icu_locid/extensions/unicode/
attributes.rs

Help
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
7use crate::shortvec::ShortBoxSlice;
8use alloc::vec::Vec;
9use core::ops::Deref;
10
11/// A set of [`Attribute`] elements as defined in [`Unicode Extension Attributes`].
12///
13/// [`Unicode Extension Attributes`]: https://unicode.org/reports/tr35/tr35.html#u_Extension
14///
15/// # Examples
16///
17/// ```
18/// use icu::locid::extensions::unicode::{Attribute, Attributes};
19///
20/// let attribute1: Attribute =
21///     "foobar".parse().expect("Failed to parse a variant subtag.");
22///
23/// let attribute2: Attribute = "testing"
24///     .parse()
25///     .expect("Failed to parse a variant subtag.");
26/// let mut v = vec![attribute1, attribute2];
27/// v.sort();
28/// v.dedup();
29///
30/// let attributes: Attributes = Attributes::from_vec_unchecked(v);
31/// assert_eq!(attributes.to_string(), "foobar-testing");
32/// ```
33#[derive(Default, Debug, PartialEq, Eq, Clone, Hash, PartialOrd, Ord)]
34pub struct Attributes(ShortBoxSlice<Attribute>);
35
36impl Attributes {
37    /// Returns a new empty set of attributes. Same as [`default()`](Default::default()), but is `const`.
38    ///
39    /// # Examples
40    ///
41    /// ```
42    /// use icu::locid::extensions::unicode::Attributes;
43    ///
44    /// assert_eq!(Attributes::new(), Attributes::default());
45    /// ```
46    #[inline]
47    pub const fn new() -> Self {
48        Self(ShortBoxSlice::new())
49    }
50
51    /// A constructor which takes a pre-sorted list of [`Attribute`] elements.
52    ///
53    ///
54    /// # Examples
55    ///
56    /// ```
57    /// use icu::locid::extensions::unicode::{Attribute, Attributes};
58    ///
59    /// let attribute1: Attribute = "foobar".parse().expect("Parsing failed.");
60    /// let attribute2: Attribute = "testing".parse().expect("Parsing failed.");
61    /// let mut v = vec![attribute1, attribute2];
62    /// v.sort();
63    /// v.dedup();
64    ///
65    /// let attributes = Attributes::from_vec_unchecked(v);
66    /// ```
67    ///
68    /// Notice: For performance- and memory-constrained environments, it is recommended
69    /// for the caller to use [`binary_search`](slice::binary_search) instead of [`sort`](slice::sort)
70    /// and [`dedup`](Vec::dedup()).
71    pub fn from_vec_unchecked(input: Vec<Attribute>) -> Self {
72        Self(input.into())
73    }
74
75    pub(crate) fn from_short_slice_unchecked(input: ShortBoxSlice<Attribute>) -> Self {
76        Self(input)
77    }
78
79    /// Empties the [`Attributes`] list.
80    ///
81    /// Returns the old list.
82    ///
83    /// # Examples
84    ///
85    /// ```
86    /// use icu::locid::extensions::unicode::{attribute, Attributes};
87    /// use writeable::assert_writeable_eq;
88    ///
89    /// let mut attributes = Attributes::from_vec_unchecked(vec![
90    ///     attribute!("foobar"),
91    ///     attribute!("testing"),
92    /// ]);
93    ///
94    /// assert_writeable_eq!(attributes, "foobar-testing");
95    ///
96    /// attributes.clear();
97    ///
98    /// assert_writeable_eq!(attributes, "");
99    /// ```
100    pub fn clear(&mut self) -> Self {
101        core::mem::take(self)
102    }
103
104    pub(crate) fn for_each_subtag_str<E, F>(&self, f: &mut F) -> Result<(), E>
105    where
106        F: FnMut(&str) -> Result<(), E>,
107    {
108        self.deref().iter().map(|t| t.as_str()).try_for_each(f)
109    }
110}
111
112impl_writeable_for_subtag_list!(Attributes, "foobar", "testing");
113
114impl Deref for Attributes {
115    type Target = [Attribute];
116
117    fn deref(&self) -> &[Attribute] {
118        self.0.deref()
119    }
120}
icu_locid/extensions/unicode/attributes.rs

icu_locid/extensions/unicode/
attributes.rs
