use derive_more::Display;
use thiserror::Error;
use self::Month::*;
use core::str::FromStr;
/// Months of the year
#[derive(Copy, Clone, Eq, PartialEq, Hash, Debug, Display, PartialOrd, Ord)]
#[repr(u8)]
pub enum Month {
January = 1,
February = 2,
March = 3,
April = 4,
May = 5,
June = 6,
July = 7,
August = 8,
September = 9,
October = 10,
November = 11,
December = 12,
}
impl Month {
/// Get the month based on the number.
/// Returns `None` if the input is 0 or greater than 12.
///
/// # Example
///
/// ```
/// use botic::Month;
///
/// assert_eq!(Some(Month::January), Month::from_u8(1));
/// assert_eq!(None, Month::from_u8(0));
/// assert_eq!(None, Month::from_u8(13));
#[must_use]
pub const fn from_u8(num: u8) -> Option<Self> {
match num {
1 => Some(January),
2 => Some(February),
3 => Some(March),
4 => Some(April),
5 => Some(May),
6 => Some(June),
7 => Some(July),
8 => Some(August),
9 => Some(September),
10 => Some(October),
11 => Some(November),
12 => Some(December),
_ => None,
}
}
/// Get the month from the given string,
/// which is assumed to be the month's abbreviation.
/// Returns `None` if the string is not a valid abbrevation of a month
///
/// # Example
///
/// ```
/// use botic::Month;
///
/// assert_eq!(Some(Month::January), Month::from_abbreviation("Jan"));
/// assert_eq!(None, Month::from_abbreviation("Janu"));
/// ```
#[must_use]
pub fn from_abbreviation(abbreviation: &str) -> Option<Self> {
match abbreviation {
"Jan" => Some(January),
"Feb" => Some(February),
"Mar" => Some(March),
"Apr" => Some(April),
"May" => Some(May),
"Jun" => Some(June),
"Jul" => Some(July),
"Aug" => Some(August),
"Sep" => Some(September),
"Oct" => Some(October),
"Nov" => Some(November),
"Dec" => Some(December),
_ => None,
}
}
/// Get the month from the given string,
/// which is assumed to be the month's name.
/// Returns `None` if the string is not a valid month
///
/// # Example
///
/// ```
/// use botic::Month;
///
/// assert_eq!(Some(Month::January), Month::from_name("January"));
/// assert_eq!(None, Month::from_name("Janu"));
/// ```
#[must_use]
pub fn from_name(name: &str) -> Option<Self> {
match name {
"January" => Some(January),
"February" => Some(February),
"March" => Some(March),
"April" => Some(April),
"May" => Some(May),
"June" => Some(June),
"July" => Some(July),
"August" => Some(August),
"September" => Some(September),
"October" => Some(October),
"November" => Some(November),
"December" => Some(December),
_ => None,
}
}
/// Get the number of the month
///
/// # Example
///
/// ```
/// use botic::Month;
///
/// assert_eq!(1, Month::January.number());
/// ```
#[must_use]
pub const fn number(self) -> u8 {
self as u8
}
/// Get the name of the month
///
/// # Example
///
/// ```
/// use botic::Month;
///
/// assert_eq!("January", Month::January.name());
/// ```
#[must_use]
pub const fn name(self) -> &'static str {
match self {
January => "January",
February => "February",
March => "March",
April => "April",
May => "May",
June => "June",
July => "July",
August => "August",
September => "September",
October => "October",
November => "November",
December => "December",
}
}
/// Get the abbreviated name of the month. This is always three letters
///
/// # Example
///
/// ```
/// use botic::Month;
///
/// assert_eq!("Jan", Month::January.abbreviation());
/// ```
#[must_use]
pub const fn abbreviation(self) -> &'static str {
match self {
January => "Jan",
February => "Feb",
March => "Mar",
April => "Apr",
May => "May",
June => "Jun",
July => "Jul",
August => "Aug",
September => "Sep",
October => "Oct",
November => "Nov",
December => "Dec",
}
}
// TODO docs
// TODO handle ordinals greater than 365
#[must_use]
pub const fn from_ordinal_common(ordinal: u16) -> Self {
if ordinal < 31 {
January
} else if ordinal < 59 {
February
} else if ordinal < 90 {
March
} else if ordinal < 120 {
April
} else if ordinal < 151 {
May
} else if ordinal < 181 {
June
} else if ordinal < 212 {
July
} else if ordinal < 243 {
August
} else if ordinal < 273 {
September
} else if ordinal < 304 {
October
} else if ordinal < 334 {
November
} else {
December
}
}
#[must_use]
pub const fn from_ordinal_leap(ordinal: u16) -> Self {
if ordinal < 31 {
January
} else if ordinal < 60 {
February
} else if ordinal < 91 {
March
} else if ordinal < 121 {
April
} else if ordinal < 152 {
May
} else if ordinal < 182 {
June
} else if ordinal < 213 {
July
} else if ordinal < 244 {
August
} else if ordinal < 274 {
September
} else if ordinal < 305 {
October
} else if ordinal < 335 {
November
} else {
December
}
}
#[must_use]
pub const fn from_ordinal(ordinal: u16, leap_year: bool) -> Self {
if leap_year {
Self::from_ordinal_leap(ordinal)
} else {
Self::from_ordinal_common(ordinal)
}
}
/// Get the next month.
///
/// ```rust
/// use botic::Month;
///
/// assert_eq!(Month::January.next(), Month::February);
/// ```
#[must_use]
pub const fn next(self) -> Self {
match self {
January => February,
February => March,
March => April,
April => May,
May => June,
June => July,
July => August,
August => September,
September => October,
October => November,
November => December,
December => January,
}
}
/// Get the previous month.
///
/// ```rust
/// use botic::Month;
///
/// assert_eq!(Month::January.previous(), Month::December);
/// ```
#[must_use]
pub const fn previous(self) -> Self {
match self {
January => December,
February => January,
March => February,
April => March,
May => April,
June => May,
July => June,
August => July,
September => August,
October => September,
November => October,
December => November,
}
}
// TODO examples
/// Returns the number of days up to the end of the month in a year.
/// This doesn't account for leap day
#[must_use]
pub const fn last_day_ordinal_common(self) -> u16 {
match self {
January => 31,
February => 59,
March => 90,
April => 120,
May => 151,
June => 181,
July => 212,
August => 243,
September => 273,
October => 304,
November => 334,
December => 365,
}
}
pub const fn days_common_year(self) -> u8 {
match self {
January => 31,
February => 28,
March => 31,
April => 30,
May => 31,
June => 30,
July => 31,
August => 31,
September => 30,
October => 31,
November => 30,
December => 31,
}
}
pub const fn days_leap_year(self) -> u8 {
match self {
January => 31,
February => 29,
March => 31,
April => 30,
May => 31,
June => 30,
July => 31,
August => 31,
September => 30,
October => 31,
November => 30,
December => 31,
}
}
pub const fn days(self, leap_year: bool) -> u8 {
if leap_year {
self.days_leap_year()
} else {
self.days_common_year()
}
}
/// Returns the number of days up to the end of the month in a leap year.
#[must_use]
pub const fn last_day_ordinal_leap(self) -> u16 {
match self {
January => 31,
February => 60,
March => 91,
April => 121,
May => 152,
June => 182,
July => 213,
August => 244,
September => 274,
October => 305,
November => 335,
December => 366,
}
}
/// Returns the number of days up to the end of the month.
/// Whether or not it's a leap year must be indicated
#[must_use]
pub const fn last_day_ordinal(self, leap_year: bool) -> u16 {
if leap_year {
self.last_day_ordinal_leap()
} else {
self.last_day_ordinal_common()
}
}
pub const fn add_overflowing(self, months: i8) -> (Self, u8) {
let zero_indexed_num = ((self as u16) - 1) + months as u16;
let wraps = (zero_indexed_num as u8) / 12;
let zero_indexed_month = zero_indexed_num % 12;
let month = match Self::from_u8((zero_indexed_month as u8) + 1) {
Some(month) => month,
None => unsafe { std::hint::unreachable_unchecked() },
};
(month, wraps)
}
}
impl From<Month> for u8 {
fn from(month: Month) -> Self {
month as u8
}
}
#[derive(Copy, Clone, Eq, PartialEq, Hash, Debug, Error)]
#[error("Failed to parse the month")]
// TODO Consider trying to figure out what month the user meant to use
pub struct ParseMonthError;
// TODO optimize to look like this: https://github.com/chronotope/chrono/blob/main/src/format/scan.rs#L102
// TODO make case-insensitive
impl FromStr for Month {
type Err = ParseMonthError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if let Ok(num) = u8::from_str(s) {
if let Some(month) = Month::from_u8(num) {
Ok(month)
} else {
Err(ParseMonthError)
}
} else if let Some(month) = Month::from_abbreviation(s) {
Ok(month)
} else if let Some(month) = Month::from_name(s) {
Ok(month)
} else {
Err(ParseMonthError)
}
}
}
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