Use wyrand final v4.2 constants for gen_u64()

src/lib.rs

@@ -148,9 +148,14 @@ impl Rng {
     /// Generates a random `u64`.
     #[inline]
     fn gen_u64(&mut self) -> u64 {
-        let s = self.0.wrapping_add(0xA0761D6478BD642F);
+        // Constants for WyRand taken from: https://github.com/wangyi-fudan/wyhash/blob/master/wyhash.h#L151
+        // Updated for the final v4.2 implementation with improved constants for better entropy output.
+        const WY_CONST_0: u64 = 0x2d35_8dcc_aa6c_78a5;
+        const WY_CONST_1: u64 = 0x8bb8_4b93_962e_acc9;
+
+        let s = self.0.wrapping_add(WY_CONST_0);
         self.0 = s;
-        let t = u128::from(s) * u128::from(s ^ 0xE7037ED1A0B428DB);
+        let t = u128::from(s) * u128::from(s ^ WY_CONST_1);
         (t as u64) ^ (t >> 64) as u64
     }