no_std: refactor random primitives to use getrandom

crates/steel-core/Cargo.toml

@@ -46,8 +46,7 @@ cargo-steel-lib = { path = "../cargo-steel-lib", version = "0.2.0", optional = t
 chrono = { version = "0.4.23", default-features = false, features = ["std", "clock"], optional = true }
 env_home = "0.1.0"
 weak-table = "0.3.2"
-# TODO: Consider whether rand needs to be here
-rand = "0.9.0"
+getrandom = { version = "0.3.1", default-features = false }
 num-bigint = "0.4.6"
 num-rational = "0.4.2"
 num-traits = "0.2.19"
@@ -110,7 +109,7 @@ steel-imbl = { version = "7.1", optional = true, features = ["serde"] }
 icu_casemap = "2.0.0"
 
 [target.'cfg(target_family = "wasm")'.dependencies]
-getrandom = { version = "0.3.1", features = ["wasm_js"] }
+getrandom = { version = "0.3.1", default-features = false, features = ["wasm_js"] }
 js-sys = "0.3.69"
 
 [target.'cfg(not(target_family = "wasm"))'.dependencies]
@@ -126,7 +125,7 @@ criterion = "0.5.1"
 [features]
 # TODO: Deprecate the modules feature flag, it no longer does anything
 default = ["std", "modules"]
-std = ["dep:chrono"]
+std = ["getrandom/std", "dep:chrono"]
 modules = []
 jit = ["dep:cranelift", "dep:cranelift-module", "dep:cranelift-jit"]
 sandbox = []

crates/steel-core/src/primitives/random.rs

@@ -1,9 +1,5 @@
-use rand::{prelude::*, rng};
-
+use crate::steel_vm::builtin::BuiltInModule;
 use crate::steel_vm::register_fn::RegisterFn;
-use crate::{rvals::Custom, steel_vm::builtin::BuiltInModule};
-
-impl Custom for ThreadRng {}
 
 // pub(crate) const THREAD_RNG_DOC: DocTemplate<'static> = DocTemplate {
 //     signature: "(thread-rng!) -> ThreadRng?",
@@ -26,9 +22,35 @@ pub fn random_module() -> BuiltInModule {
     module
         // .register_fn("thread-rng!", thread_rng)
         // .register_doc("thread-rng!", THREAD_RNG_DOC)
-        .register_fn("rng->gen-usize", || rng().random::<u64>())
+        .register_fn("rng->gen-usize", random_u64)
         // .register_doc("rng->gen-usize", RNG_GEN_USIZE)
-        .register_fn("rng->gen-range", |x: i64, y: i64| rng().random_range(x..y));
+        .register_fn("rng->gen-range", random_range_i64);
 
     module
 }
+
+fn random_u64() -> u64 {
+    let mut bytes = [0u8; 8];
+    getrandom::fill(&mut bytes).expect("getrandom failed");
+    u64::from_ne_bytes(bytes)
+}
+
+fn random_range_i64(start: i64, end: i64) -> i64 {
+    assert!(start < end, "random range is empty");
+    let span = (end as i128 - start as i128) as u64;
+    if span == 1 {
+        return start;
+    }
+    let offset = random_range_u64(span) as i128;
+    (start as i128 + offset) as i64
+}
+
+fn random_range_u64(span: u64) -> u64 {
+    let zone = u64::MAX - (u64::MAX % span);
+    loop {
+        let value = random_u64();
+        if value < zone {
+            return value % span;
+        }
+    }
+}

crates/steel-core/src/steel_vm/engine.rs

@@ -2743,7 +2743,7 @@ fn test_raw_engine() {
 fn test_ctx_func() {
     let mut engine = Engine::new();
 
-    let mut module = BuiltInModule::new("test/module");
+    let mut module = BuiltInModule::new("test/module-ctx-func");
 
     module.register_fn("foo", |implicit: SteelVal| {
         println!("Called with implicit: {}", implicit);
@@ -2755,7 +2755,9 @@ fn test_ctx_func() {
 
     engine.register_module(module);
 
-    engine.run("(require-builtin test/module)").unwrap();
+    engine
+        .run("(require-builtin test/module-ctx-func)")
+        .unwrap();
     engine.run("(foo)").unwrap();
     engine.update_value("global-context", SteelVal::IntV(10));
     engine.run("(foo)").unwrap();
@@ -2765,7 +2767,7 @@ fn test_ctx_func() {
 fn test_ctx_func_registration() {
     let mut engine = Engine::new();
 
-    let mut module = BuiltInModule::new("test/module-func");
+    let mut module = BuiltInModule::new("test/module-ctx-func-registration");
     engine.register_value("global-context", SteelVal::StringV("Hello world!".into()));
 
     module.register_fn_with_ctx("global-context", "foo", |implicit: SteelVal| {
@@ -2774,7 +2776,9 @@ fn test_ctx_func_registration() {
 
     engine.register_module(module);
 
-    engine.run("(require-builtin test/module-func)").unwrap();
+    engine
+        .run("(require-builtin test/module-ctx-func-registration)")
+        .unwrap();
     engine.run("(foo)").unwrap();
     engine.update_value("global-context", SteelVal::IntV(10));
     engine.run("(foo)").unwrap();
@@ -2784,7 +2788,7 @@ fn test_ctx_func_registration() {
 fn test_ctx_func_registration_multiple() {
     let mut engine = Engine::new();
 
-    let mut module = BuiltInModule::new("test/module-ctx");
+    let mut module = BuiltInModule::new("test/module-ctx-func-registration-multiple");
     engine.register_value("global-context", SteelVal::StringV("Hello world!".into()));
 
     module.register_fn_with_ctx("global-context", "foo", |implicit: SteelVal| {
@@ -2801,7 +2805,9 @@ fn test_ctx_func_registration_multiple() {
 
     engine.register_module(module);
 
-    engine.run("(require-builtin test/module-ctx)").unwrap();
+    engine
+        .run("(require-builtin test/module-ctx-func-registration-multiple)")
+        .unwrap();
     engine.run("(bar 10)").unwrap();
     engine.update_value("global-context", SteelVal::IntV(10));
     engine.run("(bar 100)").unwrap();