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
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
// 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 crate::parser::{ParseError, SubtagIterator};
use crate::shortvec::{ShortBoxSlice, ShortBoxSliceIntoIter};
use crate::subtags::{subtag, Subtag};
use alloc::vec::Vec;
use core::str::FromStr;

/// A value used in a list of [`Keywords`](super::Keywords).
///
/// 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::locale::extensions::unicode::{value, Value};
/// use writeable::assert_writeable_eq;
///
/// assert_writeable_eq!(value!("gregory"), "gregory");
/// assert_writeable_eq!(
///     "islamic-civil".parse::<Value>().unwrap(),
///     "islamic-civil"
/// );
///
/// // The value "true" has the special, empty string representation
/// assert_eq!(value!("true").to_string(), "");
/// ```
#[derive(Debug, PartialEq, Eq, Clone, Hash, PartialOrd, Ord, Default)]
pub struct Value(ShortBoxSlice<Subtag>);

const TRUE_VALUE: Subtag = subtag!("true");

impl Value {
    /// A constructor which str slice, parses it and
    /// produces a well-formed [`Value`].
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::extensions::unicode::Value;
    ///
    /// Value::try_from_str("buddhist").expect("Parsing failed.");
    /// ```
    #[inline]
    pub fn try_from_str(s: &str) -> Result<Self, ParseError> {
        Self::try_from_utf8(s.as_bytes())
    }

    /// See [`Self::try_from_str`]
    pub fn try_from_utf8(code_units: &[u8]) -> Result<Self, ParseError> {
        let mut v = ShortBoxSlice::new();

        if !code_units.is_empty() {
            for chunk in SubtagIterator::new(code_units) {
                let subtag = Subtag::try_from_utf8(chunk)?;
                if subtag != TRUE_VALUE {
                    v.push(subtag);
                }
            }
        }
        Ok(Self(v))
    }

    /// Returns a reference to a single [`Subtag`] if the [`Value`] contains exactly one
    /// subtag, or `None` otherwise.
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::extensions::unicode::Value;
    /// use core::str::FromStr;
    ///
    /// let value1 = Value::from_str("foo")
    ///     .expect("failed to parse a Value");
    /// let value2 = Value::from_str("foo-bar")
    ///     .expect("failed to parse a Value");
    ///
    /// assert!(value1.as_single_subtag().is_some());
    /// assert!(value2.as_single_subtag().is_none());
    /// ```
    pub const fn as_single_subtag(&self) -> Option<&Subtag> {
        self.0.single()
    }

    /// Destructs into a single [`Subtag`] if the [`Value`] contains exactly one
    /// subtag, or returns `None` otherwise.
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::extensions::unicode::Value;
    /// use core::str::FromStr;
    ///
    /// let value1 = Value::from_str("foo")
    ///     .expect("failed to parse a Value");
    /// let value2 = Value::from_str("foo-bar")
    ///     .expect("failed to parse a Value");
    ///
    /// assert!(value1.into_single_subtag().is_some());
    /// assert!(value2.into_single_subtag().is_none());
    /// ```
    pub fn into_single_subtag(self) -> Option<Subtag> {
        self.0.into_single()
    }

    #[doc(hidden)]
    pub fn as_subtags_slice(&self) -> &[Subtag] {
        &self.0
    }

    /// Appends a subtag to the back of a [`Value`].
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::{
    ///     extensions::unicode::Value,
    ///     subtags::subtag,
    /// };
    ///
    /// let mut v = Value::default();
    /// v.push_subtag(subtag!("foo"));
    /// v.push_subtag(subtag!("bar"));
    /// assert_eq!(v, "foo-bar");
    /// ```
    pub fn push_subtag(&mut self, subtag: Subtag) {
        self.0.push(subtag);
    }

    /// Returns the number of subtags in the [`Value`].
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::{
    ///     extensions::unicode::Value,
    ///     subtags::subtag,
    /// };
    ///
    /// let mut v = Value::default();
    /// assert_eq!(v.subtag_count(), 0);
    /// v.push_subtag(subtag!("foo"));
    /// assert_eq!(v.subtag_count(), 1);
    /// ```
    pub fn subtag_count(&self) -> usize {
        self.0.len()
    }

    /// Returns `true` if the Value has no subtags.
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::{
    ///     extensions::unicode::Value,
    ///     subtags::subtag,
    /// };
    ///
    /// let mut v = Value::default();
    /// assert_eq!(v.is_empty(), true);
    /// ```
    pub fn is_empty(&self) -> bool {
        self.0.is_empty()
    }

    /// Removes and returns the subtag at position `index` within the value,
    /// shifting all subtags after it to the left.
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::{
    ///     extensions::unicode::Value,
    ///     subtags::subtag,
    /// };
    /// let mut v = Value::default();
    /// v.push_subtag(subtag!("foo"));
    /// v.push_subtag(subtag!("bar"));
    /// v.push_subtag(subtag!("baz"));
    ///
    /// assert_eq!(v.remove_subtag(1), Some(subtag!("bar")));
    /// assert_eq!(v, "foo-baz");
    /// ```
    pub fn remove_subtag(&mut self, idx: usize) -> Option<Subtag> {
        if self.0.len() < idx {
            None
        } else {
            let item = self.0.remove(idx);
            Some(item)
        }
    }

    /// Returns a reference to a subtag at index.
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::{
    ///     extensions::unicode::Value,
    ///     subtags::subtag,
    /// };
    /// let mut v = Value::default();
    /// v.push_subtag(subtag!("foo"));
    /// v.push_subtag(subtag!("bar"));
    /// v.push_subtag(subtag!("baz"));
    ///
    /// assert_eq!(v.get_subtag(1), Some(&subtag!("bar")));
    /// assert_eq!(v.get_subtag(3), None);
    /// ```
    pub fn get_subtag(&self, idx: usize) -> Option<&Subtag> {
        self.0.get(idx)
    }

    #[doc(hidden)]
    pub const fn from_subtag(subtag: Option<Subtag>) -> Self {
        match subtag {
            None | Some(TRUE_VALUE) => Self(ShortBoxSlice::new()),
            Some(val) => Self(ShortBoxSlice::new_single(val)),
        }
    }

    /// A constructor which takes a pre-sorted list of [`Value`] elements.
    ///
    ///
    /// # Examples
    ///
    /// ```
    /// use icu::locale::extensions::unicode::Value;
    /// use icu::locale::subtags::subtag;
    ///
    /// let subtag1 = subtag!("foobar");
    /// let subtag2 = subtag!("testing");
    /// let mut v = vec![subtag1, subtag2];
    /// v.sort();
    /// v.dedup();
    ///
    /// let value = Value::from_vec_unchecked(v);
    /// ```
    ///
    /// Notice: For performance- and memory-constrained environments, it is recommended
    /// for the caller to use [`binary_search`](slice::binary_search) instead of [`sort`](slice::sort)
    /// and [`dedup`](Vec::dedup()).
    pub fn from_vec_unchecked(input: Vec<Subtag>) -> Self {
        Self(input.into())
    }

    pub(crate) fn from_short_slice_unchecked(input: ShortBoxSlice<Subtag>) -> Self {
        Self(input)
    }

    pub(crate) const fn parse_subtag_from_utf8(t: &[u8]) -> Result<Option<Subtag>, ParseError> {
        match Subtag::try_from_utf8(t) {
            Ok(TRUE_VALUE) => Ok(None),
            Ok(s) => Ok(Some(s)),
            Err(_) => Err(ParseError::InvalidSubtag),
        }
    }

    pub(crate) fn for_each_subtag_str<E, F>(&self, f: &mut F) -> Result<(), E>
    where
        F: FnMut(&str) -> Result<(), E>,
    {
        self.0.iter().map(Subtag::as_str).try_for_each(f)
    }
}

impl IntoIterator for Value {
    type Item = Subtag;

    type IntoIter = ShortBoxSliceIntoIter<Subtag>;

    fn into_iter(self) -> Self::IntoIter {
        self.0.into_iter()
    }
}

impl FromIterator<Subtag> for Value {
    fn from_iter<T: IntoIterator<Item = Subtag>>(iter: T) -> Self {
        Self(ShortBoxSlice::from_iter(iter))
    }
}

impl Extend<Subtag> for Value {
    fn extend<T: IntoIterator<Item = Subtag>>(&mut self, iter: T) {
        for i in iter {
            self.0.push(i);
        }
    }
}

impl FromStr for Value {
    type Err = ParseError;

    #[inline]
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Self::try_from_str(s)
    }
}

impl PartialEq<&str> for Value {
    fn eq(&self, other: &&str) -> bool {
        writeable::cmp_bytes(self, other.as_bytes()).is_eq()
    }
}

impl_writeable_for_subtag_list!(Value, "islamic", "civil");

/// A macro allowing for compile-time construction of valid Unicode [`Value`] subtag.
///
/// The macro only supports single-subtag values.
///
/// # Examples
///
/// ```
/// use icu::locale::extensions::unicode::{key, value};
/// use icu::locale::Locale;
///
/// let loc: Locale = "de-u-ca-buddhist".parse().unwrap();
///
/// assert_eq!(
///     loc.extensions.unicode.keywords.get(&key!("ca")),
///     Some(&value!("buddhist"))
/// );
/// ```
///
/// [`Value`]: crate::extensions::unicode::Value
#[macro_export]
#[doc(hidden)] // macro
macro_rules! extensions_unicode_value {
    ($value:literal) => {{
        // What we want:
        // const R: $crate::extensions::unicode::Value =
        //     match $crate::extensions::unicode::Value::try_from_single_subtag($value.as_bytes()) {
        //         Ok(r) => r,
        //         #[allow(clippy::panic)] // const context
        //         _ => panic!(concat!("Invalid Unicode extension value: ", $value)),
        //     };
        // Workaround until https://github.com/rust-lang/rust/issues/73255 lands:
        const R: $crate::extensions::unicode::Value =
            $crate::extensions::unicode::Value::from_subtag(
                match $crate::subtags::Subtag::try_from_utf8($value.as_bytes()) {
                    Ok(r) => Some(r),
                    _ => panic!(concat!("Invalid Unicode extension value: ", $value)),
                },
            );
        R
    }};
}
#[doc(inline)]
pub use extensions_unicode_value as value;