generic_array/
impl_const_default.rs

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
//! Const default implementation

use crate::{ArrayLength, GenericArray, GenericArrayImplEven, GenericArrayImplOdd};
use const_default::ConstDefault;

impl<T, U: ConstDefault> ConstDefault for GenericArrayImplEven<T, U> {
    const DEFAULT: Self = Self {
        parent1: U::DEFAULT,
        parent2: U::DEFAULT,
        _marker: core::marker::PhantomData,
    };
}

impl<T: ConstDefault, U: ConstDefault> ConstDefault for GenericArrayImplOdd<T, U> {
    const DEFAULT: Self = Self {
        parent1: U::DEFAULT,
        parent2: U::DEFAULT,
        data: T::DEFAULT,
    };
}

impl<T, U: ArrayLength> ConstDefault for GenericArray<T, U>
where
    U::ArrayType<T>: ConstDefault,
{
    const DEFAULT: Self = Self {
        data: ConstDefault::DEFAULT,
    };
}

// `T: ConstDefault` is intentionally redundant to provide better hints in the docs
impl<T: ConstDefault, U: ArrayLength> GenericArray<T, U>
where
    Self: ConstDefault,
{
    /// Returns the constant "default value" for an array using [ConstDefault]
    #[inline(always)]
    pub const fn const_default() -> Self {
        Self::DEFAULT
    }
}