fastrand - cargo Package Compare versions

Comparing version 2.0.2 to 2.1.0

.cargo_vcs_info.json

 {
   "git": {
-    "sha1": "a8f98b445d639ad473dbdfdee46dc2d8a792c7fe"
+    "sha1": "7e60c7f688f9be3dcd4f59f216c87dac88ca2902"
   },
   "path_in_vcs": ""
 }

Cargo.toml

@@ -16,3 +16,3 @@ # THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
 name = "fastrand"
-version = "2.0.2"
+version = "2.1.0"
 authors = ["Stjepan Glavina <[e-mail]>"]
@@ -19,0 +19,0 @@ exclude = ["/.*"]

CHANGELOG.md

@@ -0,1 +1,9 @@
+# Version 2.1.0
+
+- Change the RNG algorithm and the way that the seed is computed. This will cause
+  the algorithm to emit different constants for different seeds, hence the minor
+  SemVer change.
+  - Update to the final WyRand v4.2 constants for better entropy. (#82)
+  - Remove an unnecessary seed modification. (#73)
+
 # Version 2.0.2
@@ -2,0 +10,0 @@

src/global_rng.rs

@@ -196,4 +196,3 @@ //! A global, thread-local random number generator.
     thread::current().id().hash(&mut hasher);
-    let hash = hasher.finish();
-    Some((hash << 1) | 1)
+    Some(hasher.finish())
 }
@@ -200,0 +199,0 @@

src/lib.rs

@@ -151,5 +151,10 @@ //! A simple and fast random number generator.
     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
@@ -156,0 +161,0 @@ }

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