From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 compiler/rustc_data_structures/src/small_str.rs | 68 +++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 compiler/rustc_data_structures/src/small_str.rs

(limited to 'compiler/rustc_data_structures/src/small_str.rs')

diff --git a/compiler/rustc_data_structures/src/small_str.rs b/compiler/rustc_data_structures/src/small_str.rs
new file mode 100644
index 000000000..800acb1b0
--- /dev/null
+++ b/compiler/rustc_data_structures/src/small_str.rs
@@ -0,0 +1,68 @@
+use smallvec::SmallVec;
+
+#[cfg(test)]
+mod tests;
+
+/// Like SmallVec but for strings.
+#[derive(Default)]
+pub struct SmallStr<const N: usize>(SmallVec<[u8; N]>);
+
+impl<const N: usize> SmallStr<N> {
+    #[inline]
+    pub fn new() -> Self {
+        SmallStr(SmallVec::default())
+    }
+
+    #[inline]
+    pub fn push_str(&mut self, s: &str) {
+        self.0.extend_from_slice(s.as_bytes());
+    }
+
+    #[inline]
+    pub fn empty(&self) -> bool {
+        self.0.is_empty()
+    }
+
+    #[inline]
+    pub fn spilled(&self) -> bool {
+        self.0.spilled()
+    }
+
+    #[inline]
+    pub fn as_str(&self) -> &str {
+        unsafe { std::str::from_utf8_unchecked(self.0.as_slice()) }
+    }
+}
+
+impl<const N: usize> std::ops::Deref for SmallStr<N> {
+    type Target = str;
+
+    #[inline]
+    fn deref(&self) -> &str {
+        self.as_str()
+    }
+}
+
+impl<const N: usize, A: AsRef<str>> FromIterator<A> for SmallStr<N> {
+    #[inline]
+    fn from_iter<T>(iter: T) -> Self
+    where
+        T: IntoIterator<Item = A>,
+    {
+        let mut s = SmallStr::default();
+        s.extend(iter);
+        s
+    }
+}
+
+impl<const N: usize, A: AsRef<str>> Extend<A> for SmallStr<N> {
+    #[inline]
+    fn extend<T>(&mut self, iter: T)
+    where
+        T: IntoIterator<Item = A>,
+    {
+        for a in iter.into_iter() {
+            self.push_str(a.as_ref());
+        }
+    }
+}
-- 
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