arrow2 0.1.0

Unofficial implementation of Apache Arrow spec in safe Rust
Documentation 
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

//! Conversion methods for dates and times.

use crate::datatypes::TimeUnit;
use chrono::{NaiveDate, NaiveDateTime, NaiveTime};

/// Number of seconds in a day
pub const SECONDS_IN_DAY: i64 = 86_400;
/// Number of milliseconds in a second
pub const MILLISECONDS: i64 = 1_000;
/// Number of microseconds in a second
pub const MICROSECONDS: i64 = 1_000_000;
/// Number of nanoseconds in a second
pub const NANOSECONDS: i64 = 1_000_000_000;
/// Number of milliseconds in a day
pub const MILLISECONDS_IN_DAY: i64 = SECONDS_IN_DAY * MILLISECONDS;
/// Number of days between 0001-01-01 and 1970-01-01
pub const EPOCH_DAYS_FROM_CE: i32 = 719_163;

/// converts a `i32` representing a `date32` to [`NaiveDateTime`]
#[inline]
pub fn date32_to_datetime(v: i32) -> NaiveDateTime {
    NaiveDateTime::from_timestamp(v as i64 * SECONDS_IN_DAY, 0)
}

/// converts a `i32` representing a `date32` to [`NaiveDate`]
#[inline]
pub fn date32_to_date(days: i32) -> NaiveDate {
    NaiveDate::from_num_days_from_ce(EPOCH_DAYS_FROM_CE + days)
}

/// converts a `i64` representing a `date64` to [`NaiveDateTime`]
#[inline]
pub fn date64_to_datetime(v: i64) -> NaiveDateTime {
    NaiveDateTime::from_timestamp(
        // extract seconds from milliseconds
        v / MILLISECONDS,
        // discard extracted seconds and convert milliseconds to nanoseconds
        (v % MILLISECONDS * MICROSECONDS) as u32,
    )
}

/// converts a `i64` representing a `date64` to [`NaiveDate`]
#[inline]
pub fn date64_to_date(milliseconds: i64) -> NaiveDate {
    date64_to_datetime(milliseconds).date()
}

/// converts a `i32` representing a `time32(s)` to [`NaiveDateTime`]
#[inline]
pub fn time32s_to_time(v: i32) -> NaiveTime {
    NaiveTime::from_num_seconds_from_midnight(v as u32, 0)
}

/// converts a `i32` representing a `time32(ms)` to [`NaiveDateTime`]
#[inline]
pub fn time32ms_to_time(v: i32) -> NaiveTime {
    let v = v as i64;
    NaiveTime::from_num_seconds_from_midnight(
        // extract seconds from milliseconds
        (v / MILLISECONDS) as u32,
        // discard extracted seconds and convert milliseconds to
        // nanoseconds
        (v % MILLISECONDS * MICROSECONDS) as u32,
    )
}

/// converts a `i64` representing a `time64(us)` to [`NaiveDateTime`]
#[inline]
pub fn time64us_to_time(v: i64) -> NaiveTime {
    NaiveTime::from_num_seconds_from_midnight(
        // extract seconds from microseconds
        (v / MICROSECONDS) as u32,
        // discard extracted seconds and convert microseconds to
        // nanoseconds
        (v % MICROSECONDS * MILLISECONDS) as u32,
    )
}

/// converts a `i64` representing a `time64(ns)` to [`NaiveDateTime`]
#[inline]
pub fn time64ns_to_time(v: i64) -> NaiveTime {
    NaiveTime::from_num_seconds_from_midnight(
        // extract seconds from nanoseconds
        (v / NANOSECONDS) as u32,
        // discard extracted seconds
        (v % NANOSECONDS) as u32,
    )
}

/// converts a `i64` representing a `timestamp(s)` to [`NaiveDateTime`]
#[inline]
pub fn timestamp_s_to_datetime(v: i64) -> NaiveDateTime {
    NaiveDateTime::from_timestamp(v, 0)
}

/// converts a `i64` representing a `timestamp(ms)` to [`NaiveDateTime`]
#[inline]
pub fn timestamp_ms_to_datetime(v: i64) -> NaiveDateTime {
    NaiveDateTime::from_timestamp(
        // extract seconds from milliseconds
        v / MILLISECONDS,
        // discard extracted seconds and convert milliseconds to nanoseconds
        (v % MILLISECONDS * MICROSECONDS) as u32,
    )
}

/// converts a `i64` representing a `timestamp(us)` to [`NaiveDateTime`]
#[inline]
pub fn timestamp_us_to_datetime(v: i64) -> NaiveDateTime {
    NaiveDateTime::from_timestamp(
        // extract seconds from microseconds
        v / MICROSECONDS,
        // discard extracted seconds and convert microseconds to nanoseconds
        (v % MICROSECONDS * MILLISECONDS) as u32,
    )
}

/// converts a `i64` representing a `timestamp(ns)` to [`NaiveDateTime`]
#[inline]
pub fn timestamp_ns_to_datetime(v: i64) -> NaiveDateTime {
    NaiveDateTime::from_timestamp(
        // extract seconds from nanoseconds
        v / NANOSECONDS,
        // discard extracted seconds
        (v % NANOSECONDS) as u32,
    )
}

/// Calculates the scale factor between two TimeUnits. The function returns the
/// scale that should multiply the TimeUnit "b" to have the same time scale as
/// the TimeUnit "a".
pub fn timeunit_scale(a: &TimeUnit, b: &TimeUnit) -> f64 {
    match (a, b) {
        (TimeUnit::Second, TimeUnit::Second) => 1.0,
        (TimeUnit::Second, TimeUnit::Millisecond) => 0.001,
        (TimeUnit::Second, TimeUnit::Microsecond) => 0.000_001,
        (TimeUnit::Second, TimeUnit::Nanosecond) => 0.000_000_001,
        (TimeUnit::Millisecond, TimeUnit::Second) => 1_000.0,
        (TimeUnit::Millisecond, TimeUnit::Millisecond) => 1.0,
        (TimeUnit::Millisecond, TimeUnit::Microsecond) => 0.001,
        (TimeUnit::Millisecond, TimeUnit::Nanosecond) => 0.000_001,
        (TimeUnit::Microsecond, TimeUnit::Second) => 1_000_000.0,
        (TimeUnit::Microsecond, TimeUnit::Millisecond) => 1_000.0,
        (TimeUnit::Microsecond, TimeUnit::Microsecond) => 1.0,
        (TimeUnit::Microsecond, TimeUnit::Nanosecond) => 0.001,
        (TimeUnit::Nanosecond, TimeUnit::Second) => 1_000_000_000.0,
        (TimeUnit::Nanosecond, TimeUnit::Millisecond) => 1_000_000.0,
        (TimeUnit::Nanosecond, TimeUnit::Microsecond) => 1_000.0,
        (TimeUnit::Nanosecond, TimeUnit::Nanosecond) => 1.0,
    }
}