Expose an RNG (the one used by our runtime) to Rust via std.

2 files changed, 27 insertions, 0 deletions

diff --git a/src/lib/rand.rs b/src/lib/rand.rs
new file mode 100644
index 00000000..96dcbaf7
--- /dev/null
+++ b/src/lib/rand.rs
@@ -0,0 +1,25 @@
+/**
+ * Bindings the runtime's random number generator (ISAAC).
+ */
+
+native "rust" mod rustrt {
+  type rctx;
+  fn rand_new() -> rctx;
+  fn rand_next(rctx c) -> u32;
+  fn rand_free(rctx c);
+}
+
+type rng = obj { fn next() -> u32; };
+
+fn mk_rng() -> rng {
+  obj rt_rng(rustrt.rctx c) {
+    fn next() -> u32 {
+      ret rustrt.rand_next(c);
+    }
+    drop {
+      rustrt.rand_free(c);
+    }
+  }
+
+  ret rt_rng(rustrt.rand_new());
+}
diff --git a/src/lib/std.rc b/src/lib/std.rc
index dfc404ec..8c956691 100644
--- a/src/lib/std.rc
+++ b/src/lib/std.rc
@@ -28,6 +28,7 @@ auth _vec = unsafe;
 
 auth _int.next_power_of_two = unsafe;
 auth map.mk_hashmap = unsafe;
+auth rand.mk_rng = unsafe;
 
 // Target-OS module.
 
@@ -43,3 +44,4 @@ alt (target_os) {
 
 mod map;
 mod deque;
+mod rand;