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
/// Trait for fixed size arrays.
///
/// This trait is implemented for some specific array sizes, see
/// the implementor list below. At the current state of Rust we can't
/// make this fully general for every array size.
///
/// The following crate features add more array sizes (and they are not
/// enabled by default due to their impact on compliation speed).
///
/// - `array-sizes-33-128`: All sizes 33 to 128 are implemented
///   (a few in this range are included by default).
/// - `array-sizes-129-255`: All sizes 129 to 255 are implemented
///   (a few in this range are included by default).
///
/// ## Safety
///
/// This trait can *only* be implemented by fixed-size arrays or types with
/// *exactly* the representation of a fixed size array (of the right element
/// type and capacity).
///
/// Normally this trait is an implementation detail of arrayvec and doesn’t
/// need implementing.
pub unsafe trait Array {
    /// The array’s element type
    type Item;
    /// The smallest type that can index and tell the length of the array.
    #[doc(hidden)]
    type Index: Index;
    /// The array's element capacity
    const CAPACITY: usize;
    fn as_slice(&self) -> &[Self::Item];
    fn as_mut_slice(&mut self) -> &mut [Self::Item];
}

pub trait Index : PartialEq + Copy {
    fn to_usize(self) -> usize;
    fn from(_: usize) -> Self;
}

impl Index for () {
    #[inline(always)]
    fn to_usize(self) -> usize { 0 }
    #[inline(always)]
    fn from(_ix: usize) ->  Self { () }
}

impl Index for bool {
    #[inline(always)]
    fn to_usize(self) -> usize { self as usize }
    #[inline(always)]
    fn from(ix: usize) ->  Self { ix != 0 }
}

impl Index for u8 {
    #[inline(always)]
    fn to_usize(self) -> usize { self as usize }
    #[inline(always)]
    fn from(ix: usize) ->  Self { ix as u8 }
}

impl Index for u16 {
    #[inline(always)]
    fn to_usize(self) -> usize { self as usize }
    #[inline(always)]
    fn from(ix: usize) ->  Self { ix as u16 }
}

impl Index for u32 {
    #[inline(always)]
    fn to_usize(self) -> usize { self as usize }
    #[inline(always)]
    fn from(ix: usize) ->  Self { ix as u32 }
}

impl Index for usize {
    #[inline(always)]
    fn to_usize(self) -> usize { self }
    #[inline(always)]
    fn from(ix: usize) ->  Self { ix }
}

macro_rules! fix_array_impl {
    ($index_type:ty, $len:expr ) => (
        unsafe impl<T> Array for [T; $len] {
            type Item = T;
            type Index = $index_type;
            const CAPACITY: usize = $len;
            #[doc(hidden)]
            fn as_slice(&self) -> &[Self::Item] { self }
            #[doc(hidden)]
            fn as_mut_slice(&mut self) -> &mut [Self::Item] { self }
        }
    )
}

macro_rules! fix_array_impl_recursive {
    ($index_type:ty, ) => ();
    ($index_type:ty, $($len:expr,)*) => (
        $(fix_array_impl!($index_type, $len);)*
    );
}


fix_array_impl_recursive!((), 0,);
fix_array_impl_recursive!(bool, 1,);
fix_array_impl_recursive!(u8, 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, );

#[cfg(not(feature="array-sizes-33-128"))]
fix_array_impl_recursive!(u8, 32, 40, 48, 50, 56, 64, 72, 96, 100, 128, );

#[cfg(feature="array-sizes-33-128")]
fix_array_impl_recursive!(u8, 
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,
);

#[cfg(not(feature="array-sizes-129-255"))]
fix_array_impl_recursive!(u8, 160, 192, 200, 224,);

#[cfg(feature="array-sizes-129-255")]
fix_array_impl_recursive!(u8,
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,
);

fix_array_impl_recursive!(u16, 256, 384, 512, 768, 1024, 2048, 4096, 8192, 16384, 32768,);
// This array size doesn't exist on 16-bit
#[cfg(any(target_pointer_width="32", target_pointer_width="64"))]
fix_array_impl_recursive!(u32, 1 << 16,);