diff options
| -rw-r--r-- | src/libcore/array.rs | 53 | ||||
| -rw-r--r-- | src/libcore/tests/array.rs | 23 | ||||
| -rw-r--r-- | src/libstd/error.rs | 8 | ||||
| -rw-r--r-- | src/libstd/lib.rs | 2 |
4 files changed, 86 insertions, 0 deletions
diff --git a/src/libcore/array.rs b/src/libcore/array.rs index 6a7926fecde..3d24f8902bd 100644 --- a/src/libcore/array.rs +++ b/src/libcore/array.rs @@ -21,6 +21,7 @@ use borrow::{Borrow, BorrowMut}; use cmp::Ordering; +use convert::TryFrom; use fmt; use hash::{Hash, self}; use marker::Unsize; @@ -57,6 +58,30 @@ unsafe impl<T, A: Unsize<[T]>> FixedSizeArray<T> for A { } } +/// The error type returned when a conversion from a slice to an array fails. +#[unstable(feature = "try_from", issue = "33417")] +#[derive(Debug, Copy, Clone)] +pub struct TryFromSliceError(()); + +impl fmt::Display for TryFromSliceError { + #[inline] + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + fmt::Display::fmt(self.__description(), f) + } +} + +impl TryFromSliceError { + #[unstable(feature = "array_error_internals", + reason = "available through Error trait and this method should not \ + be exposed publicly", + issue = "0")] + #[inline] + #[doc(hidden)] + pub fn __description(&self) -> &str { + "could not convert slice to array" + } +} + macro_rules! __impl_slice_eq1 { ($Lhs: ty, $Rhs: ty) => { __impl_slice_eq1! { $Lhs, $Rhs, Sized } @@ -123,6 +148,34 @@ macro_rules! array_impls { } } + #[unstable(feature = "try_from", issue = "33417")] + impl<'a, T> TryFrom<&'a [T]> for &'a [T; $N] { + type Error = TryFromSliceError; + + fn try_from(slice: &[T]) -> Result<&[T; $N], TryFromSliceError> { + if slice.len() == $N { + let ptr = slice.as_ptr() as *const [T; $N]; + unsafe { Ok(&*ptr) } + } else { + Err(TryFromSliceError(())) + } + } + } + + #[unstable(feature = "try_from", issue = "33417")] + impl<'a, T> TryFrom<&'a mut [T]> for &'a mut [T; $N] { + type Error = TryFromSliceError; + + fn try_from(slice: &mut [T]) -> Result<&mut [T; $N], TryFromSliceError> { + if slice.len() == $N { + let ptr = slice.as_mut_ptr() as *mut [T; $N]; + unsafe { Ok(&mut *ptr) } + } else { + Err(TryFromSliceError(())) + } + } + } + #[stable(feature = "rust1", since = "1.0.0")] impl<T: Hash> Hash for [T; $N] { fn hash<H: hash::Hasher>(&self, state: &mut H) { diff --git a/src/libcore/tests/array.rs b/src/libcore/tests/array.rs index 6af031dee58..6278d5e23e0 100644 --- a/src/libcore/tests/array.rs +++ b/src/libcore/tests/array.rs @@ -8,6 +8,7 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. use core::array::FixedSizeArray; +use core::convert::TryFrom; #[test] fn fixed_size_array() { @@ -26,3 +27,25 @@ fn fixed_size_array() { assert_eq!(FixedSizeArray::as_mut_slice(&mut empty_array).len(), 0); assert_eq!(FixedSizeArray::as_mut_slice(&mut empty_zero_sized).len(), 0); } + +#[test] +fn array_try_from() { + macro_rules! test { + ($($N:expr)+) => { + $({ + type Array = [u8; $N]; + let array: Array = [0; $N]; + let slice: &[u8] = &array[..]; + + let result = <&Array>::try_from(slice); + assert_eq!(&array, result.unwrap()); + })+ + } + } + test! { + 0 1 2 3 4 5 6 7 8 9 + 10 11 12 13 14 15 16 17 18 19 + 20 21 22 23 24 25 26 27 28 29 + 30 31 32 + } +} diff --git a/src/libstd/error.rs b/src/libstd/error.rs index 166439692d4..231b0be9276 100644 --- a/src/libstd/error.rs +++ b/src/libstd/error.rs @@ -57,6 +57,7 @@ use borrow::Cow; use cell; use char; use convert; +use core::array; use fmt::{self, Debug, Display}; use mem::transmute; use num; @@ -282,6 +283,13 @@ impl Error for num::TryFromIntError { } } +#[unstable(feature = "try_from", issue = "33417")] +impl Error for array::TryFromSliceError { + fn description(&self) -> &str { + self.__description() + } +} + #[stable(feature = "rust1", since = "1.0.0")] impl Error for num::ParseFloatError { fn description(&self) -> &str { diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs index 012883d0853..5cf1d225b90 100644 --- a/src/libstd/lib.rs +++ b/src/libstd/lib.rs @@ -243,6 +243,7 @@ #![feature(allow_internal_unsafe)] #![feature(allow_internal_unstable)] #![feature(align_offset)] +#![feature(array_error_internals)] #![feature(asm)] #![feature(attr_literals)] #![feature(box_syntax)] @@ -267,6 +268,7 @@ #![feature(core_intrinsics)] #![feature(dropck_eyepatch)] #![feature(exact_size_is_empty)] +#![feature(fixed_size_array)] #![feature(float_from_str_radix)] #![feature(fn_traits)] #![feature(fnbox)] |