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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/encode_unicode/src/utf16_iterators.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz
fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/encode_unicode/src/utf16_iterators.rs')
-rw-r--r--vendor/encode_unicode/src/utf16_iterators.rs270
1 files changed, 270 insertions, 0 deletions
diff --git a/vendor/encode_unicode/src/utf16_iterators.rs b/vendor/encode_unicode/src/utf16_iterators.rs
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+/* Copyright 2016 The encode_unicode Developers
+ *
+ * Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+ * http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+ * http://opensource.org/licenses/MIT>, at your option. This file may not be
+ * copied, modified, or distributed except according to those terms.
+ */
+
+use traits::CharExt;
+use utf16_char::Utf16Char;
+use errors::EmptyStrError;
+extern crate core;
+use self::core::fmt;
+use self::core::borrow::Borrow;
+
+// Invalid values that says the field is consumed or empty.
+const FIRST_USED: u16 = 0x_dc_00;
+const SECOND_USED: u16 = 0;
+
+/// Iterate over the units of the UTF-16 representation of a codepoint.
+#[derive(Clone)]
+pub struct Utf16Iterator {
+ first: u16,
+ second: u16,
+}
+impl From<char> for Utf16Iterator {
+ fn from(c: char) -> Self {
+ let (first, second) = c.to_utf16_tuple();
+ Utf16Iterator{ first: first, second: second.unwrap_or(SECOND_USED) }
+ }
+}
+impl From<Utf16Char> for Utf16Iterator {
+ fn from(uc: Utf16Char) -> Self {
+ let (first, second) = uc.to_tuple();
+ Utf16Iterator{ first: first, second: second.unwrap_or(SECOND_USED) }
+ }
+}
+impl Iterator for Utf16Iterator {
+ type Item=u16;
+ fn next(&mut self) -> Option<u16> {
+ match (self.first, self.second) {
+ (FIRST_USED, SECOND_USED) => { None },
+ (FIRST_USED, second ) => {self.second = SECOND_USED; Some(second)},
+ (first , _ ) => {self.first = FIRST_USED; Some(first )},
+ }
+ }
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (self.len(), Some(self.len()))
+ }
+}
+impl ExactSizeIterator for Utf16Iterator {
+ fn len(&self) -> usize {
+ (if self.first == FIRST_USED {0} else {1}) +
+ (if self.second == SECOND_USED {0} else {1})
+ }
+}
+impl fmt::Debug for Utf16Iterator {
+ fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result {
+ let mut clone = self.clone();
+ match (clone.next(), clone.next()) {
+ (Some(one), None) => write!(fmtr, "[{}]", one),
+ (Some(a), Some(b)) => write!(fmtr, "[{}, {}]", a, b),
+ (None, _) => write!(fmtr, "[]"),
+ }
+ }
+}
+
+
+
+/// Converts an iterator of `Utf16Char` (or `&Utf16Char`)
+/// to an iterator of `u16`s.
+/// Is equivalent to calling `.flat_map()` on the original iterator,
+/// but the returned iterator is about twice as fast.
+///
+/// The exact number of units cannot be known in advance, but `size_hint()`
+/// gives the possible range.
+///
+/// # Examples
+///
+/// From iterator of values:
+///
+/// ```
+/// use encode_unicode::{iter_units, CharExt};
+///
+/// let iterator = "foo".chars().map(|c| c.to_utf16() );
+/// let mut units = [0; 4];
+/// for (u,dst) in iter_units(iterator).zip(&mut units) {*dst=u;}
+/// assert_eq!(units, ['f' as u16, 'o' as u16, 'o' as u16, 0]);
+/// ```
+///
+/// From iterator of references:
+///
+#[cfg_attr(feature="std", doc=" ```")]
+#[cfg_attr(not(feature="std"), doc=" ```no_compile")]
+/// use encode_unicode::{iter_units, CharExt, Utf16Char};
+///
+/// // (💣 takes two units)
+/// let chars: Vec<Utf16Char> = "💣 bomb 💣".chars().map(|c| c.to_utf16() ).collect();
+/// let units: Vec<u16> = iter_units(&chars).collect();
+/// let flat_map: Vec<u16> = chars.iter().flat_map(|u16c| *u16c ).collect();
+/// assert_eq!(units, flat_map);
+/// ```
+pub fn iter_units<U:Borrow<Utf16Char>, I:IntoIterator<Item=U>>
+(iterable: I) -> Utf16CharSplitter<U, I::IntoIter> {
+ Utf16CharSplitter{ inner: iterable.into_iter(), prev_second: 0 }
+}
+
+/// The iterator type returned by `iter_units()`
+#[derive(Clone)]
+pub struct Utf16CharSplitter<U:Borrow<Utf16Char>, I:Iterator<Item=U>> {
+ inner: I,
+ prev_second: u16,
+}
+impl<I:Iterator<Item=Utf16Char>> From<I> for Utf16CharSplitter<Utf16Char,I> {
+ /// A less generic constructor than `iter_units()`
+ fn from(iter: I) -> Self {
+ iter_units(iter)
+ }
+}
+impl<U:Borrow<Utf16Char>, I:Iterator<Item=U>> Utf16CharSplitter<U,I> {
+ /// Extracts the source iterator.
+ ///
+ /// Note that `iter_units(iter.into_inner())` is not a no-op:
+ /// If the last returned unit from `next()` was a leading surrogate,
+ /// the trailing surrogate is lost.
+ pub fn into_inner(self) -> I {
+ self.inner
+ }
+}
+impl<U:Borrow<Utf16Char>, I:Iterator<Item=U>> Iterator for Utf16CharSplitter<U,I> {
+ type Item = u16;
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.prev_second == 0 {
+ self.inner.next().map(|u16c| {
+ let units = u16c.borrow().to_array();
+ self.prev_second = units[1];
+ units[0]
+ })
+ } else {
+ let prev_second = self.prev_second;
+ self.prev_second = 0;
+ Some(prev_second)
+ }
+ }
+ fn size_hint(&self) -> (usize,Option<usize>) {
+ // Doesn't need to handle unlikely overflows correctly because
+ // size_hint() cannot be relied upon anyway. (the trait isn't unsafe)
+ let (min, max) = self.inner.size_hint();
+ let add = if self.prev_second == 0 {0} else {1};
+ (min.wrapping_add(add), max.map(|max| max.wrapping_mul(2).wrapping_add(add) ))
+ }
+}
+
+
+
+/// An iterator over the codepoints in a `str` represented as `Utf16Char`.
+#[derive(Clone)]
+pub struct Utf16CharIndices<'a>{
+ str: &'a str,
+ index: usize,
+}
+impl<'a> From<&'a str> for Utf16CharIndices<'a> {
+ fn from(s: &str) -> Utf16CharIndices {
+ Utf16CharIndices{str: s, index: 0}
+ }
+}
+impl<'a> Utf16CharIndices<'a> {
+ /// Extract the remainder of the source `str`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use encode_unicode::{StrExt, Utf16Char};
+ /// let mut iter = "abc".utf16char_indices();
+ /// assert_eq!(iter.next_back(), Some((2, Utf16Char::from('c'))));
+ /// assert_eq!(iter.next(), Some((0, Utf16Char::from('a'))));
+ /// assert_eq!(iter.as_str(), "b");
+ /// ```
+ pub fn as_str(&self) -> &'a str {
+ &self.str[self.index..]
+ }
+}
+impl<'a> Iterator for Utf16CharIndices<'a> {
+ type Item = (usize,Utf16Char);
+ fn next(&mut self) -> Option<(usize,Utf16Char)> {
+ match Utf16Char::from_str_start(&self.str[self.index..]) {
+ Ok((u16c, bytes)) => {
+ let item = (self.index, u16c);
+ self.index += bytes;
+ Some(item)
+ },
+ Err(EmptyStrError) => None
+ }
+ }
+ fn size_hint(&self) -> (usize,Option<usize>) {
+ let len = self.str.len() - self.index;
+ // For len+3 to overflow, the slice must fill all but two bytes of
+ // addressable memory, and size_hint() doesn't need to be correct.
+ (len.wrapping_add(3)/4, Some(len))
+ }
+}
+impl<'a> DoubleEndedIterator for Utf16CharIndices<'a> {
+ fn next_back(&mut self) -> Option<(usize,Utf16Char)> {
+ if self.index < self.str.len() {
+ let rev = self.str.bytes().rev();
+ let len = 1 + rev.take_while(|b| b & 0b1100_0000 == 0b1000_0000 ).count();
+ let starts = self.str.len() - len;
+ let (u16c,_) = Utf16Char::from_str_start(&self.str[starts..]).unwrap();
+ self.str = &self.str[..starts];
+ Some((starts, u16c))
+ } else {
+ None
+ }
+ }
+}
+impl<'a> fmt::Debug for Utf16CharIndices<'a> {
+ fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result {
+ fmtr.debug_tuple("Utf16CharIndices")
+ .field(&self.index)
+ .field(&self.as_str())
+ .finish()
+ }
+}
+
+
+/// An iterator over the codepoints in a `str` represented as `Utf16Char`.
+#[derive(Clone)]
+pub struct Utf16Chars<'a>(Utf16CharIndices<'a>);
+impl<'a> From<&'a str> for Utf16Chars<'a> {
+ fn from(s: &str) -> Utf16Chars {
+ Utf16Chars(Utf16CharIndices::from(s))
+ }
+}
+impl<'a> Utf16Chars<'a> {
+ /// Extract the remainder of the source `str`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use encode_unicode::{StrExt, Utf16Char};
+ /// let mut iter = "abc".utf16chars();
+ /// assert_eq!(iter.next(), Some(Utf16Char::from('a')));
+ /// assert_eq!(iter.next_back(), Some(Utf16Char::from('c')));
+ /// assert_eq!(iter.as_str(), "b");
+ /// ```
+ pub fn as_str(&self) -> &'a str {
+ self.0.as_str()
+ }
+}
+impl<'a> Iterator for Utf16Chars<'a> {
+ type Item = Utf16Char;
+ fn next(&mut self) -> Option<Utf16Char> {
+ self.0.next().map(|(_,u16c)| u16c )
+ }
+ fn size_hint(&self) -> (usize,Option<usize>) {
+ self.0.size_hint()
+ }
+}
+impl<'a> DoubleEndedIterator for Utf16Chars<'a> {
+ fn next_back(&mut self) -> Option<Utf16Char> {
+ self.0.next_back().map(|(_,u16c)| u16c )
+ }
+}
+impl<'a> fmt::Debug for Utf16Chars<'a> {
+ fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result {
+ fmtr.debug_tuple("Utf16Chars")
+ .field(&self.as_str())
+ .finish()
+ }
+}