Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 170 insertions, 0 deletions

diff --git a/third_party/rust/unicode-normalization/src/stream_safe.rs b/third_party/rust/unicode-normalization/src/stream_safe.rs
new file mode 100644
index 0000000000..30fe8100dc
--- /dev/null
+++ b/third_party/rust/unicode-normalization/src/stream_safe.rs
@@ -0,0 +1,170 @@
+use crate::lookups::{
+    canonical_combining_class, canonical_fully_decomposed, compatibility_fully_decomposed,
+    stream_safe_trailing_nonstarters,
+};
+use crate::normalize::{hangul_decomposition_length, is_hangul_syllable};
+use crate::tables::stream_safe_leading_nonstarters;
+
+pub(crate) const MAX_NONSTARTERS: usize = 30;
+const COMBINING_GRAPHEME_JOINER: char = '\u{034F}';
+
+/// UAX15-D4: This iterator keeps track of how many non-starters there have been
+/// since the last starter in *NFKD* and will emit a Combining Grapheme Joiner
+/// (U+034F) if the count exceeds 30.
+pub struct StreamSafe<I> {
+    iter: I,
+    nonstarter_count: usize,
+    buffer: Option<char>,
+}
+
+impl<I> StreamSafe<I> {
+    pub(crate) fn new(iter: I) -> Self {
+        Self {
+            iter,
+            nonstarter_count: 0,
+            buffer: None,
+        }
+    }
+}
+
+impl<I: Iterator<Item = char>> Iterator for StreamSafe<I> {
+    type Item = char;
+
+    #[inline]
+    fn next(&mut self) -> Option<char> {
+        let next_ch = match self.buffer.take().or_else(|| self.iter.next()) {
+            None => return None,
+            Some(c) => c,
+        };
+        let d = classify_nonstarters(next_ch);
+        if self.nonstarter_count + d.leading_nonstarters > MAX_NONSTARTERS {
+            // Since we're emitting a CGJ, the suffix of the emitted string in NFKD has no trailing
+            // nonstarters, so we can reset the counter to zero. Put `next_ch` back into the
+            // iterator (via `self.buffer`), and we'll reclassify it next iteration.
+            self.nonstarter_count = 0;
+            self.buffer = Some(next_ch);
+            return Some(COMBINING_GRAPHEME_JOINER);
+        }
+
+        // Is the character all nonstarters in NFKD? If so, increment our counter of contiguous
+        // nonstarters in NKFD.
+        if d.leading_nonstarters == d.decomposition_len {
+            self.nonstarter_count += d.decomposition_len;
+        }
+        // Otherwise, reset the counter to the decomposition's number of trailing nonstarters.
+        else {
+            self.nonstarter_count = d.trailing_nonstarters;
+        }
+        Some(next_ch)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct Decomposition {
+    pub(crate) leading_nonstarters: usize,
+    pub(crate) trailing_nonstarters: usize,
+    pub(crate) decomposition_len: usize,
+}
+
+#[inline]
+pub(crate) fn classify_nonstarters(c: char) -> Decomposition {
+    // As usual, fast path for ASCII (which is always a starter)
+    if c <= '\x7f' {
+        return Decomposition {
+            leading_nonstarters: 0,
+            trailing_nonstarters: 0,
+            decomposition_len: 1,
+        };
+    }
+    // Next, special case Hangul, since it's not handled by our tables.
+    if is_hangul_syllable(c) {
+        return Decomposition {
+            leading_nonstarters: 0,
+            trailing_nonstarters: 0,
+            decomposition_len: hangul_decomposition_length(c),
+        };
+    }
+    let decomp = compatibility_fully_decomposed(c).or_else(|| canonical_fully_decomposed(c));
+    match decomp {
+        Some(decomp) => Decomposition {
+            leading_nonstarters: stream_safe_leading_nonstarters(c),
+            trailing_nonstarters: stream_safe_trailing_nonstarters(c),
+            decomposition_len: decomp.len(),
+        },
+        None => {
+            let is_nonstarter = canonical_combining_class(c) != 0;
+            let nonstarter = if is_nonstarter { 1 } else { 0 };
+            Decomposition {
+                leading_nonstarters: nonstarter,
+                trailing_nonstarters: nonstarter,
+                decomposition_len: 1,
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{classify_nonstarters, StreamSafe};
+    use crate::lookups::canonical_combining_class;
+    use crate::normalize::decompose_compatible;
+
+    #[cfg(not(feature = "std"))]
+    use crate::no_std_prelude::*;
+
+    use core::char;
+
+    fn stream_safe(s: &str) -> String {
+        StreamSafe::new(s.chars()).collect()
+    }
+
+    #[test]
+    fn test_simple() {
+        let technically_okay = "Da\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{031d}ngerzone";
+        assert_eq!(stream_safe(technically_okay), technically_okay);
+
+        let too_much = "Da\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{031d}\u{032e}ngerzone";
+        let fixed_it = "Da\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{031d}\u{034f}\u{032e}ngerzone";
+        assert_eq!(stream_safe(too_much), fixed_it);
+
+        let woah_nelly = "Da\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{031d}\u{032e}\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{031d}\u{032e}ngerzone";
+        let its_cool = "Da\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{031d}\u{034f}\u{032e}\u{0300}\u{0301}\u{0302}\u{0303}\u{0304}\u{0305}\u{0306}\u{0307}\u{0308}\u{0309}\u{030a}\u{030b}\u{030c}\u{030d}\u{030e}\u{030f}\u{0310}\u{0311}\u{0312}\u{0313}\u{0314}\u{0315}\u{0316}\u{0317}\u{0318}\u{0319}\u{031a}\u{031b}\u{031c}\u{034f}\u{031d}\u{032e}ngerzone";
+        assert_eq!(stream_safe(woah_nelly), its_cool);
+    }
+
+    #[test]
+    fn test_all_nonstarters() {
+        let s = "\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}\u{0300}";
+        let expected = "\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{034F}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}\u{300}";
+        assert_eq!(stream_safe(s), expected);
+    }
+
+    #[test]
+    fn test_classify_nonstarters() {
+        // Highest character in the `compat_fully_decomp` table is 2FA1D
+        for ch in 0..0x2FA1E {
+            let ch = match char::from_u32(ch) {
+                Some(c) => c,
+                None => continue,
+            };
+            let c = classify_nonstarters(ch);
+            let mut s = Vec::new();
+            decompose_compatible(ch, |c| s.push(c));
+
+            assert_eq!(s.len(), c.decomposition_len);
+
+            let num_leading = s
+                .iter()
+                .take_while(|&c| canonical_combining_class(*c) != 0)
+                .count();
+            let num_trailing = s
+                .iter()
+                .rev()
+                .take_while(|&c| canonical_combining_class(*c) != 0)
+                .count();
+
+            assert_eq!(num_leading, c.leading_nonstarters);
+            assert_eq!(num_trailing, c.trailing_nonstarters);
+        }
+    }
+}