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//! Helpers for implementing formatting for ISO 8601.
use std::io;
use crate::convert::*;
use crate::format_description::well_known::iso8601::{
DateKind, EncodedConfig, OffsetPrecision, TimePrecision,
};
use crate::format_description::well_known::Iso8601;
use crate::formatting::{format_float, format_number_pad_zero, write, write_if, write_if_else};
use crate::{error, Date, Time, UtcOffset};
/// Format the date portion of ISO 8601.
pub(super) fn format_date<const CONFIG: EncodedConfig>(
output: &mut impl io::Write,
date: Date,
) -> Result<usize, error::Format> {
let mut bytes = 0;
match Iso8601::<CONFIG>::DATE_KIND {
DateKind::Calendar => {
let (year, month, day) = date.to_calendar_date();
if Iso8601::<CONFIG>::YEAR_IS_SIX_DIGITS {
bytes += write_if_else(output, year < 0, b"-", b"+")?;
bytes += format_number_pad_zero::<6>(output, year.unsigned_abs())?;
} else if !(0..=9999).contains(&year) {
return Err(error::Format::InvalidComponent("year"));
} else {
bytes += format_number_pad_zero::<4>(output, year as u32)?;
}
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b"-")?;
bytes += format_number_pad_zero::<2>(output, month as u8)?;
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b"-")?;
bytes += format_number_pad_zero::<2>(output, day)?;
}
DateKind::Week => {
let (year, week, day) = date.to_iso_week_date();
if Iso8601::<CONFIG>::YEAR_IS_SIX_DIGITS {
bytes += write_if_else(output, year < 0, b"-", b"+")?;
bytes += format_number_pad_zero::<6>(output, year.unsigned_abs())?;
} else if !(0..=9999).contains(&year) {
return Err(error::Format::InvalidComponent("year"));
} else {
bytes += format_number_pad_zero::<4>(output, year as u32)?;
}
bytes += write_if_else(output, Iso8601::<CONFIG>::USE_SEPARATORS, b"-W", b"W")?;
bytes += format_number_pad_zero::<2>(output, week)?;
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b"-")?;
bytes += format_number_pad_zero::<1>(output, day.number_from_monday())?;
}
DateKind::Ordinal => {
let (year, day) = date.to_ordinal_date();
if Iso8601::<CONFIG>::YEAR_IS_SIX_DIGITS {
bytes += write_if_else(output, year < 0, b"-", b"+")?;
bytes += format_number_pad_zero::<6>(output, year.unsigned_abs())?;
} else if !(0..=9999).contains(&year) {
return Err(error::Format::InvalidComponent("year"));
} else {
bytes += format_number_pad_zero::<4>(output, year as u32)?;
}
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b"-")?;
bytes += format_number_pad_zero::<3>(output, day)?;
}
}
Ok(bytes)
}
/// Format the time portion of ISO 8601.
pub(super) fn format_time<const CONFIG: EncodedConfig>(
output: &mut impl io::Write,
time: Time,
) -> Result<usize, error::Format> {
let mut bytes = 0;
// The "T" can only be omitted in extended format where there is no date being formatted.
bytes += write_if(
output,
Iso8601::<CONFIG>::USE_SEPARATORS || Iso8601::<CONFIG>::FORMAT_DATE,
b"T",
)?;
let (hours, minutes, seconds, nanoseconds) = time.as_hms_nano();
match Iso8601::<CONFIG>::TIME_PRECISION {
TimePrecision::Hour { decimal_digits } => {
let hours = (hours as f64)
+ (minutes as f64) / Minute.per(Hour) as f64
+ (seconds as f64) / Second.per(Hour) as f64
+ (nanoseconds as f64) / Nanosecond.per(Hour) as f64;
format_float(output, hours, 2, decimal_digits)?;
}
TimePrecision::Minute { decimal_digits } => {
bytes += format_number_pad_zero::<2>(output, hours)?;
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b":")?;
let minutes = (minutes as f64)
+ (seconds as f64) / Second.per(Minute) as f64
+ (nanoseconds as f64) / Nanosecond.per(Minute) as f64;
bytes += format_float(output, minutes, 2, decimal_digits)?;
}
TimePrecision::Second { decimal_digits } => {
bytes += format_number_pad_zero::<2>(output, hours)?;
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b":")?;
bytes += format_number_pad_zero::<2>(output, minutes)?;
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b":")?;
let seconds = (seconds as f64) + (nanoseconds as f64) / Nanosecond.per(Second) as f64;
bytes += format_float(output, seconds, 2, decimal_digits)?;
}
}
Ok(bytes)
}
/// Format the UTC offset portion of ISO 8601.
pub(super) fn format_offset<const CONFIG: EncodedConfig>(
output: &mut impl io::Write,
offset: UtcOffset,
) -> Result<usize, error::Format> {
if Iso8601::<CONFIG>::FORMAT_TIME && offset.is_utc() {
return Ok(write(output, b"Z")?);
}
let mut bytes = 0;
let (hours, minutes, seconds) = offset.as_hms();
if seconds != 0 {
return Err(error::Format::InvalidComponent("offset_second"));
}
bytes += write_if_else(output, offset.is_negative(), b"-", b"+")?;
bytes += format_number_pad_zero::<2>(output, hours.unsigned_abs())?;
if Iso8601::<CONFIG>::OFFSET_PRECISION == OffsetPrecision::Hour && minutes != 0 {
return Err(error::Format::InvalidComponent("offset_minute"));
} else if Iso8601::<CONFIG>::OFFSET_PRECISION == OffsetPrecision::Minute {
bytes += write_if(output, Iso8601::<CONFIG>::USE_SEPARATORS, b":")?;
bytes += format_number_pad_zero::<2>(output, minutes.unsigned_abs())?;
}
Ok(bytes)
}