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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221
// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
use core::cmp::{Ord, PartialOrd};
use core::fmt;
use displaydoc::Display;
use zerovec::ule::{AsULE, UleError, ULE};
/// An error relating to the length of a field within a date pattern.
#[derive(Display, Debug, PartialEq, Copy, Clone)]
#[non_exhaustive]
pub enum LengthError {
/// The length of the field string within the pattern is invalid, according to
/// the field type and its supported field patterns in LDML. See [`FieldLength`].
#[displaydoc("Invalid length")]
InvalidLength,
}
#[cfg(feature = "std")]
impl std::error::Error for LengthError {}
/// An enum representing the length of a field within a date or time formatting pattern string.
///
/// Such strings represent fields as a letter occurring 1 or more times in a row, ex:
/// `MMM`, `dd`, `y`. See the
/// [LDML documentation in UTS 35](https://unicode.org/reports/tr35/tr35-dates.html#Date_Format_Patterns)
/// for more details.
#[derive(Debug, Eq, PartialEq, Clone, Copy, Ord, PartialOrd)]
#[cfg_attr(feature = "datagen", derive(serde::Serialize, databake::Bake))]
#[cfg_attr(feature = "datagen", databake(path = icu_datetime::fields))]
#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
#[allow(clippy::exhaustive_enums)] // part of data struct
pub enum FieldLength {
/// Numeric: minimum digits
///
/// Text: same as [`Self::Three`]
One,
/// Numeric: pad to 2 digits
///
/// Text: same as [`Self::Three`]
Two,
/// Numeric: pad to 3 digits
///
/// Text: Abbreviated format.
Three,
/// Numeric: pad to 4 digits
///
/// Text: Wide format.
Four,
/// Numeric: pad to 5 digits
///
/// Text: Narrow format.
Five,
/// Numeric: pad to 6 digits
///
/// Text: Short format.
Six,
/// FieldLength::One (numeric), but overridden with a different numbering system
NumericOverride(FieldNumericOverrides),
}
/// First index used for numeric overrides in compact FieldLength representation
///
/// Currently 17 due to decision in <https://unicode-org.atlassian.net/browse/CLDR-17217>,
/// may become 16 if the `> 16` is updated to a ` >= 16`
const FIRST_NUMERIC_OVERRIDE: u8 = 17;
/// Last index used for numeric overrides
const LAST_NUMERIC_OVERRIDE: u8 = 31;
impl FieldLength {
#[inline]
pub(crate) fn idx(&self) -> u8 {
match self {
FieldLength::One => 1,
FieldLength::Two => 2,
FieldLength::Three => 3,
FieldLength::Four => 4,
FieldLength::Five => 5,
FieldLength::Six => 6,
FieldLength::NumericOverride(o) => FIRST_NUMERIC_OVERRIDE
.saturating_add(*o as u8)
.min(LAST_NUMERIC_OVERRIDE),
}
}
#[inline]
pub(crate) fn from_idx(idx: u8) -> Result<Self, LengthError> {
Ok(match idx {
1 => Self::One,
2 => Self::Two,
3 => Self::Three,
4 => Self::Four,
5 => Self::Five,
6 => Self::Six,
idx if (FIRST_NUMERIC_OVERRIDE..=LAST_NUMERIC_OVERRIDE).contains(&idx) => {
Self::NumericOverride((idx - FIRST_NUMERIC_OVERRIDE).try_into()?)
}
_ => return Err(LengthError::InvalidLength),
})
}
#[inline]
pub(crate) fn to_len(self) -> usize {
match self {
FieldLength::One => 1,
FieldLength::Two => 2,
FieldLength::Three => 3,
FieldLength::Four => 4,
FieldLength::Five => 5,
FieldLength::Six => 6,
FieldLength::NumericOverride(o) => FIRST_NUMERIC_OVERRIDE as usize + o as usize,
}
}
/// UTS 35 defines several 1 and 2 symbols to be the same as 3 symbols (abbreviated).
/// For example, 'a' represents an abbreviated day period, the same as 'aaa'.
///
/// This function maps field lengths 1 and 2 to field length 3.
pub(crate) fn numeric_to_abbr(self) -> Self {
match self {
FieldLength::One | FieldLength::Two => FieldLength::Three,
other => other,
}
}
}
#[repr(transparent)]
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct FieldLengthULE(u8);
impl AsULE for FieldLength {
type ULE = FieldLengthULE;
fn to_unaligned(self) -> Self::ULE {
FieldLengthULE(self.idx())
}
fn from_unaligned(unaligned: Self::ULE) -> Self {
#[allow(clippy::unwrap_used)] // OK because the ULE is pre-validated
Self::from_idx(unaligned.0).unwrap()
}
}
impl FieldLengthULE {
#[inline]
pub(crate) fn validate_byte(byte: u8) -> Result<(), UleError> {
FieldLength::from_idx(byte)
.map(|_| ())
.map_err(|_| UleError::parse::<FieldLength>())
}
}
// Safety checklist for ULE:
//
// 1. Must not include any uninitialized or padding bytes (true since transparent over a ULE).
// 2. Must have an alignment of 1 byte (true since transparent over a ULE).
// 3. ULE::validate_bytes() checks that the given byte slice represents a valid slice.
// 4. ULE::validate_bytes() checks that the given byte slice has a valid length
// (true since transparent over a type of size 1).
// 5. All other methods must be left with their default impl.
// 6. Byte equality is semantic equality.
unsafe impl ULE for FieldLengthULE {
fn validate_bytes(bytes: &[u8]) -> Result<(), UleError> {
for byte in bytes {
Self::validate_byte(*byte)?;
}
Ok(())
}
}
/// Various numeric overrides for datetime patterns
/// as found in CLDR
#[derive(Debug, Eq, PartialEq, Clone, Copy, Ord, PartialOrd)]
#[cfg_attr(feature = "datagen", derive(serde::Serialize, databake::Bake))]
#[cfg_attr(feature = "datagen", databake(path = icu_datetime::fields))]
#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
#[non_exhaustive]
pub enum FieldNumericOverrides {
/// `hanidec`
Hanidec = 0,
/// `hanidays`
Hanidays = 1,
/// `hebr`
Hebr = 2,
/// `romanlow`
Romanlow = 3,
/// `jpnyear`
Jpnyear = 4,
}
impl TryFrom<u8> for FieldNumericOverrides {
type Error = LengthError;
fn try_from(other: u8) -> Result<Self, LengthError> {
Ok(match other {
0 => Self::Hanidec,
1 => Self::Hanidays,
2 => Self::Hebr,
3 => Self::Romanlow,
4 => Self::Jpnyear,
_ => return Err(LengthError::InvalidLength),
})
}
}
impl FieldNumericOverrides {
/// Convert this to the corresponding string code
pub fn as_str(self) -> &'static str {
match self {
Self::Hanidec => "hanidec",
Self::Hanidays => "hanidays",
Self::Hebr => "hebr",
Self::Romanlow => "romanlow",
Self::Jpnyear => "jpnyear",
}
}
}
impl fmt::Display for FieldNumericOverrides {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.as_str().fmt(f)
}
}