From a6795c6b60209f3c7516b67c6d76db7d59bbc012 Mon Sep 17 00:00:00 2001
From: Alexander van Ratingen <470642+alvra@users.noreply.github.com>
Date: Tue, 19 Sep 2023 13:43:53 +0200
Subject: [PATCH 1/3] Implement comparing strings.

---
 src/lib.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 795eade..8a10551 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -341,6 +341,13 @@ impl<T: ConstantTimeEq> ConstantTimeEq for [T] {
     }
 }
 
+impl ConstantTimeEq for str {
+    #[inline]
+    fn ct_eq(&self, rhs: &Self) -> Choice {
+        self.as_bytes().ct_eq(rhs.as_bytes())
+    }
+}
+
 impl ConstantTimeEq for Choice {
     #[inline]
     fn ct_eq(&self, rhs: &Choice) -> Choice {

From 6a202d5575ee25f291de7533d766f06161a189d3 Mon Sep 17 00:00:00 2001
From: Alexander van Ratingen <470642+alvra@users.noreply.github.com>
Date: Tue, 13 Feb 2024 11:18:37 +0100
Subject: [PATCH 2/3] Document that string comparisons short-circuit if the
 lengths differ.

---
 src/lib.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 8a10551..da5cd85 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -342,6 +342,13 @@ impl<T: ConstantTimeEq> ConstantTimeEq for [T] {
 }
 
 impl ConstantTimeEq for str {
+    /// Check whether two strings are equal.
+    ///
+    /// # Note
+    ///
+    /// This function short-circuits if the lengths of the input strings
+    /// are different.  Otherwise, it should execute in time independent
+    /// of the values.
     #[inline]
     fn ct_eq(&self, rhs: &Self) -> Choice {
         self.as_bytes().ct_eq(rhs.as_bytes())

From 52c3354b5bea4884ea20e8ad1dd11f93d0ba2196 Mon Sep 17 00:00:00 2001
From: Alexander van Ratingen <470642+alvra@users.noreply.github.com>
Date: Sun, 18 Feb 2024 20:02:44 +0100
Subject: [PATCH 3/3] Add test for string comparisons.

---
 tests/mod.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/mod.rs b/tests/mod.rs
index f6b3982..90b7cb1 100644
--- a/tests/mod.rs
+++ b/tests/mod.rs
@@ -31,6 +31,13 @@ fn slices_equal() {
     assert_eq!(a_eq_c.unwrap_u8(), 0);
 }
 
+#[test]
+fn str_equal() {
+    assert_eq!("".ct_eq("").unwrap_u8(), 1);
+    assert_eq!("xxx".ct_eq("xxxx").unwrap_u8(), 0);
+    assert_eq!("abcd".ct_eq("abcd").unwrap_u8(), 1);
+}
+
 #[test]
 fn conditional_assign_i32() {
     let mut a: i32 = 5;