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
145
146
147
148
149
150
151
152
153
154
155
156
157

//! # Utilities for chrono DateTimes
use chrono::{Duration,NaiveDateTime, DateTime, TimeZone, Utc};

///Generate a chrono NaiveDateTime from a i64 value of milliseconds
pub fn naive_datetime_from_millis(istamp:i64)->NaiveDateTime{
    let secs: i64 = istamp/1000;
    let nsecs: u32 = ((istamp % 1000) * 1000000) as u32;
    NaiveDateTime::from_timestamp(secs, nsecs)
}

/// This trait defines the contract for rounding a T via the methods in timeutils
pub trait DurationRoudable<T>{
    fn get_utc_millis_since_epoch(&self) -> i64;
    fn repr_from_utc_millis(&self, utc_milli_stamp: i64) -> T; //need the self here to push the timezone down 
}

impl DurationRoudable<NaiveDateTime> for NaiveDateTime{
    fn get_utc_millis_since_epoch(&self) -> i64{
        self.timestamp_millis()
    }
    fn repr_from_utc_millis(&self, utc_milli_stamp: i64) -> NaiveDateTime {
        naive_datetime_from_millis(utc_milli_stamp)
    }
}

impl<TZInfo: TimeZone> DurationRoudable<DateTime<TZInfo>> for DateTime<TZInfo>{
    fn get_utc_millis_since_epoch(&self) -> i64{
        let ndt = self.naive_utc();
        ndt.timestamp_millis()
    }
    fn repr_from_utc_millis(&self, utc_milli_stamp: i64) -> DateTime<TZInfo> {
        let ndt = naive_datetime_from_millis(utc_milli_stamp);
        let utcdt = DateTime::<Utc>::from_utc(ndt,Utc);
        utcdt.with_timezone(&self.timezone())
    }
}

//SRC:: https://stackoverflow.com/questions/31210357/is-there-a-modulus-not-remainder-function-operation
trait ModuloSignedExt {
    fn modulo(&self, n: Self) -> Self;
}
macro_rules! modulo_signed_ext_impl {
    ($($t:ty)*) => ($(
        impl ModuloSignedExt for $t {
            #[inline]
            fn modulo(&self, n: Self) -> Self {
                (self % n + n) % n
            }
        }
    )*)
}
modulo_signed_ext_impl! { i8 i16 i32 i64 i128 }


//Below are Derived from C# implementations here: https://stackoverflow.com/questions/7029353/how-can-i-round-up-the-time-to-the-nearest-x-minutes/7029464

/// Max precision is milliseconds
/// 
/// Rounds a TDate up to the nearest duration, i.e. if you had a chrono::NaiveDateTime{2020-12-31T12:35:00Z} and you rounding to Duration{15mins} it would return 12:45
pub fn round_up_to_nearest_duration<TDate>(timestamp: &TDate, sample_size :&Duration) -> TDate
where TDate : DurationRoudable<TDate>
{
    let mod_ticks = timestamp.get_utc_millis_since_epoch().modulo(sample_size.num_milliseconds());
    // Orginal impl
    // let delta = match mod_ticks != 0 {
    //     true => sample_size.num_milliseconds()  - mod_ticks,
    //     false => 0
    // };
    let delta = std::cmp::max(sample_size.num_milliseconds()  - mod_ticks,0);
    let rs =  timestamp.get_utc_millis_since_epoch() + delta;
    timestamp.repr_from_utc_millis(rs)
}

/// Max precision is milliseconds
/// 
/// Rounds a TDate down to the nearest duration, i.e. if you had a chrono::NaiveDateTime{2020-12-31T12:35:00Z} and you rounding to Duration{15mins} it would return 12:30
pub fn round_down_to_nearest_duration<TDate>(timestamp: &TDate, sample_size :&Duration) -> TDate
where TDate : DurationRoudable<TDate>
{
    let mod_ticks = timestamp.get_utc_millis_since_epoch().modulo(sample_size.num_milliseconds());
    let rs =  timestamp.get_utc_millis_since_epoch() - mod_ticks;
    timestamp.repr_from_utc_millis(rs)
}

/// Max precision is milliseconds
/// 
/// Rounds a TDate to the nearest duration, i.e. if you had a chrono::NaiveDateTime{2020-12-31T12:35:00Z} and you rounding to Duration{15mins} it would return 12:30
pub fn round_nearest_to_nearest_duration<TDate>(timestamp: &TDate, sample_size :&Duration) -> TDate
where TDate : DurationRoudable<TDate>
{
    let mod_ticks = timestamp.get_utc_millis_since_epoch().modulo(sample_size.num_milliseconds());
    let offset = match mod_ticks > (sample_size.num_milliseconds()/2) {
        true => sample_size.num_milliseconds(),
        false => 0
    };
    let rs =  timestamp.get_utc_millis_since_epoch() + offset - mod_ticks;
    timestamp.repr_from_utc_millis(rs)
}


/// -----------------------------------------------------------------------------------------------------------------------------------------
/// Unit Test Area
/// -----------------------------------------------------------------------------------------------------------------------------------------
#[cfg(test)]
mod tests {
    use super::*;
    use chrono::NaiveDate;

    #[test]
    fn test_rounding_up() {

        let date1 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 34, 56, 789);
        let dur = Duration::minutes(1);
        let rounded = round_up_to_nearest_duration(&date1, &dur);
        let exp1 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 35, 0, 0);
        assert_eq!(rounded,exp1);

        let dur2 = Duration::minutes(15);
        let rounded2 = round_up_to_nearest_duration(&date1, &dur2);
        let exp2 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 45, 0, 0);
        assert_eq!(rounded2,exp2);

    }

    #[test]
    fn test_rounding_down() {

        let date1 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 34, 56, 789);
        let dur = Duration::minutes(1);
        let rounded = round_down_to_nearest_duration(&date1, &dur);
        let exp1 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 34, 0, 0);
        assert_eq!(rounded,exp1);

        let dur2 = Duration::minutes(15);
        let rounded2 = round_down_to_nearest_duration(&date1, &dur2);
        let exp2 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 30, 0, 0);
        assert_eq!(rounded2,exp2);

    }

    #[test]
    fn test_rounding_nearest() {

        let date1 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 34, 30, 789);
        let dur = Duration::minutes(1);
        let rounded = round_nearest_to_nearest_duration(&date1, &dur);
        let exp1 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 35, 0, 0);
        assert_eq!(rounded,exp1);

        let dur2 = Duration::minutes(15);
        let rounded2 = round_nearest_to_nearest_duration(&date1, &dur2);
        let exp2 = NaiveDate::from_ymd(2010,12,10).and_hms_milli(12, 30, 0, 0);
        assert_eq!(rounded2,exp2);

    }

}