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
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
//! `AsSlice` and `AsMutSlice` traits
//!
//! These traits are somewhat similar to the `AsRef` and `AsMut` except that they are **NOT**
//! polymorphic (no input type parameter) and their methods always return slices (`[T]`).
//!
//! The main use case of these traits is writing generic code that accepts (fixed size) buffers. For
//! example, a bound `T: StableDeref + AsMutSlice<Element = u8> + 'static` will accepts types like
//! `&'static mut [u8]`, `&'static mut [u8; 128]` and `&'static mut GenericArray<u8, U1024>` -- all
//! of them are appropriate for DMA transfers.

#![deny(missing_docs)]
#![deny(warnings)]
#![no_std]

extern crate generic_array;
extern crate stable_deref_trait;

use generic_array::{ArrayLength, GenericArray};

/// Something that can be seen as an immutable slice
///
/// **NOTE**: This trait is implemented for arrays (`[T; N]`) of sizes 0 to 256 (inclusive). These
/// implementations don't show in the documentation because they would reduce readability.
pub trait AsSlice {
    /// The element type of the slice view
    type Element;

    /// Returns the immutable slice view of `Self`
    fn as_slice(&self) -> &[Self::Element];
}

/// Something that can be seen as an mutable slice
///
/// **NOTE**: This trait is implemented for arrays (`[T; N]`) of sizes 0 to 256 (inclusive). These
/// implementations don't show in the documentation because they would reduce readability.
pub trait AsMutSlice: AsSlice {
    /// Returns the mutable slice view of `Self`
    fn as_mut_slice(&mut self) -> &mut [Self::Element];
}

impl<'a, S> AsSlice for &'a S
where
    S: ?Sized + AsSlice,
{
    type Element = S::Element;

    fn as_slice(&self) -> &[S::Element] {
        (**self).as_slice()
    }
}

impl<'a, S> AsSlice for &'a mut S
where
    S: ?Sized + AsSlice,
{
    type Element = S::Element;

    fn as_slice(&self) -> &[S::Element] {
        (**self).as_slice()
    }
}

impl<'a, S> AsMutSlice for &'a mut S
where
    S: ?Sized + AsMutSlice,
{
    fn as_mut_slice(&mut self) -> &mut [S::Element] {
        (**self).as_mut_slice()
    }
}

impl<T> AsSlice for [T] {
    type Element = T;

    fn as_slice(&self) -> &[T] {
        self
    }
}

impl<T> AsMutSlice for [T] {
    fn as_mut_slice(&mut self) -> &mut [T] {
        self
    }
}

impl<T, N> AsSlice for GenericArray<T, N>
where
    N: ArrayLength<T>,
{
    type Element = T;

    fn as_slice(&self) -> &[T] {
        &**self
    }
}

impl<T, N> AsMutSlice for GenericArray<T, N>
where
    N: ArrayLength<T>,
{
    fn as_mut_slice(&mut self) -> &mut [T] {
        &mut **self
    }
}

macro_rules! array {
    ($($N:expr),+) => {
        $(
            #[doc(hidden)]
            impl<T> AsSlice for [T; $N] {
                type Element = T;

                fn as_slice(&self) -> &[T] {
                    self
                }
            }

            #[doc(hidden)]
            impl<T> AsMutSlice for [T; $N] {
                fn as_mut_slice(&mut self) -> &mut [T] {
                    self
                }
            }
        )+
    }
}

array!(
    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, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
    50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,
    74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
    98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116,
    117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135,
    136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154,
    155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173,
    174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192,
    193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211,
    212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230,
    231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249,
    250, 251, 252, 253, 254, 255, 256
);