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//! Formatting for various types.
pub(crate) mod formattable;
mod iso8601;
use core::num::NonZeroU8;
use std::io;
pub use self::formattable::Formattable;
use crate::convert::*;
use crate::format_description::{modifier, Component};
use crate::{error, Date, OffsetDateTime, Time, UtcOffset};
#[allow(clippy::missing_docs_in_private_items)]
const MONTH_NAMES: [&[u8]; 12] = [
b"January",
b"February",
b"March",
b"April",
b"May",
b"June",
b"July",
b"August",
b"September",
b"October",
b"November",
b"December",
];
#[allow(clippy::missing_docs_in_private_items)]
const WEEKDAY_NAMES: [&[u8]; 7] = [
b"Monday",
b"Tuesday",
b"Wednesday",
b"Thursday",
b"Friday",
b"Saturday",
b"Sunday",
];
// region: extension trait
/// A trait that indicates the formatted width of the value can be determined.
///
/// Note that this should not be implemented for any signed integers. This forces the caller to
/// write the sign if desired.
pub(crate) trait DigitCount {
/// The number of digits in the stringified value.
fn num_digits(self) -> u8;
}
impl DigitCount for u8 {
fn num_digits(self) -> u8 {
// Using a lookup table as with u32 is *not* faster in standalone benchmarks.
if self < 10 {
1
} else if self < 100 {
2
} else {
3
}
}
}
impl DigitCount for u16 {
fn num_digits(self) -> u8 {
// Using a lookup table as with u32 is *not* faster in standalone benchmarks.
if self < 10 {
1
} else if self < 100 {
2
} else if self < 1_000 {
3
} else if self < 10_000 {
4
} else {
5
}
}
}
impl DigitCount for u32 {
fn num_digits(self) -> u8 {
/// Lookup table
const TABLE: &[u64] = &[
0x0001_0000_0000,
0x0001_0000_0000,
0x0001_0000_0000,
0x0001_FFFF_FFF6,
0x0002_0000_0000,
0x0002_0000_0000,
0x0002_FFFF_FF9C,
0x0003_0000_0000,
0x0003_0000_0000,
0x0003_FFFF_FC18,
0x0004_0000_0000,
0x0004_0000_0000,
0x0004_0000_0000,
0x0004_FFFF_D8F0,
0x0005_0000_0000,
0x0005_0000_0000,
0x0005_FFFE_7960,
0x0006_0000_0000,
0x0006_0000_0000,
0x0006_FFF0_BDC0,
0x0007_0000_0000,
0x0007_0000_0000,
0x0007_0000_0000,
0x0007_FF67_6980,
0x0008_0000_0000,
0x0008_0000_0000,
0x0008_FA0A_1F00,
0x0009_0000_0000,
0x0009_0000_0000,
0x0009_C465_3600,
0x000A_0000_0000,
0x000A_0000_0000,
];
((self as u64 + TABLE[31_u32.saturating_sub(self.leading_zeros()) as usize]) >> 32) as _
}
}
// endregion extension trait
/// Write all bytes to the output, returning the number of bytes written.
pub(crate) fn write(output: &mut impl io::Write, bytes: &[u8]) -> io::Result<usize> {
output.write_all(bytes)?;
Ok(bytes.len())
}
/// If `pred` is true, write all bytes to the output, returning the number of bytes written.
pub(crate) fn write_if(output: &mut impl io::Write, pred: bool, bytes: &[u8]) -> io::Result<usize> {
if pred { write(output, bytes) } else { Ok(0) }
}
/// If `pred` is true, write `true_bytes` to the output. Otherwise, write `false_bytes`.
pub(crate) fn write_if_else(
output: &mut impl io::Write,
pred: bool,
true_bytes: &[u8],
false_bytes: &[u8],
) -> io::Result<usize> {
write(output, if pred { true_bytes } else { false_bytes })
}
/// Write the floating point number to the output, returning the number of bytes written.
///
/// This method accepts the number of digits before and after the decimal. The value will be padded
/// with zeroes to the left if necessary.
pub(crate) fn format_float(
output: &mut impl io::Write,
value: f64,
digits_before_decimal: u8,
digits_after_decimal: Option<NonZeroU8>,
) -> io::Result<usize> {
match digits_after_decimal {
Some(digits_after_decimal) => {
let digits_after_decimal = digits_after_decimal.get() as usize;
let width = digits_before_decimal as usize + 1 + digits_after_decimal;
write!(output, "{value:0>width$.digits_after_decimal$}")?;
Ok(width)
}
None => {
let value = value.trunc() as u64;
let width = digits_before_decimal as usize;
write!(output, "{value:0>width$}")?;
Ok(width)
}
}
}
/// Format a number with the provided padding and width.
///
/// The sign must be written by the caller.
pub(crate) fn format_number<const WIDTH: u8>(
output: &mut impl io::Write,
value: impl itoa::Integer + DigitCount + Copy,
padding: modifier::Padding,
) -> Result<usize, io::Error> {
match padding {
modifier::Padding::Space => format_number_pad_space::<WIDTH>(output, value),
modifier::Padding::Zero => format_number_pad_zero::<WIDTH>(output, value),
modifier::Padding::None => format_number_pad_none(output, value),
}
}
/// Format a number with the provided width and spaces as padding.
///
/// The sign must be written by the caller.
pub(crate) fn format_number_pad_space<const WIDTH: u8>(
output: &mut impl io::Write,
value: impl itoa::Integer + DigitCount + Copy,
) -> Result<usize, io::Error> {
let mut bytes = 0;
for _ in 0..(WIDTH.saturating_sub(value.num_digits())) {
bytes += write(output, b" ")?;
}
bytes += write(output, itoa::Buffer::new().format(value).as_bytes())?;
Ok(bytes)
}
/// Format a number with the provided width and zeros as padding.
///
/// The sign must be written by the caller.
pub(crate) fn format_number_pad_zero<const WIDTH: u8>(
output: &mut impl io::Write,
value: impl itoa::Integer + DigitCount + Copy,
) -> Result<usize, io::Error> {
let mut bytes = 0;
for _ in 0..(WIDTH.saturating_sub(value.num_digits())) {
bytes += write(output, b"0")?;
}
bytes += write(output, itoa::Buffer::new().format(value).as_bytes())?;
Ok(bytes)
}
/// Format a number with no padding.
///
/// If the sign is mandatory, the sign must be written by the caller.
pub(crate) fn format_number_pad_none(
output: &mut impl io::Write,
value: impl itoa::Integer + Copy,
) -> Result<usize, io::Error> {
write(output, itoa::Buffer::new().format(value).as_bytes())
}
/// Format the provided component into the designated output. An `Err` will be returned if the
/// component requires information that it does not provide or if the value cannot be output to the
/// stream.
pub(crate) fn format_component(
output: &mut impl io::Write,
component: Component,
date: Option<Date>,
time: Option<Time>,
offset: Option<UtcOffset>,
) -> Result<usize, error::Format> {
use Component::*;
Ok(match (component, date, time, offset) {
(Day(modifier), Some(date), ..) => fmt_day(output, date, modifier)?,
(Month(modifier), Some(date), ..) => fmt_month(output, date, modifier)?,
(Ordinal(modifier), Some(date), ..) => fmt_ordinal(output, date, modifier)?,
(Weekday(modifier), Some(date), ..) => fmt_weekday(output, date, modifier)?,
(WeekNumber(modifier), Some(date), ..) => fmt_week_number(output, date, modifier)?,
(Year(modifier), Some(date), ..) => fmt_year(output, date, modifier)?,
(Hour(modifier), _, Some(time), _) => fmt_hour(output, time, modifier)?,
(Minute(modifier), _, Some(time), _) => fmt_minute(output, time, modifier)?,
(Period(modifier), _, Some(time), _) => fmt_period(output, time, modifier)?,
(Second(modifier), _, Some(time), _) => fmt_second(output, time, modifier)?,
(Subsecond(modifier), _, Some(time), _) => fmt_subsecond(output, time, modifier)?,
(OffsetHour(modifier), .., Some(offset)) => fmt_offset_hour(output, offset, modifier)?,
(OffsetMinute(modifier), .., Some(offset)) => fmt_offset_minute(output, offset, modifier)?,
(OffsetSecond(modifier), .., Some(offset)) => fmt_offset_second(output, offset, modifier)?,
(Ignore(_), ..) => 0,
(UnixTimestamp(modifier), Some(date), Some(time), Some(offset)) => {
fmt_unix_timestamp(output, date, time, offset, modifier)?
}
_ => return Err(error::Format::InsufficientTypeInformation),
})
}
// region: date formatters
/// Format the day into the designated output.
fn fmt_day(
output: &mut impl io::Write,
date: Date,
modifier::Day { padding }: modifier::Day,
) -> Result<usize, io::Error> {
format_number::<2>(output, date.day(), padding)
}
/// Format the month into the designated output.
fn fmt_month(
output: &mut impl io::Write,
date: Date,
modifier::Month {
padding,
repr,
case_sensitive: _, // no effect on formatting
}: modifier::Month,
) -> Result<usize, io::Error> {
match repr {
modifier::MonthRepr::Numerical => format_number::<2>(output, date.month() as u8, padding),
modifier::MonthRepr::Long => write(output, MONTH_NAMES[date.month() as usize - 1]),
modifier::MonthRepr::Short => write(output, &MONTH_NAMES[date.month() as usize - 1][..3]),
}
}
/// Format the ordinal into the designated output.
fn fmt_ordinal(
output: &mut impl io::Write,
date: Date,
modifier::Ordinal { padding }: modifier::Ordinal,
) -> Result<usize, io::Error> {
format_number::<3>(output, date.ordinal(), padding)
}
/// Format the weekday into the designated output.
fn fmt_weekday(
output: &mut impl io::Write,
date: Date,
modifier::Weekday {
repr,
one_indexed,
case_sensitive: _, // no effect on formatting
}: modifier::Weekday,
) -> Result<usize, io::Error> {
match repr {
modifier::WeekdayRepr::Short => write(
output,
&WEEKDAY_NAMES[date.weekday().number_days_from_monday() as usize][..3],
),
modifier::WeekdayRepr::Long => write(
output,
WEEKDAY_NAMES[date.weekday().number_days_from_monday() as usize],
),
modifier::WeekdayRepr::Sunday => format_number::<1>(
output,
date.weekday().number_days_from_sunday() + one_indexed as u8,
modifier::Padding::None,
),
modifier::WeekdayRepr::Monday => format_number::<1>(
output,
date.weekday().number_days_from_monday() + one_indexed as u8,
modifier::Padding::None,
),
}
}
/// Format the week number into the designated output.
fn fmt_week_number(
output: &mut impl io::Write,
date: Date,
modifier::WeekNumber { padding, repr }: modifier::WeekNumber,
) -> Result<usize, io::Error> {
format_number::<2>(
output,
match repr {
modifier::WeekNumberRepr::Iso => date.iso_week(),
modifier::WeekNumberRepr::Sunday => date.sunday_based_week(),
modifier::WeekNumberRepr::Monday => date.monday_based_week(),
},
padding,
)
}
/// Format the year into the designated output.
fn fmt_year(
output: &mut impl io::Write,
date: Date,
modifier::Year {
padding,
repr,
iso_week_based,
sign_is_mandatory,
}: modifier::Year,
) -> Result<usize, io::Error> {
let full_year = if iso_week_based {
date.iso_year_week().0
} else {
date.year()
};
let value = match repr {
modifier::YearRepr::Full => full_year,
modifier::YearRepr::LastTwo => (full_year % 100).abs(),
};
let format_number = match repr {
#[cfg(feature = "large-dates")]
modifier::YearRepr::Full if value.abs() >= 100_000 => format_number::<6>,
#[cfg(feature = "large-dates")]
modifier::YearRepr::Full if value.abs() >= 10_000 => format_number::<5>,
modifier::YearRepr::Full => format_number::<4>,
modifier::YearRepr::LastTwo => format_number::<2>,
};
let mut bytes = 0;
if repr != modifier::YearRepr::LastTwo {
if full_year < 0 {
bytes += write(output, b"-")?;
} else if sign_is_mandatory || cfg!(feature = "large-dates") && full_year >= 10_000 {
bytes += write(output, b"+")?;
}
}
bytes += format_number(output, value.unsigned_abs(), padding)?;
Ok(bytes)
}
// endregion date formatters
// region: time formatters
/// Format the hour into the designated output.
fn fmt_hour(
output: &mut impl io::Write,
time: Time,
modifier::Hour {
padding,
is_12_hour_clock,
}: modifier::Hour,
) -> Result<usize, io::Error> {
let value = match (time.hour(), is_12_hour_clock) {
(hour, false) => hour,
(0 | 12, true) => 12,
(hour, true) if hour < 12 => hour,
(hour, true) => hour - 12,
};
format_number::<2>(output, value, padding)
}
/// Format the minute into the designated output.
fn fmt_minute(
output: &mut impl io::Write,
time: Time,
modifier::Minute { padding }: modifier::Minute,
) -> Result<usize, io::Error> {
format_number::<2>(output, time.minute(), padding)
}
/// Format the period into the designated output.
fn fmt_period(
output: &mut impl io::Write,
time: Time,
modifier::Period {
is_uppercase,
case_sensitive: _, // no effect on formatting
}: modifier::Period,
) -> Result<usize, io::Error> {
match (time.hour() >= 12, is_uppercase) {
(false, false) => write(output, b"am"),
(false, true) => write(output, b"AM"),
(true, false) => write(output, b"pm"),
(true, true) => write(output, b"PM"),
}
}
/// Format the second into the designated output.
fn fmt_second(
output: &mut impl io::Write,
time: Time,
modifier::Second { padding }: modifier::Second,
) -> Result<usize, io::Error> {
format_number::<2>(output, time.second(), padding)
}
/// Format the subsecond into the designated output.
fn fmt_subsecond<W: io::Write>(
output: &mut W,
time: Time,
modifier::Subsecond { digits }: modifier::Subsecond,
) -> Result<usize, io::Error> {
use modifier::SubsecondDigits::*;
let nanos = time.nanosecond();
if digits == Nine || (digits == OneOrMore && nanos % 10 != 0) {
format_number_pad_zero::<9>(output, nanos)
} else if digits == Eight || (digits == OneOrMore && (nanos / 10) % 10 != 0) {
format_number_pad_zero::<8>(output, nanos / 10)
} else if digits == Seven || (digits == OneOrMore && (nanos / 100) % 10 != 0) {
format_number_pad_zero::<7>(output, nanos / 100)
} else if digits == Six || (digits == OneOrMore && (nanos / 1_000) % 10 != 0) {
format_number_pad_zero::<6>(output, nanos / 1_000)
} else if digits == Five || (digits == OneOrMore && (nanos / 10_000) % 10 != 0) {
format_number_pad_zero::<5>(output, nanos / 10_000)
} else if digits == Four || (digits == OneOrMore && (nanos / 100_000) % 10 != 0) {
format_number_pad_zero::<4>(output, nanos / 100_000)
} else if digits == Three || (digits == OneOrMore && (nanos / 1_000_000) % 10 != 0) {
format_number_pad_zero::<3>(output, nanos / 1_000_000)
} else if digits == Two || (digits == OneOrMore && (nanos / 10_000_000) % 10 != 0) {
format_number_pad_zero::<2>(output, nanos / 10_000_000)
} else {
format_number_pad_zero::<1>(output, nanos / 100_000_000)
}
}
// endregion time formatters
// region: offset formatters
/// Format the offset hour into the designated output.
fn fmt_offset_hour(
output: &mut impl io::Write,
offset: UtcOffset,
modifier::OffsetHour {
padding,
sign_is_mandatory,
}: modifier::OffsetHour,
) -> Result<usize, io::Error> {
let mut bytes = 0;
if offset.is_negative() {
bytes += write(output, b"-")?;
} else if sign_is_mandatory {
bytes += write(output, b"+")?;
}
bytes += format_number::<2>(output, offset.whole_hours().unsigned_abs(), padding)?;
Ok(bytes)
}
/// Format the offset minute into the designated output.
fn fmt_offset_minute(
output: &mut impl io::Write,
offset: UtcOffset,
modifier::OffsetMinute { padding }: modifier::OffsetMinute,
) -> Result<usize, io::Error> {
format_number::<2>(output, offset.minutes_past_hour().unsigned_abs(), padding)
}
/// Format the offset second into the designated output.
fn fmt_offset_second(
output: &mut impl io::Write,
offset: UtcOffset,
modifier::OffsetSecond { padding }: modifier::OffsetSecond,
) -> Result<usize, io::Error> {
format_number::<2>(output, offset.seconds_past_minute().unsigned_abs(), padding)
}
// endregion offset formatters
/// Format the Unix timestamp into the designated output.
fn fmt_unix_timestamp(
output: &mut impl io::Write,
date: Date,
time: Time,
offset: UtcOffset,
modifier::UnixTimestamp {
precision,
sign_is_mandatory,
}: modifier::UnixTimestamp,
) -> Result<usize, io::Error> {
let date_time = date
.with_time(time)
.assume_offset(offset)
.to_offset(UtcOffset::UTC);
if date_time < OffsetDateTime::UNIX_EPOCH {
write(output, b"-")?;
} else if sign_is_mandatory {
write(output, b"+")?;
}
match precision {
modifier::UnixTimestampPrecision::Second => {
format_number_pad_none(output, date_time.unix_timestamp().unsigned_abs())
}
modifier::UnixTimestampPrecision::Millisecond => format_number_pad_none(
output,
(date_time.unix_timestamp_nanos() / Nanosecond.per(Millisecond) as i128).unsigned_abs(),
),
modifier::UnixTimestampPrecision::Microsecond => format_number_pad_none(
output,
(date_time.unix_timestamp_nanos() / Nanosecond.per(Microsecond) as i128).unsigned_abs(),
),
modifier::UnixTimestampPrecision::Nanosecond => {
format_number_pad_none(output, date_time.unix_timestamp_nanos().unsigned_abs())
}
}
}