Merge "reserve" and "do_reserve"

Author: garychia

crates/bevy_ecs/src/storage/blob_vec.rs

@@ -122,21 +122,20 @@ impl BlobVec {
     /// Reserves the minimum capacity for at least `additional` more elements to be inserted in the given `BlobVec`.
     #[inline]
     pub fn reserve(&mut self, additional: usize) {
-        if self.capacity - self.len < additional {
-            self.do_reserve(additional);
+        /// Similar to `reserve_exact`. This method ensures that the capacity will grow at least `self.capacity()` if there is no
+        /// enough space to hold `additional` more elements.
+        #[cold]
+        fn do_reserve(slf: &mut BlobVec, additional: usize) {
+            if slf.item_layout.size() > 0 {
+                let increment = slf.capacity.max(additional - (slf.capacity - slf.len));
+                let increment = NonZeroUsize::new(increment).unwrap();
+                // SAFETY: not called for ZSTs
+                unsafe { slf.grow_exact(increment) };
+            }
         }
-    }
 
-    /// Similar to `reserve_exact`. This method ensures that the capacity will grow at least `self.capacity()` if there is no
-    /// enough space to hold `additional` more elements.
-    #[cold]
-    fn do_reserve(&mut self, additional: usize) {
-        let available_space = self.capacity - self.len;
-        if available_space < additional && self.item_layout.size() > 0 {
-            let increment = self.capacity.max(additional - available_space);
-            let increment = NonZeroUsize::new(increment).unwrap();
-            // SAFETY: not called for ZSTs
-            unsafe { self.grow_exact(increment) };
+        if self.capacity - self.len < additional {
+            do_reserve(self, additional);
         }
     }