From 62ec524dba1833396963ad995a2af3f51fdbe4e4 Mon Sep 17 00:00:00 2001
From: sander <sander.wittwer@gmail.com>
Date: Fri, 15 Mar 2024 09:45:17 +0100
Subject: [PATCH 1/4] add strncasecmp

---
 Cargo.toml         |  2 ++
 src/lib.rs         |  4 ++++
 src/strncasecmp.rs | 53 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+)
 create mode 100644 src/strncasecmp.rs

diff --git a/Cargo.toml b/Cargo.toml
index 79a379e..87122e3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,6 +22,7 @@ all = [
     "abs",
     "strcmp",
     "strncmp",
+    "strncasecmp",
     "strcpy",
     "strncpy",
     "strlen",
@@ -46,6 +47,7 @@ all = [
 abs = []
 strcmp = []
 strncmp = []
+strncasecmp = []
 strcpy = []
 strncpy = []
 strlen = []
diff --git a/src/lib.rs b/src/lib.rs
index e5db6f4..12f5030 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -43,6 +43,10 @@ mod strncmp;
 #[cfg(feature = "strncmp")]
 pub use self::strncmp::strncmp;
 
+mod strncasecmp;
+#[cfg(feature = "strncasecmp")]
+pub use self::strncasecmp::strncasecmp;
+
 mod strcpy;
 #[cfg(feature = "strcpy")]
 pub use self::strcpy::strcpy;
diff --git a/src/strncasecmp.rs b/src/strncasecmp.rs
new file mode 100644
index 0000000..7041755
--- /dev/null
+++ b/src/strncasecmp.rs
@@ -0,0 +1,53 @@
+//! Rust implementation of C library function `strncasecmp`
+//!
+//! Licensed under the Blue Oak Model Licence 1.0.0
+
+use crate::{CChar, CInt};
+
+/// Rust implementation of C library function `strncasecmp`. Passing NULL
+/// (core::ptr::null()) gives undefined behaviour.
+#[cfg_attr(feature = "strncasecmp", no_mangle)]
+pub unsafe extern "C" fn strncasecmp(s1: *const CChar, s2: *const CChar, n: usize) -> CInt {
+	for i in 0..n as isize {
+		let s1_i = s1.offset(i);
+		let s2_i = s2.offset(i);
+
+		let val = (*s1_i).to_ascii_lowercase() as CInt - (*s2_i).to_ascii_lowercase() as CInt;
+		if val != 0 || *s1_i == 0 {
+			return val;
+		}
+	}
+	0
+}
+
+#[cfg(test)]
+mod test {
+	use super::*;
+
+	#[test]
+	fn matches() {
+		let a = b"abc\0";
+		let b = b"AbCDEF\0";
+		let result = unsafe { strncasecmp(a.as_ptr(), b.as_ptr(), 3) };
+		// Match!
+		assert_eq!(result, 0);
+	}
+
+	#[test]
+	fn no_match() {
+		let a = b"123\0";
+		let b = b"x1234\0";
+		let result = unsafe { strncasecmp(a.as_ptr(), b.as_ptr(), 3) };
+		// No match, first string first
+		assert!(result < 0);
+	}
+
+	#[test]
+	fn no_match2() {
+		let a = b"bbbbb\0";
+		let b = b"aaaaa\0";
+		let result = unsafe { strncasecmp(a.as_ptr(), b.as_ptr(), 3) };
+		// No match, second string first
+		assert!(result > 0);
+	}
+}

From 9671ce9453d33dee831d0d7cb68153e8a804262a Mon Sep 17 00:00:00 2001
From: sander <sander.wittwer@gmail.com>
Date: Fri, 15 Mar 2024 09:47:56 +0100
Subject: [PATCH 2/4] update changelog

---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 79bf4ed..2f4c59c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## Unreleased
 
-* None
+* [#23] - Add `strncasecmp` 
 
 ## v0.3.0 (2022-10-18)
 

From 83499ec24ffdf7a3c1311fc238555fa7fa441223 Mon Sep 17 00:00:00 2001
From: sander <sander.wittwer@gmail.com>
Date: Fri, 15 Mar 2024 16:33:36 +0100
Subject: [PATCH 3/4] strncasecmp: use `add` instead of `offset` to avoid
 casting

---
 src/strncasecmp.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/strncasecmp.rs b/src/strncasecmp.rs
index 7041755..d8cc45b 100644
--- a/src/strncasecmp.rs
+++ b/src/strncasecmp.rs
@@ -8,9 +8,9 @@ use crate::{CChar, CInt};
 /// (core::ptr::null()) gives undefined behaviour.
 #[cfg_attr(feature = "strncasecmp", no_mangle)]
 pub unsafe extern "C" fn strncasecmp(s1: *const CChar, s2: *const CChar, n: usize) -> CInt {
-	for i in 0..n as isize {
-		let s1_i = s1.offset(i);
-		let s2_i = s2.offset(i);
+	for i in 0..n {
+		let s1_i = s1.add(i);
+		let s2_i = s2.add(i);
 
 		let val = (*s1_i).to_ascii_lowercase() as CInt - (*s2_i).to_ascii_lowercase() as CInt;
 		if val != 0 || *s1_i == 0 {

From e733587364dc8cefe678d80f0d6a9053482a9185 Mon Sep 17 00:00:00 2001
From: sander <sander.wittwer@gmail.com>
Date: Fri, 15 Mar 2024 16:40:49 +0100
Subject: [PATCH 4/4] README: add strncasecmp

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index a5e000a..ac155e0 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,7 @@ This crate basically came about so that the [nrfxlib](https://github.com/NordicP
 * isupper
 * strcmp
 * strncmp
+* strncasecmp
 * strcpy
 * strncpy
 * strlen