[rustc.git] / src / libcore / array.rs

// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Implementations of things like `Eq` for fixed-length arrays
//! up to a certain length. Eventually we should able to generalize
//! to all lengths.
//!
//! *[See also the array primitive type](../primitive.array.html).*

#![unstable(feature = "fixed_size_array",
            reason = "traits and impls are better expressed through generic \
                      integer constants",
            issue = "27778")]

use borrow::{Borrow, BorrowMut};
use clone::Clone;
use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
use convert::{AsRef, AsMut};
use default::Default;
use fmt;
use hash::{Hash, self};
use iter::IntoIterator;
use marker::{Copy, Sized, Unsize};
use option::Option;
use slice::{Iter, IterMut, SliceExt};

/// Utility trait implemented only on arrays of fixed size
///
/// This trait can be used to implement other traits on fixed-size arrays
/// without causing much metadata bloat.
///
/// The trait is marked unsafe in order to restrict implementors to fixed-size
/// arrays. User of this trait can assume that implementors have the exact
/// layout in memory of a fixed size array (for example, for unsafe
/// initialization).
///
/// Note that the traits AsRef and AsMut provide similar methods for types that
/// may not be fixed-size arrays. Implementors should prefer those traits
/// instead.
pub unsafe trait FixedSizeArray<T> {
    /// Converts the array to immutable slice
    fn as_slice(&self) -> &[T];
    /// Converts the array to mutable slice
    fn as_mut_slice(&mut self) -> &mut [T];
}

unsafe impl<T, A: Unsize<[T]>> FixedSizeArray<T> for A {
    #[inline]
    fn as_slice(&self) -> &[T] {
        self
    }
    #[inline]
    fn as_mut_slice(&mut self) -> &mut [T] {
        self
    }
}

macro_rules! __impl_slice_eq1 {
    ($Lhs: ty, $Rhs: ty) => {
        __impl_slice_eq1! { $Lhs, $Rhs, Sized }
    };
    ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
        #[stable(feature = "rust1", since = "1.0.0")]
        impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
            #[inline]
            fn eq(&self, other: &$Rhs) -> bool { self[..] == other[..] }
            #[inline]
            fn ne(&self, other: &$Rhs) -> bool { self[..] != other[..] }
        }
    }
}

macro_rules! __impl_slice_eq2 {
    ($Lhs: ty, $Rhs: ty) => {
        __impl_slice_eq2! { $Lhs, $Rhs, Sized }
    };
    ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
        __impl_slice_eq1!($Lhs, $Rhs, $Bound);

        #[stable(feature = "rust1", since = "1.0.0")]
        impl<'a, 'b, A: $Bound, B> PartialEq<$Lhs> for $Rhs where B: PartialEq<A> {
            #[inline]
            fn eq(&self, other: &$Lhs) -> bool { self[..] == other[..] }
            #[inline]
            fn ne(&self, other: &$Lhs) -> bool { self[..] != other[..] }
        }
    }
}

// macro for implementing n-ary tuple functions and operations
macro_rules! array_impls {
    ($($N:expr)+) => {
        $(
            impl<T> AsRef<[T]> for [T; $N] {
                #[inline]
                fn as_ref(&self) -> &[T] {
                    &self[..]
                }
            }

            impl<T> AsMut<[T]> for [T; $N] {
                #[inline]
                fn as_mut(&mut self) -> &mut [T] {
                    &mut self[..]
                }
            }

            #[stable(feature = "array_borrow", since = "1.4.0")]
            impl<T> Borrow<[T]> for [T; $N] {
                fn borrow(&self) -> &[T] {
                    self
                }
            }

            #[stable(feature = "array_borrow", since = "1.4.0")]
            impl<T> BorrowMut<[T]> for [T; $N] {
                fn borrow_mut(&mut self) -> &mut [T] {
                    self
                }
            }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<T:Copy> Clone for [T; $N] {
                fn clone(&self) -> [T; $N] {
                    *self
                }
            }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<T: Hash> Hash for [T; $N] {
                fn hash<H: hash::Hasher>(&self, state: &mut H) {
                    Hash::hash(&self[..], state)
                }
            }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<T: fmt::Debug> fmt::Debug for [T; $N] {
                fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                    fmt::Debug::fmt(&&self[..], f)
                }
            }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<'a, T> IntoIterator for &'a [T; $N] {
                type Item = &'a T;
                type IntoIter = Iter<'a, T>;

                fn into_iter(self) -> Iter<'a, T> {
                    self.iter()
                }
            }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<'a, T> IntoIterator for &'a mut [T; $N] {
                type Item = &'a mut T;
                type IntoIter = IterMut<'a, T>;

                fn into_iter(self) -> IterMut<'a, T> {
                    self.iter_mut()
                }
            }

            // NOTE: some less important impls are omitted to reduce code bloat
            __impl_slice_eq1! { [A; $N], [B; $N] }
            __impl_slice_eq2! { [A; $N], [B] }
            __impl_slice_eq2! { [A; $N], &'b [B] }
            __impl_slice_eq2! { [A; $N], &'b mut [B] }
            // __impl_slice_eq2! { [A; $N], &'b [B; $N] }
            // __impl_slice_eq2! { [A; $N], &'b mut [B; $N] }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<T:Eq> Eq for [T; $N] { }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<T:PartialOrd> PartialOrd for [T; $N] {
                #[inline]
                fn partial_cmp(&self, other: &[T; $N]) -> Option<Ordering> {
                    PartialOrd::partial_cmp(&&self[..], &&other[..])
                }
                #[inline]
                fn lt(&self, other: &[T; $N]) -> bool {
                    PartialOrd::lt(&&self[..], &&other[..])
                }
                #[inline]
                fn le(&self, other: &[T; $N]) -> bool {
                    PartialOrd::le(&&self[..], &&other[..])
                }
                #[inline]
                fn ge(&self, other: &[T; $N]) -> bool {
                    PartialOrd::ge(&&self[..], &&other[..])
                }
                #[inline]
                fn gt(&self, other: &[T; $N]) -> bool {
                    PartialOrd::gt(&&self[..], &&other[..])
                }
            }

            #[stable(feature = "rust1", since = "1.0.0")]
            impl<T:Ord> Ord for [T; $N] {
                #[inline]
                fn cmp(&self, other: &[T; $N]) -> Ordering {
                    Ord::cmp(&&self[..], &&other[..])
                }
            }
        )+
    }
}

array_impls! {
     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
}

// The Default impls cannot be generated using the array_impls! macro because
// they require array literals.

macro_rules! array_impl_default {
    {$n:expr, $t:ident $($ts:ident)*} => {
        #[stable(since = "1.4.0", feature = "array_default")]
        impl<T> Default for [T; $n] where T: Default {
            fn default() -> [T; $n] {
                [$t::default(), $($ts::default()),*]
            }
        }
        array_impl_default!{($n - 1), $($ts)*}
    };
    {$n:expr,} => {
        #[stable(since = "1.4.0", feature = "array_default")]
        impl<T> Default for [T; $n] {
            fn default() -> [T; $n] { [] }
        }
    };
}

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}
Commit	Line	Data
1a4d82fc JJ	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.
	4	//
	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.
	10
	11	//! Implementations of things like `Eq` for fixed-length arrays
	12	//! up to a certain length. Eventually we should able to generalize
	13	//! to all lengths.
c1a9b12d SL	14	//!
c1a9b12d SL	15	//! [See also the array primitive type](../primitive.array.html).
1a4d82fc	16
62682a34 SL	17	#![unstable(feature = "fixed_size_array",
62682a34 SL	18	reason = "traits and impls are better expressed through generic \
e9174d1e SL	19	integer constants",
e9174d1e SL	20	issue = "27778")]
c34b1796	21
e9174d1e	22	use borrow::{Borrow, BorrowMut};
1a4d82fc JJ	23	use clone::Clone;
1a4d82fc JJ	24	use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
c34b1796	25	use convert::{AsRef, AsMut};
e9174d1e	26	use default::Default;
1a4d82fc	27	use fmt;
85aaf69f SL	28	use hash::{Hash, self};
85aaf69f SL	29	use iter::IntoIterator;
e9174d1e	30	use marker::{Copy, Sized, Unsize};
1a4d82fc	31	use option::Option;
85aaf69f	32	use slice::{Iter, IterMut, SliceExt};
1a4d82fc	33
c34b1796 AL	34	/// Utility trait implemented only on arrays of fixed size
	35	///
	36	/// This trait can be used to implement other traits on fixed-size arrays
	37	/// without causing much metadata bloat.
b039eaaf SL	38	///
	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
	42	/// initialization).
	43	///
	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
	46	/// instead.
	47	pub unsafe trait FixedSizeArray<T> {
c34b1796 AL	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];
	52	}
	53
b039eaaf	54	unsafe impl<T, A: Unsize<[T]>> FixedSizeArray<T> for A {
e9174d1e SL	55	#[inline]
	56	fn as_slice(&self) -> &[T] {
	57	self
	58	}
	59	#[inline]
	60	fn as_mut_slice(&mut self) -> &mut [T] {
	61	self
	62	}
	63	}
	64
92a42be0 SL	65	macro_rules! __impl_slice_eq1 {
	66	($Lhs: ty, $Rhs: ty) => {
	67	__impl_slice_eq1! { $Lhs, $Rhs, Sized }
	68	};
	69	($Lhs: ty, $Rhs: ty, $Bound: ident) => {
	70	#[stable(feature = "rust1", since = "1.0.0")]
	71	impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
	72	#[inline]
	73	fn eq(&self, other: &$Rhs) -> bool { self[..] == other[..] }
	74	#[inline]
	75	fn ne(&self, other: &$Rhs) -> bool { self[..] != other[..] }
	76	}
	77	}
	78	}
	79
	80	macro_rules! __impl_slice_eq2 {
	81	($Lhs: ty, $Rhs: ty) => {
	82	__impl_slice_eq2! { $Lhs, $Rhs, Sized }
	83	};
	84	($Lhs: ty, $Rhs: ty, $Bound: ident) => {
	85	__impl_slice_eq1!($Lhs, $Rhs, $Bound);
	86
	87	#[stable(feature = "rust1", since = "1.0.0")]
	88	impl<'a, 'b, A: $Bound, B> PartialEq<$Lhs> for $Rhs where B: PartialEq<A> {
	89	#[inline]
	90	fn eq(&self, other: &$Lhs) -> bool { self[..] == other[..] }
	91	#[inline]
	92	fn ne(&self, other: &$Lhs) -> bool { self[..] != other[..] }
	93	}
	94	}
	95	}
	96
1a4d82fc JJ	97	// macro for implementing n-ary tuple functions and operations
	98	macro_rules! array_impls {
	99	($($N:expr)+) => {
	100	$(
c34b1796 AL	101	impl<T> AsRef<[T]> for [T; $N] {
	102	#[inline]
	103	fn as_ref(&self) -> &[T] {
	104	&self[..]
	105	}
	106	}
	107
c34b1796 AL	108	impl<T> AsMut<[T]> for [T; $N] {
	109	#[inline]
	110	fn as_mut(&mut self) -> &mut [T] {
	111	&mut self[..]
	112	}
	113	}
	114
e9174d1e SL	115	#[stable(feature = "array_borrow", since = "1.4.0")]
	116	impl<T> Borrow<[T]> for [T; $N] {
	117	fn borrow(&self) -> &[T] {
	118	self
	119	}
	120	}
	121
	122	#[stable(feature = "array_borrow", since = "1.4.0")]
	123	impl<T> BorrowMut<[T]> for [T; $N] {
	124	fn borrow_mut(&mut self) -> &mut [T] {
	125	self
	126	}
	127	}
	128
85aaf69f	129	#[stable(feature = "rust1", since = "1.0.0")]
1a4d82fc JJ	130	impl<T:Copy> Clone for [T; $N] {
	131	fn clone(&self) -> [T; $N] {
	132	*self
	133	}
	134	}
	135
85aaf69f SL	136	#[stable(feature = "rust1", since = "1.0.0")]
	137	impl<T: Hash> Hash for [T; $N] {
	138	fn hash<H: hash::Hasher>(&self, state: &mut H) {
	139	Hash::hash(&self[..], state)
	140	}
	141	}
	142
	143	#[stable(feature = "rust1", since = "1.0.0")]
	144	impl<T: fmt::Debug> fmt::Debug for [T; $N] {
1a4d82fc	145	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
85aaf69f SL	146	fmt::Debug::fmt(&&self[..], f)
	147	}
	148	}
	149
	150	#[stable(feature = "rust1", since = "1.0.0")]
	151	impl<'a, T> IntoIterator for &'a [T; $N] {
	152	type Item = &'a T;
	153	type IntoIter = Iter<'a, T>;
	154
	155	fn into_iter(self) -> Iter<'a, T> {
	156	self.iter()
	157	}
	158	}
	159
	160	#[stable(feature = "rust1", since = "1.0.0")]
	161	impl<'a, T> IntoIterator for &'a mut [T; $N] {
	162	type Item = &'a mut T;
	163	type IntoIter = IterMut<'a, T>;
	164
	165	fn into_iter(self) -> IterMut<'a, T> {
	166	self.iter_mut()
1a4d82fc JJ	167	}
	168	}
	169
c34b1796 AL	170	// NOTE: some less important impls are omitted to reduce code bloat
	171	__impl_slice_eq1! { [A; $N], [B; $N] }
	172	__impl_slice_eq2! { [A; $N], [B] }
	173	__impl_slice_eq2! { [A; $N], &'b [B] }
	174	__impl_slice_eq2! { [A; $N], &'b mut [B] }
	175	// __impl_slice_eq2! { [A; $N], &'b [B; $N] }
	176	// __impl_slice_eq2! { [A; $N], &'b mut [B; $N] }
1a4d82fc	177
85aaf69f	178	#[stable(feature = "rust1", since = "1.0.0")]
1a4d82fc JJ	179	impl<T:Eq> Eq for [T; $N] { }
1a4d82fc JJ	180
85aaf69f	181	#[stable(feature = "rust1", since = "1.0.0")]
1a4d82fc JJ	182	impl<T:PartialOrd> PartialOrd for [T; $N] {
	183	#[inline]
	184	fn partial_cmp(&self, other: &[T; $N]) -> Option<Ordering> {
85aaf69f	185	PartialOrd::partial_cmp(&&self[..], &&other[..])
1a4d82fc JJ	186	}
	187	#[inline]
	188	fn lt(&self, other: &[T; $N]) -> bool {
85aaf69f	189	PartialOrd::lt(&&self[..], &&other[..])
1a4d82fc JJ	190	}
	191	#[inline]
	192	fn le(&self, other: &[T; $N]) -> bool {
85aaf69f	193	PartialOrd::le(&&self[..], &&other[..])
1a4d82fc JJ	194	}
	195	#[inline]
	196	fn ge(&self, other: &[T; $N]) -> bool {
85aaf69f	197	PartialOrd::ge(&&self[..], &&other[..])
1a4d82fc JJ	198	}
	199	#[inline]
	200	fn gt(&self, other: &[T; $N]) -> bool {
85aaf69f	201	PartialOrd::gt(&&self[..], &&other[..])
1a4d82fc JJ	202	}
	203	}
	204
85aaf69f	205	#[stable(feature = "rust1", since = "1.0.0")]
1a4d82fc JJ	206	impl<T:Ord> Ord for [T; $N] {
	207	#[inline]
	208	fn cmp(&self, other: &[T; $N]) -> Ordering {
85aaf69f	209	Ord::cmp(&&self[..], &&other[..])
1a4d82fc JJ	210	}
	211	}
	212	)+
	213	}
	214	}
	215
	216	array_impls! {
	217	0 1 2 3 4 5 6 7 8 9
	218	10 11 12 13 14 15 16 17 18 19
	219	20 21 22 23 24 25 26 27 28 29
	220	30 31 32
	221	}
e9174d1e SL	222
	223	// The Default impls cannot be generated using the array_impls! macro because
	224	// they require array literals.
	225
	226	macro_rules! array_impl_default {
	227	{$n:expr, $t:ident $($ts:ident)*} => {
	228	#[stable(since = "1.4.0", feature = "array_default")]
	229	impl<T> Default for [T; $n] where T: Default {
	230	fn default() -> [T; $n] {
	231	[$t::default(), $($ts::default()),*]
	232	}
	233	}
	234	array_impl_default!{($n - 1), $($ts)*}
	235	};
	236	{$n:expr,} => {
	237	#[stable(since = "1.4.0", feature = "array_default")]
	238	impl<T> Default for [T; $n] {
	239	fn default() -> [T; $n] { [] }
	240	}
	241	};
	242	}
	243
	244	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}