Shrink try_insert_no_grow

Author: Markus Westerlind

src/raw/mod.rs

@@ -865,15 +865,13 @@ impl<T, A: Allocator + Clone> RawTable<T, A> {
     #[cfg_attr(feature = "inline-more", inline)]
     pub fn try_insert_no_grow(&mut self, hash: u64, value: T) -> Result<Bucket<T>, T> {
         unsafe {
-            let index = self.table.find_insert_slot(hash);
-            let old_ctrl = *self.table.ctrl(index);
-            if unlikely(self.table.growth_left == 0 && special_is_empty(old_ctrl)) {
-                Err(value)
-            } else {
-                self.table.record_item_insert_at(index, old_ctrl, hash);
-                let bucket = self.bucket(index);
-                bucket.write(value);
-                Ok(bucket)
+            match self.table.prepare_insert_no_grow(hash) {
+                Ok(index) => {
+                    let bucket = self.bucket(index);
+                    bucket.write(value);
+                    Ok(bucket)
+                }
+                Err(()) => Err(value),
             }
         }
     }
@@ -1266,6 +1264,21 @@ impl<A: Allocator + Clone> RawTableInner<A> {
         }
     }
 
+    /// Returns the index of a bucket for which a value must be inserted if there is enough rooom
+    /// in the table, otherwise returns error
+    #[cfg(feature = "raw")]
+    #[inline]
+    unsafe fn prepare_insert_no_grow(&mut self, hash: u64) -> Result<usize, ()> {
+        let index = self.find_insert_slot(hash);
+        let old_ctrl = *self.ctrl(index);
+        if unlikely(self.growth_left == 0 && special_is_empty(old_ctrl)) {
+            Err(())
+        } else {
+            self.record_item_insert_at(index, old_ctrl, hash);
+            Ok(index)
+        }
+    }
+
     #[inline]
     unsafe fn record_item_insert_at(&mut self, index: usize, old_ctrl: u8, hash: u64) {
         self.growth_left -= special_is_empty(old_ctrl) as usize;