vendor/time-core/src/convert.rs

   1 //! Conversion between units of time.
   2
   3 use self::sealed::Per;
   4
   5 mod 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.
  19 macro_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
  60 impl_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 }