }
 
+impl<A, T> ops::Index<ops::RangeTo<usize>> for Aligned<A, [T]>
+where
+    A: sealed::Alignment,
+{
+    type Output = Aligned<A, [T]>;
+
+    fn index(&self, range: ops::RangeTo<usize>) -> &Aligned<A, [T]> {
+        unsafe { &*(&self.value[range] as *const [T] as *const Aligned<A, [T]>) }
+    }
+}
+
 impl<A, T> AsSlice for Aligned<A, T>
 where
     A: sealed::Alignment,
@@ -139,6 +150,22 @@ fn sanity() {
     assert_eq!(z.len(), 3);
     assert_eq!(w.len(), 3);
 
+    // alignment should be preserved after slicing
+    let x: &Aligned<_, [_]> = &x;
+    let y: &Aligned<_, [_]> = &y;
+    let z: &Aligned<_, [_]> = &z;
+    let w: &Aligned<_, [_]> = &w;
+
+    let x: &Aligned<_, _> = &x[..2];
+    let y: &Aligned<_, _> = &y[..2];
+    let z: &Aligned<_, _> = &z[..2];
+    let w: &Aligned<_, _> = &w[..2];
+
+    assert!(x.as_ptr() as usize % 2 == 0);
+    assert!(y.as_ptr() as usize % 4 == 0);
+    assert!(z.as_ptr() as usize % 8 == 0);
+    assert!(w.as_ptr() as usize % 16 == 0);
+
     // alignment should be preserved after boxing
     let x: Box<Aligned<A2, [u8]>> = Box::new(Aligned([0u8; 3]));
     let y: Box<Aligned<A4, [u8]>> = Box::new(Aligned([0u8; 3]));
@@ -150,7 +177,7 @@ fn sanity() {
     assert_eq!(mem::align_of_val(&*z), 8);
     assert_eq!(mem::align_of_val(&*w), 16);
 
-    // test deref-ing
+    // test coercions
     let x: Aligned<A2, _> = Aligned([0u8; 3]);
     let y: &Aligned<A2, [u8]> = &x;
     let _: &[u8] = y;