global: snapshot

crates/brk_computer/src/internal/per_block/computed/rolling_average.rs

@@ -1,7 +1,12 @@
 //! PerBlock with rolling average (no distribution stats).
 //!
-//! Stored height data + f64 cumulative + lazy 4-window rolling averages.
+//! Stored height data + cumulative + lazy 4-window rolling averages.
 //! Rolling averages are computed on-the-fly from the cumulative via DeltaAvg.
+//!
+//! Type parameters:
+//! - `T`: per-block value type
+//! - `C`: cumulative type, defaults to `T`. Use a wider type (e.g., `StoredU64`)
+//!   when the prefix sum of `T` values could overflow `T`.
 
 use brk_error::Result;
 
@@ -15,20 +20,22 @@ use crate::indexes;
 use crate::internal::{LazyRollingAvgsFromHeight, NumericValue, WindowStartVec, Windows};
 
 #[derive(Traversable)]
-pub struct PerBlockRollingAverage<T, M: StorageMode = Rw>
+pub struct PerBlockRollingAverage<T, C = T, M: StorageMode = Rw>
 where
     T: NumericValue + JsonSchema,
+    C: NumericValue + JsonSchema,
 {
     pub block: M::Stored<EagerVec<PcoVec<Height, T>>>,
     #[traversable(hidden)]
-    pub cumulative: M::Stored<EagerVec<PcoVec<Height, T>>>,
+    pub cumulative: M::Stored<EagerVec<PcoVec<Height, C>>>,
     #[traversable(flatten)]
-    pub average: LazyRollingAvgsFromHeight<T>,
+    pub average: LazyRollingAvgsFromHeight<C>,
 }
 
-impl<T> PerBlockRollingAverage<T>
+impl<T, C> PerBlockRollingAverage<T, C>
 where
-    T: NumericValue + JsonSchema,
+    T: NumericValue + JsonSchema + Into<C>,
+    C: NumericValue + JsonSchema,
 {
     pub(crate) fn forced_import(
         db: &Database,
@@ -38,11 +45,11 @@ where
         cached_starts: &Windows<&WindowStartVec>,
     ) -> Result<Self> {
         let block: EagerVec<PcoVec<Height, T>> = EagerVec::forced_import(db, name, version)?;
-        let cumulative: EagerVec<PcoVec<Height, T>> =
-            EagerVec::forced_import(db, &format!("{name}_cumulative"), version + Version::ONE)?;
+        let cumulative: EagerVec<PcoVec<Height, C>> =
+            EagerVec::forced_import(db, &format!("{name}_cumulative"), version + Version::TWO)?;
         let average = LazyRollingAvgsFromHeight::new(
             &format!("{name}_average"),
-            version + Version::ONE,
+            version + Version::TWO,
             &cumulative,
             cached_starts,
             indexes,