1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Implementations of things like `Eq` for fixed-length arrays
12 //! up to a certain length. Eventually we should able to generalize
15 //! *[See also the array primitive type](../primitive.array.html).*
17 #![unstable(feature = "fixed_size_array",
18 reason = "traits and impls are better expressed through generic \
22 use borrow::{Borrow, BorrowMut};
24 use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
25 use convert::{AsRef, AsMut};
28 use hash::{Hash, self};
29 use iter::IntoIterator;
30 use marker::{Copy, Sized, Unsize};
32 use slice::{Iter, IterMut, SliceExt};
34 /// Utility trait implemented only on arrays of fixed size
36 /// This trait can be used to implement other traits on fixed-size arrays
37 /// without causing much metadata bloat.
39 /// The trait is marked unsafe in order to restrict implementors to fixed-size
40 /// arrays. User of this trait can assume that implementors have the exact
41 /// layout in memory of a fixed size array (for example, for unsafe
44 /// Note that the traits AsRef and AsMut provide similar methods for types that
45 /// may not be fixed-size arrays. Implementors should prefer those traits
47 pub unsafe trait FixedSizeArray<T> {
48 /// Converts the array to immutable slice
49 fn as_slice(&self) -> &[T];
50 /// Converts the array to mutable slice
51 fn as_mut_slice(&mut self) -> &mut [T];
54 unsafe impl<T, A: Unsize<[T]>> FixedSizeArray<T> for A {
56 fn as_slice(&self) -> &[T] {
60 fn as_mut_slice(&mut self) -> &mut [T] {
65 // macro for implementing n-ary tuple functions and operations
66 macro_rules! array_impls {
69 impl<T> AsRef<[T]> for [T; $N] {
71 fn as_ref(&self) -> &[T] {
76 impl<T> AsMut<[T]> for [T; $N] {
78 fn as_mut(&mut self) -> &mut [T] {
83 #[stable(feature = "array_borrow", since = "1.4.0")]
84 impl<T> Borrow<[T]> for [T; $N] {
85 fn borrow(&self) -> &[T] {
90 #[stable(feature = "array_borrow", since = "1.4.0")]
91 impl<T> BorrowMut<[T]> for [T; $N] {
92 fn borrow_mut(&mut self) -> &mut [T] {
97 #[stable(feature = "rust1", since = "1.0.0")]
98 impl<T:Copy> Clone for [T; $N] {
99 fn clone(&self) -> [T; $N] {
104 #[stable(feature = "rust1", since = "1.0.0")]
105 impl<T: Hash> Hash for [T; $N] {
106 fn hash<H: hash::Hasher>(&self, state: &mut H) {
107 Hash::hash(&self[..], state)
111 #[stable(feature = "rust1", since = "1.0.0")]
112 impl<T: fmt::Debug> fmt::Debug for [T; $N] {
113 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
114 fmt::Debug::fmt(&&self[..], f)
118 #[stable(feature = "rust1", since = "1.0.0")]
119 impl<'a, T> IntoIterator for &'a [T; $N] {
121 type IntoIter = Iter<'a, T>;
123 fn into_iter(self) -> Iter<'a, T> {
128 #[stable(feature = "rust1", since = "1.0.0")]
129 impl<'a, T> IntoIterator for &'a mut [T; $N] {
130 type Item = &'a mut T;
131 type IntoIter = IterMut<'a, T>;
133 fn into_iter(self) -> IterMut<'a, T> {
138 // NOTE: some less important impls are omitted to reduce code bloat
139 __impl_slice_eq1! { [A; $N], [B; $N] }
140 __impl_slice_eq2! { [A; $N], [B] }
141 __impl_slice_eq2! { [A; $N], &'b [B] }
142 __impl_slice_eq2! { [A; $N], &'b mut [B] }
143 // __impl_slice_eq2! { [A; $N], &'b [B; $N] }
144 // __impl_slice_eq2! { [A; $N], &'b mut [B; $N] }
146 #[stable(feature = "rust1", since = "1.0.0")]
147 impl<T:Eq> Eq for [T; $N] { }
149 #[stable(feature = "rust1", since = "1.0.0")]
150 impl<T:PartialOrd> PartialOrd for [T; $N] {
152 fn partial_cmp(&self, other: &[T; $N]) -> Option<Ordering> {
153 PartialOrd::partial_cmp(&&self[..], &&other[..])
156 fn lt(&self, other: &[T; $N]) -> bool {
157 PartialOrd::lt(&&self[..], &&other[..])
160 fn le(&self, other: &[T; $N]) -> bool {
161 PartialOrd::le(&&self[..], &&other[..])
164 fn ge(&self, other: &[T; $N]) -> bool {
165 PartialOrd::ge(&&self[..], &&other[..])
168 fn gt(&self, other: &[T; $N]) -> bool {
169 PartialOrd::gt(&&self[..], &&other[..])
173 #[stable(feature = "rust1", since = "1.0.0")]
174 impl<T:Ord> Ord for [T; $N] {
176 fn cmp(&self, other: &[T; $N]) -> Ordering {
177 Ord::cmp(&&self[..], &&other[..])
186 10 11 12 13 14 15 16 17 18 19
187 20 21 22 23 24 25 26 27 28 29
191 // The Default impls cannot be generated using the array_impls! macro because
192 // they require array literals.
194 macro_rules! array_impl_default {
195 {$n:expr, $t:ident $($ts:ident)*} => {
196 #[stable(since = "1.4.0", feature = "array_default")]
197 impl<T> Default for [T; $n] where T: Default {
198 fn default() -> [T; $n] {
199 [$t::default(), $($ts::default()),*]
202 array_impl_default!{($n - 1), $($ts)*}
205 #[stable(since = "1.4.0", feature = "array_default")]
206 impl<T> Default for [T; $n] {
207 fn default() -> [T; $n] { [] }
212 array_impl_default!{32, T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T}