icu_locale_core/extensions/unicode/
attributes.rs

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1// This file is part of ICU4X. For terms of use, please see the file
2// called LICENSE at the top level of the ICU4X source tree
3// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5use super::Attribute;
6
7#[cfg(feature = "alloc")]
8use crate::parser::SubtagIterator;
9use crate::shortvec::ShortBoxSlice;
10#[cfg(feature = "alloc")]
11use crate::ParseError;
12#[cfg(feature = "alloc")]
13use alloc::vec::Vec;
14use core::ops::Deref;
15#[cfg(feature = "alloc")]
16use core::str::FromStr;
17
18/// A set of [`Attribute`] elements as defined in [`Unicode Extension Attributes`].
19///
20/// [`Unicode Extension Attributes`]: https://unicode.org/reports/tr35/tr35.html#u_Extension
21///
22/// # Examples
23///
24/// ```
25/// use icu::locale::extensions::unicode::{Attribute, Attributes};
26///
27/// let attribute1: Attribute =
28///     "foobar".parse().expect("Failed to parse a variant subtag.");
29///
30/// let attribute2: Attribute = "testing"
31///     .parse()
32///     .expect("Failed to parse a variant subtag.");
33/// let mut v = vec![attribute1, attribute2];
34/// v.sort();
35/// v.dedup();
36///
37/// let attributes: Attributes = Attributes::from_vec_unchecked(v);
38/// assert_eq!(attributes.to_string(), "foobar-testing");
39/// ```
40#[derive(Default, Debug, PartialEq, Eq, Clone, Hash, PartialOrd, Ord)]
41pub struct Attributes(ShortBoxSlice<Attribute>);
42
43impl Attributes {
44    /// Returns a new empty set of attributes. Same as [`default()`](Default::default()), but is `const`.
45    ///
46    /// # Examples
47    ///
48    /// ```
49    /// use icu::locale::extensions::unicode::Attributes;
50    ///
51    /// assert_eq!(Attributes::new(), Attributes::default());
52    /// ```
53    #[inline]
54    pub const fn new() -> Self {
55        Self(ShortBoxSlice::new())
56    }
57
58    /// A constructor which takes a str slice, parses it and
59    /// produces a well-formed [`Attributes`].
60    #[inline]
61    #[cfg(feature = "alloc")]
62    pub fn try_from_str(s: &str) -> Result<Self, ParseError> {
63        Self::try_from_utf8(s.as_bytes())
64    }
65
66    /// See [`Self::try_from_str`]
67    #[cfg(feature = "alloc")]
68    pub fn try_from_utf8(code_units: &[u8]) -> Result<Self, ParseError> {
69        let mut iter = SubtagIterator::new(code_units);
70        Self::try_from_iter(&mut iter)
71    }
72
73    /// A constructor which takes a pre-sorted list of [`Attribute`] elements.
74    ///
75    ///
76    /// # Examples
77    ///
78    /// ```
79    /// use icu::locale::extensions::unicode::{Attribute, Attributes};
80    ///
81    /// let attribute1: Attribute = "foobar".parse().expect("Parsing failed.");
82    /// let attribute2: Attribute = "testing".parse().expect("Parsing failed.");
83    /// let mut v = vec![attribute1, attribute2];
84    /// v.sort();
85    /// v.dedup();
86    ///
87    /// let attributes = Attributes::from_vec_unchecked(v);
88    /// ```
89    ///
90    /// Notice: For performance- and memory-constrained environments, it is recommended
91    /// for the caller to use [`binary_search`](slice::binary_search) instead of [`sort`](slice::sort)
92    /// and [`dedup`](Vec::dedup()).
93    #[cfg(feature = "alloc")]
94    pub fn from_vec_unchecked(input: Vec<Attribute>) -> Self {
95        Self(input.into())
96    }
97
98    /// Empties the [`Attributes`] list.
99    ///
100    /// Returns the old list.
101    ///
102    /// # Examples
103    ///
104    /// ```
105    /// use icu::locale::extensions::unicode::{attribute, Attributes};
106    /// use writeable::assert_writeable_eq;
107    ///
108    /// let mut attributes = Attributes::from_vec_unchecked(vec![
109    ///     attribute!("foobar"),
110    ///     attribute!("testing"),
111    /// ]);
112    ///
113    /// assert_writeable_eq!(attributes, "foobar-testing");
114    ///
115    /// attributes.clear();
116    ///
117    /// assert_writeable_eq!(attributes, "");
118    /// ```
119    pub fn clear(&mut self) -> Self {
120        core::mem::take(self)
121    }
122
123    #[cfg(feature = "alloc")]
124    pub(crate) fn try_from_iter(iter: &mut SubtagIterator) -> Result<Self, ParseError> {
125        let mut attributes = ShortBoxSlice::new();
126
127        while let Some(subtag) = iter.peek() {
128            if let Ok(attr) = Attribute::try_from_utf8(subtag) {
129                if let Err(idx) = attributes.binary_search(&attr) {
130                    attributes.insert(idx, attr);
131                }
132            } else {
133                break;
134            }
135            iter.next();
136        }
137        Ok(Self(attributes))
138    }
139
140    pub(crate) fn for_each_subtag_str<E, F>(&self, f: &mut F) -> Result<(), E>
141    where
142        F: FnMut(&str) -> Result<(), E>,
143    {
144        self.deref().iter().map(|t| t.as_str()).try_for_each(f)
145    }
146}
147
148#[cfg(feature = "alloc")]
149impl FromStr for Attributes {
150    type Err = ParseError;
151
152    #[inline]
153    fn from_str(s: &str) -> Result<Self, Self::Err> {
154        Self::try_from_str(s)
155    }
156}
157
158impl_writeable_for_subtag_list!(Attributes, "foobar", "testing");
159
160impl Deref for Attributes {
161    type Target = [Attribute];
162
163    fn deref(&self) -> &[Attribute] {
164        self.0.deref()
165    }
166}
167
168#[cfg(test)]
169mod tests {
170    use super::*;
171
172    #[test]
173    fn test_attributes_fromstr() {
174        let attrs: Attributes = "foo-bar".parse().expect("Failed to parse Attributes");
175        assert_eq!(attrs.to_string(), "bar-foo");
176    }
177}
icu_locale_core/extensions/unicode/attributes.rs

icu_locale_core/extensions/unicode/
attributes.rs
