reduce bitshifts in from_u64_pair

benches/new.rs

@@ -0,0 +1,23 @@
+#![feature(test)]
+extern crate test;
+
+use test::Bencher;
+use uuid::Uuid;
+
+#[bench]
+fn from_bytes(b: &mut Bencher) {
+    b.iter(|| Uuid::from_bytes([
+        0xF9, 0x16, 0x8C, 0x5E, 0xCE, 0xB2, 0x4F, 0xAA, 0xB6, 0xBF, 0x32, 0x9B, 0xF3, 0x9F,
+        0xA1, 0xE4,
+    ]));
+}
+
+#[bench]
+fn from_u128(b: &mut Bencher) {
+    b.iter(|| Uuid::from_u128(0xa1a2a3a4b1b2c1c2d1d2d3d4d5d6d7d8));
+}
+
+#[bench]
+fn from_u64_pair(b: &mut Bencher) {
+    b.iter(|| Uuid::from_u64_pair(0xa1a2a3a4b1b2c1c2, 0xd1d2d3d4d5d6d7d8));
+}

src/builder.rs

@@ -252,24 +252,7 @@ impl Uuid {
     /// );
     /// ```
     pub const fn from_u64_pair(high_bits: u64, low_bits: u64) -> Self {
-        Uuid::from_bytes([
+        Uuid::from_u128((high_bits as u128 << 64) | low_bits as u128)
-            (high_bits >> 56) as u8,
-            (high_bits >> 48) as u8,
-            (high_bits >> 40) as u8,
-            (high_bits >> 32) as u8,
-            (high_bits >> 24) as u8,
-            (high_bits >> 16) as u8,
-            (high_bits >> 8) as u8,
-            high_bits as u8,
-            (low_bits >> 56) as u8,
-            (low_bits >> 48) as u8,
-            (low_bits >> 40) as u8,
-            (low_bits >> 32) as u8,
-            (low_bits >> 24) as u8,
-            (low_bits >> 16) as u8,
-            (low_bits >> 8) as u8,
-            low_bits as u8,
-        ])
     }
 
     /// Creates a UUID using the supplied bytes.