add util functors for is_zero/is_equal; move clamp to math utils

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/math.rs

@@ -53,6 +53,38 @@ macro_rules! validated {
 	($($input:tt)+) => { $crate::expected!($($input)+) }
 }
 
+/// Functor for equality to zero
+#[macro_export]
+macro_rules! is_zero {
+	() => {
+		$crate::is_matching!(0)
+	};
+}
+
+/// Functor for equality i.e. .is_some_and(is_equal!(2))
+#[macro_export]
+macro_rules! is_equal_to {
+	($val:expr) => {
+		|x| (x == $val)
+	};
+}
+
+/// Functor for less i.e. .is_some_and(is_less_than!(2))
+#[macro_export]
+macro_rules! is_less_than {
+	($val:expr) => {
+		|x| (x < $val)
+	};
+}
+
+/// Functor for matches! i.e. .is_some_and(is_matching!('A'..='Z'))
+#[macro_export]
+macro_rules! is_matching {
+	($val:expr) => {
+		|x| matches!(x, $val)
+	};
+}
+
 /// Returns false if the exponential backoff has expired based on the inputs
 #[inline]
 #[must_use]
@@ -118,3 +150,6 @@ fn try_into_err<Dst: TryFrom<Src>, Src>(e: <Dst as TryFrom<Src>>::Error) -> Erro
 		type_name::<Dst>()
 	))
 }
+
+#[inline]
+pub fn clamp<T: Ord>(val: T, min: T, max: T) -> T { cmp::min(cmp::max(val, min), max) }

src/core/utils/mod.rs

@@ -14,8 +14,6 @@ pub mod sys;
 mod tests;
 pub mod time;
 
-use std::cmp;
-
 pub use ::ctor::{ctor, dtor};
 pub use algorithm::common_elements;
 pub use bytes::{increment, u64_from_bytes, u64_from_u8, u64_from_u8x8};
@@ -24,6 +22,7 @@ pub use debug::slice_truncated as debug_slice_truncated;
 pub use hash::calculate_hash;
 pub use html::Escape as HtmlEscape;
 pub use json::{deserialize_from_str, to_canonical_object};
+pub use math::clamp;
 pub use mutex_map::{Guard as MutexMapGuard, MutexMap};
 pub use rand::string as random_string;
 pub use string::{str_from_bytes, string_from_bytes};
@@ -31,14 +30,7 @@ pub use sys::available_parallelism;
 pub use time::now_millis as millis_since_unix_epoch;
 
 #[inline]
-pub fn clamp<T: Ord>(val: T, min: T, max: T) -> T { cmp::min(cmp::max(val, min), max) }
-
-#[inline]
-pub fn exchange<T: Clone>(state: &mut T, source: T) -> T {
-	let ret = state.clone();
-	*state = source;
-	ret
-}
+pub fn exchange<T>(state: &mut T, source: T) -> T { std::mem::replace(state, source) }
 
 #[must_use]
 pub fn generate_keypair() -> Vec<u8> {