Add abs

CHANGELOG.md

@@ -3,8 +3,10 @@
 ## Unreleased
 
 * [#7] - Add `strtoul` and `strcpy`
+* [#8] - Add `abs`
 
 [#7]: https://github.com/rust-embedded-community/tinyrlibc/pull/7
+[#8]: https://github.com/rust-embedded-community/tinyrlibc/pull/8
 
 ## v0.2.2 (2022-03-17)
 

README.md

@@ -8,6 +8,7 @@ This crate basically came about so that the [nrfxlib](https://github.com/NordicP
 
 ## Implemented so far
 
+* abs
 * strol
 * atoi
 * strcmp

src/abs.rs

@@ -0,0 +1,36 @@
+//! Rust implementation of C library function `abs`
+//!
+//! Licensed under the Blue Oak Model Licence 1.0.0
+
+use crate::CInt;
+
+/// Calculates the integer absolute value
+///
+/// ```
+/// use tinyrlibc::abs;
+/// assert_eq!(abs(-2), 2);
+/// ```
+#[no_mangle]
+pub extern "C" fn abs(i: CInt) -> CInt {
+	i.abs()
+}
+
+#[cfg(test)]
+mod test {
+	use super::*;
+
+	#[test]
+	fn neg() {
+		assert_eq!(abs(-2), 2);
+	}
+
+	#[test]
+	fn pos() {
+		assert_eq!(abs(3), 3);
+	}
+
+	#[test]
+	fn zero() {
+		assert_eq!(abs(0), 0);
+	}
+}

src/lib.rs

@@ -13,6 +13,9 @@
 #[allow(unused_imports)]
 use std as core;
 
+mod abs;
+pub use self::abs::abs;
+
 mod strcmp;
 pub use self::strcmp::strcmp;