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// 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
use crate::parser::{ParserError, SubtagIterator};
use crate::shortvec::ShortBoxSlice;
use core::ops::RangeInclusive;
use core::str::FromStr;
use tinystr::TinyAsciiStr;
/// A value used in a list of [`Fields`](super::Fields).
///
/// The value has to be a sequence of one or more alphanumerical strings
/// separated by `-`.
/// Each part of the sequence has to be no shorter than three characters and no
/// longer than 8.
///
/// # Examples
///
/// ```
/// use icu::locid::extensions::transform::Value;
///
/// "hybrid".parse::<Value>().expect("Valid Value.");
///
/// "hybrid-foobar".parse::<Value>().expect("Valid Value.");
///
/// "no".parse::<Value>().expect_err("Invalid Value.");
/// ```
#[derive(Debug, PartialEq, Eq, Clone, Hash, PartialOrd, Ord, Default)]
pub struct Value(ShortBoxSlice<TinyAsciiStr<{ *TYPE_LENGTH.end() }>>);
const TYPE_LENGTH: RangeInclusive<usize> = 3..=8;
const TRUE_TVALUE: TinyAsciiStr<8> = tinystr::tinystr!(8, "true");
impl Value {
/// A constructor which takes a utf8 slice, parses it and
/// produces a well-formed [`Value`].
///
/// # Examples
///
/// ```
/// use icu::locid::extensions::transform::Value;
///
/// let value = Value::try_from_bytes(b"hybrid").expect("Parsing failed.");
/// ```
pub fn try_from_bytes(input: &[u8]) -> Result<Self, ParserError> {
let mut v = ShortBoxSlice::default();
let mut has_value = false;
for subtag in SubtagIterator::new(input) {
if !Self::is_type_subtag(subtag) {
return Err(ParserError::InvalidExtension);
}
has_value = true;
let val =
TinyAsciiStr::from_bytes(subtag).map_err(|_| ParserError::InvalidExtension)?;
if val != TRUE_TVALUE {
v.push(val);
}
}
if !has_value {
return Err(ParserError::InvalidExtension);
}
Ok(Self(v))
}
pub(crate) fn from_short_slice_unchecked(
input: ShortBoxSlice<TinyAsciiStr<{ *TYPE_LENGTH.end() }>>,
) -> Self {
Self(input)
}
pub(crate) fn is_type_subtag(t: &[u8]) -> bool {
TYPE_LENGTH.contains(&t.len()) && t.iter().all(u8::is_ascii_alphanumeric)
}
pub(crate) fn parse_subtag(
t: &[u8],
) -> Result<Option<TinyAsciiStr<{ *TYPE_LENGTH.end() }>>, ParserError> {
let s = TinyAsciiStr::from_bytes(t).map_err(|_| ParserError::InvalidSubtag)?;
if !TYPE_LENGTH.contains(&t.len()) || !s.is_ascii_alphanumeric() {
return Err(ParserError::InvalidExtension);
}
let s = s.to_ascii_lowercase();
if s == TRUE_TVALUE {
Ok(None)
} else {
Ok(Some(s))
}
}
pub(crate) fn for_each_subtag_str<E, F>(&self, f: &mut F) -> Result<(), E>
where
F: FnMut(&str) -> Result<(), E>,
{
if self.0.is_empty() {
f("true")?;
} else {
self.0.iter().map(TinyAsciiStr::as_str).try_for_each(f)?;
}
Ok(())
}
}
impl FromStr for Value {
type Err = ParserError;
fn from_str(source: &str) -> Result<Self, Self::Err> {
Self::try_from_bytes(source.as_bytes())
}
}
impl_writeable_for_each_subtag_str_no_test!(Value, selff, selff.0.is_empty() => alloc::borrow::Cow::Borrowed("true"));
#[test]
fn test_writeable() {
use writeable::assert_writeable_eq;
let hybrid = "hybrid".parse().unwrap();
let foobar = "foobar".parse().unwrap();
assert_writeable_eq!(Value::default(), "true");
assert_writeable_eq!(
Value::from_short_slice_unchecked(vec![hybrid].into()),
"hybrid"
);
assert_writeable_eq!(
Value::from_short_slice_unchecked(vec![hybrid, foobar].into()),
"hybrid-foobar"
);
}