Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

adds changes for Ord implementation of Timestamp #410

Merged
merged 5 commits into from
Sep 1, 2022
Merged

adds changes for Ord implementation of Timestamp #410

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
d744dea
adds changes for Ord implementation of Timestamp
desaikd Aug 30, 2022
29cff65
adds non strict comparison for `Ord` implementation of `Timestamp`
desaikd Aug 31, 2022
27959d5
adds changes to simplify Ord logic for Timestamp
desaikd Sep 1, 2022
9600908
renamed is_empty_ignore_exponent() to is_zero()
desaikd Sep 1, 2022
5bff7cc
removes unused enum and modifies doc comment
desaikd Sep 1, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
86 changes: 63 additions & 23 deletions src/types/timestamp.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -88,12 +88,22 @@ trait EmptyMantissa {
/// sub-second precision at all. For example, `Mantissa::Digits(0)` or
/// `Mantissa::Arbitrary(Decimal::new(0, 0))`.
fn is_empty(&self) -> bool;

/// Returns true if the Mantissa's value is equivalent to a zero value
/// For example, `Mantissa::Digits(0)` or `Mantissa::Arbitrary(Decimal::new(0, x))`.
/// For Decimal, it ignores the exponent value for a zero coefficient.
fn is_zero(&self) -> bool;
}

impl EmptyMantissa for Decimal {
fn is_empty(&self) -> bool {
self.coefficient.is_zero() && self.exponent == 0
}

fn is_zero(&self) -> bool {
// if the coefficient is zero then ignore the exponent value
self.coefficient.is_zero()
}
}

impl EmptyMantissa for Mantissa {
Expand All @@ -106,6 +116,16 @@ impl EmptyMantissa for Mantissa {
_ => false,
}
}

fn is_zero(&self) -> bool {
match self {
// Look at zero digits of the DateTime's nanoseconds
Mantissa::Digits(0) => true,
// Or a Decimal with a coefficient of zero (any sign).
Mantissa::Arbitrary(d) => d.is_zero(),
_ => false,
}
}
}

/// Returns the first `num_digits` digits of the specified `value`.
Expand Down Expand Up @@ -254,14 +274,14 @@ impl Timestamp {
) {
(None, None) => Ordering::Equal,
(Some(m), None) => {
if m.is_empty() {
if m.is_zero() {
Ordering::Equal
} else {
Ordering::Greater
}
}
(None, Some(m)) => {
if m.is_empty() {
if m.is_zero() {
Ordering::Equal
} else {
Ordering::Less
Expand All @@ -288,14 +308,22 @@ impl Timestamp {
/// only be called if both Timestamps have a precision of [Precision::Second].
fn fractional_seconds_equal(&self, other: &Timestamp) -> bool {
use Mantissa::*;
match (
self.fractional_seconds.as_ref(),
other.fractional_seconds.as_ref(),
) {
(None, None) => true,
(Some(m), None) => m.is_empty(),
(None, Some(m)) => m.is_empty(),
(Some(Digits(d1)), Some(Digits(d2))) => {

// TODO: make Timestamp::fractional_seconds to be Mantissa when creating a Timestamp to get rid of below conversion
// convert Option<&Mantissa> to &Mantissa
let m1 = match &self.fractional_seconds {
None => &Mantissa::Digits(0),
Some(m) => m,
};

let m2 = match &other.fractional_seconds {
None => &Mantissa::Digits(0),
Some(m) => m,
};

// compare fractional seconds
match (m1, m2) {
(Digits(d1), Digits(d2)) => {
if d1 != d2 {
// Different precisions
return false;
Expand All @@ -304,17 +332,24 @@ impl Timestamp {
let d2 = first_n_digits_of(*d2, other.date_time.nanosecond());
d1 == d2
}
(Some(Arbitrary(d1)), Some(Arbitrary(d2))) => Mantissa::decimals_equal(d1, d2),
(Some(Digits(_d1)), Some(Arbitrary(d2))) => {
let d1 = &self.fractional_seconds_as_decimal().unwrap();
Mantissa::decimals_equal(d1, d2)
(Arbitrary(d1), Arbitrary(d2)) => Mantissa::decimals_equal(d1, d2),
(Digits(_d1), Arbitrary(d2)) => {
let d1 = match self.fractional_seconds_as_decimal() {
Some(decimal_value) => decimal_value,
None => Decimal::new(0, 0),
};
Mantissa::decimals_equal(&d1, d2)
}
(Some(Arbitrary(d1)), Some(Digits(_d2))) => {
let d2 = &other.fractional_seconds_as_decimal().unwrap();
Mantissa::decimals_equal(d1, d2)
(Arbitrary(d1), Digits(_d2)) => {
let d2 = match other.fractional_seconds_as_decimal() {
Some(decimal_value) => decimal_value,
None => Decimal::new(0, 0),
};
Mantissa::decimals_equal(d1, &d2)
}
}
}

/// Writes the fractional seconds portion of a text timestamp, including a leading `.`.
pub(crate) fn format_fractional_seconds<W: std::fmt::Write>(
&self,
Expand Down Expand Up @@ -524,11 +559,6 @@ impl PartialOrd for Timestamp {

impl Ord for Timestamp {
fn cmp(&self, other: &Self) -> Ordering {
let fractional_seconds_comparison = self.fractional_seconds_compare(other);
if fractional_seconds_comparison != Ordering::Equal {
return fractional_seconds_comparison;
}

let self_datetime = self.date_time.with_nanosecond(0).unwrap();
let other_datetime = other.date_time.with_nanosecond(0).unwrap();

Expand All @@ -541,7 +571,16 @@ impl Ord for Timestamp {
.map(|offset| offset.from_utc_datetime(&other_datetime))
.unwrap_or_else(|| FixedOffset::east(0).from_utc_datetime(&other_datetime));

self_datetime.cmp(&other_datetime)
let date_time_comparison = self_datetime.cmp(&other_datetime);

match date_time_comparison {
// if the datetime comparison is Ordering::Equal,
// then return fractional seconds comparison result
Ordering::Equal => self.fractional_seconds_compare(other),
// if datetime comparison is not equal,
// then no need to check for fractional seconds comparison
_ => date_time_comparison,
}
}
}

Expand Down Expand Up @@ -1637,6 +1676,7 @@ mod timestamp_tests {
#[case::timestamp_with_same_offset(Timestamp::with_ymd_hms(2021, 4, 6, 10, 15, 0).build_at_offset(-5 * 60).unwrap(), Timestamp::with_ymd_hms(2021, 4, 6, 10, 15, 0).build_at_offset(-5 * 60).unwrap(), Ordering::Equal)]
#[case::timestamp_with_different_offset(Timestamp::with_ymd_hms(2021, 4, 6, 10, 15, 0).build_at_offset(5 * 60).unwrap(), Timestamp::with_ymd_hms(2021, 4, 6, 10, 15, 0).build_at_offset(-5 * 60).unwrap(), Ordering::Less)]
#[case::timestamp_with_unknown_offset(Timestamp::with_ymd_hms(2021, 4, 6, 10, 15, 0).build_at_unknown_offset().unwrap(), Timestamp::with_ymd_hms(2021, 4, 6, 10, 15, 0).build_at_offset(-5 * 60).unwrap(), Ordering::Less)]
#[case::timestamp_with_second_precison_and_year_precision(Timestamp::with_ymd(2001, 1, 1).build().unwrap(), Timestamp::with_ymd_hms(2001, 1, 1, 0, 0, 0).with_fractional_seconds(Decimal::new(00000000000000000000u128, -20)).build_at_unknown_offset().unwrap(), Ordering::Equal)]
fn timestamp_ordering_tests(
#[case] this: Timestamp,
#[case] other: Timestamp,
Expand Down