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

//! Implementation of `Distribution` for various structs.

use crate::{
    date::{MAX_YEAR, MIN_YEAR},
    internals, Date, Duration, OffsetDateTime, PrimitiveDateTime, Time, UtcOffset, Weekday,
};
use rand::{
    distributions::{Distribution, Standard},
    Rng,
};

impl Distribution<Time> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Time {
        Time {
            hour: rng.gen_range(0, 24),
            minute: rng.gen_range(0, 60),
            second: rng.gen_range(0, 60),
            nanosecond: rng.gen_range(0, 1_000_000_000),
        }
    }
}

impl Distribution<Date> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Date {
        /// The minimum date allowed to be represented.
        const MIN_DATE: Date = internals::Date::from_ymd_unchecked(MIN_YEAR, 1, 1);
        /// The maximum date allowed to be represented.
        const MAX_DATE: Date = internals::Date::from_ymd_unchecked(MAX_YEAR, 12, 31);

        Date::from_julian_day(rng.gen_range(MIN_DATE.julian_day(), MAX_DATE.julian_day() + 1))
    }
}

impl Distribution<UtcOffset> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> UtcOffset {
        UtcOffset {
            seconds: rng.gen_range(-86_399, 86_400),
        }
    }
}

impl Distribution<PrimitiveDateTime> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> PrimitiveDateTime {
        PrimitiveDateTime::new(Standard.sample(rng), Standard.sample(rng))
    }
}

impl Distribution<OffsetDateTime> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> OffsetDateTime {
        OffsetDateTime::new_assuming_offset(Standard.sample(rng), Standard.sample(rng))
    }
}

impl Distribution<Duration> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Duration {
        let seconds = Standard.sample(rng);
        Duration::new(
            seconds,
            seconds.signum() as i32 * rng.gen_range(0, 1_000_000_000),
        )
    }
}

impl Distribution<Weekday> for Standard {
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Weekday {
        use Weekday::*;

        match rng.gen_range(0, 7) {
            0 => Monday,
            1 => Tuesday,
            2 => Wednesday,
            3 => Thursday,
            4 => Friday,
            5 => Saturday,
            6 => Sunday,
            _ => unreachable!("values are 0 to 6 inclusive"),
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn time() {
        let mut rng = rand::rngs::mock::StepRng::new(0, 1);

        let _ = rng.gen::<Time>();
        let _ = rng.gen::<Date>();
        let _ = rng.gen::<UtcOffset>();
        let _ = rng.gen::<PrimitiveDateTime>();
        let _ = rng.gen::<OffsetDateTime>();
        let _ = rng.gen::<Duration>();
        let _ = rng.gen::<Weekday>();
    }
}