perf: improve non-std round for f32/f64 with non-branching impl

Author: roderickvd

dasp_sample/src/ops.rs

@@ -20,11 +20,7 @@ pub mod f32 {
     #[cfg(not(feature = "std"))]
     #[inline]
     pub fn round(x: f32) -> f32 {
-        if x >= 0.0 {
-            (x + 0.5) as i32 as f32
-        } else {
-            (x - 0.5) as i32 as f32
-        }
+        (x + 0.5_f32.copysign(x)) as i64 as f32
     }
     #[cfg(feature = "std")]
     #[inline]
@@ -55,11 +51,7 @@ pub mod f64 {
     #[cfg(not(feature = "std"))]
     #[inline]
     pub fn round(x: f64) -> f64 {
-        if x >= 0.0 {
-            (x + 0.5) as i64 as f64
-        } else {
-            (x - 0.5) as i64 as f64
-        }
+        (x + 0.5_f64.copysign(x)) as i64 as f64
     }
     #[cfg(feature = "std")]
     #[inline]