From: Joshua Simmons <josh@nega.tv>
Date: Sat, 29 Oct 2022 14:09:14 +0000 (+0200)
Subject: Add `is_aligned_to` and `is_aligned` functions
X-Git-Url: https://git.nega.tv//gitweb.cgi?a=commitdiff_plain;h=e0c723f62ecb2d0e562be76a2a94ebafe42baab3;p=josh%2Fnarcissus

Add `is_aligned_to` and `is_aligned` functions
---

diff --git a/narcissus-core/src/lib.rs b/narcissus-core/src/lib.rs
index 7a4b304..a503bc5 100644
--- a/narcissus-core/src/lib.rs
+++ b/narcissus-core/src/lib.rs
@@ -271,6 +271,20 @@ pub fn align_offset(x: usize, align: usize) -> usize {
     (x + align - 1) & !(align - 1)
 }
 
+#[must_use]
+pub fn is_aligned_to<T>(ptr: *const T, align: usize) -> bool {
+    if align == 0 || !align.is_power_of_two() {
+        panic!("is_aligned_to: align is not a power-of-two");
+    }
+
+    (ptr as usize) & (align - 1) == 0
+}
+
+#[must_use]
+pub fn is_aligned<T>(ptr: *const T) -> bool {
+    is_aligned_to(ptr, std::mem::align_of::<T>())
+}
+
 pub fn page_size() -> usize {
     4096
 }