time_core/
convert.rs

1//! Conversion between units of time.
2
3use self::sealed::Per;
4
5mod sealed {
6    /// A trait for defining the ratio of two units of time.
7    ///
8    /// This trait is used to implement the `per` method on the various structs.
9    pub trait Per<T> {
10        /// The smallest unsigned integer type that can represent [`VALUE`](Self::VALUE).
11        type Output;
12
13        /// The number of one unit of time in the other.
14        const VALUE: Self::Output;
15    }
16}
17
18/// Declare and implement `Per` for all relevant types. Identity implementations are automatic.
19macro_rules! impl_per {
20    ($($t:ident ($str:literal) per {$(
21        $larger:ident : $output:ty = $value:expr
22    )*})*) => {$(
23        #[doc = concat!("A unit of time representing exactly one ", $str, ".")]
24        #[derive(Debug, Clone, Copy)]
25        pub struct $t;
26
27        impl $t {
28            #[doc = concat!("Obtain the number of times `", stringify!($t), "` can fit into `T`.")]
29            #[doc = concat!("If `T` is smaller than `", stringify!($t), "`, the code will fail to")]
30            /// compile. The return type is the smallest unsigned integer type that can represent
31            /// the value.
32            ///
33            /// Valid calls:
34            ///
35            #[doc = concat!("  - `", stringify!($t), "::per(", stringify!($t), ")` (returns `u8`)")]
36            $(#[doc = concat!("  - `", stringify!($t), "::per(", stringify!($larger), ")` (returns `", stringify!($output), "`)")])*
37            pub const fn per<T>(_larger: T) -> <Self as Per<T>>::Output
38            where
39                Self: Per<T>,
40                T: Copy,
41            {
42                Self::VALUE
43            }
44        }
45
46        impl Per<$t> for $t {
47            type Output = u8;
48
49            const VALUE: u8 = 1;
50        }
51
52        $(impl Per<$larger> for $t {
53            type Output = $output;
54
55            const VALUE: $output = $value;
56        })*
57    )*};
58}
59
60impl_per! {
61    Nanosecond ("nanosecond") per {
62        Microsecond: u16 = 1_000
63        Millisecond: u32 = 1_000_000
64        Second: u32 = 1_000_000_000
65        Minute: u64 = 60_000_000_000
66        Hour: u64 = 3_600_000_000_000
67        Day: u64 = 86_400_000_000_000
68        Week: u64 = 604_800_000_000_000
69    }
70    Microsecond ("microsecond") per {
71        Millisecond: u16 = 1_000
72        Second: u32 = 1_000_000
73        Minute: u32 = 60_000_000
74        Hour: u32 = 3_600_000_000
75        Day: u64 = 86_400_000_000
76        Week: u64 = 604_800_000_000
77    }
78    Millisecond ("millisecond") per {
79        Second: u16 = 1_000
80        Minute: u16 = 60_000
81        Hour: u32 = 3_600_000
82        Day: u32 = 86_400_000
83        Week: u32 = 604_800_000
84    }
85    Second ("second") per {
86        Minute: u8 = 60
87        Hour: u16 = 3_600
88        Day: u32 = 86_400
89        Week: u32 = 604_800
90    }
91    Minute ("minute") per {
92        Hour: u8 = 60
93        Day: u16 = 1_440
94        Week: u16 = 10_080
95    }
96    Hour ("hour") per {
97        Day: u8 = 24
98        Week: u8 = 168
99    }
100    Day ("day") per {
101        Week: u8 = 7
102    }
103    Week ("week") per {}
104}
time_core/convert.rs

time_core/
convert.rs
