From 643c100f1bfc853927f30b32f695a992e0666701 Mon Sep 17 00:00:00 2001
From: colagy <xu@colagy.com>
Date: Wed, 18 Jan 2023 22:01:27 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=9E=E7=8E=B0random,=20=E6=8F=90=E4=BE=9B?=
 =?UTF-8?q?=E4=BA=86next(),=20next=5Fbool()=E6=96=B9=E6=B3=95?=
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---
 src/util/random.rs      | 20 +++++++++++--
 src/util/random_test.rs | 62 ++++++++++++++++++++++++++++++++++++++---
 2 files changed, 75 insertions(+), 7 deletions(-)

diff --git a/src/util/random.rs b/src/util/random.rs
index 805cd3c..331175a 100644
--- a/src/util/random.rs
+++ b/src/util/random.rs
@@ -26,7 +26,8 @@ impl Random {
             }
         }
     }
-    /// 获取一个随机数
+
+    /// 获取一个随机数(u32)
     ///
     /// # Examples
     ///
@@ -37,11 +38,23 @@ impl Random {
         // mod
         let m = 2147483647_u32;
         let a = 16807_u32;
-        let product = self.seed * a;
+        let product = self.seed.wrapping_mul(a);
         self.seed = (product >> 31) + (product & m);
         if self.seed > m { self.seed -= m }
         self.seed
     }
+
+    /// 获取一个随机数(bool)
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let num = random.next();
+    /// ```
+    pub fn next_bool(&mut self) -> bool {
+        self.one_in(2)
+    }
+
     /// 生成随机数并对n取模
     ///
     /// # Arguments
@@ -75,6 +88,7 @@ impl Random {
     pub fn one_in(&mut self, n: u32) -> bool {
         (self.next() % n) == 0
     }
+
     /// 对随机数进行倾斜
     ///
     /// # Arguments
@@ -89,7 +103,7 @@ impl Random {
     /// let skewed_num = random.skewed(10);
     /// ```
     pub fn skewed(&mut self, max_log: u32) -> u32 {
-        let bits = 1 << self.uniform(max_log + 1);
+        let bits = 1_u32.wrapping_shl(self.uniform(max_log + 1));
         self.uniform(bits)
     }
 }
\ No newline at end of file
diff --git a/src/util/random_test.rs b/src/util/random_test.rs
index 7e7bacc..e442612 100644
--- a/src/util/random_test.rs
+++ b/src/util/random_test.rs
@@ -1,28 +1,82 @@
 mod test {
+    use std::time::{SystemTime, UNIX_EPOCH};
     use crate::util::random::Random;
 
+    fn get_timestamp() -> u32 {
+        let now = SystemTime::now();
+        now
+            .duration_since(UNIX_EPOCH)
+            .expect("get_current_unix_err")
+            .as_secs() as u32
+    }
+
+    fn get_seed(use_timestamp: bool) -> u32 {
+        match use_timestamp {
+            true => get_timestamp(),
+            false => 32
+        }
+    }
+
     #[test]
     pub fn test_next() {
-        let mut random = Random::new(32);
+        let mut random = Random::new(get_seed(false));
         let num = random.next();
         println!("{}", num);
+        assert_eq!(num, 537824);
         let num2 = random.next();
         println!("{}", num2);
         assert_ne!(num, num2);
+        assert_eq!(num2, 449273376);
     }
 
     #[test]
     pub fn test_uniform() {
-        todo!()
+        let mut random = Random::new(get_seed(false));
+        let num = random.uniform(4);
+        println!("{}", num);
+        assert_eq!(num, 0);
+
+        let num2 = random.uniform(5);
+        println!("{}", num2);
+        assert_eq!(num2, 1);
     }
 
     #[test]
     pub fn test_one_in() {
-        todo!()
+        let mut random = Random::new(get_seed(false));
+        let one_in = random.one_in(2);
+        println!("{}", one_in);
+        assert_eq!(one_in, true);
+
+        let mut random = Random::new(get_seed(false) + 1);
+        let one_in = random.one_in(2);
+        println!("{}", one_in);
+        assert_eq!(one_in, false);
+    }
+
+    #[test]
+    pub fn test_next_bool() {
+        let mut random = Random::new(get_seed(false));
+        let num = random.next_bool();
+        println!("{}", num);
+        assert_eq!(num, true);
+
+        let mut random = Random::new(get_seed(false) + 1);
+        let num = random.next_bool();
+        println!("{}", num);
+        assert_eq!(num, false);
     }
 
     #[test]
     pub fn test_skesed() {
-        todo!()
+        let mut random = Random::new(1021);
+        let base = random.next();
+        let num = random.skewed(31);
+        let uniform = random.uniform(31);
+        println!("num: {}", num);
+        println!("base: {}", base);
+        println!("uniform: {}", uniform);
+        assert_eq!(num != base, true);
+        assert_eq!(num != uniform, true);
     }
 }
\ No newline at end of file
-- 
Gitee