let ty = cx.tcx.item_type(did);
let adt = ty.ty_adt_def().expect("already checked whether this is an enum");
- let mut sizes = Vec::new();
- let mut variants = Vec::new();
+ let mut smallest_variant: Option<(_, _)> = None;
+ let mut largest_variant: Option<(_, _)> = None;
- for variant in &adt.variants {
+ for (i, variant) in adt.variants.iter().enumerate() {
let data_layout = TargetDataLayout::parse(cx.sess());
cx.tcx.infer_ctxt((), Reveal::All).enter(|infcx| {
let size: u64 = variant.fields
})
.sum();
- sizes.push(size);
- variants.push(variant);
+ let grouped = (size, (i, variant));
+
+ update_if(&mut smallest_variant, grouped, |a, b| b.0 <= a.0);
+ update_if(&mut largest_variant, grouped, |a, b| b.0 >= a.0);
});
}
- let mut grouped = sizes.into_iter().zip(variants.into_iter().enumerate()).collect::<Vec<_>>();
-
- grouped.sort_by_key(|g| g.0);
-
- let smallest_variant = grouped.first();
- let largest_variant = grouped.last();
-
if let (Some(smallest), Some(largest)) = (smallest_variant, largest_variant) {
let difference = largest.0 - smallest.0;
}
}
}
+
+fn update_if<T, F>(old: &mut Option<T>, new: T, f: F) where F: Fn(&T, &T) -> bool {
+ if let Some(ref mut val) = *old {
+ if f(val, &new) {
+ *val = new;
+ }
+ } else {
+ *old = Some(new);
+ }
+}