From 03c1bd52d2eaa4adea5cbfd798f68cc1995b52c2 Mon Sep 17 00:00:00 2001
From: DaniPopes <57450786+DaniPopes@users.noreply.github.com>
Date: Wed, 26 Jul 2023 09:41:38 +0200
Subject: [PATCH] perf: optimize `byte` method

---
 src/bits.rs  | 12 ++++++++++--
 src/bytes.rs | 11 +++--------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/bits.rs b/src/bits.rs
index 02e47a5..1ad045c 100644
--- a/src/bits.rs
+++ b/src/bits.rs
@@ -67,9 +67,17 @@ impl<const BITS: usize, const LIMBS: usize> Uint<BITS, LIMBS> {
     #[inline]
     #[must_use]
     #[track_caller]
-    #[allow(clippy::cast_possible_truncation)] // intentional
     pub const fn byte(&self, index: usize) -> u8 {
-        (self.limbs[index / 8] >> ((index % 8) * 8)) as u8
+        #[cfg(target_endian = "little")]
+        {
+            self.as_le_slice()[index]
+        }
+
+        #[cfg(target_endian = "big")]
+        #[allow(clippy::cast_possible_truncation)] // intentional
+        {
+            (self.limbs[index / 8] >> ((index % 8) * 8)) as u8
+        }
     }
 
     /// Reverses the order of bits in the integer. The least significant bit
diff --git a/src/bytes.rs b/src/bytes.rs
index 3d2103e..f68105c 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -6,10 +6,7 @@ use crate::{
     Uint,
 };
 use alloc::{borrow::Cow, vec::Vec};
-use core::{
-    ptr::{addr_of, addr_of_mut},
-    slice,
-};
+use core::slice;
 
 // OPT: *_to_smallvec to avoid allocation.
 impl<const BITS: usize, const LIMBS: usize> Uint<BITS, LIMBS> {
@@ -27,8 +24,7 @@ impl<const BITS: usize, const LIMBS: usize> Uint<BITS, LIMBS> {
     #[must_use]
     #[inline(always)]
     pub const fn as_le_slice(&self) -> &[u8] {
-        let data = addr_of!(self.limbs).cast();
-        unsafe { slice::from_raw_parts(data, Self::BYTES) }
+        unsafe { slice::from_raw_parts(self.limbs.as_ptr().cast(), Self::BYTES) }
     }
 
     /// Access the underlying store as a mutable little-endian slice of bytes.
@@ -44,8 +40,7 @@ impl<const BITS: usize, const LIMBS: usize> Uint<BITS, LIMBS> {
     #[must_use]
     #[inline(always)]
     pub unsafe fn as_le_slice_mut(&mut self) -> &mut [u8] {
-        let data = addr_of_mut!(self.limbs).cast();
-        slice::from_raw_parts_mut(data, Self::BYTES)
+        unsafe { slice::from_raw_parts_mut(self.limbs.as_mut_ptr().cast(), Self::BYTES) }
     }
 
     /// Access the underlying store as a little-endian bytes.