From: Adrián Arroyo Calle <adrian.arroyocalle@gmail.com>
Date: Wed, 20 Sep 2023 19:54:14 +0000 (+0200)
Subject: Use a SeedableRng to generate random numbers
X-Git-Tag: remove~95^2
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=7cf6e77f4ddc04d1c5c009a269445935af41ea20;p=scryer-prolog.git

Use a SeedableRng to generate random numbers
---

diff --git a/src/machine/mock_wam.rs b/src/machine/mock_wam.rs
index cd8f7836..2b8f2ca0 100644
--- a/src/machine/mock_wam.rs
+++ b/src/machine/mock_wam.rs
@@ -246,6 +246,7 @@ impl Machine {
             runtime,
             #[cfg(feature = "ffi")]
             foreign_function_table: Default::default(),
+	    rng: StdRng::from_entropy(),
         };
 
         let mut lib_path = current_dir();
diff --git a/src/machine/mod.rs b/src/machine/mod.rs
index 7e456d4e..d9f68ac3 100644
--- a/src/machine/mod.rs
+++ b/src/machine/mod.rs
@@ -54,6 +54,8 @@ use std::env;
 use std::path::PathBuf;
 use std::sync::atomic::AtomicBool;
 use tokio::runtime::Runtime;
+use rand::rngs::StdRng;
+use rand::SeedableRng;
 
 lazy_static! {
     pub static ref INTERRUPT: AtomicBool = AtomicBool::new(false);
@@ -71,6 +73,7 @@ pub struct Machine {
     pub(super) runtime: Runtime,
     #[cfg(feature = "ffi")]
     pub(super) foreign_function_table: ForeignFunctionTable,
+    pub(super) rng: StdRng,
 }
 
 #[derive(Debug)]
@@ -472,6 +475,7 @@ impl Machine {
             runtime,
             #[cfg(feature = "ffi")]
             foreign_function_table: Default::default(),
+	    rng: StdRng::from_entropy(),
         };
 
         let mut lib_path = current_dir();
diff --git a/src/machine/system_calls.rs b/src/machine/system_calls.rs
index 412afca6..81680e9b 100644
--- a/src/machine/system_calls.rs
+++ b/src/machine/system_calls.rs
@@ -42,7 +42,6 @@ use indexmap::IndexSet;
 
 pub(crate) use ref_thread_local::RefThreadLocal;
 
-use std::borrow::BorrowMut;
 use std::cell::Cell;
 use std::cmp::Ordering;
 use std::collections::BTreeSet;
@@ -4216,15 +4215,13 @@ impl Machine {
 
     #[inline(always)]
     pub(crate) fn maybe(&mut self) {
-        fn generate_random_bits(num_bits: usize) -> u64 {
-            let mut rng = rand::thread_rng();
-            let rand = rng.borrow_mut();
+        fn generate_random_bits(rng: &mut rand::rngs::StdRng, num_bits: usize) -> u64 {
             let mut random_bits: u64 = 0;
 
             for _ in 0..num_bits {
                 random_bits <<= 1;
 
-                if rand.gen_bool(0.5) {
+                if rng.gen_bool(0.5) {
                     random_bits |= 1;
                 }
             }
@@ -4232,7 +4229,7 @@ impl Machine {
             random_bits
         }
 
-        let result = { generate_random_bits(1) == 0 };
+        let result = { generate_random_bits(&mut self.rng, 1) == 0 };
 
         self.machine_st.fail = result;
     }
@@ -6184,16 +6181,19 @@ impl Machine {
         match Number::try_from(seed) {
             Ok(Number::Fixnum(n)) => {
                 let n: u64 = Integer::from(n).try_into().unwrap();
-                let _: StdRng = SeedableRng::seed_from_u64(n);
+                let rng: StdRng = SeedableRng::seed_from_u64(n);
+		self.rng = rng;
             },
             Ok(Number::Integer(n)) => {
                 let n: u64 = (&*n).try_into().unwrap();
-                let _: StdRng = SeedableRng::seed_from_u64(n);
+                let rng: StdRng = SeedableRng::seed_from_u64(n);
+		self.rng = rng;
             },
             Ok(Number::Rational(n)) => {
                 if n.denominator() == &UBig::from(1 as u32) {
                     let n: u64 = n.numerator().try_into().unwrap();
-                    let _: StdRng = SeedableRng::seed_from_u64(n);
+                    let rng: StdRng = SeedableRng::seed_from_u64(n);
+		    self.rng = rng;
                 }
             }
             _ => {