1 files changed, 52 insertions, 0 deletions
diff --git a/third_party/rust/ryu/tests/exhaustive.rs b/third_party/rust/ryu/tests/exhaustive.rs
new file mode 100644
index 0000000000..569bcff921
--- /dev/null
+++ b/third_party/rust/ryu/tests/exhaustive.rs
@@ -0,0 +1,52 @@
+#![cfg(exhaustive)]
+
+use std::str;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+use std::thread;
+
+#[test]
+fn test_exhaustive() {
+    const BATCH_SIZE: u32 = 1_000_000;
+    let counter = Arc::new(AtomicUsize::new(0));
+    let finished = Arc::new(AtomicUsize::new(0));
+
+    let mut workers = Vec::new();
+    for _ in 0..num_cpus::get() {
+        let counter = counter.clone();
+        let finished = finished.clone();
+        workers.push(thread::spawn(move || loop {
+            let batch = counter.fetch_add(1, Ordering::Relaxed) as u32;
+            if batch > u32::max_value() / BATCH_SIZE {
+                return;
+            }
+
+            let min = batch * BATCH_SIZE;
+            let max = if batch == u32::max_value() / BATCH_SIZE {
+                u32::max_value()
+            } else {
+                min + BATCH_SIZE - 1
+            };
+
+            let mut bytes = [0u8; 24];
+            let mut buffer = ryu::Buffer::new();
+            for u in min..=max {
+                let f = f32::from_bits(u);
+                if !f.is_finite() {
+                    continue;
+                }
+                let n = unsafe { ryu::raw::format32(f, &mut bytes[0]) };
+                assert_eq!(Ok(Ok(f)), str::from_utf8(&bytes[..n]).map(str::parse));
+                assert_eq!(Ok(f), buffer.format_finite(f).parse());
+            }
+
+            let increment = (max - min + 1) as usize;
+            let update = finished.fetch_add(increment, Ordering::Relaxed);
+            println!("{}", update + increment);
+        }));
+    }
+
+    for w in workers {
+        w.join().unwrap();
+    }
+}